ECUtune Stage 2 version 3 ( 2v3 )

[longassname]

We have decided to replace the nitrous oxide tuning software with the much asked for software for using a larger mass air flow meter.

As many of you know, the SVX mass air meter is maxed out at the factory peak horse power and needs to be upgraded if you want to get more peak power than you already have. There is the possibility that this upgrade will improve your performance beyond that of stage 1v4 without any further hardware modifications but this is not yet known. We are not going to do any dyno measurements on our own right away but one of our customers is and we will share that information when it becomes available.

Of course the real impetus behind this upgrade and the reason we've gotten so many requests for it is because many of you do want to do mechanical upgrades to your svx to increase power. This software paves the way for supercharging, turbocharging, and running higher rpms.

Now to the nuts and bolts of it. The stage 2v3 software is the stage 1v4 software further modified to run a z32 mass air flow meter instead of the factory svx mass air meter. Just like the stage 1 software there is a second version of software on the memory adaptor with 5 degrees less ignition advance and without the aggressive ignition advance seek used in the base stage 1v4 software. When power is sent to the input pin of the memory adaptor it runs off of the second version of software. This enables you to run premium unleaded fuel or regular unleaded fuel at the flick of a switch. It also provides a good tune for forced induction.

Here are the particulars on the mass air meters and some of the basics on the adjustments made for the switch. The z32 mass air meter can measure two and a half times as much air as the svx mass air meter; however due to a mathmatical limitation we can only utilize it to measure about 1.9 times as much air in this version of the software. Still that's good for about 440 hp.

The mass air meters give a voltage signal between 0 and 5.12 volts according to how much air is flowing through them. In the ECU software there is a highly acurate table used to translate this voltage into a number used to represent air flow. I'm not calling it an actual airflow measurement because the # isn't in any particular unit for measure of flow and most importantly it isn't scaled to represent the actual airflow yet.
Here is a plot of both translation tables.
http://www.ecutune.com/posts/stage2/maf1.gif

You'll notice there that the plot of the z32 meter is lower than that of the svx meter. That does not mean that it is measuring less air. Remember that all mass air meters measure in a range of 0 to 5.12 volts. The value generated by these curves is multiplied by a constant the size of which varies depending on the flow rate of the mass air meter and the flow rate of the fuel injectors. A higher flow rate mass air meter has a bigger constant. Lower flow rate fuel injectors have a bigger constant. The z32 mass air meter flows 2.5 times as much air as the svx mass air meter and the constant should be made 2.5 times larger when switching mass air meters. Unfortunately with the size fuel injectors we only have enough digits to make our constant about 1.9 times bigger before it maxes out.

Of course we can't have our constant and translation table values not generate the correct #'s so our work around is to use the commutative property of multiplication/division and adjust the values in the translatoin table by the ratio of what the constant would be with the factory 300z translation table and what it actually is in our software. You'll notice not supprisingly that now the curves match up very closely. You'll also notice that while the meter makes accurate measurments on up to 5.12 volts we lost some of the top voltage measurements because now the table values are maxed out. Because of this we are only able to measure 1.9 times as much air instead of 2.5 so we will max out at 440 hp instead of the 575 that the stage 3 software maxes out at.
http://www.ecutune.com/posts/stage2/maf2.gif

This graph shows the comparitive airflow measured by each mass air meter. It shows the value output by each translation table multiplied by the ratio of the constants.
http://www.ecutune.com/posts/stage2/maf3.gif

That about sums it up. The software gives all of the benefits of stage 1 but now uses a z32 mass air meter so that timing is accurately controlled for loads up to 440 horse power and fuel will be accurately supplied to the utter physical limits of the fuel injectors.

[Chiketkd]

Great explanation Michael.

-Chike (now just offer this for the OBDII folks and then we'll be talking... ;) )

[immortal_suby]

Do you have a timeline for when this will be available?
Sounds like a great project.
Already trolling ebay for a used MAF. :D

[longassname]

Do you have a timeline for when this will be available?
Sounds like a great project.
Already trolling ebay for a used MAF. :D


It's available now. I haven't done a bang up job with the stage 2 page of the website yet but it has been changed to the new stage 2v3.

http://www.ecutune.com/svx-stage2.htm

[svxsubaru1]

So do you think we could combine this stage 2V3 with a Apex-i Super AFC and run larger injectors for a turbo (like sti 550s, or even the Q-45 370cc?)

[longassname]

So do you think we could combine this stage 2V3 with a Apex-i Super AFC and run larger injectors for a turbo (like sti 550s, or even the Q-45 370cc?)

No, you definitely do not want to mess with the voltage signal from the maf meter--that would completely mess up the ignition timing which would be dissasterous. I would first build your system and see if you need additional fuel. I think you will find that if you run a walboro fuel pump the increased fuel pressure and the fuel injectors being able to be driven to 100% duty will give you enough fuel unless you have an engine built to a lower compression ratio. If you need additional fuel then use additional injectors with a seperate controller to add the fuel.

Most people don't have a very thorough understanding of what happens if you go beyond the ability of the fuel injectors to deliver fuel. It's important to note where/when you would actually run low on fuel. When we talk about the size of a fuel injector we are talking about it's flow rate, the amount of fuel over a set time. It's when the time is short for fuel delivery that the injector is most limited in it's ability to deliver fuel. That means high rpms. The higher the rpms the shorter the time the fuel injector has to deliver the fuel necessary for the intake charge in the cyllinder. In driving that means the first place you can expect to go lean is the last place you will find yourself, high rpms at top gear. In the lower gears you will be shifting before you get up to redline. Our shift point is 5600 rpms. 5600/2 = 2800 intake rpms 2800rpms/60sec=46.67 rps 1 sec/46.67 rps = 0.0214 sec per rev = 21.4 milliseconds to deliver fuel. This is quite a bit of time. I certainly wouldn't recomend sacrificing accurate engine managment for 99.9999% of your driving time to get a higher flow rate for high rpms. The stage 2v3 software will run forced induction well--it lights up the tires on our stage 3 system at will. Build your system first after it's running if you find you need more fuel add it without messing with engine management.

[MaxImUmZ]

Any idea how long it will be till we see some dyno results on this? I'm pretty sure I have a friend that should have like 2 MAF sensors laying around. And depending on how many people are looking for these I may be able to talk to some of my old Z buddies and see what I can do about getting some of these cheap. In case you can't tell I can't wait to get enough money to get my hands on one.

[longassname]

Any idea how long it will be till we see some dyno results on this? I'm pretty sure I have a friend that should have like 2 MAF sensors laying around. And depending on how many people are looking for these I may be able to talk to some of my old Z buddies and see what I can do about getting some of these cheap. In case you can't tell I can't wait to get enough money to get my hands on one.


We won't be dynoing the stage 2 code ourselves any time soon. Our demo car has a blower on it which i think would qualify as cheating. Like I said though one of our customers has indicated that he will dyno the stage 1v4 and the stage 2v3 back to back on his car before installing his turbo system. He has a low miles engine and manual transmission so he should get some good clear results for us.

[svxsubaru1]

So running a upgraded fuel pump, and running higher fuel presure will be acounted for in the engine managment. I just thought the ECU ran off of a constant fuel presaure and doesnt check up on it, if it were to change.

[MaxImUmZ]

We won't be dynoing the stage 2 code ourselves any time soon. Our demo car has a blower on it which i think would qualify as cheating. Like I said though one of our customers has indicated that he will dyno the stage 1v4 and the stage 2v3 back to back on his car before installing his turbo system. He has a low miles engine and manual transmission so he should get some good clear results for us.

when will that be happening, any idea?

Possibly discount about the price of dyno costs, if Im willing to do the same thing? :D

[SVXRide]

snip* I think you will find that if you run a walboro fuel pump the increased fuel pressure and the fuel injectors being able to be driven to 100% duty will give you enough fuel unless you have an engine built to a lower compression ratio. If you need additional fuel then use additional injectors with a seperate controller to add the fuel.

Most people don't have a very thorough understanding of what happens if you go beyond the ability of the fuel injectors to deliver fuel. It's important to note where/when you would actually run low on fuel. When we talk about the size of a fuel injector we are talking about it's flow rate, the amount of fuel over a set time. It's when the time is short for fuel delivery that the injector is most limited in it's ability to deliver fuel. snip*.

