3 inch exhaust on an auto q's

[dikdiamond]

A few weeks ago I purchased a Tsudo 3-inch exhaust(catback)for my Eclipse. Took it to my local mechanic to change out the stock exhaust,and I ended up removing the cat because the flanges were pretty much rusted away,and had a test pipe welded to the downpipe. It sounds great,not as loud as I thought,even after I took off the resonator. My question is,should an auto really have a 3-inch exhaust and/or catalytic converter? I've noticed a difference in how fast my car picks up speed with the overdrive off,like when I'm driving around town,and when I go into boost(14 psi with small 16g)...seems I have to push the pedal down a little more than before. I've read the threads on backpressure but none mention automatics. My miles per gallon seem up. Anyone with some knowledge on this chime in.

 

[crimsondragon]

It doesn't matter if you're an auto or not. When increasing the diameter of the exhaust system, the pros/cons you'll see are increased mileage, lost of low end torque, and slightly more HP gain.

 

[dikdiamond]

Thanks. I wondered about the loss of the low end torque,and perhaps a gain on top? I noticed today that going from 70 mph to 80 mph didn't take much effort(slow driver in the passing lane). Looks like I need to keep reading abit more threads about the effects of the bigger exhaust.

I wondered if the manual tanny made better use of the size of the exhaust because of the fact that you can shift gears.