I just bought a 3"cat back exhaust and I have it on now and its a little louder than my stock exhaust with just a muffler but it sounds great. My
question is if I get one of those hi-flow cats/test pipes on ebay will the exhaust be even louder and sound like shit?

i have a greddy evo2 gst catback with a magnaflow hiflow cat on it. it sounds great, not too loud, way better than stock. mine is 3" from the turbo back as well.

this would normally go under the perfomance/engine section.

But to answer your question, yes it will be louder.
Catalytic converers operate as an in-line resonator and do quiet exhaust noise because of seperating the exhaust pulse. A high flow cat has a freer flowing amount of substrate material and will usually cause a raspy tone on top of making the exhaust noise a little louder. If no cat is used, it will be louder yet. Keep in mind though that if used on a turbo application it will not be as aggressive because the turbo itself will cause the exhaust to be quieter than NA applications.


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know me as santiago
boosted 420a and ej2o..(my 2liter v8 eaters)

Originally posted by corsagsbo
this would normally go under the perfomance/engine section. But to answer your question, yes it will be louder. Catalytic converers operate as an in-line resonator and do quiet exhaust noise because of seperating the exhaust pulse. A high flow cat has a freer flowing amount of substrate material and will usually cause a raspy tone on top of making the exhaust noise a little louder. If no cat is used, it will be louder yet. Keep in mind though that if used on a turbo application it will not be as aggressive because the turbo itself will cause the exhaust to be quieter than NA applications. -------------------------------------- know me as santiago boosted 420a and ej2o..(my 2liter v8 eaters)

x2
my turbo car with an open downpipe is quieter then a lot of all motor Hondas I have heard with a header, 2.5" catback, test pipe and muffler, and the Squires Turbo System for F-bodys replaces the muffler with the turbo (its the worst design for a turbo system ever, but thats not my point) and those things are very quiet.

my friend has a 3 inch catback and hi flow cat. he is NA so he lost a lot of torque. but is sounds ok. i personaly like the sound of my cutout better. it cuts out right before the cat and makes the turbo spool sound great. and it is alot cheaper then a full catback and test pipe. my 10 cents

I had a 2.5" catback and now have a stock GST catback both a test pipe and it did not sound raspy at all. The turbine takes most of the sonic energy out. Now I wanna gut out my cat in place of the testpipe for "Police" reasons.
Alvin

http://www.cardomain.com/id/96rst

I had a test pipe with my greddy evo catback on my 2g. It didn't change the sound at all but sure helped the turbo spool faster.

Right now I'm N/A with Greddy headers, and a high flow cat with a turbo muffler (the cherry bomb thing). The high flow cat you will def. lose some low-end torque, but gain a little more top end. However, if your turbo, than by all means, do it! Less backpressure = More power. As far as sound goes, I think its O.K. now, its quiet when I'm cruising, but gets annoying when I go W.O.T, and turbo applications it may get a little louder, but not obnoxious. Hope that helped!

Currently, I've got a customer 2.5" downpipe, 2.5" high-flow cat, and an ERT 3" catback (prototype unit). It sounds just a hair louder than stock and it's a nice rumble. Under 2500rpms, if you engine brake, it gurgles a little (I kind of like it).