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Old 01-06-2004, 04:32 PM   #1
Subasaurus Rex
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Question Need help with swap plans... those with WRX motor in GC body please comment

OK... I can't seem to decide what to do, so I'm seeking your advice.

I was originally going to turbo my 2.5 with WRX parts and a standalone ECU. But, because of the obvious reliability issues, I have chosen to scrap that idea. I'm now thinking of doing a complete swap to either a 2.0 WRX engine, or a 2.5 STi engine and use the appropriate wiring harness/ECU. I want to go this route because it seems (to me anyway) to be a more reliable way of getting the power I want. I'm kind of leaning towards the WRX motor, and then tuning it up to around 275-300hp. I'm a little afraid that the STi motor will destroy my existing tranny/drivetrain (which I would rather not swap out).

Could the people that have done either of these swaps into a GC body please comment on their setup, how they like it, how reliable it is, and how does the car perform compared to your original motor? Will I lose a lot of the low-end grunt compared to the 2.5n/a when going to the WRX setup, or does that get evened out because it's in a lighter chassis?

Please let me know your comments. Thanks.
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Old 01-07-2004, 12:17 AM   #2
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JDM is the BEST!
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Old 01-07-2004, 03:28 AM   #3
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Quote:
Originally posted by AWJunkies
JDM is the BEST!
Adam, did you have any smog issues? Or do you have...friends?
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Old 01-07-2004, 08:00 AM   #4
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Quote:
Originally posted by AWJunkies
JDM is the BEST!
no, its just more expensive and harder to find parts for. USDM = easier and cheaper
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Old 01-07-2004, 11:46 AM   #5
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for once subiekid is 100% correct
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Old 01-07-2004, 02:55 PM   #6
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As funny as it may be, both the people I know who have JDM swaps (although not really JDM swaps but more like JDM engines) wish they would have gone USDM. Just a little food for thought.

For torque, there is nothing better than a high compression, boosted EJ25. As far as reliability goes, however, you are a lot better off if you go for a low compression, boosted EJ20 or EJ25.

For me, I now have a factory reliable turbo car. Parts are readily replaceable and easily findable. Hell, I could take my car to the Subaru dealership for service

My car (as soon as I fix two missing sensors) will pass Utah state emissions with flying colors.

-Jon
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Old 01-07-2004, 04:16 PM   #7
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hmm that said my jdm motor +tec 2+ usdm 2nd and 3rd cat passed idaho emmisions with flying colors too

but i have a pre obd-2 car
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Old 01-07-2004, 05:52 PM   #8
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Quote:
Originally posted by Jaxx
for once subiekid is 100% correct


Yes subiekid is correct. Anytime you do a swap you are gonna run into the most common issue that everyone has had. MISSING PARTS. If you are missing parts from a JDM engine you have to call Japan and wait who knows how long to get them. USDM you call the dealer and 90% of the time they will have the part you need you have in stock and you can carry on with the project as planned. On top of all that you a JDM engine you also have to worry about weather or not the vendor you are buying it from is shady or not and if you will actually get an engine that he claims to be selling.

One more vote for a USDM EJ20 swap.

Z
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Old 01-07-2004, 08:44 PM   #9
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Quote:
Originally posted by AWJunkies
JDM is the BEST!
Having a previous jdm swap EJ20G motor, and currently doing another, I can agree with the mixed sentiment about jdm swaps. Indeed, they are sweeter, get better parts, more power, better ratios, and are usually pretty low milage. Getting wiring diagrams and pinouts for them, on the other hand, is impossible at best. Fortunately, Rallispec always gets me my jdm parts needs, so its not a big deal, plus getting the 16g turbo and 8.5 to 1 compression of an EJ20G makes for a bad ass street car. My '94 L was 2580 lbs, and tuned to over 300 hp, so talk about a beast of a sleeper.

I would say if you're going jdm, do it on an obd-I car.

