J Posted April 24, 2003 Report Share Posted April 24, 2003 when i get the Z34 parts on my car in a week or so i'm going to need to get dual exhaust, i am gonna go with black muffs with chrome dual round tips, but anyway should i cut the cat off it just get a new high flow one? I am wondering this because i know our cars (3.1) need back pressure to operate properly. Thanks guys Jay Quote Link to comment Share on other sites More sharing options...
Robby1870 Posted April 24, 2003 Report Share Posted April 24, 2003 A high flo cat will still give the right amount of backpressure to keep low end torque up. A straight pipe and no cat on a 3.1L usually doesnt work out well. Get a high-flo cat or cut it out and go with a glass pack or turbo tube or something Robby Quote Link to comment Share on other sites More sharing options...
Drache Rott Posted April 24, 2003 Report Share Posted April 24, 2003 I wont go into a long drawn out thing...but back pressure is not nessisary for these motors..(it's not for any motor).the only problem you might incounter is if you also made the pipe larger (too much larger)....there by slowing the exaust gasses by losing exaust pulse pull...if you did that you would lose some low end torque... I saw better gas milage and more power when I had mine off......the down side is you WONT pass emmissions and you can get FINED big time if they catch you...get a good high flow cat if your worried about it Quote Link to comment Share on other sites More sharing options...
J Posted April 24, 2003 Author Report Share Posted April 24, 2003 Ithe down side is you WONT pass emmissions and you can get FINED big time if they catch you... Gotta love MI and no emmissions!!!! Thanks guys -JAY- Quote Link to comment Share on other sites More sharing options...
toastemcutlass Posted April 24, 2003 Report Share Posted April 24, 2003 i tried taking the cat off my car for a while(3.4) and got some off idle power but less power after that. the funny part is that i work at the emmisions place and not only me but my manager didnt have a cat either. On my other car i did a performance cat and no muffler and the compliments never stopped rolling in how good it sounded, but of course it was a v-8 not sure what the 6 would sound like. Quote Link to comment Share on other sites More sharing options...
Brian P Posted April 24, 2003 Report Share Posted April 24, 2003 If I had your cat (or anyones) I'd kill it too Quote Link to comment Share on other sites More sharing options...
GrandPrix34 Posted April 24, 2003 Report Share Posted April 24, 2003 If I had your cat (or anyones) I'd kill it too Quote Link to comment Share on other sites More sharing options...
Drache Rott Posted April 24, 2003 Report Share Posted April 24, 2003 Jay MI might not have any emimision laws but there are federal emmission laws...one of which is that no car made after I think 1984 maybe run on the street without a cat (it maybe even older then that )and if one of the cops there so decides if he thinks your exaust isnt legal and he wants to pull you over for some reason he can use that as his excuse...they do that out here and I'm sure they do it there too Quote Link to comment Share on other sites More sharing options...
J Posted April 24, 2003 Author Report Share Posted April 24, 2003 what we do over here in MI is jsut take the cover off the cat and use that on strait pipe. Looks really good and no problems with the coppers! Later Jay Quote Link to comment Share on other sites More sharing options...
RedZMonte Posted April 24, 2003 Report Share Posted April 24, 2003 I wont go into a long drawn out thing...but back pressure is not nessisary for these motors..(it's not for any motor).the only problem you might incounter is if you also made the pipe larger (too much larger)....there by slowing the exaust gasses by losing exaust pulse pull...if you did that you would lose some low end torque... I saw better gas milage and more power when I had mine off......the down side is you WONT pass emmissions and you can get FINED big time if they catch you...get a good high flow cat if your worried about it 1st I would run a high flow cat for legal reasons. As long as you have the rest of your exhaust backpressure should not be an issue. N/A Cars need backpressure in most cases. I ran my monte w/ nothing but a downpipe and a cat. I toped out in "D" at ~45mph. no backpressure made my car barly go anywhere (LOUD AS HELL AS WELL!). I was actually driving to the Muffler shop to get my Borla catback installed. i ended up towing it to the muffler shop. as soon as the borla kit was installed, it instantly gained all its power back. I would do a carsound high flow cat and a set of good flowing mufflers (borla, Magnaflow and dynomax ultraflow are my fav's.) RedZ Quote Link to comment Share on other sites More sharing options...
RedZMonte Posted April 24, 2003 Report Share Posted April 24, 2003 what we do over here in MI is jsut take the cover off the cat and use that on strait pipe. Looks really good and no problems with the coppers! Later Jay or unbolt the cat, bust up the internals and empty the cat. then bolt it backup. Shane Quote Link to comment Share on other sites More sharing options...
Slade901 Posted April 24, 2003 Report Share Posted April 24, 2003 I don't want to step on anyone's toes but as far as back pressure build up is concerned, it would not be a good thing to an engine. Partially clogged/poisoned catalytic converter causes back pressure between the catalytic converter and the exhaust manifold. Gradually, the engine has to work hard to expel the exhaust to get past the partially clogged/poisoned catalytic converter and sooner or later the engine will eventually die or car experiences power loss (won't move at all). Below is an article that I want to share with you folks. 8) http://www.nsxprime.com/FAQ/Miscellaneous/exhausttheory.htm Quote Link to comment Share on other sites More sharing options...
Drache Rott Posted April 25, 2003 Report Share Posted April 25, 2003 red...back pressure is a common miss conception.... you dont want any actual back pressure.....what is happening is the bigger exaust pipe and no cat combined with the higher flow muffler makes the air flow lose veloicty and there by it does not help pull the rest of the burnt gasses out of the combustion chamber....the remaining gases get trapped in there and take up the space that the fuel air mixture would go in meaning less fuel is there to get burnt and that causes the loss of torque and hp..... back pressure on your motor is what happens when some jack ass shoves a patato in your exaust pipe...go do it and tell me how well it runs..... Quote Link to comment Share on other sites More sharing options...
Black Pheonix Posted April 25, 2003 Report Share Posted April 25, 2003 Quote Link to comment Share on other sites More sharing options...
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