Michael,
Based on your understanding on how the SVX's ECU operates, how does it "close the loop" with the injectors with regards to factoring in injector duty cycle and BSFC??
Thanks.
-Bill

[mbtoloczko]

This thread finally prompted me to hook up the MAF signal and tachometer signal to my LM-1 data logger. Below are the results for a WOT run that I made this morning on the way to work. The outside air temperature was about 82F, so there was a bit less oxygen than usual. The MAF is peaking right at around 4.5 volts in all four gears. According to Michael's plots, that leaves about 20% headroom for engine mods. But there should be at least 10% reserve for driving in cold temperatures where the air has about 10% greater density. So, realistically, the stock MAF does indeed have only about 10% headroom for engine mods which isn't much (only about 230*1.1 ~ 250 max HP).

http://www.subaru-svx.net/photos/files/mbtoloczko/27877.gif

[Chiketkd]

Great plots Mychailo. That definitely explains sheds light on the situation. I couldn't accurately tell from the graphs, but what was the richest afr you saw? Seems like you got pretty rich at the top of 4th gear...

-Chike

[longassname]

This thread finally prompted me to hook up the MAF signal and tachometer signal to my LM-1 data logger. Below are the results for a WOT run that I made this morning on the way to work. The outside air temperature was about 82F, so there was a bit less oxygen than usual. The MAF is peaking right at around 4.5 volts in all four gears. According to Michael's plots, that leaves about 20% headroom for engine mods. But there should be at least 10% reserve for driving in cold temperatures where the air has about 10% greater density. So, realistically, the stock MAF does indeed have only about 10% headroom for engine mods which isn't much (only about 230*1.1 ~ 250 max HP).

http://www.subaru-svx.net/photos/files/mbtoloczko/27877.gif

Actually 4.56 volts is 86.3% and 4.64 volts is 90.2% of the theoretical max of the svx mass air meter and is only 4 and 3 readings down respectively from the theoretical max--as you can see resolution at this far extreme of the meter is poor. With the z32maf this reading would be around 3.76 volts and lie right in the meaty belly of the curve.

[poweredx2]

Well I have access to a few 90-96 maximas and two 94 na 300zxs.Do I have to switch connectors.

[longassname]

So running a upgraded fuel pump, and running higher fuel presure will be acounted for in the engine managment. I just thought the ECU ran off of a constant fuel presaure and doesnt check up on it, if it were to change.


No the ECU does not monitor fuel pressure. With the faster fuel pump your fuel pressure is raised accross the board increasing fuel delivery accross the board so that your afr is richer accross the board. At idle and cruise the ecu uses the oxygen sensors to move the afr back to stoichiometric for efficiency. The fuel pressure regulator maintains fuel pressure in relation to manifold pressure. When there is vacuum the fuel pressure is decreased and thus fuel delivery is decreased. As forced induction creates positive manifold pressure fuel pressure increases and thus the amount of fuel delivered increases. This is all mechanical not ecu controlled.

[poweredx2]

Don't answer my prior question that was answered on your new page,but will I still be able to run a 150 shot with the new software.I understand it retards timing for forced induction,if not I'll just get the software and stick with the two stage zex 125 shot I'm running.

[longassname]

Well I have access to a few 90-96 maximas and two 94 na 300zxs.Do I have to switch connectors.

z32 means 1990's 300zx. turbo or na doesn't matter, they both use the same meter.

[mbtoloczko]

Great plots Mychailo. That definitely explains sheds light on the situation. I couldn't accurately tell from the graphs, but what was the richest afr you saw? Seems like you got pretty rich at the top of 4th gear...

-Chike

Hi Chike. The richest was about 11.5:1 in 4th gear. This is pretty much what I observed before. Looking at the MAF reading and the AFR ratio, my guess is that the engine ran leaner in the lower gears because the MAF did not have a fast enough response time. Either that or the inertia of the air in the intake system was not allowing air to get into the engine quickly enough (intake restriction effects).

[Chiketkd]

Hi Chike. The richest was about 11.5:1 in 4th gear. This is pretty much what I observed before. Looking at the MAF reading and the AFR ratio, my guess is that the engine ran leaner in the lower gears because the MAF did not have a fast enough response time. Either that or the inertia of the air in the intake system was not allowing air to get into the engine quickly enough (intake restriction effects).
And as you have a 5spd, the top of 4th gear is around 110mph or so? (basically equivalent to the top of 3rd gear on my 4.44 4EAT)

Interesting to see the afr stays put at 12.5:1 in 1st-3rd gear, and only really richens up a lot in 4th.

Again, great info!

-Chike

[mbtoloczko]

...

Interesting to see the afr stays put at 12.5:1 in 1st-3rd gear, and only really richens up a lot in 4th.

Its starting to richen up in 3rd gear too.

[longassname]

is all that up and down gyration in the latter gears an artifact of your logging or real?

[mbtoloczko]

is all that up and down gyration in the latter gears an artifact of your logging or real?

The LM-1 has an input signal resolution of ~0.005 volts, and it acquires data at a rate of about 12 times per second. The manual doesn't say how long it reads the signals. I'm reading the MAF signal where it enters the ECU. I'm using a ground wire on the ECU as the voltage reference. I'd guess that the MAF voltage oscilliations are real. Seems to be happening at higher air flow rates. Maybe turbulence in the MAF? Maybe something to do with the MAF response time?

[Chiketkd]

Its starting to richen up in 3rd gear too.
True. What's your mph at the top of 3rd & 4th gears in your 5mt?

-Chike

[svxsubaru1]

No the ECU does not monitor fuel pressure. With the faster fuel pump your fuel pressure is raised accross the board increasing fuel delivery accross the board so that your afr is richer accross the board. At idle and cruise the ecu uses the oxygen sensors to move the afr back to stoichiometric for efficiency. The fuel pressure regulator maintains fuel pressure in relation to manifold pressure. When there is vacuum the fuel pressure is decreased and thus fuel delivery is decreased. As forced induction creates positive manifold pressure fuel pressure increases and thus the amount of fuel delivered increases. This is all mechanical not ecu controlled.

So you think that this would work well enough for turbo charged vehicle. Do you know what the Fuel preasure would max out at if i were to run 7 PSI.

[longassname]

The LM-1 has an input signal resolution of ~0.005 volts, and it acquires data at a rate of about 12 times per second. The manual doesn't say how long it reads the signals. I'm reading the MAF signal where it enters the ECU. I'm using a ground wire on the ECU as the voltage reference. I'd guess that the MAF voltage oscilliations are real. Seems to be happening at higher air flow rates. Maybe turbulence in the MAF? Maybe something to do with the MAF response time?


Well if those are real then there is the explanation of the afr going screwy at high flow rates. A half volt is a lot anywhere but because it's at the top end of the curve that half volt oscilation in voltage is a huge fluctuation in the load reading--25%-30% accross the range where it's happening.

[Chiketkd]

No the ECU does not monitor fuel pressure. With the faster fuel pump your fuel pressure is raised accross the board increasing fuel delivery accross the board so that your afr is richer accross the board. At idle and cruise the ecu uses the oxygen sensors to move the afr back to stoichiometric for efficiency. The fuel pressure regulator maintains fuel pressure in relation to manifold pressure. When there is vacuum the fuel pressure is decreased and thus fuel delivery is decreased. As forced induction creates positive manifold pressure fuel pressure increases and thus the amount of fuel delivered increases. This is all mechanical not ecu controlled.
In regards to the above statement Michael, how well would the Stage 2v3 chip work with an OBDI SVX that has an Impreza fpr installed (fuel pressure raised to 43.5psi, instead of the stock 36psi)?

-Chike

[longassname]

So you think that this would work well enough for turbo charged vehicle. Do you know what the Fuel preasure would max out at if i were to run 7 PSI.

I believe 7 psi will raise your fuel pressure 7 psi. Like I said, I'm driving our stage III car on it now and it works fantastically. Our stage III car is probably getting a better bsfc than you will get but it is also putting out more power than i believe you can get from a turbo system. We are running 8 psi which seems to be the most the engine wants to run due to it's relatively high compression ratio. I haven't taken the car to high rpms to see if the fuel injectors can handle it but perhaps you are not getting the full jist of what I am saying by that. Do you realize how fast you are going in 4th gear above 5600 rpms? If you need additional fuel it's not like you will be hurting till you add it. Build the system first THEN if you need additional fuel think about it. I know this is the opposite of what you've heard repeatedly from all the people discouraging everyone from building forced induction systems but now that we've realeased this software things are changed. It is still a major undertaking and is probably best left to someone with some experience or taken on as a hobbyist venture on a spare car but it is now feasible. You won't spend a lot of money and find out in the end it doesn't work because of the ECU. You will succeed or fail based on your mechanics not your electronics.

