whats the point of this? from what i read its controlled by a switch in the car and it will allow you to just release the exhaust gases right after the dp? will this actually give more power to a turbo car? and what if my car was tuned for just the dp without the cutout would i need it tuned for the cut-out? how would this worK?

 

some people claim that the car runs rough with the cut out open if your not tuned for it. I personally havnt tuned a car with a cut out so i have no experience with them. I did race another t/c with a cut out and the exact same mods. I beat him but he was tuned by another tuner. I honeslty dont see more than 5hp being made with the cut out.. Does sound pretty mean under WOT though

 

It works like a plate, that is rotated by a little electric motor (think of a throttle body), closed the exhaust gases route through the exhaust system as normal. Open they just dump to atmosphere.

There is definitely power to be gained here if they are set up correctly, as far as I know in a turbo car the cut-out can be located anywhere really in the DP, in an all-motor car they should be set-up using the same principles as a collector extension on an open header car.


As an example of what can be gained, I dyno'd my car back to back (open/closed) to shut up some kids on one of the J-Body forums I was on who didn't believe they did ****.

Closed (full exhaust, 4-1 header, no cat, 2.25" piping, Borla Superturbo muffler) car put down:
160whp 137wtq

Open (4-1 header, about 24" of 2.25" pipe from the collector, 3" cut-out) car put down:
169whp 151wtq

Dyno runs were done within 5 mins of eachother.

Only TQ loss was under 2500rpm, after that it made more TQ through the entire band.

(Note: TQ is lower due to the engine being cammed)