Ok well I have the mods listed in my sig. I was running long tube headers with only the y pipe and no muffler. Car was running great. So then I welded up the ole flowmaster today and it actualy made the car slower by quite a bit. And I am not just saying that because of the sound, it actualy is slower. I doubt I was getting enough back pressure with open y-pipe. But yet think I am getting too much backpressure with the flowmaster. Does this sound right to you guys?

 

Flowmasters are known for not flowing as well as other mufflers. chances are you picked up more torque by increasing the backpressure, but lost top end horsepower, that's probably why it feels slower. same things happened with several other cars I owned.

 

A muffler is a restriction to your exhaust which will cost some power. To top it off, the Flowmasters have a good reputation for not being the best flowing kits on the market.