General exhaust tuning guidelines/tips

drewski86 · 12-11-2008, 10:14 AM

With a turbo you really just want to get the exhaust out as efficiently as possible. You don't want to go any smaller than the turbo exit diameter. Pre-turbo most use 2" OD pipes and keep runners equal length. The thing with turbos are you can always raise boost to overcome poor exhaust.

It is also optimal to have the header run out a few inches from the motor before the first bends and to keep the bends smooth. There is a lot of theory that floats around about exhaust design. Some speak highly of expansion chambers while others say it won't work since it is a 2-stroke design. Some say run the primarys back to the rear diff. (>90") before merging for a road race setup, while all of the ITS (stockport) and EP (streetport) cars I've seen run ~24" primarys.

12-11-2008, 10:14 AM	#5
drewski86 Slow Join Date: Jun 2008 Posts: 38 Rep Power: 0	With a turbo you really just want to get the exhaust out as efficiently as possible. You don't want to go any smaller than the turbo exit diameter. Pre-turbo most use 2" OD pipes and keep runners equal length. The thing with turbos are you can always raise boost to overcome poor exhaust. It is also optimal to have the header run out a few inches from the motor before the first bends and to keep the bends smooth. There is a lot of theory that floats around about exhaust design. Some speak highly of expansion chambers while others say it won't work since it is a 2-stroke design. Some say run the primarys back to the rear diff. (>90") before merging for a road race setup, while all of the ITS (stockport) and EP (streetport) cars I've seen run ~24" primarys. Last edited by drewski86; 12-11-2008 at 10:17 AM.