Much of the development for Perfex Manufacturing products for Porsche 928 takes place on the ex Don Hanson race car. This 6.5 liter stroker equipped car started out life as a 1991 928 GT and was heavily modified by the original owner for track days. After the vehicle changed hands several times, it found it's way to Perfex Manufacturing to be resurrected and improved with several  items developed in house . One area that was not completed to our satisfaction was the air inlet (or lack of) for the Independent Throttle Body setup- the ITB's simply had filter "socks" and no provision to access colder air outside of the engine bay.

With some careful design work and bit of trial and error, we were able to take advantage of the low pressure are in the cowling to capture cooler air. This was accomplished by trimming the leading edge of the cowl, and letting the new airbox through this area. The entire airbox is fastened to the ITB's with an clamping system, and employs an OE style Porsche 928 air filter element at the rear opening. This arrangement has been run on the dyno and on the race track.


Naturally, the powerful stroker engine has been equipped with the Perfex Manufacturing EGDS water pump design, and has seen several dyno tests as well as track days, further proving the reliabilty of the engine saving water pump design. Please read about the EGDS water pump here-


Perfex Manufacturing - 30 Commerce Drive, P.O. Box 1217, Danbury CT 06810

Phone: 203.739.0930 - Fax: 203.739.0949 - Email: