I'm researching whether or not to change my original exhaust on my '03 Touring Z to either a dual exhaust or upgraded Y-system. After speaking with several hi-per tech guys, plus my mechanic at the dealership, I'm more confused than ever. I understand that these engines are setup to have a certain amount of back pressure & if I were to switch over to some sort of dual exhaust that I would be losing some of my low end torque, but gaining horsepower at the upper end RPMs. Have any of your switched & noticed differences, either way? Which system did you liked the best? Not enterested in switching to headers, yet, just from where the Y connects back. Comments???

 

Get the true dual Borla or InJen. Yeah, you'll be reducing your backpressure, but not enough for you to notice any low end losses. It's better in the long run if you decide to do headers, cams, FI, etc.

 

From my understanding, you increase your torque by upgrading your headers and your cams. As far as losing low end torque from adding an aftermarket exhaust...I don't think you do. Plus, most exhausts have dyno sheets available for viewing. I myself have a Japtrix Y-Pipe and B-pipe. From these two mods, I felt an increase in power and the torque...not sure if I lost or gained, it kind of feels the same. I haven't dyno'ed yet, waiting for a dyno day so I can do it at a discounted price. My reason's for going w/the y-pipe instead of a full exhaust is b/c:
1. Wanted to keep stock look from the outside.
2. The OEM Y-pipe is restrictive and that you can get gains equal to or close to those of a full exhaust for a cheaper price.