Individual Throttle Bodies and Improved Airflow

[Dessertrunner]

Okay I get your point Harvey but I still think it is worth doing the excerise as regards individual throttle bodies. As to if I use the top manifold I will see. I need to decide if I am going to use ram pipes or not.
Any way sounds like there is a lot of negitive as to the whole thing so I will not bother keeping you guys updated with posting.
Tony

[AppStateSVX]

i think it's a great idea.

i've never heard of a motor not benefiting from them.

the bmw s54 comes with them stock

[subbieatnz]

I like the thought of ITBs.
Im intrested in updates on this

[Dessertrunner]

Originally Posted by AppStateSVX

i think it's a great idea.

i've never heard of a motor not benefiting from them.

the bmw s54 comes with them stock

I am in total agreement with your statement on this and that's why its worth trying.
Tony

[Boxersix]

Some cloud 9 information in here on intake reversion. The length of the intake runner does not determine the resonance effect in the runner, the resonance wave determines what the runner properties should be including length, diameter, and taper. By changing the runner length you are not changing the reversion in the intake(pressure wave speed, wave count, etc) but rather changing where the force of the pressure wave is inside the manifold during the duration of when the intake valve opens and starts closing. Engine RPM, air temp and density, and cam profiles determine what the speed and wave effect of the reversion will be in the manifold.

The SVX manifold is a key into the EG33's high VE as the manifold is tuned in according to the cam profile in the motor to have the pressure wave closing in on the intake valve as it's opening which results in good cylinder filling. Changing the manifold is going to result in drastic changes in torque production and delivery. I did the math on the Eg33 awhile back as I have an ITB setup in the works for the EG33 but am not going to pursue it until a high compression build is in order. Done so to retain torque, which is important to me. Overall airflow IS NOT as important as other variables, and often you'll find that an imporperly made ITB setup that flows 10-15% more air loses power, and kills torque as well. It's all in how the air enters the cylinder, it's speed and the use of the effective pressure wave over the entire effective cam duration.

When building an ITB system for a motor you must take into account the cam profile, engine tuned power band(rpm) you desire, port taper, runner ID, resonance wave speed, and what RV you wish to tune to. ITB you'll typically be tuning 3rd to 5th RV depending on engine RPM and runner ID. Designing the system can be very tricky if you plan to have it be of any benefit. Simply slapping on a set of universal TB's can be catastrophic on torque and often make the motor unbearable to drive around town. Most of the stuff I design starts on paper with lots of math, then progresses to Solidworks and CFD before I even begin to make a prototype.

You'll want a pair of airboxes for the throttle vs filters of the TB's. One this allows far superior flow into the ram pipes and two, it allows room to tune the ram pipes to suit situations where you want to finely adjust the power band(often done on ITB race cars). You can easily make a pair of plenums to be properly fed by a single MAS, however with a system like this you're almost always going to require heavy tuning and as such you'd be using an EMS with either alpha N or speed density tuning. Hydra is prime available option!

I have lots of info an experience in this field, so if you guys have questions please ask. While I don't have an SVX anymore, I still have an EG33(former 962 powerplant) now residing in my 2002 WRX

-Adam

[Dessertrunner]

Boxersix it going on the race engine I had built has cam's 11:1 compression, extractors. Also changed the ECU to a Wolf3D V500. Plan is to take the car and the bits to a dyno and have a day doing readings and changing parts to see what gains what. Should be interesting.
Tony

[Boxersix]

Originally Posted by Dessertrunner

Boxersix it going on the race engine I had built has cam's 11:1 compression, extractors. Also changed the ECU to a Wolf3D V500. Plan is to take the car and the bits to a dyno and have a day doing readings and changing parts to see what gains what. Should be interesting.
Tony

Oh I understood that, you're motor of all places would be a place where such a setup belongs I was just trying to clarify a few things on the thread here amongst a few other posts. Like "Rally Bobs" comment that throttle response is always better with ITB's, which is not always true(not singling you out RB, just using you as a point here

I'd like to see your data in the end though DR after the dyno runs, and get machine specifics of your ITB setup. I can correlate that stuff to what I'm doing, but also just see what, if anything, could be adjusted or tweaked. Often extremely small changes in any one of many variables in an ITB setup can make or break it's entire power production and usefullness

[RallyBob]

Originally Posted by Boxersix

Like "Rally Bobs" comment that throttle response is always better with ITB's, which is not always true (not singling you out RB, just using you as a point here

My feelings are hurt....

