Individual Throttle Bodies and Improved Airflow

[SilverSpear]

I wouldn't be surprised Bob, the EG33 ADORES cold air. I have experienced that after I've done the "stupid" copper box/K&N Filter outside the engine bay/inside the front fender. Well I have experienced a great impovement/response in my stock engine.

Well the box turned out not to be that stupid after all

[Dessertrunner]

35whp is some serious gains.
I read some where that one of the BMW engines shipped to the USA did not have the individual throttle bodies that was aviable to the rest of the world and as a result the US engine was way down on power.
Harvey made the point right from the start that I was wasting my time unless I sorted out airflow as well.

Bob do you think the change in throttle bodies will gain any power, with a speced up motor and exhaust?
Tony

[BoxerFanatic]

Originally Posted by Dessertrunner

As I see it now the ram pipes may work but I am concerned about the engine getting hot air from the engine bay. For that reason I am going to give a different approach a try. Where the throttle are now I was going to built an airfilter box and force feed the air through a bonnet scoop. In that was any pressure loss by still having the manifold may to a degree be overcome by forcing the air into the intake and the individual throttle bodies. I am also hoping to be able to raise the manifold by 20mm.
I have positioned two standard aircleaners to show what I mean in this photo. Would like to here if we anyone thinks I can get the 20mm under the bonnet.

Tony

That would be pretty slick... some sort of fresh air intake up between the throttle bodies and the firewall...

the question becomes how do you fit a MAF sensor between the throttle bodies, and the air filters.

then, after that, the question becomes, does anyone do bodywork well enough to put a Legacy-type integrated scoop and insert into an SVX hood, and make it look like the hood was stamped that way.

Kinda unfortunate that the SVX doesn't have some sort of air-channel from the grille or something, into the engine airbox. I suppose that is what a fender-draw system would be for, such as silverspear mentioned. People used those sorts of arrangements a LOT for fox-body mustangs, too, and put a thin slit intake scoop under the front bumper cover, ducted to the side air box through the passenger side fender.

[RallyBob]

Originally Posted by Dessertrunner

Bob do you think the change in throttle bodies will gain any power, with a speced up motor and exhaust?
Tony

I think large gains are possible, particularly with a high-spec engine (cams/headwork/compression). I have my eyes on the Extrudabody Porsche 911 ITB's, 48mm > 45 mm taper-bores. About $1300 US complete, plus a little bit of modification to make them adapt to the EG33 heads.

....For my next project (EG38 probably).

[RallyBob]

Originally Posted by BoxerFanatic

then, after that, the question becomes, does anyone do bodywork well enough to put a Legacy-type integrated scoop and insert into an SVX hood, and make it look like the hood was stamped that way.

Not too difficult to do really, and would look quite OEM.

[Dessertrunner]

So Bob are you game to say by what % the gain would be 5% 10% or what? Also I looked at Extrudabody and they have a kit for the SVX engine now. Its under the 6cyclinder kits and it configured on 112mm centre which is for our engines.

[Dessertrunner]

Have a look at this artical.
Tony
http://www.importtuner.com/features/...tup/index.html

[SilverSpear]

I am pretty sure Tony that your ITB setup will work on the EG33. This engine just loves to breathe... I still remember when Myxalplyx first came with the idea of the two pipes from MAF, some told him it will not work. Also when I made the external K&N setup outside the engine bay, they told me it will not work, well my butt dyno said otherwise , I can feel more power in my car...
Now you are going towards the extreme in this thing, ITB's and I know the EG33 will love this...

[RallyBob]

Originally Posted by Dessertrunner

So Bob are you game to say by what % the gain would be 5% 10% or what? Also I looked at Extrudabody and they have a kit for the SVX engine now. Its under the 6cyclinder kits and it configured on 112mm centre which is for our engines.

I really can't say without flow testing the stock intake and the ITB's back-to-back. But if it compares to some other engines I've flow tested (plenum intake vs. ITB's), I'd say there will be substantial intake airflow increases...on the order of 10-15%. Does this correlate to 10-15% more power? Usually not, especially since the EG33 has poor exhaust ports. But if I saw 5-8% more power on a 400 whp engine, that would be substantial. And throttle response is always better with ITB's.

[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

[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.

[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.

[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