Six-Bolt 4G63 Build Advice

[3VOLUTIONIST]

Ive been looking at different cams and turbo's. I think the FP 68HTA will be the best choice for a street oriented setup, as for cams, 272's will be too big I think. The Kelford 264/268 kit (1-TX268) looks to match up the best, to that turbo.
Thoughts?

 

[BMGTZ]

I have two of those turbos...

My choice would be the 272s...

 

[3VOLUTIONIST]

Opinions on the turbo/cams brian?

 

[gerryeddie]

I reckon a 68HTA and TX268's would be a pretty good option for a 2L based on the below example.

The graph below shows virtual dyno run of a GSR with high compression 2.4L long rod, FP Green for DSM, Kelford 272's, FP Cast Exhaust manifold on E85 in 3rd gear @ 21psi (running Evo 6 computer).

The "boost" trace is actually engine load (therefore ignore the boost scale), but correlates very closely to actual spool and boost curve. On the street it sees 21psi about 4100rpm in 4th tapering ever so slightly to 19-20 at redline.



The power figure is just an estimate, but feels pretty close to seat of the pants dyno and memory of other cars with more or less power. I'll be interested to see how it responds when we wind it up to 28psi or so.
I thought this setup might be slightly more responsive than this given that the twin scroll version on the newer Evo's spools this well or even a bit better on a 2L, but perhaps the twin scroll design is just that much better. The only other restriction is a ported stock dump so maybe that is robbing the setup a few hundred RPM response as well. Given that this is a one size larger turbo and cam setup than what you are looking at, I'd guess the 68HTA and 268's should be a pretty good combination for a 2L if you are happy with something similar response wise at worst - probably even better I would expect.