I just wanted to know what is the power potential of aftermarket turbos out there for the 98 RS before i get the car.

I am also looking into doing an engine swap mainly because i the power of hte RS doesn't seem satisfying to me enough (even though i have yet to drive it) but i dont know the first thing about swapping engines =\

so i just wanted to get an idea of the potential of two different worlds before i purchase the 98 RS

Thanks!

I have a 99 2.5 RS-T and i run it at 7.5 psi.

I try a 2000 "Brighton" with V3 STI engine swap and i smoke, with the ton of tq i have at low RPM and i smoke it at hi speed becose of the speed limiter the V3 STI have (180km).

So make your choise!!!

i'd say the Rs motor has the most potential of all the EJ series motors.

The jun impreza uses the RS motor, but i'm not sure if it's the Dohc or sohc.

The only 2 disadvantages the RS motor has is the pistons/Compression ratio, and it's an open deck block.

Otherwise it is the ideal starting point.

Oh the transmission is the real problem with Turbo imprezas.

There are much more disadvantages than that.

Thin cylinder walls, no oil squirters, low rev potential are three that come to mind right away.

EJ25 is just as good as any other motor. You can make it very good if you dump $ into it.

JUN spent more than I can imagine on their motor.

- Alex

One good thing about the DOHC engine is that you can use a WRX exhaust (So I've heard) including up-pipe, downpipe etc. Then slap in a VF22 instead of the pathetic WRX turbo and the WRX intake stuff and call it good. You need the WRX or turbo legacy crossmember too, but that's easy to get from a dealership.

That also opens you up to use the BPM Twister Turbo back exhaust.. god that's a sweet ass exhaust!

Oh and to add a bit to what Alex said.

High compression isn't all bad. You get better low end torque and don't need to run high boost numbers. 10psi, Cams and a good engine management can get you to 13.0 or even the 12's if you can drive.

imprezaRSX: you seemed to have overlook one thing: Tuning...(including updating the fuel sources)

i was looking into swaping motors 2, but im not sure which version is the best bang for the buck, and whihc motors if not all had the 6 speed manny trans. i dont know of any subaru engine importers in so.cal

The EJ25 (as has been stated) is a decent starting point. Without serious dough you won't be making 11 second passes down the 1/4 mile. With moderately low boost (5 psi)/limited engine management you will have a "stock WRX" hunter. The "but" that comes with this sentence though is you will have more low end grunt, less top end and overall be limited in speed due to lower final drive ratio. As Imprezer said, as you start turing up the boost you will begin to have issues with the thin cylinder wall design (which can be fixed), the lack of oil squirters, lack of revs (big turbos like higher revs, but again this can be fixed)... bottom line, if you've got the money anything is possible.

its a good learning experience!

Originally posted by fatcatturbo
imprezaRSX: you seemed to have overlook one thing: Tuning...(including updating the fuel sources)

I did?

Originally posted by ImprezaRSXCams and a good engine management can get you to 13.0 or even the 12's if you can drive.

The 98 motor sux for turbo, it can be done, but you know you want to swap a WRX motor in. It can be done, It should be done, you will be happier when it is done. Plus the abundance of aftermarket goodies for the EJ22 should be more than enough to make your decision.

Coming from a guy with a '99 RS-T :D

EJ22 or EJ20?

Well we have done both:

Engine swap or RS-T setup

Both can be reliable and fun if done correctly. In the end though the 2.5 stock block was not made for a Turbo where as the WRX engine was. In the long run the WRX engine will be better, for smogging and longevity.

i-speedusa.com

Originally posted by Imprezer
There are much more disadvantages than that.

Thin cylinder walls, no oil squirters, low rev potential are three that come to mind right away.


- Alex

I was under the impression that the 2.5 dohc in the 98 allowed for higher revs and there for aside from the open deck etc was a prime candidate for an aftermarket turbo application.
redline is higher=more exhaust energy=more energy for the turbo=more boost to put it simply

weaker internals, headgasket problems, weak block. You can rev higher, and you can control the exhaust and intake timing separately but those are on the top end, not the bottom. Really, it depends on ultimate power goals. For big power, a built 99+ 2.5 block is the way to go.