The stock turbocharger exhaust housing on the 94-98 12 valve engines is a 12 cubic centimeter that performs well on engines that are developing up to 250 hp. Once you are above this rating, the exhaust flow is so high that the stock housing offers a high drive pressure that prevents the boost pressure from entering the combustion chamber. We have a 14 cubic center meter waistegated housing that will handle this extra 250 hp + exhaust volume and reduce the amount of drive pressure required to turn the turbine wheel.

In the 1989/90 5.9 6BTA Cummins, a 18 cubic centimeter housing is a little to large and Turbo lag can be eliminated with a 16 cubic center housing.

The 91-93 engines have a 20 square center housing and Turbo lag is quite obvious. By installing the nonwastegated 16 square centimeter housing, higher boost pressure and our larger injectors can pump the engine up to a 210 hp engine with 22 pounds of boost pressure.