[longassname]

In regards to the above statement Michael, how well would the Stage 2v3 chip work with an OBDI SVX that has an Impreza fpr installed (fuel pressure raised to 43.5psi, instead of the stock 36psi)?

-Chike


That's about the same fuel pressure as with the walboro pump so it would be about the same--should work very well for forced induction. It might be a bit rich for a natrually aspirated car. You'll find the afr flattens out very nicely with the z32 meter and our software, richer in the lower rpms (decell is also improved). A naturally aspirated car should run the stock fuel pressure. A car with forced induction should run raised fuel pressure.

[Earthworm]

I wonder if this would help my situation. My engine won't rev all the way to 7400 rpm. I'm lucky to reach 7000 (w/stage I). When it reaches this limit it starts bucking but not like a normal rev limiter.

My dad's 95 does the same but gets an additional 200 rpm.

In 4th gear I reach 135mph before it starts bucking.

[longassname]

I wonder if this would help my situation. My engine won't rev all the way to 7400 rpm. I'm lucky to reach 7000 (w/stage I). When it reaches this limit it starts bucking but not like a normal rev limiter.

My dad's 95 does the same but gets an additional 200 rpm.

In 4th gear I reach 135mph before it starts bucking.


That could just be an inaccuracy in your tach or it could be something else. Subafreak has the same problem but at 6000 rpms and he used to get over 7000. We're trying to figure out what is going on now. He wired his neutral safety switch and switched versions of software around the same time. I checked the version of software i sent him and it has the same rev limit as what he used to have. I have a feeling the different rev limit that different people with manual transmissions are seeing is a result of how they wire up their neutral safety switch and that you may in fact be hitting something else i think i saw in the software. I recall seeing something that looked like a speed limiter around 152 mph from the top of my head. I think you may be hitting that. I don't have a lot of time to spend on it now but my guess is the solution will be to figure out who has the best neutral safety switch wiring and everyone do theirs the same.

[Earthworm]

My system is wired like a factory 5MT. I know Jesse is missing a few switches.

I know I'm not hitting 152mph :) Highest I've gone is about 145 on the speedo.

I hit the same RPM wall regardless of speed. I have mentioned before that resetting the ECU gives me a couple hundred more RPM for a short while.

[longassname]

My system is wired like a factory 5MT. I know Jesse is missing a few switches.

I know I'm not hitting 152mph :) Highest I've gone is about 145 on the speedo.

I hit the same RPM wall regardless of speed. I have mentioned before that resetting the ECU gives me a couple hundred more RPM for a short while.

I'm not referring to your actual speed. I'm refering to how fast the ecu may think you are going based on rpm and the signals it is getting or not getting from the inhibitor switch. It may not be the speed limit but it warrants looking into. Of course 7000 on your tach may well be 7400 actual rpms or maybe you are right and when you get to the top of your mass air meter readings the engine just doesn't want to go anymore.

[Earthworm]

Probably the only way to determine this is by measuring the AFR on my car at the limits.

[mbtoloczko]

I used to think that the bucking was due the engine hitting redline and the tach not accurately reading the engine rpm, but yesterday, I say over 6500 rpm on the tach with no bucking. In my previous cold weather runs with the air density was higher, I'd be lucky if I got to 6500 before my car started bucking. I'm beginning to think more that the bucking is an artifact of the MAF reaching 4.8 volts. Either the engine is running lean and pulling back timing, or the ecu is cutting spark/fuel when it sees 4.8 volts from the MAF.

Chike, with the SVX, RA 3rd tops out at about 80-85 mph, and RA 4th tops out at about 100-105 mph with a 3.90 axle ratio.

svxsubaru1, If you want to run the stock fuel injectors with a turbo (or SC), you'll have to increase the baseline fuel pressure (unboosted fuel pressure). Otherwise, the injectors will reach maximum duty cycle (80%) at around 250 HP. 7 psi of boost would give close to 350 bhp. To supply enough fuel to the engine for 350 HP, you'll need to bump the baseline fuel pressure up to around 60 psi. Then at full boost, you're fuel pressure will be about 67 psi.

Michael, are you planning to include any sort of afr enrichment changes in the Stage 2v3 chip?

[Chiketkd]

That's about the same fuel pressure as with the walboro pump so it would be about the same--should work very well for forced induction. It might be a bit rich for a natrually aspirated car. You'll find the afr flattens out very nicely with the z32 meter and our software, richer in the lower rpms (decell is also improved). A naturally aspirated car should run the stock fuel pressure. A car with forced induction should run raised fuel pressure.
That's the thing Michael, with yor Stage 2v3 software, n/a cars can now achieve much higher hp numbers as their MAF won't be maxed out... (saw signs of my MAF maxing out during my dyno runs last winter when air was a cool 45* in the shop and my only 'power' mod was an STI panel filter).

With the stock fuel pressure and injectors, per Mychailo's post above, at max duty cycle 250hp is the most that can be achieved. I'd just want to be sure that your stage 2v3 software would be adaptable to changes an owner might make over the life of the vehicle (e.g. high powered n/a motor -> forced induction).

I've decided to keep my SVX indefinitely and not get an '05 Legacy GT just yet. However, I'd want to get the most performance out of an n/a EG33 without cracking open the block... ;)

-Chike

[TomsSVX]

I've decided to keep my SVX indefinitely and not get an '05 Legacy GT just yet. However, I'd want to get the most performance out of an n/a EG33 without cracking open the block... ;)

-Chike

Glad to hear you are keeping it!! I guess since you don't leak oil anymore, the car is like new. Or at least looks it!!

Tom

[Duckie]

So after my stage III installed what will be left as far as options for me to suck more power out of this beast. Ideally I would hopefully get this heavy tub into the high 11's.

[Chiketkd]

Glad to hear you are keeping it!! I guess since you don't leak oil anymore, the car is like new. Or at least looks it!!

Tom
Yeah, but this car is frustrating to make faster. We'll see what the future holds. :) Even an '03+ WRX doesn't look bad at this point... ;)

-Chike

[Chiketkd]

So after my stage III installed what will be left as far as options for me to suck more power out of this beast. Ideally I would hopefully get this heavy tub into the high 11's.
I'd see where you're at after the install. You might be in the high 12's...you might be in the low 13's (maybe higher depending on how heavy your car weighs). Getting to the 11's will take alot more horsepower than the stage 3 is going to provide. Maybe the 'built' low-compression piston Stage 4 motor LAN talks about doing in the future will get you even closer to the mark as you'll be able to run much higher boost than the 7-8psi he's running on his test car.

Going from high 12's/low 13's in a WRX/STI/Evo to the 11's typically takes and increase in those light-weight (3,200lb) cars of around 150+hp at the crank. If you don't believe me, read other boards like www.clubwrx.net or www.evolutionm.net.

-Chike

[Duckie]

Oh, trust me I believe you. I have a friend who is currently just above the 11 second mark in his evo.

And hell, I am only expecting a mid to high 13's from this kit. Why? I live in reno Nevada, mine is still a stock auto, ive got 16's on my car, and my driver's seat weighs 76 pounds.

I am just looking at options of where to go further after this. I will not stop modding this car tell I get kicked off the race track for not having a cage! And weight reduction is not an option unless its an exterior change (I.E make all of the outside carbon fiber) because I want this car to remain what it should be. A luxury sports sedanish type car.

[Chiketkd]

I am just looking at options of where to go further after this. I will not stop modding this car tell I get kicked off the race track for not having a cage! And weight reduction is not an option unless its an exterior change (I.E make all of the outside carbon fiber) because I want this car to remain what it should be. A luxury sports sedanish type car.
Nice! Sounds like you have some solid plans for the car Duckie! Ever plan on driving cross-country to attend a Reading meet? If so, we should definitely meet up.

Once you get the Stage 3 in your car, if money wasn't an option, I'd buy a used low mileage 4.44 4EAT from a Legacy Outback and send it off for a Level 10 re-build including their valve body mod. Or go through the expense of doing a built 5MT or STI 6MT swap. The shorter gearing alone will improve your 1/4 mile time by over a 0.3 seconds...

The built stage 4 motor may then be the next way to go. You should be able to run 15 psi no problem as long as you have the right software from LAN to support it (which will then put you at roughly 450-460hp at the crank)!!! :eek: :cool:

-Chike

[longassname]

I used to think that the bucking was due the engine hitting redline and the tach not accurately reading the engine rpm, but yesterday, I say over 6500 rpm on the tach with no bucking. In my previous cold weather runs with the air density was higher, I'd be lucky if I got to 6500 before my car started bucking. I'm beginning to think more that the bucking is an artifact of the MAF reaching 4.8 volts. Either the engine is running lean and pulling back timing, or the ecu is cutting spark/fuel when it sees 4.8 volts from the MAF.

