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'98 JDM WRX GF8-EJ20G / GC8-EJ20K engine differences?

Posted: Mon Aug 13, 2007 8:01 pm
by BXSS
What is the internal difference between '98 GF8 (ej20g's), & GC8 (EJ20K) engines?
They both have under manifold intakes, & single coils.
They have different ECU's, trannys, power ratings (250PS vs. 280PS) & turbos, but what else if any thing is different between these 2 motors?
Do they share head port /valve size, cams...???

Posted: Mon Aug 13, 2007 10:32 pm
by Arctic Assassian
This is a search only question.

Posted: Tue Aug 14, 2007 2:26 am
by BXSS
? - I do/did not see anything specific about V3+ GF8 motors, but I did find the old post I started re a 93-96 EJ20G vs a EJ20K.

I'm not talking about '93-96 ej20g's with the COP ignition & LSS style turbo inlet & sensors like the one I have in my car, I'm asking about the '97+ motors that appear to be EJ20K's until you notice that they have TD04 turbos on them & realize they are EJ20G's.

These 97+EJ20Gs (250ps) are very different than the 93-96 EJ20Gs (220ps), & my question was what if any internal differances these motors have with the EJ20Ks of the same years (97+/280ps).

Posted: Tue Aug 14, 2007 4:26 pm
by Matt Monson
The Ej20G that you are asking about is basically the same as the world market engine used from '97-99 that was 218ps outside of Japan. The only reason it was rated higher in Japan was because they had better gas. It does have smaller head ports than an EJ20K and uses the td04 turbo on it. It's not a bad little engine. Because they were used in non-STi wagons,they are often less thrashed on than their EJ20K counterparts.

It will wire in very similarly to an Ej20K, and because it has an under inlet manifold you can upgrade to the modern turbos pretty easily. With something like a vf30 of vf39 it should deliver close to the 280ps of an EJ20K without any major changes to the ECU or tune. If you want to go with higher boost or go for 300chp, you really should get bigger injectors and some other form of EM, like an Autronic or a PowerFC...

ps. Before you ask, you could definitely drop this into an SS and run it on the stock ECU and tune. YOu would just need to change the IAC, TB, and use your intake manifold wiring. It would be a quick and easy swap if your engine is tired and needs to come out ASAP...

Posted: Tue Aug 14, 2007 7:37 pm
by BXSS
Cool, I recently got one of these engines (actually got the complete driveline/suspension) with Fujitsubo headers, Fujitsubo exhaust, STi intercooler, Clutch LSD Rear Diff, LSD front diff (? type), Cusco coilovers, STi pink pillow-ball rear lateral & trailing arms (all 6), Zero sports 24mm swaybays F&R, Cusco lower arm bars F&R, STi carbon fiber front stress bar, 4pot FHI front brakes, Apex-i intake, & Apex-i Power FC.

I already put a EJ20G (95 WRX) in my LSS which was super easy. I was actually thinking about getting a 93-95 Impreza coupe/or sedan to put this swap into.

Any HP estimates on the above set-up? Stock HP for a '98 JDM GF8 is supposed to be 250ps...