i just took off my cat converter and my pipes sound horrible over 70 im thinking if i take them off and put a flowmaster on will it sound better, somebody help me.
No, put your cat back on the car. Your not gaining any power by removing it, and if you get caught without a cat, its a very large fine for removing federally-mandated emissions equipment. Also,adding a flowmaster won't help any.
get a carsound cat to match the rest of your exhaust piping. you will actually gain low end performance by having a cat. YOUR CAR, UNLESS TURBO'D, NEEDS BACKPRESSURE.
I was a retard, and now I'm permanently banned.
Yah listen to KC. You will run your valves to hot. Will cause damage.
^^^
you will not run hot and you will not burn up valves.....cat has nothing to do with driveability itf its plugged it will run hot if not taek the damn thing off.....I didn't have a cat on my sunfire before AND after my car was turboed......why does your car NEED a cat for backpressure.......it doesn;t....its basic physics....and dont question me I have been around this stuff more than any of you.......and yes its illegal to remove a cat but its also to speed...street race...do burnouts and in a state with carb statutes its illegal to modify a car in anyeay so this is not a question of legality its physics....take your cat off and have fun
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Crash if it's basic physics and you understand the complete concept of exhaust and back pressure with an NA car.... then why would not having a cat help any at all?
I was a retard, and now I'm permanently banned.
same reason why removing an airbox helps......a cat is a restriction remove restriction......exhaust flows better.....more significant gains on a turbo car but NA is the same idea
Goodbye Bobby, May God grant you the peace you never found in life.
“Here's my counter-offer to your counter-offer: go f**k yourself.”
—Al Swearengen
everything crash has said is on the money. KC you are wrong and the bad thing is that you have got people believing you
not trying to piss anybody off but you are feeding bad info to many people.
see ya!
tristan mccauley wrote:i just took off my cat converter and my pipes sound horrible over 70 im thinking if i take them off and put a flowmaster on will it sound better, somebody help me.
You removed the cat. Did you replace it with anything? Or is your exhaust system not connected.
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Crash wrote:same reason why removing an airbox helps......a cat is a restriction remove restriction......exhaust flows better.....more significant gains on a turbo car but NA is the same idea
yeah im with you crash. Although you want to reduce back pressure, 4 cylinder cars run a little better when they have slight back pressure. By slight meaning if you removed your cat and still had a muffler. If you were to run straight pipes, you might actually lose power.
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the need for backpressure is an old hot rodders myth. it has been proven wrong many times. now it is possible to have too large an exhaust on a car, this will result in the peak HP being made very high in the RPM band and a noticable loss in low end power. exhaust size (cat, piping, muffler,etc) needs to be matched to the power output of the engine. if this is done properly gains will be had in both torque and horsepower throughout the entire powerband of the engine. now turbo engines need the least restrictive exhaust you can fit under the car. the turbo itself is a huge restriction and needs all the help it can get. however supercharged and sprayed engines need to be treated more like NA engines.
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Crash wrote:same reason why removing an airbox helps......a cat is a restriction remove restriction......exhaust flows better.....more significant gains on a turbo car but NA is the same idea
not exactly.
dont know if you ever stopped to think, but basic physics, if something is heated, when it moves AWAY from the heat source, it cools. cats basically keep things heated later down the line of exhaust.
removing the cat, allows exhaust gases to cool faster, the further they go away from the header, the more the cool. (not to mention under the car, cooler air is constantly moving underneath... so exhaust does cool decently quick)
the more gases cool, the slower they move. the slower they move.... well i dont need to make any references to how constipation of anything is bad do i?
with a turbo exhaust is pushed out so fast and hot, its not an issue.
on an NA car, you can and prob will lose power.
Quote:
TO CAT OR NOT TO CAT
Whatever you do, do not remove or gut out the catalytic converter on your street machine. The monolithic, straight-through design of modern three-way catalytic converters is usually quite free flowing on most modern imports, producing at the most, only a pound or two of extra backpressure. A gutted cat can actually hurt power as the empty box can cause flow stagnation, which effectively shortens the length of the moving gas column in the exhaust pipe. The empty box can also reduce important flow velocity. This can be felt as loss in bottom-end power.
Because of these factors, it is not unusual for cars to actually gain power with the addition of a cat. If every last bit of power must be extracted, as in real, off-the-street sanctioned racing, then the cat can be removed and replaced with a length of pipe the same diameter of the rest of the exhaust system, not simply gutted to a power robbing shell. A full race turbo or nitrous oxide system can benefit from removing the cat when racing levels of boost or nitrous are being run. Boost or nitrous flow levels you would run on the street on pump gas are not enough to warrant cat removal for performance gain.