Chike, with the SVX, RA 3rd tops out at about 80-85 mph, and RA 4th tops out at about 100-105 mph with a 3.90 axle ratio.

svxsubaru1, If you want to run the stock fuel injectors with a turbo (or SC), you'll have to increase the baseline fuel pressure (unboosted fuel pressure). Otherwise, the injectors will reach maximum duty cycle (80%) at around 250 HP. 7 psi of boost would give close to 350 bhp. To supply enough fuel to the engine for 350 HP, you'll need to bump the baseline fuel pressure up to around 60 psi. Then at full boost, you're fuel pressure will be about 67 psi.

Michael, are you planning to include any sort of afr enrichment changes in the Stage 2v3 chip?

80% isn't max....100% is max and the max hp the fuel injector is capable of depends on the time available for fuel injection. The fuel injectors are capable of producing much more power than that at much lower fuel pressures. If you were in a situation where you were choosing fuel injectors then yes you would want to keep it under 80% for sure--in fact i would go with bigger injectors so i could direct a concentrated stream of fuel onto the valve easily for complete vaporization...this is what i did with stage 3 but when you are dealing with what you have it's a different story.

[longassname]

That's the thing Michael, with yor Stage 2v3 software, n/a cars can now achieve much higher hp numbers as their MAF won't be maxed out... (saw signs of my MAF maxing out during my dyno runs last winter when air was a cool 45* in the shop and my only 'power' mod was an STI panel filter).

With the stock fuel pressure and injectors, per Mychailo's post above, at max duty cycle 250hp is the most that can be achieved. I'd just want to be sure that your stage 2v3 software would be adaptable to changes an owner might make over the life of the vehicle (e.g. high powered n/a motor -> forced induction).

I've decided to keep my SVX indefinitely and not get an '05 Legacy GT just yet. However, I'd want to get the most performance out of an n/a EG33 without cracking open the block... ;)

-Chike

Chike,

What can i say to that but ask which do you think is the better test of if you can get more out of the injectors a generic calculator or my having done it on our demo car? Theoretical speculation is great but you can't discard real data....you have to correct your assumptions or your reasoning when you find your speculation doesn't match the facts of what happens. Like i said to Mychailo 80% is 80% 100% is 100% Granted I'm getting a much better bsfc than a turbo system will but still no na svx will ever need larger injectors to run gasoline and if a turbo system needs more fuel it can get it through an additional injector controller which can supply fuel at high rpms but won't mess with the engine managment.

[mbtoloczko]

80% isn't max....100% is max and the max hp the fuel injector is capable of depends on the time available for fuel injection. The fuel injectors are capable of producing much more power than that at much lower fuel pressures...

100% may be the true max, but no one who tunes motors will recommend running anything over 85% duty cycle. I've seen flow rate vs fuel pressure curves from an SVX fuel injector, and I'd bet anything that its impossible to get 350 BHP from a boosted (SC or turbo) SVX motor running stock fuel injectors without running at least 60 psi line pressure. I'd say a more realistic number is a line pressure of 70 psi, and that may not be enough.

[Duckie]

Oops, i meant 17's on my car...not 16's lol

[longassname]

100% may be the true max, but no one who tunes motors will recommend running anything over 85% duty cycle. I've seen flow rate vs fuel pressure curves from an SVX fuel injector, and I'd bet anything that its impossible to get 350 BHP from a boosted (SC or turbo) SVX motor running stock fuel injectors without running at least 60 psi line pressure. I'd say a more realistic number is a line pressure of 70 psi, and that may not be enough.


I'm trying to make a clear point here and I'm not sure if you aren't getting it or you are trying to defend your #'s besides it confusing the point i'm trying to make. Fuel injector size calculations using bsfc and desired hp are a good way to decide what fuel injectors to purchase if you are purchasing fuel injectors; however, it is not valid to say that because a calculation using bsfc and desired hp says you should have larger fuel injectors that you can not use the fuel injectors you have. When flow rate is accepted as is the factor limiting how much power you can generate is how much time the injector has to inject fuel. If you give it long enough 1 small injector can fill a barrel with fuel. The time the injector has to inject fuel gets shorter as rpms increase and thus it is at high rpms that the injector will max out first. Maybe this will make it clearer. While the thing we are changing with forced induction is how much air we are putting into the cyllinder with each stroke it is not that the fuel injector can't put enough fuel into the cyllinder for that air it's a question of at what rpm will it no longer be able to put enough fuel into the cyllinder. I'm not going to redo the calculations so this will be ballpark # from the top of my head: at 2800 rpms you have 34 milliseconds to inject fuel into each cyllinder(a lifetime), at 4200 rpms you have 25 and half milliseconds (an awfully long time), at 5600 you have 17 milliseconds (a pretty long time). As your rpms increase the time you have to inject fuel into each cyllinder decreases and somewhere allong the yellow brick road your fuel injectors will not be able to keep up. I can't tell you exactly what rpm this will happen at. It will vary by system and you will not know till you get there. I can tell you though that your car will be plenty drivable while you decide if you want to adjust your boost down to a level the injectors can keep up with at the rpm you want to run or get an additional injector controller, or run higher fuel pressure, etc etc. I can tell you that with the additional power you'll have at low rpms you wouldn't find yourself even wanting to go into high rpms in around the town driving while you figure out what to do for additional fuel. And I can tell you that you will be better able to nail down any other bugs in your newly crafted custom system before doing anything about additional fuel. And I can tell you that you will understand things and be able to make a better choice about if and what to purchase for more fuel after you have driven your working system and nailed down any bugs. Reading is great but you don't really know what you are talking about untill you are there.

Your fuel injector size calculator may tell your injectors aren't big enough but what they don't tell you is:

1) they are big enough for the majority of operating time even if they aren't big enough for high rpms
2)you may be happy to turn down the boost to where they are big enough instead of increase fuel
3)you may want to do combinations of things like increase fuel pressure and bring down boost
4)an additional injector controller can be implemented easiest to get you into the higher rpm ranges after you have your system humming with all the bugs worked out

The short of it is that untill you have your system working you are really just speculating and the stage 2v3 software is plenty to get your system working and will handle all or close to all operating conditions. Then engine management is no longer a legitmate hold back. If you need additional fuel it will only be under throttle at high rpms and that can be done after your system is built and without screwing with the engine management.

[SilverSpear]

Well I have access to a few 90-96 maximas and two 94 na 300zxs.Do I have to switch connectors.

Does Maxima's MAFs are the same of the 300 ZX's ? i mean do they have the Z32 type? if it is so i can easily get it from here, if not i have to search for the 300ZX's which is very hard to find because this car was never imported to Lebanon by the Nissan dealership... any help? :(

[svxistentialist]

I'm trying to make a clear point here and I'm not sure if you aren't getting it or you are trying to defend your #'s besides it confusing the point i'm trying to make. Fuel injector size calculations using bsfc and desired hp are a good way to decide what fuel injectors to purchase if you are purchasing fuel injectors; however, it is not valid to say that because a calculation using bsfc and desired hp says you should have larger fuel injectors that you can not use the fuel injectors you have. When flow rate is accepted as is the factor limiting how much power you can generate is how much time the injector has to inject fuel. If you give it long enough 1 small injector can fill a barrel with fuel. The time the injector has to inject fuel gets shorter as rpms increase and thus it is at high rpms that the injector will max out first. Maybe this will make it clearer. While the thing we are changing with forced induction is how much air we are putting into the cyllinder with each stroke it is not that the fuel injector can't put enough fuel into the cyllinder for that air it's a question of at what rpm will it no longer be able to put enough fuel into the cyllinder. I'm not going to redo the calculations so this will be ballpark # from the top of my head: at 2800 rpms you have 34 milliseconds to inject fuel into each cyllinder(a lifetime), at 4200 rpms you have 25 and half milliseconds (an awfully long time), at 5600 you have 17 milliseconds (a pretty long time). As your rpms increase the time you have to inject fuel into each cyllinder decreases and somewhere allong the yellow brick road your fuel injectors will not be able to keep up. I can't tell you exactly what rpm this will happen at. It will vary by system and you will not know till you get there. I can tell you though that your car will be plenty drivable while you decide if you want to adjust your boost down to a level the injectors can keep up with at the rpm you want to run or get an additional injector controller, or run higher fuel pressure, etc etc. I can tell you that with the additional power you'll have at low rpms you wouldn't find yourself even wanting to go into high rpms in around the town driving while you figure out what to do for additional fuel. And I can tell you that you will be better able to nail down any other bugs in your newly crafted custom system before doing anything about additional fuel. And I can tell you that you will understand things and be able to make a better choice about if and what to purchase for more fuel after you have driven your working system and nailed down any bugs. Reading is great but you don't really know what you are talking about untill you are there.

