cats/ no cats
Thread Starter
Mach I Section Moderator
Joined: Mar 2007
Posts: 7,140
From: round abouts these parts
cats/ no cats
lets hear your opinions on this.
im on another forums argueing that the cats restrict ariflow and if you remove them your will gain hp/ performance. they say no the cats are designed well enough if you remove them you will not see a gain in anything, and more likely a loss of performance.
im on another forums argueing that the cats restrict ariflow and if you remove them your will gain hp/ performance. they say no the cats are designed well enough if you remove them you will not see a gain in anything, and more likely a loss of performance.
4th Gear Member
Joined: Feb 2008
Posts: 1,447
From: Charlottesville, VA
RE: cats/ no cats
Wellllll, there' s a couple sides to that coin broham. If you're living where there aren't any emissions tests I would say go no cats, as they're right it DOES give you a slight edge in HP/TQ. Though on the other side they ALSO make high-flow cats that are just about as good as a no-cat set up, just not QUITE as good.. In an emissions state if you go no cats the only place you'd be able to run it is at the track as it wouldn't be street legal. It's all in the location.. lol
6th Gear Member
Joined: Feb 2007
Posts: 11,302
From: North Carolina
RE: cats/ no cats
No cats FTW. You will gain from no cats. They don't flow that good, I took mine off and tried to look thru them....nothing but darkness and I was aiming them at the sun! My ETs also improved, butthat had to do with the combination of the larger X-Pipe and the loss of cats. Back pressure is a bad thing IMO.There is plenty of backpresure left in the mufflers as well as the stock exhaust manifolds anyway.
6th Gear Member
Joined: Feb 2007
Posts: 11,302
From: North Carolina
RE: cats/ no cats
USMC, I think those guys arguing with you are getting back pressure and scavenging confused. Back pressure is bad,hence the reason we do headers, O/R/Pipes, etc. Scavenging is balancing the gas pulsesso that they actually even out and exit faster. Everytime an exhaust valve opens, it sends a pulse down the exhaust pipe. Getting these pulses in sync create a rythm, or scavening effect, which moves the exhaust quicker.Either way, the whole goal is to move the exhaust out as fast as possible. On the other hand, using 3inch exhaust has an adverse effect because there is no longer a scavenging effect. The 3inch is just to big and allows the gases to expand too much and slows the flow down. Kinda like a spray nozzle on a garden house. But sticking a wad of ceramic in the exhaust is not helping and removing it is byno means going to causeyou to lose power.The only reason you might lose some power from removing the CATs, is when the CEL comes on and you don't use MILs or a tune to turn it off. Leaving the CEL on will/can result in a lean condition and loss of MPGs, etc.
Thread Starter
Mach I Section Moderator
Joined: Mar 2007
Posts: 7,140
From: round abouts these parts
RE: cats/ no cats
ORIGINAL: Stone629
USMC, I think those guys arguing with you are getting back pressure and scavenging confused. Back pressure is bad,hence the reason we do headers, O/R/Pipes, etc. Scavenging is balancing the gas pulsesso that they actually even out and exit faster. Everytime an exhaust valve opens, it sends a pulse down the exhaust pipe. Getting these pulses in sync create a rythm, or scavening effect, which moves the exhaust quicker.Either way, the whole goal is to move the exhaust out as fast as possible. On the other hand, using 3inch exhaust has an adverse effect because there is no longer a scavenging effect. The 3inch is just to big and allows the gases to expand too much and slows the flow down. Kinda like a spray nozzle on a garden house. But sticking a wad of ceramic in the exhaust is not helping and removing it is byno means going to causeyou to lose power.The only reason you might lose some power from removing the CATs, is when the CEL comes on and you don't use MILs or a tune to turn it off. Leaving the CEL on will/can result in a lean condition and loss of MPGs, etc.
USMC, I think those guys arguing with you are getting back pressure and scavenging confused. Back pressure is bad,hence the reason we do headers, O/R/Pipes, etc. Scavenging is balancing the gas pulsesso that they actually even out and exit faster. Everytime an exhaust valve opens, it sends a pulse down the exhaust pipe. Getting these pulses in sync create a rythm, or scavening effect, which moves the exhaust quicker.Either way, the whole goal is to move the exhaust out as fast as possible. On the other hand, using 3inch exhaust has an adverse effect because there is no longer a scavenging effect. The 3inch is just to big and allows the gases to expand too much and slows the flow down. Kinda like a spray nozzle on a garden house. But sticking a wad of ceramic in the exhaust is not helping and removing it is byno means going to causeyou to lose power.The only reason you might lose some power from removing the CATs, is when the CEL comes on and you don't use MILs or a tune to turn it off. Leaving the CEL on will/can result in a lean condition and loss of MPGs, etc.
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