Headers
Thread Starter
Racer
Joined: Dec 2004
Posts: 487
Likes: 8
From: Carolina Beach NC
C7 of Year Finalist (performance mods) 2019
Headers
What's the difference between headers with cats and without cats? I'm guessing loudness, but how much louder? Any difference in hp or performance between the two?
Also, if I go with headers, should I keep stock headers for any reason?
Also, if I go with headers, should I keep stock headers for any reason?
Life Time NCM #2196
Joined: Sep 2004
Posts: 82,592
Likes: 1,711
From: Converse TX
With Cats you will pass inspection in Texas and without not if they visually look. Without cats at a stop light or at idle you will get a tad of smell in the cabin, when moving none and only a tad louder without them and not really any difference in HP with or without.
Instructor
Joined: Jun 2010
Posts: 221
Likes: 0
From: Ponchatoula LA
I would imagine you would also get better air flow without cats but I'm not sure how much advantage you would gain from not having cats. A custom tune would probably make a difference in this matter also.
Supporting Vendor
Joined: Jul 2010
Posts: 8,550
Likes: 903
From: Republic of Texas
With high flow aftermarket cats, there's virtually zero restriction so flow rates should be nearly equal.
what i'm curious about is how they affect back pressure. Since the downstream side of a catalytic converter is hotter than the upstream side, this additional heat should influence the pressure of the air after it passes the cat (even if slightly)
In theory, this means a car without cats would sound slightly more hollow at lower engine speeds.
what i'm curious about is how they affect back pressure. Since the downstream side of a catalytic converter is hotter than the upstream side, this additional heat should influence the pressure of the air after it passes the cat (even if slightly)
In theory, this means a car without cats would sound slightly more hollow at lower engine speeds.