Last edited by annointed; 01-07-2004 at 08:52 PM.
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Old 01-08-2004, 10:43 AM   #10
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OK, just for the record... I didn't ask to start a debate over which is better - JDM or USDM. I simply want opinions from people that have put either a V8 STi, or WRX engine in a GC car. I need to decide which route to go. What would YOU do???

note: I more than likely will buy a USDM motor.

I'm looking for reliable 'daily driver' power, without any tuning issues, and I don't want to seriously upgrade the drivetrain (maybe a new gearset in the tranny, but that's about it).
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Old 01-08-2004, 10:55 AM   #11
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I say just do the swap either way is great...each have better aspects but just weigh them out when you go to buy. I used a USDM though.
Thanks, Micah
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Old 01-08-2004, 07:24 PM   #12
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Well... I finally drove a WRX today ('04). I've definately decided that nothing smaller than a 2.5 will do. Smooth power from the 2.0, but NO low end compared to my 2.5RS.

Guess I'll be saving my pennies for an STi motor.


Thanks for your comments.
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Old 01-08-2004, 08:47 PM   #13
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well don't let the stocker be your decision...up and downpipes will have you spooling much sooner than the congested stock exhaust...so you will have more low end but if you want massive torque turbo a RS
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Old 01-08-2004, 09:03 PM   #14
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It just takes a different style of driving. While the 2.5RS may feel faster off the line, the WRX is deceptively fast. That is unless you do some basic bolt-ons. My car can't hold the tires to wet pavement and just powers forward in all gears... just pic the RPM.

-Jon
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Old 01-08-2004, 10:24 PM   #15
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And don't forget the lightened flywheel. My god how that engine spins without the extra weight.

Z
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Old 01-08-2004, 11:32 PM   #16
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Ah yes, can't forget that. I was astounded at how much that changes the character of the car.

-Jon
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Old 01-12-2004, 03:37 PM   #17
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So, what you guys are saying, is that a slightly tuned (lets say an up-pipe, decent exhaust, and an ECU reflash) EJ20 in the GC would be impressive? I guess what I'm worried most about losing, is the power that I have now below 1500 rpm. I can leave my car in 5th gear at 25mph and still get decent acceleration when I step on the gas. You can't do that in a WRX.

Will the lower gearing/weight of my car make the 2.0 'feel' better down low?


What I'm really looking for is the low-end that I have now, with some more juice after 3000rpm. I know that maybe the best route for my needs would be to turbo my existing motor, but I refuse to deal with a lot of tuning and reliability issues.

I realize that I'm comparing apples to oranges...

Please feel free to add to this. Thanks.



edit..... or should I be looking for something along the lines of a JDM EJ207?

Last edited by Subasaurus Rex; 01-12-2004 at 03:43 PM.
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Old 01-12-2004, 04:03 PM   #18
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A high compression, large displacement motor is ALWAYS going to feel more responsive and have better low-end response.

My EJ20 accellerates well at 2000rpm and up. I do try to keep the rpms up above 2000 though. Driving an engine, any engine, with a high load/low rpm situation is unhealthy for it. Why drive at 1500 rpm in 5th when you could be driving at 2-3k rpm in 3rd or 2nd?

-Jon
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Old 01-12-2004, 04:24 PM   #19
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Jon,

I didn't mean that I drive around in 5th at 25mph, I was using that as an example.

I realize that a different motor might require a new style of driving.


I've read all of your posts about your swap, even printed off your 'install instructions'. How do you like your car now? Have you done anything to the engine, or is it pretty much stock? I value your input, since you've actually done this.
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Old 01-12-2004, 06:06 PM   #20
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My car is fast and very fun. There are not any dead spots in the acceleration. From 2000 on up it is very responsive. I find myself sitting at 2000rpm and accelerating due to its ability to do so. Bogging and waiting for the turbo to spool are not characteristic of my car.

My engine isn't stock, but not too far from it. I currently have a K&N filter (which is dirty and needs to be cleaned), JDM STi catless up-pipe with JetHot coating, ScoobySport H&S downpipe, Cobb Stage 2 AccessECU, and an Exedy lightweight flywheel. With those mods, my engine is sitting at circa 285hp.

