OK- does anybody have actual dyno results, at the rear wheel, showing hp/tq gains with an upgraded cat back and muffler system?
I have an 06 Gt std. and so for i have added a cai, tuner and 4.10s. What next? I have searched the board for ACTUAL DYNO results after upgrading the stock exhaust, from cat back to mufflers, and I can't seem to find a straight answer. Some people are claiming a 20 hp gain at the rear tire, while others claim only 3-5 hp gain. Most of the threads talk about how they sound, but I am ONLY interested in performance numbers. I know somebody out there has the info that I'm looking for, so PLEASE help a brother out. THANKS!

 

The reason you haven't read about performance gains with axleback mufflers is becuase there really isn't any. The 3-5hp range you mentioned is probably generous... anything more than that is BS-hype. If you don't care about the sound, save your money and keep the stock mufflers.

 

All your doing is when your buying an axle back is gaining 5 RWHP and better sound. You will gain NO MORE POWER with a CAT-BACK KIT, you will waste your money on a cat-back and receive pipes you already have from factory!!

 

I think the Xpipe, hiflow cats and long tube headders are for something like a S/C or turbo, possible a cam and head swap. I have yet to read a real increase for the money spent on the items above. Most of your HP increase on Pulleys, CAI, tune, mufflers equate to 20 bucks per HP increase. give or take some. Most Long tube header set ups are around 1300 bucks with hi flow cats and x pipe. Most will post a gain of 12-17 HP. that is about 80-100 bucks per HP.

No problem if you want that and you have the money. I say go for it. I am just trying to spend wisely for what gains I can get. But I am about to hit a wall. Now the mods for performance is not pushing several grand for either a s/c or cam and head swap.