Okay, so im a newbie to rotary engines so dont hate please. :uhh:

There appears to be a lot of backpressure in the stock exhaust because the car slightly jerks when i let off the gas quickly, im sure you guys kno what im talking about. ive looked everywhere and cannot find the answer to how big the stock piping is.

My question is, first of all, how big is the stock piping. Also, if i were to increase the piping size, would that help with the backpressure, but also, is that backpressure needed because of the small engine? Like, would i lose a lot of low end power? fill me in guys. thanks.

Here is a good place to start...you'll see only a few hp's...

http://www.rx8club.com/forumdisplay.php?s=&daysprune=&f=23

Most of your backpressure comes from in front of the cat. However to answer your direct question I believe that the stock exhaust is 2" piping I can measure it when I get home if you want.

As for your thought process...I think you are going down the wrong path. Hopefully one of the other guys will come by and correct me if I'm wrong. I believe what you are experiencing is the lack of torque that is inherint in a rotary engine. As you stop applying power the momentum of the rotor is slowed and you feel it in your butt dyno.