Increasing torque with out forced induction

[3MI Racing]

Originally Posted by W204

If the 2.5RS is any indication of boxer NA engine tuning, it is going to be tough. There are very few EJ251's(zzyzx for example) running at 300whp NA and it had such a wide array of parts such as racing cams, ported and polished heads, throttle body, and intake manifold, racing pistons, lightened crankshafts, lightened rods, etc.

first off all, the engines are completely different animals. I won't begin to compare the FA and EJ at all other than they are both boxer engines produced by Subaru.

Also, as for the zzyzx build, he didn't make 300whp. His post from WAAAAY back was that he was now making 300bhp as he was dynoing at the same power as a stock STi (300bhp).

[Dimman]

Originally Posted by 3MI Racing

first off all, the engines are completely different animals. I won't begin to compare the FA and EJ at all other than they are both boxer engines produced by Subaru.

Also, as for the zzyzx build, he didn't make 300whp. His post from WAAAAY back was that he was now making 300bhp as he was dynoing at the same power as a stock STi (300bhp).

Any news on FA/FB interchange? The mythical 94mm bore 86mm stroke FA24, possibly with 2GRFSE D4-S compatible pistons and corresponding CR reduction to 11.8:1?

[OrbitalEllipses]

Originally Posted by Dimman

Any news on FA/FB interchange? The mythical 94mm bore 86mm stroke FA24, possibly with 2GRFSE D4-S compatible pistons and corresponding CR reduction to 11.8:1?

Patiently waiting for results on a hybrid engine... or perhaps a stroker.

[00NissanNinja]

Changing the stroke can also increase the torque, but that is pretty intense change and probably not a good idea on this engine. Gotta agree with 3MI on the flywheel

[OrbitalEllipses]

Originally Posted by 00NissanNinja

Changing the stroke can also increase the torque, but that is pretty intense change and probably not a good idea on this engine. Gotta agree with 3MI on the flywheel

Totally different engine, but the EJ strokers perform like 2.5L EJ series engines due to the favorable stroke ratio (IIRC, might something else stroke related). I'd like to see something like that in this engine, though a rebuild like that is definitely 3-5 years down the road for me.

[3MI Racing]

Originally Posted by Dimman

Any news on FA/FB interchange? The mythical 94mm bore 86mm stroke FA24, possibly with 2GRFSE D4-S compatible pistons and corresponding CR reduction to 11.8:1?

I won't be able to say one way for sure without having the FA in my hands...or actual engineering drawings.
Pistons are going to be custom for it. They'll start off with the new materials that I'm currently developing on the EJ platform.

The most time extensive part will probably come with developing the dish/combustion work on the 94mm bore to work with an OTS FA20 head. I'm going to try and steal some time and work out the combustion modeling in Star.

-Micah

[Dimman]

Originally Posted by 3MI Racing

I won't be able to say one way for sure without having the FA in my hands...or actual engineering drawings.
Pistons are going to be custom for it. They'll start off with the new materials that I'm currently developing on the EJ platform.

The most time extensive part will probably come with developing the dish/combustion work on the 94mm bore to work with an OTS FA20 head. I'm going to try and steal some time and work out the combustion modeling in Star.

-Micah

I was hoping the 94mm 2GRFSE pistons would magically fit. But even if they fit , the direct injector location and spray pattern is probably different anyways...

If you end up making custom pistons, will they be more $ than typical because of machining the little bowl/dish for the DI?

[Daemione]

Originally Posted by SkullWorks

a light flywheel will reduce engine inertia and make you drive like a clutch monkey, it is a tradeoff of the first order, anyone who tells you otherwise either hasn't driven one or is arguing for the sake of the argument,

I don't agree with this. I've installed a lightweight flywheel on my past 3 cars ('97 Honda Prelude, '07 Honda Fit, and a '79 Datsun 280zx). All 3 of them were driven before & after by both my Mom and sister, without me mentioning it to them - and not a single stall. If you read deeper into a lot of accounts of people suggesting a lightweight flywheel was trickier to drive, you'll find that almost all of them "upgraded" their clutch at the same time, usually to some annoying unsprung race puck crap thing.

Maybe with an extreme 8 pound flywheel it gets trickier, but all of the ones I've done are very easy to drive. If memory serves, I had a 12lb. on the Prelude, a 10lb. on the Fit, and have an 11lb. on the Z. The Z's stock flywheel weight is almost 24 pounds.

To be honest, unless you've already got the tranny off for some reason, I wouldn't bother doing it - I think most people will be underwhelmed by the difference, and it's a lot of labor to get in there.

[arghx7]

Lightweight flywheels are a pain in the ass. Terrible return per dollar

[DarkSunrise]

If you don't want FI, your best bet is probably weight reduction + bolt ons. C/F hood, lightweight battery/exhaust/wheels, remove rear seats, spare, etc. If you can shed 100-150 lbs and pick up 10 whp from basic bolt-ons, you'd have a pretty quick car (and improved handling).

[uspspro]

Originally Posted by DarkSunrise

If you don't want FI, your best bet is probably weight reduction + bolt ons. C/F hood, lightweight battery/exhaust/wheels, remove rear seats, spare, etc. If you can shed 100-150 lbs and pick up 10 whp from basic bolt-ons, you'd have a pretty quick car (and improved handling).

The aluminum hood is really light already... just FYI. I know carbon can be lighter, but might be a big $$$/lb saved ratio

[DarkSunrise]

Originally Posted by uspspro

The aluminum hood is really light already... just FYI. I know carbon can be lighter, but might be a big $$$/lb saved ratio

Yeah I thought about that, but since no one has actually weighed the stock alum. hood yet, didn't want to rule it out completely. You're right though, there probably won't be huge weight savings going CF there.

[uspspro]

Originally Posted by DarkSunrise

Yeah I thought about that, but since no one has actually weighed the stock alum. hood yet, didn't want to rule it out completely. You're right though, there probably won't be huge weight savings going CF there.

When I lifted the hood on the demo car, I was shocked at the lightness.

[DarkSunrise]

Originally Posted by uspspro

When I lifted the hood on the demo car, I was shocked at the lightness.

:happy0180: We'll just have to find other ways of reducing weight on the car!