Thread: 3" exhaust question

This is not entirely true. Most people when going to a larger exhaust take the easy/cheap/performance minded way out and eliminate a lot of what makes the exhaust quiet, whether it be the catalytic converter, well designed stock resonators, or great noise reducing mufflers. It wasn't going from 2" to 3" that made their car louder, it was the deletion of one or more of the stock muffling components or replacing them with inferior muffling substitutes usually in the name of performance or cost.
It is possible to design a larger exhaust that is just as quiet or in some cases more quiet than factory. It just takes some effort. Granted, a larger exhaust will produce relatively lower tones than a smaller exhaust at the same volume (dB output). The human ear/brain perceives high and low tones of the same dB differently which makes the idea of "louder" in this case even muddier. =/

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^Dude, that is a low blow ! That's stock talk pfffffffff . Yeah if I used my oem cat, oem resonator, and oem muffler with 3" piping it would be a lot quiter with tons of bottle neck.

Short of a solid number guess, I think you've got your answer.

I'm not familiar with the P10 chassis, so I don't know if the Magnaflow 4x9 muffler is a better fit than the 5x8, but either are terrific choices (I went with the 5x8 on my B13 for a more "stock" look).
As for the two 5" resonators, that is a great move, if maybe a bit expensive. I went with three (yes, three) resonators but they were 4" OD. I would have considered dual 5" Magnaflows like you have if I had the money.
Overall I think you've made great choices.
As for the turn down tip... Is that how the P10s are normally?

No. You miss the point. If you use a 3" cat, resonator, and muffler with comparable noise reducing qualities as stock you'd have an exhuast as quiet as stock. Instead of going with the "performance" cat that gives 70% of the emissions reduction of OEM and 30% increased flow of OEM get a 3" cat with comparable emissions reduction to OEM and you'll get comparable noise cancellation. Instead of a 3" straight through resonator, get a baffled type like factory. Instead of a straight through or performance muffler of what ever kind, get a 3" Flowmaster with noise cancellation as it's primary function.
You will have a full 3" exhaust with much higher performance potential than OEM and you will have noise levels just as quiet as OEM. There's nothing intrinsically "louder" about a larger exhaust. Exhaust size changes audio frequency, not audio volume.

Serban has that exact muffler on his P10 and it looks pretty decent. Its on page 17 (IIRC?) of his I got a new G thread.

Yes, the two 5" resonators will be a bit more expensive, but I think that they will fit better than the 6" but yet still quiet the car down a good deal. At least that is what I am hoping for.

I might start with one 5" resonator + the OEM cat and then add the second if its not as quiet as I want by deleting the cat and putting another 5" resonator in its place. So that is what I am thinking right now.

As far as the stock muffler, yea, its a turndown so it would keep it looking from out of the ordinary.

Any thoughts?

you guys love beating a dead horse to death huh. anyone who works on cars should be able to come up with the answer them selves. no offence to the op.

3 inch exhuast get a BIG resonator. get a GOOD muffler. get a good exhaust shop to weld it up and put in a few extra hangers with good rubbers.

should be more then fine. plus blair your going turbo soon so who cares about the n/a performance.

stratton.

I think you're on the right track. Those resonators are 14" so you could even fit both on there and retain the/a catalytic converter if you really want to.

As for the muffler, on second look I see it's the 14" version. I'm not 100% sure, but the 18" version should fit without any issues (it's the 22" that's a very tight fit). You should consider the 18" muffler. Don't take my word for it though, as I don't know the P10 very well.

Part number? I'd like to look at it online then take some measurements. Keep in mind it needs to be an offset muffler, the stock setup is a bit different than a B13.

4" x 9" x 18", satin stainless, 3" offset outlet:
MagnaFlow Performance Exhaust
(11259)

4" x 9" x 18" polished stainless, 3" offset outlet:
MagnaFlow Performance Exhaust
(14359)

Magnaflow's site is terrific for navigating and finding the size(s) you need.

^I'm not missing the point. I get what you are saying. I just know that my 2.5" VRS SS exhaust system is loud on my car due to the 2.5"x14"x4" magnaflow resonator and the Apexi WS2. That muffler is stupid loud on a N/A car if you don't have the right resonator. You mentioned a lot of OEM talk and I get that. A lot of factory trucks come with 2.75" or 3" exhaust system from the factory and are quite. I know this. Stratton said what needed to be said and that sums it up.

The one in the picture on page one is part #11259