5 replies to this topic

[Scotty]

Hi all,
Is the 1999 wrx Impreza 2.0 turbo engine the same as the 2004 wrx 2.0 engine, looking at do a rebuild and swap over.
Thanks

[Robert]

Short answer yes

Long answer kinda
You shouldn't put an older motor in a later model

With your manifold it would work , and swapping the cam tone wheel
But I think the 04 wrx has Avcs so that's another problem

[andrew_k]

No, they are not the same.
The have directly compatible short blocks.
They have considerably different heads. They have different fuel systems (side feed vs top feed, total different vapor emissions system, fuel pump controller with PWM vs constant voltage driver). Different wiring, different ecu, different dash, different sensors (fron and rear o2 sensors, different AFM). Different radiator fans (2 speed vs 1 speed), and more.

If you are going to put the 99 engine in an 04, it is illegal and not able to be engineered in Australia. If you are planning to put the 04 engine in the 99, pull the bulkhead and engine bay looms from both vehicles to send to AM Auto to merge.

If you needed to ask this question, you will need experienced assistance overcoming the incompatibilities. There are basically 4 paths
- your heads etc on 04 short block. Pro: easiest. Con: all the 99 limits, none of the 04 improvements
- 04 longblock, your ecu/dash, 99 crank sensor and cam sensor. Pro: not sure tbh Con: will need to disable/remove AVCS, can't tune with open source.
- 04 complete motor + ecu, merged wiring harness. Pro: open source tuning, AVCS, better motor, keep your dash etc.
- 04 everything, complete engine, dash, all wiring from drivers doors forward. Pro: everything is as it was designed for 04. Easier to maintain as there are no custom parts. Con: huge effort, includes cutting and welding firewall and dash bar if you want perfect fit. I'm doing this and don't recommend it unless it's a hobby project with no real time pressure.

[Scotty]

Ok thanks, can get a 1999 GC8 engine cheap ( just the bottom end ) was going to put all my stuff on it after rebuild.

[Scotty]

Thanks for the help Guys, will look for another 2004 engine.

[andrew_k]

If you're just looking at the bottom end (short block) you're all good. 99 used same 8 bolt transmission mounting as your 04.