Cut-out?!?!?!
05-15-2008, 06:02 PM
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Cut-out?!?!?! Can a cut-out before the cat be anywhere near as good as headers? I guess my real question is on a stock 99' LS1 (except for SLP intake, TB Bypass, and MAF screen removal) can a cut-out be "almost" as beneficial as headers? If anyone knows how much back-pressure is elevated due to headers and then with a cut-out, that would be nice.
05-15-2008, 06:12 PM
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Well i dont think they will do as great of a job as if you were to have Lt headers and the cut out. I don't see it being as beneficial, but it will help a bit than having to go through the factory exhaust.
-Joel
-Joel
05-15-2008, 06:23 PM
#3
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Some help yes, a big difference no.
Headers are designed with flow in mind. Manifolds just do not flow well. Look at a header and a manifold and tell me which looks like the smoother faster way for exhaust to exit.
I think if you are going to take the time to fabricate putting cutouts on a stock exhaust, I would hold off, buy a nice set of headers and a good Y pipe and then even if you are going to stick with the stock cat back, incorporate the cutouts into that. That way there, you are opening doors to better mods in the future.
IMO get your exhaust squared away before you mod the engine. She has to breathe before she makes power.
Headers are designed with flow in mind. Manifolds just do not flow well. Look at a header and a manifold and tell me which looks like the smoother faster way for exhaust to exit.
I think if you are going to take the time to fabricate putting cutouts on a stock exhaust, I would hold off, buy a nice set of headers and a good Y pipe and then even if you are going to stick with the stock cat back, incorporate the cutouts into that. That way there, you are opening doors to better mods in the future.
IMO get your exhaust squared away before you mod the engine. She has to breathe before she makes power.
05-16-2008, 11:32 AM
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I agree! the main restriction in flow is within the stock manifolds. By having a Cutout post-manifiold pre-cat, your mearly eleaviating the small amount of restrition put on the flow by the Y-pipe which is miniscule at best.
Not to mention your computer will hate you as the rear O2's will read that the cats aren't working. IMO Put'er in the Y under the pass. seat and put some LT's on er. Good Luck!
Not to mention your computer will hate you as the rear O2's will read that the cats aren't working. IMO Put'er in the Y under the pass. seat and put some LT's on er. Good Luck!
05-16-2008, 12:54 PM
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Can a cut-out before the cat be anywhere near as good as headers? I guess my real question is on a stock 99' LS1 (except for SLP intake, TB Bypass, and MAF screen removal) can a cut-out be "almost" as beneficial as headers? If anyone knows how much back-pressure is elevated due to headers and then with a cut-out, that would be nice.
https://ls1tech.com/forums/generation-iii-external-engine/520845-mod-guide-induction-exhaust-please-read-before-posting.html
Here's a quote from it:
The first misconception that needs to be cleared up is that a header relieves backpressure, but a certain amount of backpressure is needed for optimum performance. Just the opposite is true. A good header not only relieves the backpressure, but goes one step further and creates a vacuum in the system. When the next cylinder's exhaust valve opens, the vacuum in the system pulls the exhaust out of the cylinder. This is what the term "Scavenging" means.
05-16-2008, 03:50 PM
#7
Like everyone else said, the restriction is the crappy size and design of the stock manifolds and Y pipe. Do it right and put longtubes and a ORY on it. I dont know about some set ups, but with mine the cats hook right to the manifolds so I dont know where you would put a cut out.