A couple items you have to remember when comparing your 2001 RS to a 2004 WRX:
  • The 2001 RS is considerably lighter than a WRX. It weighs in at around 300lbs lighter, in fact. This has a profound difference in acceleration feel; somewhere to the tune of .3 seconds in the quarter mile if all other things are the same besides weight.
  • The RS has gearing that is much more favorable to acceleration. The RS will top out at ~50mph in second gear where the WRX will pull all the way through 60mph. This gives you around a 1000rpm difference in 5th gear at cruising speeds; a difference between the start of torque peak and the economy rpm. Comparing same speeds and same gears between the two cars will give you different results due to this large gearing difference. With all that said, though, my car is using the WRX transmission and still feels very fast. I've been told the EJ20 with the RS gearing is even better for low-end acceleration.
  • The stock WRX comes with three catalytic converters. Their purpose in life is to use the exhaust energy and burn off excessive particles. A turbo is built around exhaust energy, that very exhaust energy that is being used up. Response is then hampered because of the depriving nature of the cats. Furthermore, the cat in the downpipe is positioned in the worse possible place when taking performance into account. It is disrupting the exhaust flow and creating backpressure. Since the turbo works pressure differences to its advantage, this further hampers response.

Now, I do not condone dropping all cats in search for ultimate performance, but rather I am pointing out potential bottlenecks that can be addressed.

Just to give you a little bit of an idea, I took my car over to the local tuning shop and the first thing he says is "EJ20s are fast in GCs, huh?"

-Jon
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Old 01-12-2004, 06:45 PM   #21
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Quote:
Originally posted by stimpy
[*]The RS has gearing that is much more favorable to acceleration. The RS will top out at ~50mph in second gear where the WRX will pull all the way through 60mph. This gives you around a 1000rpm difference in 5th gear at cruising speeds; a difference between the start of torque peak and the economy rpm. Comparing same speeds and same gears between the two cars will give you different results due to this large gearing difference. With all that said, though, my car is using the WRX transmission and still feels very fast. I've been told the EJ20 with the RS gearing is even better for low-end acceleration.
You are 100% correct here only the numbers using a USDM EJ20 mated to an RS trans are alot better than you have stated. Second gear with two blips on the limiter is 64 mph third gear with two blips on the limiter is 91 mph. 125 mph is really really really easy to do in 4th and still have plenty of revs left to go before you run out of steam. The RS is just plain old sick with the EJ20 and the RS trans. Oh this was with an uppipe lightened flywheel and the stock turbo back exhaust too. I can't wait for Sunday and my my swap to be finished

Z
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Old 01-12-2004, 09:26 PM   #22
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Well..I have done both motors in my 2000 RS...currently I have the USDM WRX motor in mine....I had previously done a Minnam stage 2 on my 2.5 motor....Without a shadow of a doubt I am Very Glad I have the USDM motor in it now....as far as low end...Bahhhhh....I disagree with that....I have more power and torque in my 2.0 than I ever did with the RS motor even with a aftermarket turbo kit on it.....I am coming on boost at 1700 RPMs.....Full Boost is about 2300.....My car is as fast as a STi is new....I do have a few upgrades to the motor tho.. ...BPM Turbo back, Uppipe, UTEC, Deadbolt Speed Turbo, Extrude honed manifold, Port matched intake and Intercooler, Perrin Goodies (inlet pipe and intercooler hoses) for flow..and 16.5 lbs of boost... ...and the most important parts
is the RS gearing... and the lighter weight...Oh...Dyno'd HP to the wheels....242 with 245lb of torque at 4100 RPM's... so I personally think its a matter of what you like.......

Bill
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Old 01-12-2004, 11:01 PM   #23
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Are there any reliability issues with using a stock 2.5rs tranny with a USDM 2.0L motor?
I know of the issues some WRX's were having with their tranny's, just worried about the same thing with the RS tranny
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Old 01-13-2004, 12:51 AM   #24
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Issues are the same with the RS transmission, but no worse.

-Jon
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Old 01-13-2004, 10:59 AM   #25
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The RS tranny is basically the same as the WRX, just different gear ratios.
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