14-10-2014, 05:09 PM
A bore reduction at the back end of the system isn't nearly as restrictive as at the front end as the exhaust gasses are cooler so far more dense. At the turbo/ hot end of the system the gasses are expanded so need more space to exit the turbo efficiently.
That's why a good elbow and downpipe design even with the standard exhaust bore size will give a noticeable improvement on a turbo car but adding a 3" system to a standard elbow and downpipe will have very little effect.
That's why a good elbow and downpipe design even with the standard exhaust bore size will give a noticeable improvement on a turbo car but adding a 3" system to a standard elbow and downpipe will have very little effect.