So far I've had two exhaust systems on my fairly stock camaro:

SLP Loudmouth I and the Magnaflow. I'm just curious about real HP gains with all the systems available in the aftermarket for our f-bodies (catback hp gains only). What is everyone's opinion on which system delivers the most power? and is there any dyno sheets out there with gains from any of these catbacks?

help complete this as well, here's all that I could think of off the top of my head.

SLP Loudmouth
SLP 20TL
Magnaflow
Flowmaster
Edelbrock
BB Triflow
Borla
Corsa
GMMG
Hooker
TSP rumbler

 

With exception of the chambered mufflers like Flows, they'll all pretty well be the same as far as gains.

The main differences come with the price your pay, materials used, looks (since some come with very nice tips), and sound.

 

There seems to be a big misconception on this board that Flowmasters are not capable of performing like other exhaust systems.

A few weeks ago, I had my car dyno'd. Two of the passes were with open cutouts (one behind each header) and one with them closed. The peak hp numbers only varied by 2hp, and the peak torque increased by 17 ft-lbs with open cutouts (the torque curve was shifted from low to mid range).

My point is you will not really notice these number on a street car, so IMO you should order and exhaust more by its sound than anything. In the end they will all be within a few hp of eachother.

 

There are plenty of dynos showing a loss with flowmaster 80 series or a noticable gain going from flowmaster to another catback on LS1's. I've seen the same with spintech transverse mufflers too. This has been relatively well documented in the LS1 community.

Do you honestly think that a muffler with several baffles, corners, and dead ends that disrupt flow are going to perform the same as a muffler that you can see straight through.

 

put the same catback on 10 different cars, and you'll see 10 different hp gains.

no car is the same, and typically no dyno is accurate enough to show the variation between them.

figure 10-15hp for the "better flowing" catbacks out there: LM, Magnaflow, Corsa, Borla (glorified cutout), and TSP rumbler.


go by price, sound and looks....not claims...

if you want max power...and in most opinions BEST SOUND...true duals

just put some on a buddy's car....swapped off the magnaflow (which i actually love) to TSP duals with spintechs.... huge improvement!!

 

When I pick up a muffler,and hold it up to the light,and look though one end of it, if I can see light,that's the one for me.

 

a while back in gm http they had best bang for the buck combos under 1500 with dyno numbers to back it up. The only combo they had for an lt1 was intake and exhaust. It was hooker exhaust (i think) and a moroso cai. They picked up 28rwhp an 29rwtq. Intake and exhaust on a lt or ls motor does quite a bit.

 

The hooker mufflers are supposed to be one of the best flowing mufflers for our cars. I've heard GMMG's getting 12-14 HP on LS1's, although I can't back that up with a dyno test.

When I took my Flowmaster/no cat combo off and put on the GMMG/high flow cat, I noticed a performance boost.