Your fuel injector size calculator may tell your injectors aren't big enough but what they don't tell you is:

1) they are big enough for the majority of operating time even if they aren't big enough for high rpms
2)you may be happy to turn down the boost to where they are big enough instead of increase fuel
3)you may want to do combinations of things like increase fuel pressure and bring down boost
4)an additional injector controller can be implemented easiest to get you into the higher rpm ranges after you have your system humming with all the bugs worked out

The short of it is that untill you have your system working you are really just speculating and the stage 2v3 software is plenty to get your system working and will handle all or close to all operating conditions. Then engine management is no longer a legitmate hold back. If you need additional fuel it will only be under throttle at high rpms and that can be done after your system is built and without screwing with the engine management.


Thanks very much for all this meticulous explanation Michael. It makes it easier to see that a rolling test bed can be done, without harm.

One point I see that would be relevant for forced induction. Bolting on a turbo would seem to be easier than a supercharger. However, the turbo is normally giving its best power at high rpm, where the belt driven Roots or twin screw is delivering full pressure off tickover. This implies to me that anyone considering a turbo will be more likely to run into the maxed out injector problem at high revs, because that is where they are getting their best fun to money ratio.

The supercharger will give you all the power at low rpms where even the stock injectors will work. That is why I am going to fit a blower. I will be going with the bigger intank pump, higher pressure and maybe 550cc injectors anyway, but nice to know the stock system would work OK.

Thanks again,

Joe

PS I will be wanting the Stage 2 v 3 from you :)

[longassname]

Does Maxima's MAFs are the same of the 300 ZX's ? i mean do they have the Z32 type? if it is so i can easily get it from here, if not i have to search for the 300ZX's which is very hard to find because this car was never imported to Lebanon by the Nissan dealership... any help? :(

No I don't think it is the same meter; however, an infity j30 is the same.

[TomsSVX]

Just a quick question for ya Mike. Sometimes when I hit WOT in first and second my car seems to buck. i have a feeling it is because I am pulling too much air and maxing out the MAF. Is this possible for a car with few mods like mine?

Tom

[Chiketkd]

Michael,

A lot of performance minded members have installed a 43.5psi impreza fpr in their SVXs. How hard and more expensive would it be to offer a Stage 2v3 for SVX's with this fpr?

As you can tell, I have little interest in your Stage 1 OBDII chip, and a lot more in the OBDII version of the Stage 2v3 chip whenever it's released. I just don't want to go back to the stock fpr as I'll be doing some fresh mods on my engine which haven't been undertaken before. ;)

-Chike

[longassname]

Michael,

A lot of performance minded members have installed a 43.5psi impreza fpr in their SVXs. How hard and more expensive would it be to offer a Stage 2v3 for SVX's with this fpr?

As you can tell, I have little interest in your Stage 1 OBDII chip, and a lot more in the OBDII version of the Stage 2v3 chip whenever it's released. I just don't want to go back to the stock fpr as I'll be doing some fresh mods on my engine which haven't been undertaken before. ;)

-Chike

As for the obdI line up I offer those products that best meet the needs of the most people. I think the stage 2v3 is a good product that will open up a lot of avenues for performance modification of the svx. You probably do get a performance benefit on your car from an imprezza fpr because you don't have our software and your car would otherwise be running too lean. I believe in most cases it will not improve performance to use an imprezza fpr with our software but that is up to each individual to test and figure out for his or her particular set up. If I tuned the software specifically for an imprezza fpr on a naturally aspirated svx it would be to the detriment of the tuning for forced induction or all those who have naturally aspriated svx's with svx fuel pressure regulators. I listen to all ideas from customers and potential customers to determine the needs, both actual and percieved, of the market and then make the best fit product line to meet those needs. I do appreciate your input but I do not feel that at this time there is sufficient merrit to creating a new product tuned for using an imprezza fuel pressure regulator.

Now let me give you my usual non-answer regarding the obdII stuff: I still can not share any information about when or what we will be releasing for the obdII svx but rest assured that I have listened to everyone during the product development process.

[longassname]

Just a quick question for ya Mike. Sometimes when I hit WOT in first and second my car seems to buck. i have a feeling it is because I am pulling too much air and maxing out the MAF. Is this possible for a car with few mods like mine?

Tom


You are running a manual transmission so if you are refering to high rpms then yes it is completely possible. If you are referring to low rpms then no. I have not done any personal experimentation/logging/measuring the mass air flow readings on a stock svx. I only know about the software and hardware but I don't know about the airflow on the stock svx from personal experience. This was never needed information for me and this project developed after I no longer had a stock svx on hand to make measurements on in order to give you information to work with. I know the mass air meter maxes out somewhere right around the max output of a stock svx engine but not exactly where. The plots Mychailo posted indicate that the meter is also wildly inaccurate at high airlfows if his log is accurate and his specific case is the case in general then whether you are actually at the max reading on the meter or in the wildly inaccurate reading area of the meter then the maf reading should be suspect for any problems you are running into.

[Chiketkd]

Now let me give you my usual non-answer regarding the obdII stuff: I still can not share any information about when or what we will be releasing for the obdII svx but rest assured that I have listened to everyone during the product development process.
Understood. I'll be waiting - with cash in hand. ;)

-Chike

[SilverSpear]

No I don't think it is the same meter; however, an infity j30 is the same.

You saved me.... :D :D :D (<----- this smile means the beginning of something wicked is going to happen...)

[ssnsltd]

Understood. I'll be waiting - with cash in hand. ;)

-Chike


DITO

I am just excited it is even a possibility. . .

[Chiketkd]

DITO

I am just excited it is even a possibility. . .
The only other possibility is to go to a tuner shop w/ dyno and have them dyno tune your car. This will get around the maxed out maf as they can dial in extra/less fuel & timing at any rpm - but it will be much pricier! ;)

-Chike

[Phast SVX]

The only other possibility is to go to a tuner shop w/ dyno and have them dyno tune your car. This will get around the maxed out maf as they can dial in extra/less fuel & timing at any rpm - but it will be much pricier! ;)

-Chike
You mean using an air flow converter? that merey tricks the esignal. also im not aware of a program that can adjust timing on the stock computer.
phil

[Chiketkd]

You mean using an air flow converter? that merey tricks the esignal. also im not aware of a program that can adjust timing on the stock computer.
phil
Maybe timing cannot be adjusted, but the stock ECU is always trying to maximize timing as long as no knock is detected. I do know this particular shop I have in mind has a machine that's able to flash the ECUs of OBDII cars. Either way, most people won't touch an SVX with a ten foot pole.

LAN is doing our community a great service, and I hope he services his OBDII customers as well as he's servicing the OBDI... ;)

-Chike

[Phast SVX]

well as usual im happy to dive in first. Placed my order today and will be ordering my tomei connector on monday. I also have a maf lined up to arrive around the same time. I willl have both maf harneses(sp?) fitted on my car for easy analysis and dynoing.
phil

[Chiketkd]

well as usual im happy to dive in first. Placed my order today and will be ordering my tomei connector on monday. I also have a maf lined up to arrive around the same time. I willl have both maf harneses(sp?) fitted on my car for easy analysis and dynoing.
phil
Congrats Phil! Make some big numbers on the dyno and scare a few SRT-4's at the track! :p :D

-Chike

[MaxImUmZ]

well as usual im happy to dive in first. Placed my order today and will be ordering my tomei connector on monday. I also have a maf lined up to arrive around the same time. I willl have both maf harneses(sp?) fitted on my car for easy analysis and dynoing.
phil

I may not be as quick to dive in. Get those dynos up as soon as possible and if they should significant power gains Ill be all over getting a stage II.

[Phast SVX]

I may not be as quick to dive in. Get those dynos up as soon as possible and if they should significant power gains Ill be all over getting a stage II.

the power gains out of the box are not what im looking for. If there are a few ponies to be gained that will be great, but i bought it for the turbo system i have cooking.
phil

[ssnsltd]

$329 just for an upgrade chip for my $219 1v4 box.
Ouch.

I hope the dyno results are REALY good.

[Phast SVX]

$329 just for an upgrade chip for my $219 1v4 box.
Ouch.

