Headers = Airflow!

Well finally took the car to the dyno saturday, the only difference from last year was a new set of larger tube headers and a larger down pipe, with this it completely changed everything, at 3700 RPM it was already making 613 lb ft of torque, but couldnt get past 4000 rpm, with the additional airflow and the 1 to 1 boost regulator, it started dumping a crap load of fuel, I just got tired and decided to take a step back and redo the entire tune then go back to the dyno..

How big of a downpipe did you have and went to? Should be ~1.5x larger than turbine outlet.

The original went from 3" then necked down to a 2 1/2', so now its 3" all the way, the headers are now 1 3/4"