A Quieter M&K ???

[RV Flyer]

OK, with about 1,500 miles now on my SSI + M&K (2 in 1 out) combo, on an otherwise stock '78 SC, I find that the exhaust is a little too noisy too much of the time for my tastes. This engine is pretty happy between 2,000 and 3,000 rpm in routine driving, and is geared accordingly, but this is exactly the range where I get a real droning/resonance from the M&K - about 2,400 to 2,800 is the worst.

Any suggestions for toning things down a bit without losing significant HP or torque? I would think that the SSIs can stay but perhaps a change in muffler would help. Ben, do you do any mods on your mufflers if a customer wants something quieter?

Along with the noise issue for me as driver, I find as I've gotten older that drawing less attention to myself with the "law enforcement community" - as opposed to more - is a good thing, and I am a little concerned in that regard with the current setup, too.

John

[rs6er]

John,

I am in exactly the same boat as you. In fact, I already addressed this question to Ben. With SSI and 2 in - 1 out, my car is just too loud. I live on a narrow little street and in 2nd gear, in that RPM range you spoke about, I am always setting off the alarm on a Firebird parked on the street (belongs to a cop). My wife teaches yoga at various places in town, and she says she can hear me anytime I drive the car.

I asked Ben if he made some kind of baffle (like a Supertrap) that could be attached to the tailpipe to quiet it down when I'm not "blowing up the countryside" as my kids like to say. Ben replied that he didn't make anything like that. Maybe he would if there was enough interest. Heck, years ago my friend used to stuff steel wool in the tailpipes of his TVR so that he could pass inspection.

Anyone else?

[PorscheGuy79]

Odd note, I have SSIs and a twin out sport muffler from Ben, my father has SSIs and a single out like you guys are talking about. His car (though a 3.2 vs my 3.0) sounds a good bit louder than mine despite having only one out. Not saying this is the answer, just saying.

Just a note, a twin out sport muffler is different than the normal twin out Ben makes.

[SoCal70RSR]

I may be in the same both with my M&K 2 in - 2 out and SSI's. The car is not driveable at the moment, but I wouldn't dare start the engine past 7 PM as not to piss-off the neighbors I also hear what you're saying John, about calling unwanted police attention.

[rs6er]

Originally posted by SoCal70RSR
I I also hear what you're saying John, about calling unwanted police attention.

The cops only ticket ricers for their exhausts around here, but this guy is my neighbor! Now I coast past his house with the clutch in.

[SoCal70RSR]

I heard some time back that Ben could cut open the muffler and install baffles ??

[mb911]

well guys not much for options here. I can tell you no matter what 2 in muffler(all brands) you choose they will never be any bit close to stealthy unless you use the stock mufflers. everything is in stereo so to speak. you could try supertrapp insert, or use a restrictor in the tail pipe all would help a bit. We have not been installing any more baffles do to keeping with the sound that so many desire. The droning statement is odd to me. I drobe porscheguy79 's dads car not that long ago and only heard a bit of drone below 2300 rpms. I suppose allot is do to the load put on the engine etc. you could try the steel wool trick but I would doubt much would result from that. The one thing though is reshaping the tail pipe changes sound as well(meaning cut like a stock domestic car) this will disapaite some of the sound as well. I sense most of the issue is volume????????? Sorry not much help here.

[JP911]

I tried bolting a supertrapp on the end of my M&K 2-in, 1-out and it didn't do much, except to resrict exhaust flow and make my carbs unhappy.

[mb911]

the triads are about the queitest I have heard aside from stock but they are 3 "glasspacks" inseries so that explains that

[Zeke]

One thing I noticed about the M & K is the light and excellent construction (it's made to aircraft standards). I think this lends itself to the noise that some like and some don't. I didn't like it so much, so I built some baffles. I cut the noise in half, but not the characteristics of the noise. Same explosion at 4000 RPM, just less ear splitting. I had the widespread R type.

The stock mufflers are curved and heavy, so I do believe there is an advantage to that. They are also full of passages to keep things on the quiet side.

I'm beginning to wonder what Ben's muffler would sound like with racing headers (short, no heat unfortunately) with 2 pre-mufflers leading into the dual inlet model.

[rs6er]

Milt-
Care to tell us more about the baffles? Pics?

[mb911]

Originally posted by milt
One thing I noticed about the M & K is the light and excellent construction (it's made to aircraft standards). I think this lends itself to the noise that some like and some don't. I didn't like it so much, so I built some baffles. I cut the noise in half, but not the characteristics of the noise. Same explosion at 4000 RPM, just less ear splitting. I had the widespread R type.

