[64speed]

The Engine Masters episode that did the comprehensive study of exhaust diameter proved that pretty much there was no such thing as too big an exhaust. I was talking to the guy at the muffler shop and told him my Dougs headers had 3.5 inch outlets with necked down 3 inch collectors. I told him I was going to buy the pypes kit without mufflers and use the Dynomax mufflers that everyone says have no drone (can’t remember part number). He started telling me that he knew cars running in the 10s with 2.5 and that he would have a hard time getting me ground clearance with the 3 inch and that my performance would suffer with the 3 inch (Before anyone says anything I am aware I mentioned this conversation in another post). The impression I took away from the conversation was not performance loss or gain but that he didn’t want the pain in the ass of installing the 3 inch system. Anyway I was about to place the order for my header back kit on Summit and I noticed that Pypes themselves told a customer in the tech section that their performance would suffer if they went 3 inch over 2.5. This is in direct contrast to what Engine Masters proved on the dyno. I know that 2.5 inch would probably be quieter and that I am not making 800 HP or anything like that but how can bigger exhaust hurt the performance? Please enlighten me.