JDM Supra conversion to USDM Supra

[Feel-IX]

Originally Posted by pwpanas

There are only 3 significant differences between the two versions: injectors, intake-side cam, and turbos. To me personally, the slightly smaller turbos aren't really that much of a problem in raising horsepower, because they should handle a slightly higher boost level without issue (based on what we generally know about raising boost in the Mkiv). The jdm-spec 440cc injectors theoretically should handle 320hp no problem (but note they will not handle the higher "bpu++" horsepower levels that the us-spec 2jz-gte's 550cc injectors do). Lastly, changing the intake side cam to us-spec, although ideal, would likely cause tuning issues with the jdm's map-based setup. As a result, unless you want to get into some extensive re-tuning with (for example) a GReddy e-Manage, I'd suggest you do not change the intake side cam. In other words, with premium fuel, I'd suggest raising the boost level slightly in the jdm mkiv tt is all you should need to do in order to achieve that 320hp rating of the us-spec mkiv tt.

P.S. Fwiw, I believe that the jdm mkiv tt's published spec of 276hp was underrated by a large margin. In other words, it may in fact be much closer to 320hp without any changes at all. That said, note that bone stock (very low mileage) us-spec Mkiv TT's have actually dyno'd at 310-325 hp, at the wheels! In other words, even if you do get 320 hp at the crank out of a jdm Mkiv tt, you won't necessarily match the performance of a us-spec bone-stock Mkiv TT.

thanks a lot pwpanas, you are an infinite source of knowledge as always