Full Version: Hi Flow cats vs. cutout(s)
so what exactly are the pros and cons between having a cutout and having a hi flow cat set up? is there much of a difference in power gain or sound?
There is definitely a difference between the two setups. Sound, for one, is going to be very different. When you remove the cat, or bypass it, you are going to have one LOUD car. The cat does a good job of quieting the exhaust down, and hi-flow cats really don't restrict too much air trying to escape out. Plus, the cat will keep your car legal, and cops may find that cutout and slap you with all sorts of fines, depending on your local laws. And (now correct me if i'm wrong guy) i'm pretty sure that with an open cutout, you will lose a little bit of power down low. I personally don't like getting cutouts, they sound too "raw" and unrefined.
QUOTE(Freshbake @ Apr 11 2008, 12:22 AM) 
There is definitely a difference between the two setups. Sound, for one, is going to be very different. When you remove the cat, or bypass it, you are going to have one LOUD car. The cat does a good job of quieting the exhaust down, and hi-flow cats really don't restrict too much air trying to escape out. Plus, the cat will keep your car legal, and cops may find that cutout and slap you with all sorts of fines, depending on your local laws. And (now correct me if i'm wrong guy) i'm pretty sure that with an open cutout, you will lose a little bit of power down low. I personally don't like getting cutouts, they sound too "raw" and unrefined.
That's just the thing...my car really isn't THAT loud...it's got a decent rumble, but it isnt insanely loud...my buddy took the muffler off his stock 96 z28 and its waaaaaay louder...he has manifods and 2 stock cats...my car is much quiter than any stock vehicle without a muffler...plus we have a billion cops around here, yes, but ive been pulled over a billion times and theyve never said anything about it being too loud...and they will nail you for ANYTHING they think they can...so volume isnt an issue really, its just the quality of sound...
Those two items are totally different and serve two totally different purposes. The cat helps keep your car emissions legal while a cut-out (when it's open) bypasses the rest of the exhaust system after it. So really you can have both and have the best of both worlds (emissions legal and a loud car).
BTW, incase you didn't know, a cut-out goes on AFTER the cat, not in place of it. One end of it attaches where the I-pipe usually attaches to the cat and then the I-pipe is shorted a bit to make room for the cut-out pipe to go in and then the I-pipe is attached to that end. Once the cut-out pipe/cut-out is opened the exhaust gases go through the headers and the cat(s) then exit out the cut-out opening when it's open rather then traveling down the rest of the exhaust system and exiting out the exhaust tips. Depending on what type of cut-out you get to open it you'll either need to get under the car and remove 3 bolts that keep the cut-out closure plate on so you can get that off or if you get an electric cut-out all you have to do is throw a switch inside your car to open up that plate. To close the cut-out you just do the reverse, depending on which one you'd have.
I know people who have both styles and the ones with the electric ones say if they ever replace theirs that they'd go with a manual cut-out rather then getting an electric one again cause they've all had issues with the electric ones "dying" on them and then they can't either open or close it. The only nice thing about the electric one vs the manual one is that with the electric one you can open it up whenever you want, especially when that annoying ricer is sitting next to you and revving. It's great watching their faces when all of a sudden that quiet car they're sitting next to get really loud when it revs back at them.
Another thing you might want to know, most of the time it's better to leave the cut-out closed unless you're at the track cause with it open your car can get really loud and attact unwanted attention from the boys and girls in blue.
BTW, incase you didn't know, a cut-out goes on AFTER the cat, not in place of it. One end of it attaches where the I-pipe usually attaches to the cat and then the I-pipe is shorted a bit to make room for the cut-out pipe to go in and then the I-pipe is attached to that end. Once the cut-out pipe/cut-out is opened the exhaust gases go through the headers and the cat(s) then exit out the cut-out opening when it's open rather then traveling down the rest of the exhaust system and exiting out the exhaust tips. Depending on what type of cut-out you get to open it you'll either need to get under the car and remove 3 bolts that keep the cut-out closure plate on so you can get that off or if you get an electric cut-out all you have to do is throw a switch inside your car to open up that plate. To close the cut-out you just do the reverse, depending on which one you'd have.
I know people who have both styles and the ones with the electric ones say if they ever replace theirs that they'd go with a manual cut-out rather then getting an electric one again cause they've all had issues with the electric ones "dying" on them and then they can't either open or close it. The only nice thing about the electric one vs the manual one is that with the electric one you can open it up whenever you want, especially when that annoying ricer is sitting next to you and revving. It's great watching their faces when all of a sudden that quiet car they're sitting next to get really loud when it revs back at them.
Another thing you might want to know, most of the time it's better to leave the cut-out closed unless you're at the track cause with it open your car can get really loud and attact unwanted attention from the boys and girls in blue.
Yup Sue is spot on. I used to run (well I still do but I removed the cut out.)
I have a Random tech High flow cat and they are awesome i used to have a QTP electronic cut out just before the cat to bypass everything on the track but that is just for track use unless you instal it behind the cat then you can have a loud car and b legal. In most states there is a visual inspection for a cat and if it isn't there you fail!
I would ge a good high flow cat and an electronic cut out behind the cat. Do you have a good aftermarket cat back system? You will want one.
Doug
I have a Random tech High flow cat and they are awesome i used to have a QTP electronic cut out just before the cat to bypass everything on the track but that is just for track use unless you instal it behind the cat then you can have a loud car and b legal. In most states there is a visual inspection for a cat and if it isn't there you fail!
I would ge a good high flow cat and an electronic cut out behind the cat. Do you have a good aftermarket cat back system? You will want one.
Doug
My 97 trans am is runnin with both stock cats and a cut-out about 3/4 back the I-pipe. letting the car breathe is always going to help power and with it being further down the pipe, I get that sound but there is still some that goes through to the muffler. It has a nice sound and cops pass me all the time and dont think twice about it. I just cant stand those like 4.6 L mustangs with the H-pipes and straight pipes back...its sounds so raspy and gargly. I hate mustangs in general but thats my 2 cents. If you want straight cutouts, go as close as you can to the exhaust manifolds, headers or whatnot, but if you want emissions legal, go as far down the I-pipe you can.
"I'm sorry officer, I didn't know I couldn't do that.."
"I'm sorry officer, I didn't know I couldn't do that.."
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