I hope the dyno results are REALY good.
Your missing the point. This software and maf on its own dosnt create much more power on a factor svx)that i would think, could be wrong we will see) It allows for forced induction to boost past maxed out stock mass airflow sensor. Also, the stock sensor seems to operate very irradictly at high flow levels(which is pretty much anything wot on an SVX)
phil

[ssnsltd]

Oh I didn't miss the point,

I am just trying to work through why it would be so expensive, especialy for just the upgrade ROM vs. the entire 1v4. . .

[Phast SVX]

Oh I didn't miss the point,

I am just trying to work through why it would be so expensive, especialy for just the upgrade ROM vs. the entire 1v4. . .

consider yourself lucky. The wolf ecu is much more for nissians that want this conversion. It allows the stock computer to do things only a full standalone would allow.
phil

[Chiketkd]

consider yourself lucky. The wolf ecu is much more for nissians that want this conversion. It allows the stock computer to do things only a full standalone would allow.
phil
Amen. I'm very familiar with Jim Wolf Technology and their prices from having owned a '90 300ZX TT.

You'll be a pioneer Phil. Good luck with your turbo project. You finally have the software to make it happen... ;)

-Chike

[SVXRide]

snip* Also, the stock sensor seems to operate very irradictly at high flow levels(which is pretty much anything wot on an SVX)
phil


Phil,
Maybe I missed a post by LAN...have we seen any evidence that the z32 MAF won't be just as erratic at high flow levels? As far as I know, Mychailo's recent plots are the only ones that actually show what the MAF voltage is doing at higher rpms.
-Bill (constantly in search of more SVX knowledge :cool: )

[Phast SVX]

Phil,
Maybe I missed a post by LAN...have we seen any evidence that the z32 MAF won't be just as erratic at high flow levels? As far as I know, Mychailo's recent plots are the only ones that actually show what the MAF voltage is doing at higher rpms.
-Bill (constantly in search of more SVX knowledge :cool: )
if you reach those high flow, high voltage levels of 400+ hp on the z32 maf let me know. most sr20 and ka turbos use this afm without a problem.
phil

[KCROGUEDOG]

i 2 will be waiting cash in hand for the obduece 2v3 version and would like to have the imprezzas fpr. just have not force my self to buy yet.

[SVXRide]

if you reach those high flow, high voltage levels of 400+ hp on the z32 maf let me know. most sr20 and ka turbos use this afm without a problem.
phil

Phil,
Understood....yet "without a problem" doesn't mean that this maf's trace isn't just as erratic (and the ecu is just covering for it...)
-Bill

[SVXtasy]

i should be getting mine this week i will post a review.

[Chiketkd]

i should be getting mine this week i will post a review.
Nice! Can't wait to hear your results! :)

-Chike

[KCROGUEDOG]

chike of topic but i got your attention when installing your es bushings on the 11/16 ones u drilled out to 18mm. did u use a 18mm grinding bit. the closest i can find is 17.5 which is 11/16 at home depot and other spots. or did u use that size bit and wing it to 18mm? sorry for the hijacking ignore this.

[Chiketkd]

chike of topic but i got your attention when installing your es bushings on the 11/16 ones u drilled out to 18mm. did u use a 18mm grinding bit. the closest i can find is 17.5 which is 11/16 at home depot and other spots. or did u use that size bit and wing it to 18mm? sorry for the hijacking ignore this.
You know, Svxfiles might have found an 18mm grinding bit at Sears, but if you can't get your hands on one, using the 11/16" and grinding a little extra to reach 18mm will be just fine. :)

-Chike

[svxfiles]

Actually, I bought a 3/4" grinding ball, on a 1/4" shaft, at Lowes, and lightly ground it down on a bench grinder till it fit a 18mm open end wrench. :)

[shotgunslade]

I think, the other day, I may have experienced the topping out of the stock MAF that people have been describing. At WOT in second gear from about 6000rpm to the shift point at 6400-6500 rpm, there was a very slight but rapid shudder in the engine note. My only engine mods are Stage 1v4, the exhaust system and the green air filter, but the new exhaust system gives the engine a very continuous drone that wavered slightly in the above condition. That said, is there likely to be any benefit of Stage 2v3 for non-forced draft mods, such as porting and polishing or perhaps a larger throttle body?

[longassname]

The word thus far is that it pulls much better to red line. I've been told that where you can feel the power drop off in a stock car with manual transmission and know you need to shift that with stage2v3 it keeps pulling hard on up through 7000rpms. We'll have dyno results soon and then we'll really know what the benefit is for stock cars.

[SilverSpear]

The word thus far is that it pulls much better to red line. I've been told that where you can feel the power drop off in a stock car with manual transmission and know you need to shift that with stage2v3 it keeps pulling hard on up through 7000rpms. We'll have dyno results soon and then we'll really know what the benefit is for stock cars.

LAN, my car is still automatic, i am having the same symptoms... not just on high rpms but also you can feel that the accelerations has dropped from what they used to be... really i am not joking. Maybe the manual guys are not experiencing it becasue of the manual factor, but believe me i know my SVX by heart, and i am telling you the power has dropped.

When i sensed at first the shuddering in my car, i thought the tranny was going out, but after reading the postings over here, i knew what it was now...

[longassname]

I have no idea what you are trying to say. Acceleration has dropped from what because of what? None of us are talking about a loss of power below that of factory. We are talking about the possiblity that the factory equipment is limiting power at high rpms.


LAN, my car is still automatic, i am having the same symptoms... not just on high rpms but also you can feel that the accelerations has dropped from what they used to be... really i am not joking. Maybe the manual guys are not experiencing it becasue of the manual factor, but believe me i know my SVX by heart, and i am telling you the power has dropped.

When i sensed at first the shuddering in my car, i thought the tranny was going out, but after reading the postings over here, i knew what it was now...

[SilverSpear]

I have no idea what you are trying to say. Acceleration has dropped from what because of what? None of us are talking about a loss of power below that of factory. We are talking about the possiblity that the factory equipment is limiting power at high rpms.

LAN, most of the guys now have manuals and are commenting on this issue, but really i am feeling a little lag in my automatic... I cleaned the air filter, i checked the spark plugs, i cleaned the intake manifold, I checked the alternator, the spark plugs wiring....etc... to see if they are the cause... I still feel a little loss of power when accelerating... or when going from 0 to 60... the car reacts better than stock, but less than the max performance i got after installing that chip... I still wanna check something before i hold to this comment, the exhaust system... Hold that thought.

[longassname]

I think you missread what the others have said. There are a couple of people having problems reaching the raised rev limit of 7400 rpms nobody said anything about power gains going away.


LAN, most of the guys now have manuals and are commenting on this issue, but really i am feeling a little lag in my automatic... I cleaned the air filter, i checked the spark plugs, i cleaned the intake manifold, I checked the alternator, the spark plugs wiring....etc... to see if they are the cause... I still feel a little loss of power when accelerating... or when going from 0 to 60... the car reacts better than stock, but less than the max performance i got after installing that chip... I still wanna check something before i hold to this comment, the exhaust system... Hold that thought.

[SilverSpear]

I think you missread what the others have said. There are a couple of people having problems reaching the raised rev limit of 7400 rpms nobody said anything about power gains going away.

No i didn't misread that LAN, i am just adding to it. I may be wrong in my statement, just let me check the Aftermarket exhaust, maybe i have a decompression somewhere in it...

[shotgunslade]

Any progress on the dyno tests for the new chip?

[longassname]

Any progress on the dyno tests for the new chip?


The guy we had dynoing for us is still waiting for the dyno operator to give him the print outs. The basic gist of his results were what I was expecting. The afr is moved .8 richer accross the board to better tune for forced induction. Because of the richer afr power drops of slightly above 4900 rpms where the afr gets below 12.4. This is the same as what we had seen during trial runs on the dyno when we developed the original stage 1 software.

When i developed the stage2v3 code I developed it for foced induction. There seems to be a lot of interest in using the z32 maf meter on na cars so I've decided to tune the 1st version of code that is on the adaptor for na. The second version of code on the adaptor is perfect for forced induction and is going to remain as is. Since stage 2 is for those more performance oriented I am going to be more aggressive in the changes in order to get more power. I will be bringing the lower rpm afr down closer to 12.5 and bringing the upper rpm afr up closer to 12.5. I will then take advantage of the new afr to increase ignition advance. Instead of just doing the ignition timing revision table which mainly affects part throttle around the town driving I will edit the base ignition advance table to get more wide open throttle power.

I'm doing the tuning this weekend and will call monday to schedule the dyno as early as it's available. I don't think there will be a very long wait.

