Does catless xpipe on SC add power w/o tune?
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True to a certain level. Less exhaust restriction adds air flow but only to the point where intake restrictions become the limit and fuel mapping and fuel flow capacity can meet the demand. When that is the case, you will see increased power. After that, you will need a better cam, better fueling, head porting, etc. and at that point a new tune.
Last edited by Factoid; Feb 13, 2023 at 09:31 AM.
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From: Charlotte, NC (formerly Endicott, NY)
Not enough power to notice in the seat of your pants and more than likely not noticeable in a reduced section time when powering off a corner and down a straight.
Bill
Bill
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True to a certain level. Less exhaust restriction adds air flow but only to the point where intake restrictions become the limit and fuel mapping and fuel flow capacity can meet the demand. When that is the case, you will see increased power. After that, you will need a better cam, better fueling, head porting, etc. and at that point a new tune.
1. Catless xpipe
2. Catted mid length headers with catless x pipe
3. catless mid length headers
I'm at 500 RWHP/500TQ It be cool to be anything between 520-540rwhp.
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So putting an x pipe is only for sound but doesn't free up air flow? Okay so what about the other two options?
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From: Bonneville Salt Flats
If you want more power you need more boost and more fuel, all of which require better internal engine parts, other drive-train parts, etc. to stay together if you're really going to use it somewhere. Consider everything manufacturers do with blown engines like the Z06 for starters. All the best. 
Thread Starter
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If you want more power you need more boost and more fuel, all of which require better internal engine parts, other drive-train parts, etc. to stay together if you're really going to use it somewhere. Consider everything manufacturers do with blown engines like the Z06 for starters. All the best.
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Michael S. Palmer
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Catless X pipe = Little to no power, extra sound, no need for a re-tune
Midlength headers = more power, but if you don't want to tune you will need the catted version and use the O2 inserts post Cat. But if you do this and leave the stock X pipe, you will not get any extra sound. Since you will have 4 cats in place it will still be stock sounding except for at the top of the RPM band at WOT. The best bet here is to get the catted mids, use the O2 reducer inserts post cat, and install a catless X pipe with it. However, you might still get a cat efficiency code pop up on occasion and need to reset the codes.
Long Tube headers = Most power and sound but you will need a tune.
Midlength headers = more power, but if you don't want to tune you will need the catted version and use the O2 inserts post Cat. But if you do this and leave the stock X pipe, you will not get any extra sound. Since you will have 4 cats in place it will still be stock sounding except for at the top of the RPM band at WOT. The best bet here is to get the catted mids, use the O2 reducer inserts post cat, and install a catless X pipe with it. However, you might still get a cat efficiency code pop up on occasion and need to reset the codes.
Long Tube headers = Most power and sound but you will need a tune.
Le Mans Master
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From: Atlanta GA
^^^^^^^^THIS^^^^^^
If you are considering headers go with the long tubes and high flow cats as its just as much work and cost as Mid tubes and cats but they make more power ...
Also go with HIGH FLOW cats , you can thank me later when you don't get out of the car smelling like a lawn mower ..people say you can tune the smell out , I say BS ....you can tell which car has cats and which car does not have cats by standing behind it
And one added benefit that I know you will be pleased with , you will make more power but your boost preasure will go down because of the reduced restriction in exhaust.
And since you are on the East Coast where 93 octane is plentyful , tune it for 93 , the tune and the headers in your case is going to add 60 hp at a lower boost level
Dave
If you are considering headers go with the long tubes and high flow cats as its just as much work and cost as Mid tubes and cats but they make more power ...
Also go with HIGH FLOW cats , you can thank me later when you don't get out of the car smelling like a lawn mower ..people say you can tune the smell out , I say BS ....you can tell which car has cats and which car does not have cats by standing behind it
And one added benefit that I know you will be pleased with , you will make more power but your boost preasure will go down because of the reduced restriction in exhaust.
And since you are on the East Coast where 93 octane is plentyful , tune it for 93 , the tune and the headers in your case is going to add 60 hp at a lower boost level
Dave
Thread Starter
Instructor
Joined: Dec 2021
Posts: 122
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^^^^^^^^THIS^^^^^^
If you are considering headers go with the long tubes and high flow cats as its just as much work and cost as Mid tubes and cats but they make more power ...
Also go with HIGH FLOW cats , you can thank me later when you don't get out of the car smelling like a lawn mower ..people say you can tune the smell out , I say BS ....you can tell which car has cats and which car does not have cats by standing behind it
And one added benefit that I know you will be pleased with , you will make more power but your boost preasure will go down because of the reduced restriction in exhaust.
And since you are on the East Coast where 93 octane is plentyful , tune it for 93 , the tune and the headers in your case is going to add 60 hp at a lower boost level
Dave
If you are considering headers go with the long tubes and high flow cats as its just as much work and cost as Mid tubes and cats but they make more power ...
Also go with HIGH FLOW cats , you can thank me later when you don't get out of the car smelling like a lawn mower ..people say you can tune the smell out , I say BS ....you can tell which car has cats and which car does not have cats by standing behind it
And one added benefit that I know you will be pleased with , you will make more power but your boost preasure will go down because of the reduced restriction in exhaust.
And since you are on the East Coast where 93 octane is plentyful , tune it for 93 , the tune and the headers in your case is going to add 60 hp at a lower boost level
Dave