Previously we have been working on Project 987.2 Caymans Suspension and Brakes to get them up to Cup Car standards. With that work being completed we are now going to attack the engine and transmission performance. Our goal is to try to equal or surpass the power of the 3.8 liter 981 GT4 in a car costing many times less money with the main goal for the car to turn better lap times than the GT4 as well.
If we can get better engine performance we feel that our car can be significantly faster because our car has Porsches acclaimed PDK dual-clutch transmission. With some minor tuning, the PDK in the Cayman can be turned into the lighting fast-shifting race-box like transmission as found in the GT3RS with 7 speeds and a deep overdrive to boot! This will bode well against the manual transmission only GT4 which has a tall first geat and wide spacing between gears 1-2-3 which affects the car’s acceleration and driveabitly around a road course to boot. The PDK also has a huge advantage as it can be upshifted and downshifted in a turn without messing up the car’s balance. There is a reason why Porshe makes the GT3 available with the PDK as the standard transmission and the PDK version is much faster around a road course than the manual 6-speed version of the car.
So what are we going be doing to get our lowly Cayman S up into the range of the rare GT4? Read and see!
The first part of an engine build usually includes an exhaust and our car is no exception. We selected Fabspeeds Valvetronic exhaust. The Valvetronic exhaust is perfect for our intended dual use as it can work as both a straight-through race exhaust or a muffled exhaust to avoid attracting too much attention on the street.
The Valvetronic system uses this vacuum actuator to open and close a valve that can divert the exhaust gasses through the mufflers or run straight out the back of the car with minimal backpressure. The Valvetronic system is compatible with the OEM Porsche PSE sports exhaust system with the center console switch or you could use the Fabspeed Valve Controler kit and use their remote control to operate the valve.
You can see the actuator and the valve here. They are constructed of stainless steel to reduce the chances of corrosion and sticking. Fabspeed has some other exhausts with even more direct cutouts that empty into short cutouts for the very minimal in backpressure but we wanted our exhaust to empty into the same location as stock so we would not have any problems with fit with our upcoming Verus Engineering rear diffuser.