[Budfreak]

Oh Happy Day!!:D:D:D

[SVXRide]

The guy we had dynoing for us is still waiting for the dyno operator to give him the print outs. The basic gist of his results were what I was expecting. The afr is moved .8 richer accross the board to better tune for forced induction. Because of the richer afr power drops of slightly above 4900 rpms where the afr gets below 12.4. This is the same as what we had seen during trial runs on the dyno when we developed the original stage 1 software.

When i developed the stage2v3 code I developed it for foced induction. There seems to be a lot of interest in using the z32 maf meter on na cars so I've decided to tune the 1st version of code that is on the adaptor for na. The second version of code on the adaptor is perfect for forced induction and is going to remain as is. Since stage 2 is for those more performance oriented I am going to be more aggressive in the changes in order to get more power. I will be bringing the lower rpm afr down closer to 12.5 and bringing the upper rpm afr up closer to 12.5. I will then take advantage of the new afr to increase ignition advance. Instead of just doing the ignition timing revision table which mainly affects part throttle around the town driving I will edit the base ignition advance table to get more wide open throttle power.

I'm doing the tuning this weekend and will call monday to schedule the dyno as early as it's available. I don't think there will be a very long wait.

Michael,
Outstanding!! Anyway you could swap in an Impreza (43psi) FPR on your engine before you do the dyno runs so those of us already running it don't end up running too rich with the 2v4 chip?
-Bill
p.s by "down closer to" you mean making a richer mixture and by "up closer to" you mean making a leaner mixture?

[shotgunslade]

So, does just substituting the Impreza FPR improve power without other mods on an NA engine? I am running the Green Filter and a Magnaflow exhaust, but no other mods.

[mbtoloczko]

So, does just substituting the Impreza FPR improve power without other mods on an NA engine? I am running the Green Filter and a Magnaflow exhaust, but no other mods.

The Impreza RS fpr operates at 43 psi at WOT vs the SVX fpr which operates at 36 psi at WOT. The increase in fuel pressure results in a little over a 1 point richening of the afr when the ecu is operating in open-loop (aggressive driving). With the SVX fpr, the afr is a little lean for max power at moderate rpms and right on the money near redline. With the Impreza RS fpr, the afr right in the optimum range at moderate rpms, but near redline, it starts getting a bit too rich. Have a look in my locker to see what the Impreza fpr does to the afr. This will happen regardless of whether or not you have done any intake or exhaust mods.

[longassname]

So, does just substituting the Impreza FPR improve power without other mods on an NA engine? I am running the Green Filter and a Magnaflow exhaust, but no other mods.


An impreza fpr probably costs a little bit of power and worsens fuel efficiency on a car with our software. It might improve things a bit on a car with a stock ecu since the cars run way too lean at low rpms from the factory but we've already taken care of that in our software.

[SVXRide]

An impreza fpr probably costs a little bit of power and worsens fuel efficiency on a car with our software. It might improve things a bit on a car with a stock ecu since the cars run way too lean at low rpms from the factory but we've already taken care of that in our software.

Michael,
Thus my question about the 2V3 chip for those of us runing the Impreza FPR and upgrading to the 2V3 w/z32 in a NA mode ;) Definitely don't want to be doing anything that's going to reduce the amount of Hp/Torque being created (and I really don't want to have to go back in and swap out the Impreza FPR, since my stock FPR was on its last legs when I replaced it with the Impreza FPR...) :D
-Bill
p.s. Long term, I think the Impreza FPR is the right way to go, as it pumps up the output of the stock injectors so they'll be capable of supporting the higher Hp/Torque we're all working towards :cool:

[longassname]

Michael,
Thus my question about the 2V3 chip for those of us runing the Impreza FPR and upgrading to the 2V3 w/z32 in a NA mode ;) Definitely don't want to be doing anything that's going to reduce the amount of Hp/Torque being created (and I really don't want to have to go back in and swap out the Impreza FPR, since my stock FPR was on its last legs when I replaced it with the Impreza FPR...) :D
-Bill
p.s. Long term, I think the Impreza FPR is the right way to go, as it pumps up the output of the stock injectors so they'll be capable of supporting the higher Hp/Torque we're all working towards :cool:


But if I tuned for the impreza fpr then everyone who doesn't have one would need to get one when they wouldn't otherwise need it. I feel your pain but I don't think the majority of people would want to buy a new fpr that they don't need.

[SVXRide]

But if I tuned for the impreza fpr then everyone who doesn't have one would need to get one when they wouldn't otherwise need it. I feel your pain but I don't think the majority of people would want to buy a new fpr that they don't need.

Michael,
I fully understand your thinking, from a business standpoint (must be that minor in Economics that came with the Mechanical Engineering degree :D )...I just keep coming back to the following:

Stock FPR with Stock Injectors = 36psi with 240 cc/min = 230 HP @ crank

Impreza FPR with Stock Injectors = 43 psi with 270 cc/min = 260 HP@crank (Based on BSFC=.45 and Max Duty Cycle = 75%)


Granted this is a "theoretical" calculation...it just gets me to thinking that, just as the stock MAF has become a "bottleneck" for further HP gains (2v3 w/z32 MAF to the rescue!!), the stock injectors with the stock FPR are the next "bottleneck" we're faced with and the Impreza FPR does help us in this regard.

-Bill

[mbtoloczko]

But if I tuned for the impreza fpr then everyone who doesn't have one would need to get one when they wouldn't otherwise need it. I feel your pain but I don't think the majority of people would want to buy a new fpr that they don't need.

Bill kinda does have a good point. Your stage 2v3 will provide the capability to measure much more air flowrate into the motor, but how do you intend to deal with the limitations in fuel flow for the stock engine? If you tune for stock fuel injectors and the stock fpr, then what are people going to do when they hit the fuel flowrate limit? The stock fuel injectors and fuel pressure regulator are only good to maybe 250 HP. I guess you could just presume that people will add auxillary injectors and control those with an auxillary injector control unit. Was that the plan?

[longassname]

If you are running lean because you have reached the limit of the fuel injectors and then add the fpr to increase your fuel flow then you won't be running too rich and loosing power will you? ;) At that point you are correcting your afr to get back to the sweet spot; however, using the fpr to raise your fuel pressure if you have not increased your airflow is a bad idea and asking that I take out extra fuel to undo a few people's bad idea to the detriment of everyone else is kind of well..you know.

If you start running lean by all means raise your fuel pressure.

You are worrying over nothing anyway. By now you should realize I always tune in a way to allow the largest margins of variablity between cars. Not like I went and pulled the walboro out of the demo car I did the fuel tuning on. In the demo car it runs 12.9 to 12.4 at wot accross all rpms on the street.

[shotgunslade]

It seems like the Stage 2 chip is designed to handle increased air flow, which, if it were available might tax the stock FPR. So, for those of us who are not yet ready to put $5-6K into a forced draft system, what might be the options for increasing airflow, so that we could get to this lovely dilemma of being too lean?

[SVXRide]

If you are running lean because you have reached the limit of the fuel injectors and then add the fpr to increase your fuel flow then you won't be running too rich and loosing power will you? ;) At that point you are correcting your afr to get back to the sweet spot; however, using the fpr to raise your fuel pressure if you have not increased your airflow is a bad idea and asking that I take out extra fuel to undo a few people's bad idea to the detriment of everyone else is kind of well..you know.

If you start running lean by all means raise your fuel pressure.

You are worrying over nothing anyway. By now you should realize I always tune in a way to allow the largest margins of variablity between cars. Not like I went and pulled the walboro out of the demo car I did the fuel tuning on. In the demo car it runs 12.9 to 12.4 at wot accross all rpms on the street.

Michael,
Great! Given the dyno results I got when I put the 1v4 in my car - AFR curve indicating a little richer than I'd like in the upper rpm range (backed up by very black head pipes) - I've been axiously waiting for your next "stage" :cool: Looks like the 2v4 w/z32 might just get those of us looking for even more Hp/Torque into the "sweet spot" :D
Can't wait to get everything together and get back to the dyno (yes, I've addressed the issues we discussed with my last runs ;) :D )
-Bill
p.s. the 12.9 to 12.4 you refered to is with the 2v4 w/z32 MAF?

[mbtoloczko]

If you are running lean because you have reached the limit of the fuel injectors and then add the fpr to increase your fuel flow then you won't be running too rich and loosing power will you? ;)....

