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1994 L Wagon Grey
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Discussion Starter #1
ok, let me state a few things.
I am an automatic, I am not out to ahev the fastest car nor am I out to have a car that can handle 5 billion PSI. I am looking for a mid 13 sec auto daily driver.

Right now I have a custom kit that is waiting for a few more custom fabs to be done before the install is ready. But I am not shooting for 13s with this install at this stage. Just 14s. Small boost for a 17sec 2002 automatic (thats what they are stock) But I want to make a reliable car with out engine management.(I know what to do for fuel and engine managment)

I want to stay with 2.5l and not "de"bore it to a 2.2 or 2.4 or whateva.

What needs to be built up internaly?What needs to happen to the engine?

Sorry if this was asked before. I am just trying to answer all of the questions I got flying around in my head.
-Neal
 

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2001 2.5RS
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Hello Doctor Nick,

I've been resarching the same question lately. I've come to the conclusion that pistons will have to be swapped out for forged ones, becuase the stock are cast. Every horror story with RST seems to have the pistons as the week link. I figure the $600-? for the pistons would be a good investment and keep you from having to rebuild the engine.

http://www.jepistons.com

Also, you may want to replace the springs and valves too. This probably isn't needed as much, but since you're in the engine why not? Making a reliable RST is a PITA, and much more involved than I ever though it would be, but the upside is I've learned more about cars in the last 2 months than I have in the last 20 years.

oh ya I'm planning on cams to, but the wait time is like 2-3 months from COBB... WTF well... I'll have time to save up for everything else in the meantime.
 

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1994 L Wagon Grey
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Discussion Starter #3
Thanks for the reply.
I justs did cams a month ago in preperation for bolting on my turbo kit, but I think I got hit in the head one to many times or somthing. I relised that if I am going to do it. I Should do it as close to right as my bank account will show. I am realy feeling that boost bug but I decided that I need to make it a safe long distance runner. I wanna be able to drive it for 16 hours a day and have it run on tip top shape. (the former school drive was a long 16 hour drive from chicago to savanah, Georgia.

I am being told by local guys that 9 to 1 is the sweet spot for buying pistons on our cars...any opinions on that?
 

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for low boost, good driveability, and power,.......I would go with 9:1 pistons with stronger rods and valvesprings. extrude hone the intake manifold and port/polish the throttle body. injectors and ecu will help too. :cool:
 

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You can't buy 9:1 without having custom pistons made. JE carries 8.5:1 forged units, no overbore. This compression ratio is fine. While you are into the block, you should replace the rods as well. Knife-edging the crank should only cost $150 at a reputable machine shop. This keeps excess oil off of the crank and has a similar effect as lightening your flywheel. Don't bother touching the throttle body or intake manifold, for the gains you are looking for, it would be a total waste of money. Leave the valvetrain alone, you will see no benifits there as well. A good intercooler will help with reliability tremendously. If you can afford to have the piping made for a front mount intercooler, do it. Don't listen to people telling you that the top mount is more efficiant and all the bs that usually goes with that argument. Once the car stops moving, you might as well not have an intercooler, with a top mount. What are you doing for engine management anyways?
Kevin
 

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I am sorry scooby25rs, but i disagreee with you. If he wants to build a reliable motor, then do it right the first time. If you already have the motor torn apart, then why not get better valvesprings. number 1 and 2 will make a difference on a turboed car.
here is the list of things:

1. extrude honed intake manifold
2. port/polish throttle body
3. valve springs
4. 8:5:1 or 9:1 pistons
5. stronger rods
6. knife edge and balanced crank
7. maybe rework the heads <----------optional.
8. fuel injectors, fuel pump, parallel fuel rails or rrfpr.
9. piggyback ecu or standalone. I recommend standalone, but more$$$$$$$.
10. intercooler. fmic or tmic will work. if you plan on running more boost, I would go fmic. It does help alot in lowering temps.

add the other little necessary things, get it tuned and have fun. :)

ps, this is how I would build my engine if I was going forced induction.

-aaron
 

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'99 RS, '02 Legacy, '10 'beca
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Nick...

What's your boost level plans?

That will help us a lot.

If you don't up the redline, have very percise proper tuning and don't plan to run more than 10 Psi, you don't need to do anything to your engine.

Most problems people have with pistons and such is that they are running stock Compression ratio with piggybacks. Tuning is key.

Jon
 

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Little update on the JE pistons... The ones in there catalogue are for the older model imprezas. I have a 2001 and I was quoted 155 a piston and the rods would have to be modified for them to fit. He also said that the engine would have to be mocked up, but I'm not sure what that means. Well, that'll cost over 1 large just for pistons and install. I'm going to try cobb next, but the wait time is probably horrendous.

-Rich
 

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$155 a piston? Holy crap it makes me miss the days of buying GTI-R parts where it cost $35 a piston and they were already upgraded pistons compared to the Silvia.
 

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WRC, did you even read the first post? He is not looking for absolute power. Why would he spend $700 on extrude honing a manifold for maybe 10 HP? Nobody has had any valve related problems with our motors. It is pointless to spend the money on heads with his low power goals. He wants a reliable motor, not a screamer. Cobb will happily sell you JE pistons over the retail price. Something everyone must understand is that Non Subaru vendors think the WRX is a 2001 and newer. When JE said it was for the older car, that means a GC8, your car. The 8.5:1 piston is an off the shelf JE part. Just tell him you have a 2000 2.5 liter car so he doesn't get confused next time. There is no massaging necesary, they bolt right in.
WRC, one last flame for you :flame: You are telling him to use a rising rate fuel pressure regulator, upgraded injectors, AND a standalone ecu? Do you really know what any of these things do? I'm sorry, I really don't like flaming, but I can't stand it when the uneducated benchtop racers (dreamers) try to give advice to people asking questions. It is people like you that confuse the hell out of those trying to learn.

Doctornick, I can get you the JE pistons for $550.
Kevin
 

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I didn't tell him to use anything. I just listed some stuff that some people use. In my case, if I was turboing my car, I believe in doing it once and doing it right. for fuel, I would probably run bigger injectors, parallel rails, fuel pump and standalone.

I don't really know why put down rrfpr, I guess that is just for a little extra fuel and probably wouldn't work well.

"uneducated benchtop racers (dreamers) "

sure, thanks:rolleyes:
 

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scoobyrs25 said:
When JE said it was for the older car, that means a GC8, your car. The 8.5:1 piston is an off the shelf JE part. Just tell him you have a 2000 2.5 liter car so he doesn't get confused next time. There is no massaging necesary, they bolt right in.
Kevin
It is correct the pistons are for the EJ25D motor and will work with my car. That is f'n great :) :) :) :) . I must be stupid to think that a non-Subaru Vendor actually knows the diffence between are car models. I thought I was going to end up paying 1 large for pistons.
 

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Discussion Starter #13
guys, I was talking about what should be upgraded in the motor. Nothing else. I have a tuner you will all know every well doing everything else. lets say if it isn't exactly what he wants it is custom :eek: fuelrails, injectors, intercooler, fuelpump....all custom. ECU and regulators he is still working on. Neways


Scoobyrs25... pistons for 550? What about rods? PM me on i-club (doctornick)


Also, right now...I am going to be cheap and run a USDM wrx turbo that I got for less then what you would think you could get a turbo that has 1k on it :biggest: . The turbo will be enough to get me in the 14s...from there I NEED to have a built motor before I move to the next step. So I want all the parts to give me a reliable setup that is STRONG for engine internals. I rather not go with changing the redline because I am an automatic. Thanks guys.
 
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