You may be bashing cat-backs, but it depends...

Take the GMMG for example...it doesn't have mufflers, so it WILL outperform other systems that use mufflers. It's as close to running straight pipes as you can get aside from the Loudmouth.

 

Nope, the GMMG uses the old 60s style "chambered muffler", It is pipe that has been crimped over and over in an offset pattern. Sorry, but if you were to look through one of those, the crimps take away nearly half of the diameter of the pipe and causes extreme flow disruption. Not flaming the system, I know alot of folks like it, but don't go around saying the mufflers are something they are not.

96fbirdA4: True, but my point is that it is dyno proven that it doesn't matter on our cars until you go beyond certain mods that are far more involved than bolt-ons. Once you get to this point in your mods, you wouldn't want a .25" increase in pipe... you would be looking at duals or a 4" Mufflex. Don't you agree?
Dave

 

For a real bang for the buck mod, just get a cutout.

 

GMMG all the way. Chambered rumble rules.

 

I agree with you to some extent. If you were going to be putting together a stroker motor or big FI, then yes you'd be looking directly for a 4" setup.

But, my point is why not get 3" pipe if its not going to cost you that much more? I'm not saying everybody should buy their exhaust off of the For Sale boards, but I didn't pay $1 more than you did and I've got the 3" pipes. For the same price, can you honestly say you're happier with the 2.75"?

Besides, how large is the Y-pipe on these cars? 2.5"? If so, why would you want two 2.5" pipes running into a 2.75" pipe?

 

My Corsa catback made 15 RWHP more than the stock SS exhaust on the dyno. The Magnaflow muffler I have on my 95' Z28 made 7 more hp than the stock muffler. I sell these systems and have dyno tested nearly every exhaust system on the market. A 3" intermediate will always outflow a 2.75" intermediate pipe. Flow does count on a car without heads and cam, I have 356 RWHP with just intake and exhaust bolt ons.

 

I couldn't have said it better myself. That extra inch of cross-sectional area makes a difference.

 

I paid $140 with professional installation. The parts were much less.
I am just fine with the set-up until I get more mods on my car. As long as I keep pulling the same/better numbers on the dyno as guys with 3" systems, I am elated!
Dave

 

OOOOOooohh professional installation.