ECUtune Stage 2 version 3 ( 2v3 ) - Page 2

longassname · #16 07-18-2005, 06:51 PM

Quote:

Originally Posted by 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.

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 · #17 07-18-2005, 06:53 PM

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 · #18 07-18-2005, 06:55 PM

Quote:

Originally Posted by poweredx2

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 · #19 07-18-2005, 09:16 PM

Quote:

Originally Posted by 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

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 · #20 07-18-2005, 09:29 PM

Quote:

Originally Posted by mbtoloczko

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 · #21 07-18-2005, 10:48 PM

Quote:

Originally Posted by Chiketkd

...

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 · #22 07-18-2005, 11:17 PM

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

mbtoloczko · #23 07-19-2005, 08:32 AM

Quote:

Originally Posted by longassname

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 · #24 07-19-2005, 10:38 AM

Quote:

Originally Posted by mbtoloczko

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 · #25 07-19-2005, 10:47 AM

Quote:

Originally Posted by longassname

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 · #26 07-19-2005, 10:50 AM

Quote:

Originally Posted by mbtoloczko

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 · #27 07-19-2005, 10:58 AM

Quote:

Originally Posted by longassname

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 · #28 07-19-2005, 11:30 AM

Quote:

Originally Posted by svxsubaru1

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 · #29 07-19-2005, 11:36 AM

Quote:

Originally Posted by Chiketkd

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 · #30 07-19-2005, 11:58 AM

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.