Which Muffler? Dynomax, Magnaflow, M&K - Dyno Charts

[85RedCarrera]

Thanks for posting those Mike!

[GG Allin]

My Dynomax finally schhit the bed. It started cracking along the seem on the rear side last year, couldn't figure out where the odd resonance was coming from. This year it got real bad, took it off and found the crack. 6 years but not that many miles.

I just got the car back with a 997 or 991 GT3 muffler installed, forget which one. I've had it for a while. I went single in, to the quite side. This one will be a lot easier to live with. It sounds great. I will say though, the Dynomax sounded better at above 4000 rpm, full throttle.

Hochman in Wheeling IL. Did the installation.

[chrisbalich]

GG, which headers are those?

[mikedsilva]

Originally Posted by chrisbalich

GG, which headers are those?

I think they might be these ones...
(tried to post ebay link, but it didn't work?)

[Kevin Stewart]

Originally Posted by GG Allin

My Dynomax finally schhit the bed. It started cracking along the seem on the rear side last year, couldn't figure out where the odd resonance was coming from. This year it got real bad, took it off and found the crack. 6 years but not that many miles.

I just got the car back with a 997 or 991 GT3 muffler installed, forget which one. I've had it for a while. I went single in, to the quite side. This one will be a lot easier to live with. It sounds great. I will say though, the Dynomax sounded better at above 4000 rpm, full throttle.

Hochman in Wheeling IL. Did the installation.

Sound clip?

[chrisbalich]

Originally Posted by mikedsilva

I think they might be these ones...
(tried to post ebay link, but it didn't work?)

Thank you.

[GG Allin]

Those headers are either S Car Go or William (Knight) Marshall versions. They're 1 3/4. They came with one of his engines I bought a few years ago.

Here's a start up and low rev sound clip.

https://youtu.be/JBXWKfnIc-g?si=uR7QRjeO3zDkjPED

[chrisbalich]

Originally Posted by GG Allin

Those headers are either S Car Go or William (Knight) Marshall versions. They're 1 3/4. They came with one of his engines I bought a few years ago.

Here's a start up and low rev sound clip.

https://youtu.be/JBXWKfnIc-g?si=uR7QRjeO3zDkjPED

Got it.
Thanks!

[KNIGHTRACE]

Looks Nice. Have a muffler this winter for SSi
William

[Qcurtis88]

I'm running a custom set of 1 5/8" headers into 2 in 2 out dansk sport muffler - sound and topend power is night and day. Added a honed TB from Steve Wong + chip and I've been beyond happy with the results. Hitting the dyno this weekend and I'll report back.

Butt dyno is guessing 240-250 crank (200-210 wheel)

Also had a custom heat box made that goes over the collectors. Gets nice and toasty

[Qcurtis88]

Sound clip - https://youtube.com/shorts/vCzl-GzkV1k?feature=share

[mikedsilva]

Originally Posted by Qcurtis88

I'm running a custom set of 1 5/8" headers into 2 in 2 out dansk sport muffler - sound and topend power is night and day. Added a honed TB from Steve Wong + chip and I've been beyond happy with the results. Hitting the dyno this weekend and I'll report back.

Butt dyno is guessing 240-250 crank (200-210 wheel)

Also had a custom heat box made that goes over the collectors. Gets nice and toasty

Those headers look nicely made.

[KNIGHTRACE]

Looks good !

[ccallana]

I'm curious about the 7 Digit Blue License plate starting with 9... does not look "stock"

[Qcurtis88]

Originally Posted by ccallana

i'm curious about the 7 digit blue license plate starting with 9... Does not look "stock"

[RarlyL8]

M&K Tuned headers designed/sized per application. Muffler is the M27ST street version of our dual inlet single out. Muffler inlets and internals (2.25" on this one) are also sized to match the headers for proper flow.

[scarceller]

I've been following along in this thread for a long time and one conclusion is that using a dynomax 17231 2in2out muffler seems to give very good results and is a simple setup.
Others have pointed out that the firing order of the 911 engine benefits from not merging the left and right exhaust banks.
The 17231 muffler for the most part keeps the banks somewhat separate.
Then if you study the GT3 muffler for the large loud input pipes you also see the exhaust banks being kept separate.
So why not use 2 individual round mufflers stacked on top of each other? Something like this Dynomax 17230 muffler?
I may attempt this in my Euro 3.2 this winter with my current long tube headers.
Has anyone attempted this idea? And any dyno results?
Also how loud will it be? I could also use 4 round cans total, 2 short ones right up against the header outlet then 2 longer cans stacked behind the bumper.

[GG Allin]

I believe the 17231 is NLA so there's that.

[scarceller]

True, but found these that look about the same design
https://www.summitracing.com/parts/gib-bm0111
https://www.summitracing.com/parts/sum-6330111
I think the summit one is a clone of the Gibson.

But I'm looking to do something a little different with 2 stacked round mufflers, same sort of idea.

Originally Posted by GG Allin

I believe the 17231 is NLA so there's that.

[mikedsilva]

Something I have realised through some experiements, is that quality mufflers tend to actually reduce db... I've used a few cheap ones and some have sounded like they did nothing, others have blown out the packing...

The Vibrant Ultra Quiet Resonator looks like a small muffler. It works. I think that two of those, running separate paths (not crossed or merged) would work well and reduce noise a lot.

If I had a lot more money, time and welding skill, I'd try them all out.