What i have right now is two 3" downpipes that merge together in the engine compartment, and a single 3" near where the stock exhaust goes, to a hooker aerochamber 3" to dual 2.5" catback. No cat. It has a pretty healthy rumble and I like the sound, but it is pretty loud. I get flak from my neighbors and my mom about it (the rent is cheap, what can i say?). I want something a little quieter so as not to **** people off, while getting better performance.


I'm pretty sure i will want a straight through, perf tube fiberglass design. I know chambered mufflers do not flow well and are a no no for turbos. I havent decided on the size of the pipe or muffler yet, but i want to keep it a single for simplicity.

So far what i'm thinking is a 3", 3.5" or 4" dynomax ultraflow straight through design. I will either keep the 3" downpipe thats on there now, or upgrade that to 3.5" (probably the max with respect to space) if you fellas think it's necessary. My goals once this heap is running right is about 600-650 hp with 15-ish psi on twin T3's.

Any advice is welcome whether its regarding selecting sizes/parts, where to route it, how to shut neighbors up etc.

 

the dynomax is much quieter...

id put that on, and if its not enough, then stick a bullet (glasspack) muffler in the I pipe...



btw, tone is probly more the issue then loudness. a semi-quiet, but very deep tone will go thru the walls, and annoy your neighbors/mom/whoever... but a slightly higher tone, wont seem as loud inside...

 

People have said mostly good things about the ultraflow from what I've read. The only ones that complained were those looking for a little more volume.

My real question is the size. Can a 3" pipe and straight through muffler support that kind of hp, or would i be better going for a 3.5" pipe and either a 3.5 or 4" muffler?

Also the length, im going to make an educated guess and say on this type of muffler, the length doesnt appear to affect flow (this is backed up by dynomax's flow numbers) and would only affect the sound absorbing factor. So the longest one i could fit the better?

 

I've got the 3" SLP catback behind the twin turbo setup right now. It's plenty quiet, and it's a stainless 3" in, dual 2.5" out perferated tube design. That's getting swapped out for a dual 3.5" open side exhaust

 

Here's going to be the plan for now: rip out the hooker catback from about halfway back, replace with 3.5" piping and one or possibly two (inline) 3.5" ultraflo's, the 6" round x 16" long variety (pn 17224). I dont really want to pull out all the 3" i have there now. It runs from where the two 3" downpipes merge all the way back and was a lot of work to fit up.

Two concerns: Is leaving that 3" in place going to hurt me too badly? I think the muffler was the worst bottleneck. And would there be any point in stepping up to 4" pipe and 4" muffler(s), or would that be reaching into the area of diminishing returns?

Thanks guys.

 

ttt for the two most important parts of my post:

I'm kind of assuming 3" would choke a potential 600 hp, would 3.5" be sufficient, or should I go ahead with 4"?

Will running more than one straight through muffler inline pose any problems?

 

Your first problem is that the Aerochamber sounds great but it's loud. It's very rumbly. I had it on my 99 Tahoe, and other friends have had them on cammin' LS1's.

In an ideal world. I'd run those 3.0 down pipes into a 3.5 merge, and then run 3.5 to the back. Dynomax bullet mufflers can mute the sound a bit, but not a whole lot. Dynomax ultraflow welded barrel mufflers are good too... Ask Guido, he use to run a 4.0 one. In my personal experience bullet mufflers quiet down a car about 20% vs. open headers. To me that's not much.

 

I have Guidos on my car now....My car is Quiet....I changed from what guido had.. I put the muffler right after the downpipe and then transition into oval tube after that.. I run my exhaust out the pass side right in front of the rear tire>>>The oval 4" equiv has the same clearance as the factory rubber skirt...

looks sick and sounds quiet..

 

kenwood, with the 4" ultraflo, are we talking stockish-sounding sleeper quiet, or just not-headache-inducingly-loud quiet? I've noticed that people are real subjective as far as loudness of exhaust.

 

Well somewhere in the middle...Lets put it this way.... My car is about = to what it was with headders and a fowmaster force 2 system...I dont see how it would be possible for me to have a quiet as stock car with a just under 700 lift solid roller cam, Big turbo and 4" exhaust, and 221 cc heads...BUT I will say this...for whats under the hood you would never expect it from the sound...It sounds like a 14.0 sec gta...

Plenty of exhaust only ls1's that are louder than mine...Mine is really not so much loud as its got a deep grumble...

I could quiet it down by running the exhaust out back and turning the tip towards the ground as well...but I dont see the point...

My car is about as sleeper as it gets for what it does..