Another exhaust thread? Not quite the same...

[scary driving]

Hello Everyone:

So I’ve searched the forums, and every time anyone asks for input on exhaust for the 911, the consensus seems to lean towards deep and throaty. I have an M&K on the SC, and I like the rasp, not the throat (no, it’s not coming off). The 2.7, on the other hand, I want to have a high pitch exhaust on it. YES, HIGH PITCH, that means, low frequencies muted, and higher frequencies not so muted. There is that high pitch resonance that the M&K makes that I love at higher RPM, but I would like the idle to be quiet and sound like a SMALL engine. If I was going to use an example, I would say I want it to sound like a 991 at idle, but wail at high RPMs. Has anyone heard an exhaust like this one? Guys who are more curious at events and ask about stuff are going to be of real help.

Thanks

[QueWhy]

This seems like a really subjective question. What model M&K do you have on your SC? It would help to have a better baseline.

[scary driving]

The SC 3.0 has SSIs and a 2 in 1 out M&K. I like how it sounds at full throttle and high revs, but I’m not fond of the rumble at idle. It’s almost harley like. I’m looking for something that sounds like a sports bike for the 2.7. It already has SSIs, just needs the muffler. I really need to research this apparently.

[QueWhy]

I put the same exhaust on my SC a couple days ago. I know what you mean about the sound at idle and high RPM.

I'm not sure if what you are after is obtainable. It may be more of a function of engine design vs the exhaust. Hopefully people more knowledgeable will be along to help.

[scary driving]

There’s a youtube video of a 1976 2.7 with the M&K GT3-S on it. The way it sounds in the clip is just about what I’m looking for, but it remain quiet at low speeds/throttle. The scart exhausts seem to have that wail really going for them, but unless I actually get to listen to different ones at an event (maybe r-grupppe?) I got to rely on someone else’s input on this. I’m absolutely jealous of my neighbor’s 991 note at idle. It’s a base model targa, and it makes my porsches sound cheap in comparison.

[RarlyL8]

I'm working on a model that sounds much like what you are describing. Our ST (street) version mufflers are much more docile than the Sport mufflers which gives a nicer idle but also gives up the sound volume up top. You still get the scream, it's just not as loud of a scream. The design we are working on now is an active version of the ST muffler, quiet at idle but the loud scream is back when you get on the pipe. Unfortunately these new mufflers are more expensive to build than the Sport versions. I cringe when I think of a muffler costing over a grand but with the labor intense construction and quality parts it gets there fast.

[scary driving]

Yeah, active, vacuum controlled seems to be the only way to go about it. Run it through baffles and chambers and straight through at full throttle. You’d get that initial bark when starting the car while the diafram builds the vacuum to close the valve. Now tuning it acoustically... That’s another can of worms right there, since even ignition timing changes would result in different exhaust gas speed, let alone fuel, cams, bore, stroke.... I don’t know if maybe “reconfigurable” version of the M&K muffler would work, as in one where you can open both sides, you can place baffles, add steel wool, open the center outlets, side outlets, etc. That would kinda make it “one size fits all”.

[macssc911]

Brian at M&K just built me that muffler a couple weeks ago, ST street . Nice deeper low grumble at idle and riding out of the neighborhood. Cruzing at highway speeds no drone maybe a little quieter than the Dansk sport I had or maybe just a different tone. However when you get down to business it does to. The pitch then gets higher in a good way. Plus it’s art work Great job Brian

[Cannon1967]

Brian how do we order this new version?

[Trackrash]

A friend of mine has one of these on his 2,2. It sounds like a sport bike when he gets on it.

[Erik Kinninger]

Scary driving, Just like Gordon posted, if your looking for high pitch exhaust note, a 2 into 1 collector is a must. My Dad Mark Kinninger started experimenting with exhaust designs that would be free flowing for his 3.6L conversion cars, subtle noise at normal driving, but at full throttle these had a great shreaking sound. His exhaust below would bolt to a set of Headers. You could have a similar set up built off your SSI's though, hers some pics, the black SC conversion you can see the 3 inch sewer pipe wrapping around, and exhaust would exit in the stock outlet under driver side rear bumper.





Erik Kinninger
81' 911 SC