biminiLX
Hard-core CEG'er
I've always followed the formula that you will double power at roughly 15# boost (2x atm), but I see your point.Personally it has been repeated on more than several occasions but i will help explain.
The 3 Liter which takes in 30% more air then the 2.5L is restricting itself with the stock svt tb at 6500-7k rpms. . Adding a larger inlet will help volume more than pressure which is still not a problem for a FI application (like this situation). So adding a larger Throttle body and even Mass air meter (which most do) go to a 80mm or 90mm would really complement the engines ability to absorb air at a much larger rate.
Remember our cars roughly take in 12psi of air from atmospheric pressure. That is why most articles show a 50% gain in power from just a 6psi kit. Seeing he is going to be pushing a 6-7psi turbo kit more flow would be needed to help maximize the engines potential.
I'm not arguing a larger TB will help, but it would be lower on my list, especially behind other things mentioned (header, hot coating, tune).
Tests I've seen show larger power than you would expect from smaller TBs in boosted applications (blow-through). Ex. my 7.0L motor would like a 90+mm TB if NA, but my 80mm TB in a turbo application is plenty (the cold side is only 3").
-J