The stock mufflers are curved and heavy, so I do believe there is an advantage to that. They are also full of passages to keep things on the quiet side.

I'm beginning to wonder what Ben's muffler would sound like with racing headers (short, no heat unfortunately) with 2 pre-mufflers leading into the dual inlet model.

folks gotta remember this was over 2 years ago and a R model like Milt said so there has been changes and improvements along the way.. All of the newer mufflers incorperate them.. It really is a blancing act.. The R style are more a visual thing and lend to loud because it is a little echo chamber(they are the loudest of the bunch) What I mean by balancing is that we need to maintain what we always had(good flow and sound) but then we want it to work for frequent drives etc. Now for me I put on 2-maybe3000 miles a year on my car so to me it never really mattered. Now then there are folks that drive their cars allot. So now you need the best of both worlds. It is tough to do that without comprimising one or the other. I am starting to think of going back to the options of which type you(loud or quiet) want when you order then we can pack all kinds of baffles in there or keep it the way it is. I suppose a perfereted cone that slips into the tail pipe would be easiest My time will free up a little in a week so I will start to look at options

[Zeke]

Originally posted by rs6er
Milt-
Care to tell us more about the baffles? Pics?

Well, I built some shorty megaphones for one of the homemade sport mufflers like this:



Then, when Ben made the R muffler, I sent these to him to have them installed as the outlets. I don't think the megaphone shape had that much to do with the overall sound as another Pelican got his R muffler with straight 2" pipes in the same box. They were both loud.

After that, I pulled the cookies out of the tips and added an inner pipe cross cut a 3rd of the way thru on the diagonal on both sides of the tube. I did this with a metal cut off saw. I then added a donut to force the gases into the center of the tube and out of the serrations. The outer end was blocked and the gases came out thru the fins of the cookie.

Someone else had done something similar before me, I just did it the way it worked for me. AFA restriction, it seemed to perform well. never dyno'd it.

I don't think there are any pics of the internal device on Pelican or my computer, sorry.

[Steve 82SC]

I have SSi's and a M&K 2-in-1-out.....somewhat loud, but I really learned to like it. My previous set-up was stock heat exchangers and a 1-in-1-out M&K and it was MUCH quieter than I thought it would be. When my car became emissions exempt, I went with the SSI's and the new M&K and was somewhat shocked at how loud it was. Ben told me that the majority of the noise factor was the SSI's. I have to believe him because I had a M&K with the stock heat exchangers......quiet sound and no noise or droning. I get a slight droning now at 2250-2300 rpm, but I'm given to wonder if the SSI's aren't the contributing factor.

Steve

[mb911]

ssis equal stereo think dual exhaust pick up truck

[azasadny]

Is there really that much difference, sound -wise between the factory exchangers and SSI's?

[RV Flyer]

I see that our host sells a factory 2 in 1 out Dansk unit for the 1974 model (p/n 911-111-025-01-M350). My recollection is that the '74 stock exhaust (including the HEs) is reputed to flow pretty well.

I'm inclined to try this muffler on my SSIs and see how it works out. Any thoughts on expected results - noise/hp/torque, or anything else?

The M&K does have nice materials and build quality, and is light weight, but I definitely want to try something a bit more discrete.

John

[tahoe_snow]

I've got about 2k miles on my SSIs+m&k sport muffler on my 3.2. I've got to admit the setup is LOUD, and people comment on it all the time. I joked before that the car would sound like a retro GT racer, but it turns it is not a joke.

It sounds unbelievable when running above 4000RPM out in the mountains, but the low RPM drone makes it difficult, especially in the city. It attracts too much of the wrong kind of attention, and it also exaggerates my somewhat uneven idle, which is another issue altogether.

I had Ben been make a block off for one of my tail pipes which I have to admit I haven't had time to install. I think this would improve the usability in the city based on my stick my foot over the pipe test.

Just be warned if you are going to do a 2in 2out setup it is going to be LOUD.

[CabMike]

I have SSIs and a 2 in 1 out M&K and I love the sound!! That said, I can't live with this every day so I just purchased a used 2 in 1 out OEM muffler to try to tone down the roar. I had a 1 in 1 out M&K with a cat bypass and that was easier to live with. Ben, If you come up with a mod for these let me know as I would take one! or send this one back for the update.

[Darryl I]

I have had M&K 2 in 2 out w/ SSI for several months now and I love the sound. But I agree with most of you in that it can be a little loud at times . Especially with the dronning at 2k to 3K. I modified one of my tail pipes with a small electric cut off "valve" and a switch in the cab. It is awsome, best of both worlds! I can shut it and tone down the noise by half (no more drone either) and flip it open all the way open for those times when I have to hear her scream.