I've been thinking about this a bit, and I think that adding the Impreza RS fpr to a stage 2v3 tuned for 36 psi fuel pressure will not *properly* fix fuel flow limitations. My thought is that adding the Impreza RS fpr will richen the afr about 1.3 points, but the car will still reach the limit of fuel flow at the same air flow rate. This is because the injectors are still going to reach 100% duty cycle (or whatever it is the the SVX ecu will run them to) at the same point as with the 36 psi fpr whether or not the SVX fpr or the Impreza RS fpr is used. On the other hand, if you tune for a 43 psi fpr, then the fuel injectors will not reach their duty cycle limit until higher air flow rates. I've posted a little picture of what I'm thinking:

http://www.subaru-svx.net/photos/files/mbtoloczko/28755.gif

[longassname]

I have it in hand. The z32 maf allows the ecu to drive the injectors harder if need be and the changes i made to the vq table in order to effect the afr has the injectors not being driven as hard as they were before at high levels of output while at the same time increasing power output--or so I believe we will find out tomorrow.

This is running a walboro fuel pump the effect of which is somewhere between stock fuel pressure and if you had an impreza fpr, a good happy medium.


The effect of this is to make the software work for everyone, to improve accuracy of the engine management at high ouput, reducing fluctuations in afr and combustion temps between cyllinders and revolutions while increasing acuracy of timing control, allowing us to increase ignition advance for further power gains, while lowering injector duty cycle at high output thus increasing possible output and rpms.

[shotgunslade]

Just got my Stage 2 V. 4 kit. For some reason, the Ecutune website wouldn't come up. Instructions not absolutely precise on one point. The switch is only for changing to lower octane rating gas, is that not correct. If we want to continue to pay through the nose for high test, we don't need to install the switch.

[SVXRide]

I have it in hand. The z32 maf allows the ecu to drive the injectors harder if need be and the changes i made to the vq table in order to effect the afr has the injectors not being driven as hard as they were before at high levels of output while at the same time increasing power output--or so I believe we will find out tomorrow.

This is running a walboro fuel pump the effect of which is somewhere between stock fuel pressure and if you had an impreza fpr, a good happy medium.


The effect of this is to make the software work for everyone, to improve accuracy of the engine management at high ouput, reducing fluctuations in afr and combustion temps between cyllinders and revolutions while increasing acuracy of timing control, allowing us to increase ignition advance for further power gains, while lowering injector duty cycle at high output thus increasing possible output and rpms.

Michael,
Why would running a walbro pump have an effect between the stock fpr and the impreza fpr? Isn't the walbro pump just increasing the maximum flow rate? Ultimately the fpr is still controlling the fuel pressure that the injectors are seeing. Maybe I'm just missing something here :confused:
Thanks again for all your hard work in support of the EG33/SVX!!
-Bill
p.s. can you provide a little more detail as to what you mean by "The z32 maf allows the ecu to drive the injectors harder if need be..." Do you mean a higher duty cycle?

[svxfiles]

When I installed my Walbro 255, it did nothing to my fuel pressure at all...

But I have had a fuel pressure dropoff when I shut off the engine, for a long time, most easily explaned by a leaking fuel injetor. :rolleyes:

[SVXRide]

When I installed my Walbro 255, it did nothing to my fuel pressure at all...

But I have had a fuel pressure dropoff when I shut off the engine, for a long time, most easily explaned by a leaking fuel injetor. :rolleyes:

Thus confirming my thinking...again, unless I'm missing something here buried deep in the entrails of the ECU :p
-Bill

[longassname]

Thus confirming my thinking...again, unless I'm missing something here buried deep in the entrails of the ECU :p
-Bill


It raises the fuel pressure. The fuel pressure regulator is nothing more than a restriction in the fuel's return path to the tank. The manifold pressure acts on it to change the size of the restriction but it's no more complicated than that. When you put a larger amount of liquid through the same size hole you get higher pressure. When you put in a higher flow fuel pump you get higher fuel pressure.

[longassname]

Just got my Stage 2 V. 4 kit. For some reason, the Ecutune website wouldn't come up. Instructions not absolutely precise on one point. The switch is only for changing to lower octane rating gas, is that not correct. If we want to continue to pay through the nose for high test, we don't need to install the switch.



:rolleyes:

excerpt from 1st section (installation overview) of first page of stage2v4 instructions:

"With switch in off position or no switch connected vehicle will run on code optimized for premium unleaded and no forced induction. If you do not wish to use the second version of software housed in the memory adaptor it is not necessary to install a switch or any additional wiring."

[oab_au]

It raises the fuel pressure. The fuel pressure regulator is nothing more than a restriction in the fuel's return path to the tank. The manifold pressure acts on it to change the size of the restriction but it's no more complicated than that. When you put a larger amount of liquid through the same size hole you get higher pressure. When you put in a higher flow fuel pump you get higher fuel pressure.

Whoo, don't agree with that mate. The pressure regulator will out put the same pressure, regardless of the input pressure. There is a spring in there that acts against the pressure on the inlet, this spring pressure is modified by the manifold pressure, to alter the restriction size, to ensure the out pressure remains the sum total of spring + manifold pressure.

The flame on your welding torch doesn't change as the bottle pressure gets less. :)

Harvey. ;)

[SVXRide]

Whoo, don't agree with that mate. The pressure regulator will out put the same pressure, regardless of the input pressure. There is a spring in there that acts against the pressure on the inlet, this spring pressure is modified by the manifold pressure, to alter the restriction size, to ensure the out pressure remains the sum total of spring + manifold pressure.

The flame on your welding torch doesn't change as the bottle pressure gets less. :)

Harvey. ;)

Harvey,
That's the way I was taught that pressure regulators worked...
-Bill

[mbtoloczko]

Harvey,
That's the way I was taught that pressure regulators worked...
-Bill

That's my understanding too. Everything I've read is that if the fuel pressure goes up with a larger fuel pump, then the fuel pressure regulator is being overdriven beyond its capability. This results in improper fuel pressure control.

[longassname]

well, according to the fuel pressure guage on the fuel line the pressure went up. I believe i even put pictures of it up at the time.

[SVXRide]

well, according to the fuel pressure guage on the fuel line the pressure went up. I believe i even put pictures of it up at the time.

Michael,
I don't recall seeing any picture...but then my memory isn't what it used to be :rolleyes: :D How much did the pressure "go up"? As Mychalio mentioned, you're probably just over driving the stock fpr which means you're applying load to the internal spring that, while probably covered in the spring's design margin, is taking the fpr out of its most efficient operational "band".
In a "bigger picture" sense, what are people more likely to replace, the fpr or the fuel pump? Personally, I'll take the fpr over dealing with electrical wires going into a container of liquid TNT every day of the week :eek: :D
-Bill

[longassname]

Michael,
I don't recall seeing any picture...but then my memory isn't what it used to be :rolleyes: :D How much did the pressure "go up"? As Mychalio mentioned, you're probably just over driving the stock fpr which means you're applying load to the internal spring that, while probably covered in the spring's design margin, is taking the fpr out of its most efficient operational "band".
In a "bigger picture" sense, what are people more likely to replace, the fpr or the fuel pump? Personally, I'll take the fpr over dealing with electrical wires going into a container of liquid TNT every day of the week :eek: :D
-Bill

You are right, I didn't put up pictures. I was confusing the pictures I took during the original stage 2 installation and the stage 3 prototype write up where I described the raise in fuel pressure after the installation of the 255lph pump. I'm not advocating that anyone replace or not replace their fuel pump just trying to answer the question that was posed to me questioning the information I shared. The fuel pressure is raised and the fuel pressure regulator does still effect fuel pressure according to manifold pressure as designed. I certainly don't want to fuel sensless debate about the engineering of a fuel pressure regulator but in case anyone feels they just can't let it drop without understanding the physics behind it. The way I see it is you are dealing with a vector of 3 forces acting upon the size of an opening. The size of the opening restricts the flow of fuel which effects the pressure of the fuel. The fuel pressure is on the supply side of the opening not the output side. The output side is just the return to the tank. It's impossible for the magnitude of one of the forces not to effect the size of the opening and thus the increase in fuel flow must increase the opening size; however, the increase is not so large that it allows the almost twice as much fuel to pass through in the same amount of time necessary to keep the pressure the same as with the prior pump.

That's how I imagine it works. I could be wrong. However it works the effect is the same. I measured it. In any case I'm not advocating the use of any given fuel pump or fuel pressure regulator. I designed the stage2 v 4 software to work with all the available fuel supply scenarios. Since the v4 revision solves the fuel injector cap problem no matter which fuel supply scenario you have I'm personally done with fuel supply discussions.

This thread is dead I think. Stage 2v3 no longer exists. The stage 2v4 write up is at http://www.subaru-svx.net/forum/showthread.php?t=28023

Please try to keep it relevant to stage2v4 though.