Installed a 3.4 with pacesetter headers. Already had 2.5 in high-flow cat, 2.5 I-pipe, and 2.5 dynomax single in- dual out muffler. With the 2.8 I was avg 28 mpg and it sounded fine.

Right now I'm using too much gas, and power isn't all that. I'm not going into closed loop as much as I think I should be, and I'm sure that's part of my gas gulping. I'm also losing fuel pressure through the return line.

The car is now too loud for my tastes. It sounds fine at low rpms, and cruizing down the freeway is a little loud but ok, when I'm accelerating from 1500 through 2800 or so it's just annoying though.

I wonder if the exhaust is a little too free-flowing now. What would be best for adding a tad more backpressure and reducing the sound some. ( I guess more backpressure will help)

2.25 in cat or 2.25 inch muffler. (stock sizes)

 

Read the stickies and tune yo' whip...

 

Well, I now know more about exhaust pipes than I did a few minutes ago. I'll have to read more of that tonight or tomorrow.

 

sounds like it needs to be tuned, backpreasure is a myth and you want as little of it as possible