Question for the GC8 nuts

[IZichard]

What are the key differences between v4 and v5/6? Different interior and different front end but is there much difference on the mechanical side of things?

[94 Leone]

37 minutes ago, IZichard said:

What are the key differences between v4 and v5/6? Different interior and different front end but is there much difference on the mechanical side of things?

Offset coil pack, first era of EJ207 (for STi) although open deck block, insert type AFM, Phase 2 Sidefeed injectors (440cc yellows for STi), Better flowing intercooler and manifold, compression ratio was 8.0:1 pretty standard among wrx engines. not sure on the internals, but they run more boost quite safely.

[Guest]

V5/6 Non vs sti

Both non and sti had 440cc yellows and afm. Only real change was the ecu for sti to match the more aggresive cams, lower c/r and a higher boost limit.

 

V4 vs v5/6 sti

Coil pack with inbuilt ignitor, offset intake mani bolt pattern, intake mani less balanced on v5/6, idle stepper on tb, thrust setup, phase 1 vs 2 injectors, afm, smaller turbo on v5/6, speedo sensor, heads, bakelite cam wheels on the latter, 8 bolt bellhousing, different pistons same material I think, alternator, bov setup, different make of ecu, water temp and boost solenoid I think. 

 

Not sure if all V4 had obd2 and test connectors mine does.

[pedro]

v5/6 STI have better conrod design and are able to handle more power..

[Guest]

8 hours ago, pedro said:

v5/6 STI have better conrod design and are able to handle more power..

 

Source of info? Ive always been told V1-6 were the same. Limited to the max power of a VF## anything further is considered unsafe.

[pedro]

1 hour ago, evowrx said:

 

Source of info? Ive always been told V1-6 were the same. Limited to the max power of a VF## anything further is considered unsafe.

 

Subaru changed the bigend bolt system after v4..