Possible causes for high rpm boost drop?
My car is done and it is making some great horsepower. I am supposed to be picking it up tomorrow hopefully. I upgraded the turbo to a GT2871 but the turbo pulls around 20psi in the mid range and drops off to 16-17psi max in the upper RPM range. I am really surprised that it does not pull more boost in the upper range especially since I have a bigger turbo on it (It did have a GT28RS).
Matt believes it is due to pressure drop in the intercooler but the intercooler seems to be not to bad in size. It appears to be bigger than what forcedfed uses but maybe it is not as efficient.
Could it be a problem with the blow off valve, wastegate, or intake restriction? Ideas? The car has a cone intake filter on it so I would think that was ok, I know they changed the wastegate (still internal), but the blow off valve was (Blowing off of the pipe) at one time. It does however pull high boost in mid range.
I guess it is making about 355hp to the rear wheels, which is great but I thought it would be about another 25hp or so, and probably would if it pulled the 20psi at higher rpm. Comments or suggestions would be appreciated. If I just need a better intercooler, maybe next year I can invest but I don't want to spend the money if that is not the issue.
2006 Elise turbo-(2 Wicked) SOON TO BE A TURBO V6 Monster