Thread: Exhaust Mix Between Performance and Quietness

Hahahah that one would be quiet fun



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Vadim, you're better off going full 3" and getting a nice long, fat resonator. Like the one Ameen (Tokes) had which is like a 6" I think. Should be plenty quiet and flow nicely also.

PhorB13, he has that 6" resonator right now and fitment for him is very poor.

Vadim, since all the advice is for 3" I wish I had mine already finished so you (and I!) could hear sound clips of it. It's 3" from the turbo back, has three resonators (42" worth of resonator and 4" diameter so you won't have to worry about fitment) and a magnaflow muffler. If it's not quiet I might consider making my own 44" long 5" diameter resonator, but I have high hopes. I've never seen anyone yet build something this "quiet". I went with three 4" diameter resonators because it was cheaper than two 5" diameter units but going with maybe three of the 5" units (if it will fit) could be even better. Just quite expensive.

My 4" exhaust was very quiet, almost dead quiet at idle. 2 12" resonators 5" dia, 2 spiral flow inserts, and a 4" magnaflow rear with a 50deg turndown.

I've only had experience with a 4" exhaust (you did mean a real 4" exhaust, yes? Because when I said mine had 4" resonators, I meant it had 4" outside diameter and the inside diameter is 3") on Dan Martin's BMW e30. He had two 16" resonators (5" diameter) and a 4" inlet/dual 3" outlet magnaflow (had a built in "X" pipe) and it was very quiet as well. Extremely nice in every way in fact. I have no doubt a large exhaust can be very quiet.

Yeah, 4" IN and OUT. so the ID of the resonators was 5". This was on a P10 though. From the turbo back was 4", Down pipe and all. The spiral flow inserts actually made the biggest difference in noise reduction. Without them it wasnt louder than any 3" setup with one resonator and magnaflow rear muffler. I still have it laying around incase I decide to use it some day...

I guess I'll go research spiral inserts (first I've heard of them but got a pretty good visual in my head).

Also for Dan's 4" exhaust pics check here, here and here.

You and I are on the same thought process wavelength. I want mine silent and I think that 5" resonator, while expensive will do the best job and fit quite well.



I'd be interested in seeing some pictures and any diagrams/info you have on that. That sounds sweet

Since I'm planning on making my own exhaust, if I buy a building kit, I will have enough left over for another car, aka probably my wife's P11 (very rusted exhaust).

I plan on keeping her car a very quiet daily driver, plus it's NA so 3" might be little overkill, so 2.5" matted to a 2.5" SSAC Header.

I have a 2.5 GREDDY from the catback and it sounds so so sooooooooo deep. Its amazing.