If you need to change your factory cat for a larger, high-flowing one, Random Technology and MagnaFlow make replacement cats with 3-inch or even larger inlets and outlets.
http://magnaflow.com/05news/magazine/05sportcpg04.asp
and the part where it says every last bit of power must be extracted... i really doubt anyone here besides those getting into 13's -12's and below are at that level.
Funny, Ian Clark says the no backpressure thing was proven wrong many times, but I failed to describe any of those times or show us proof. If people don't need backpressure, then why dont we all cut holes through our hoods and turn our exhaust manifolds upside down and have em comin out the hood!!!!! If no backpressure is such a good thing, I think I'm gonna go outside with my sawzall and do it right now!
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-3SS AWD
-Corsa Catback/Volant CAI
-LS1 e-fans
-HPTuners reflash
What about somene removing the muffler and running dual pipes (No Muffler) with the cat still on? Good/bad?
Ok, research it, technically you do not want any "backpressure" per say, there is a fine line that any given engine will run good at, backpressure is bad period. Although engines do need SOME resistance in the exhaust system as this helps pull the exhaust gasses down the rest of the system in pulses. However any way you look at it, you have too much resitance and you have backpressure, which is bad, period. If you have too little resistance then the exhaust does slow down and your engine will have trouble escaping the gasses. This is too bad. Its a fine line, find it.
<img src="http://memimage.cardomain.net/member_images/3/web/831000-831999/831395_11_full.jpg">
What about somene removing the muffler and running dual pipes (No Muffler) with the cat still on? Good/bad?
Can someone answer that?
thanx
Dam-it Muffins (Event) wrote:BadAss88GT wrote:Funny, Ian Clark says the no backpressure thing was proven wrong many times, but I failed to describe any of those times or show us proof. If people don't need backpressure, then why dont we all cut holes through our hoods and turn our exhaust manifolds upside down and have em comin out the hood!!!!! If no backpressure is such a good thing, I think I'm gonna go outside with my sawzall and do it right now!
Quote:
BACKPRESSURE = TORQUE?
An old hot-rodder's tall tale: Engines need some backpressure to work properly and make torque. That is not true. What engines need is low backpressure, but high exhaust stream velocity. A fast-moving but free-flowing gas column in the exhaust helps create a rarefaction or a negative pressure wave behind the exhaust valve as it opens. This vacuum helps scavenge the cylinder of exhaust gas faster and more thoroughly with less pumping losses. An exhaust pipe that is too big in diameter has low backpressure but lower velocity. The low velocity reduces the effectiveness of this scavenging effect, which has the greatest impact on low-end torque.
Low backpressure and high exhaust stream velocity can be achieved by running straight-through free-flowing mufflers and small pipe diameters. The only two exceptions to this are turbocharged engines and engines optimized for large amounts of nitrous oxide. Both of these devices vastly increase the exhaust gas volume and simply need larger pipes to get rid of it all.
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someone answer Orange Syn i want to know as well, straight piping it good or bad (no mufflers)
Orange Syn wrote:What about somene removing the muffler and running dual pipes (No Muffler) with the cat still on? Good/bad?
Can someone answer that?
thanx
for what logical of functional reason would you need dual pipes?
besides that, mufflers are there to absorb sound and somewhat tune the sound.
you drive 4 cylinders and 4 cylinders without mufflers sound piss poor loud, and like the car has a serious problem. these arent v6's or v8's
so if you like the car sounding like its broken, go for it.
hello there muffins! good to hear from you
uh, the open header big block chevy in my jet boat makes over 1200 hp/fps of torque to the crank...
Backpreasure is a myth. Even on 4cyl.
my 03 cavvy has 2.5" from the header to the cat, the cat is cut to 2.5" and then 2.5" cut into the cat and out the back, and makes 130-140 fps of torque @ the wheels @ 1200 rpms. It has more low end power then it did before doing the header. The torque curve in the car is so freaking flat, at any rpm you've got just about max torque.
ok now me and a friend of mine disconnected his exhaust from the headers back on his civic, and it gain alot of power. and we made it so that it is still connected but when he floors it, the exhaust comes apart. and 2-3 pounds of pressue that ppl say a stock system produces is a lie. cause i dont think 2-3 pounds of pressure in the exhaust would do that. maybe it produces that when were drivin normally but when racing, umm i dont think soo. cause i have an 01 cavi 2200 with intake and a performance muffler and i pass him easily. after doin this though, i dont leav him behind as fast. can u explain that
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