Just my observations: All the engines I've seen converted had much better response. Probably has more to do with the throttle plates' proximity to the intake ports than anything else. Or just plain luck...

Seriously, no offsense taken!

I may shoot you of some cam/engine specs and have you crunch the numbers for my next project engine, regarding the TB's.

[oab_au]

Originally Posted by Boxersix

Some cloud 9 information in here on intake reversion.
I have lots of info an experience in this field, so if you guys have questions please ask. While I don't have an SVX anymore, I still have an EG33(former 962 powerplant) now residing in my 2002 WRX

-Adam

Gid'ay Adam, you might find this post of interest along the same lines.
http://www.subaru-svx.net/forum/showthread.php?t=29170

Harvey.

[Boxersix]

Originally Posted by oab_au

Gid'ay Adam, you might find this post of interest along the same lines.
http://www.subaru-svx.net/forum/showthread.php?t=29170

Harvey.

Just read through it all; now that's my kind of post! Good information that's all spot on Seeing that you delve into this field I can ask you a specific question knowing I'll get an informative response. Have you done any sort of port geometry measuring in the EG33 head to determine the relative port taper the head has(intake specifically)?

I have been meaning to get to this myself, but just haven't had the time to tear down my EG and set the head up in my machine with the digital probe to digitize the ports and bring them to life in solidworks. Something I will get to eventually, bu I'm having too much fun with the car at the moment to render it immobile at this time

[Dessertrunner]

I need advise as the best way to go about finding out if they are of any benfit so these are the changes I am doing to the engine to make it produce more power.
- Currently it has 11.1 and as I understand cams are 152 on both (correct me if I am wrong please mike)
- Wolf ECU
- Extractors
- 550cc injectors
- Multipass radiator for cooling probelm.

Then throttle bodies

So I was planning doing everything except the the last getting maxium power up to that point and dyno it. Hopfully on the same day unbolt the existing intake and replace with the ITB and redyno. If there is a gain then try to improve this if not look at why.

Does this seem like the right way to go?
Tony

[oab_au]

Originally Posted by Dessertrunner

Okay I get your point Harvey but I still think it is worth doing the excerise as regards individual throttle bodies. As to if I use the top manifold I will see. I need to decide if I am going to use ram pipes or not.
Any way sounds like there is a lot of negitive as to the whole thing so I will not bother keeping you guys updated with posting.
Tony

Woo hang on there Tony.
We are all in the same boat, trying to get this engine to put out some real power in the higher rev range.

The writing was on the wall, when Matt did his engine, he did all that he could do as far as cams, duration and lift, and light weight solid lifters. It should have revved HARD, and put out the power that he was looking for.

When it came to seeing what the results were, it would not put out torque up the rev range. As I told him then, it was the standard inlet/exhaust manifolds that were hold the torque peak down to the resonate, 4800/5000 rpm. As the rules prevented him from modifying them, there was nothing he could do, to bring the torque peak, up the rev range.

What you are looking at, can be done, but it would take a lot of work, a lot of money, and if it was designed to length, it may do the job. The inlets would have to bend over the top to get the length in, then there has to be air cleaners, and trying to get cold air to them.

The same result can be got by modifing the standard inlet, and doing a set of short headers, all tuned to the higher rev range.

Harvey.

[Dessertrunner]

Harvey haven't heard from Matt lately but the rules I am racing under will allow for extrators so I will fit them. When we talked about the issue of cams at the start of my build I figured we need to do somthing about the inlet and exhaust flow so thats the plan.
When you see what happened to Rally Bob's intake under vacum it is hard to not come to the conclusion that that engine was starving for air inspite of all the understanding that the throttle body is big enough.
The plan is to buy them with a plan figured out how to get them ontop of the existing injector manifolds and look at what is above as we go. I have asked about 90 degree bends on the ram pipes or what ever else may be aviable.
Attached is two photos of manifolds we are dealing with.


Tony

[Dessertrunner]

Okay a bit of an update,
Got the quote for the throttle bodies and it is $525 Aust per bank so for 6 uints its $1,050. To this I still need the linkage and the return spring with stopper.
I measured the inlet size on the injector manifold and its 45mm so the plan to use the 45mm throttle bodies is correct.
Tony