impreza WRX swap

I'm thinking about getting an older Impreza, (not sure what generation it is, its before the bug-eye ones) with high miles for a low price.

What I'm planning on doing is swapping the engine out for a new WRX engine, and also replacing the transmission since there are so many miles on it.

What else should be replaced since there are so many miles on the car?

Also, if I replace the stock engine with a newer WRX engine, would I have the same HP and torque as a normal WRX? The reason why I ask this is becase I looked through a few sites with the same swap and it lists a lower HP number.

Do you think this is a good idea to do this? The reason why I want an older impreza is because I love the way they look.

Thanks a lot.

it sounds like a good idea to me also. I'm also more fond of the older imprezas (the pre-bugeye ones). Taking one and putting a WRX engine and trannie in would be nice. You'll also need the front crossmember from a turbo impreza if you buy a N/A one. You'll need the ECU and harness for the new engine also. Other than that, I couldn't see replacing anything else unless it had something wrong with it. Maybe servicing everything.

There is plenty on engine swaps in the FAQ.

I don't think it will be as simple as swapping the front cross member in from a WRX, the engine compartments between the generations are rather different.

If you want an objective view, although the pre-2001 shape is nicer on the eye, the difference in the cars is vast!
I owned a '98 RS and now have an '03 and they are worlds apart :)

What are the emissions regulations in your area?

Here in CA, the only LEGAL swaps are '02+ WRX or STi motors (because they meet current emissions standards), but the wiring can be a NIghtmare.

If emissions isn't a problem, you can get the JDM EJ20s from the GC Imprezas and have a good deal more power, but as I understand it, the wiring in those is a crap shoot, because Subaru had changed various details from year to year.

So, while mechanically this project seems straightforward, electronically it's all over the map.

Pick up a copy of the March 04 Sport Compact Car, as they have a simple swap overview article.

What I'm thinking is swapping in a US spec WRX engine, so it should be legal I think. One thing I dont get though, I was looking around different Impreza tuning shop sites, and here's what they say for a WRX engine swap into an older impreza..

Conversions Data Sheet Part 1 (What's required from the US WRX)
- '02 USDM EJ20 Turbo Engine
- '02 wrx intercooler
- '02 wrx or legacy turbo cross member
- '02 wrx fuel pump
- '02 wrx ecu
- '02 wrx harness
Conversion Data Sheet Part 2 (What's required from the converted Impreza)
- Stock radiator
- Stock driveline
- The Impreza obviously...
Conversion Data Sheet Part 3 (New parts for the Impreza Conversion)
- Clutch (the Stock Clutch works pretty well, though we are able to supply ACT Clutches)
- Flywheel (recommend Exedy 13lb flywheel, OPTIONAL)

Expected output with one of these conversions on a dynojet dyno 180 horsepower and 185 ft/lbs of torque


If it's a normal '02 USDM EJ20 Turbo engine, why does it only have 180 hp and 185 ft/lb instead of the 227 hp like in WRX's?



freakray, so your saying that the '03 feels a lot better than older generations?


Thanks for all your help.

That's the drivetrain loss that makes the difference between flywheel HP and wheel HP.


The two shops I've heard the best things about doing swaps are www.lachutesubaru.com (http://www.lachutesubaru.com) or www.i-speedusa.com (http://www.i-speedusa.com) (which seems to be where you got your list. ;)) Both seem to charge in the neighborhood of $7k.

freakray, so your saying that the '03 feels a lot better than older generations?


Thanks for all your help.

i think he's referring to the 140% or so structural rigidity the wrx has over the 2.5.

but the bug-eye just aint got that skyline styling baby

i think he's referring to the 140% or so structural rigidity the wrx has over the 2.5.

but the bug-eye just aint got that skyline styling baby

I think it's closer to 250%, not sure though.

With both relatively stock, I do think the pre-02s look better, but modded right they can all look badass. The 02-03 was the worst looking stock but probably the best modded, IMO.