A was wondering a couple of things about the RT Cat. First does it help you meet emissions with a performance y-pipe? Also does it hurt your low end acceleration because I hear it lowers back pressure? Any help would be appreciated.

 

I think that people have been passing emissions tests with RT cats and Y-pipes. The RT cat has been dynoed to make more torque, so low-end acceleration should be better.

 

Just because it dynos more torque doesn't mean it dynos more low end torque. It's easy for an aftermarket piece to make less low end, idle torque and more peak torque. It's how much it makes all over that counts. If it makes less from idle to 1500 RPM but more from 1500-6500 than the mods is worth it. It's when it only makes power from 5000-6500 that you start worrying that it's not really helping you out.

 

Justin Gadlage's dyno chart shows the torque peak to have dropped by 200 rpm, so it ought to be better lowend. Too bad his results aren't shown down to 1000rpm.

http://www.geocities.com/jgadlage/dyno.html