Headers only on LS3?
Instructor
Joined: Feb 2012
Posts: 135
Likes: 5
From: London Ontario
I know its an old thread but incase others are researching, I had the same concern.
I went with 1 3/4 long tubes and high flow 3"x2.5" catted X pipe hooked to the stock 2.5" over the axle npp exhaust with stock npp mufflers. When driving normally the sound level is basically the same as stock, but you will notice the 'header sound effect' which is sort of tinny swooshy like sound like what your plumbing in the walls of your house sounds like while the water is running, almost sounds like its leaking even when its not. Also the tone is a bit different slightly less 'tuned sounding' under part throttle and when you floor it WOT with NPP it really screams and is a completely different sound, very high pitched in comparison!!
If you want close to the same gains without sound sacrifice then go with a Z06 headers & system and from what i read you would get about 60-70% performance of LT system. One guy reported 3MPH gain in the 1/4 mile with swapping to Z06 exhaust only.
I gained 6-7MPH with my exhaust, KB intake, ported TB, ele. water pump and ECS tune.
Team Owner
Joined: Sep 2000
Posts: 25,019
Likes: 2,712
From: Far NW 'burbs of Chicago
St. Jude Donor '13
GM says the NPP dual mode exhaust adds 6 hp, SAE certified. So a catback system can add something, but whether it makes a discernable difference besides the noise, is another story.
