M&K Sport Muffler Impression

[wcarson]

Hi-
I did a lot of research reading through old posts regarding MK mufflers, trying to get a feel for how loud a 2 in 2 out sport muffler would be on a street driven car. My car is a 70T with a carburetted (webers) 3.0L motor, stock SC cam, SSI exhaust. I came across lots of old threads but still had a hard time determining just how loud it would be. I loved the look of the 2 outlet sport muffler and wanted a performance sound, but nothing over the top. Would the M&K be Ok for a street car? Too loud??

Well, I went ahead and bought the MK sport muffler (again- 2 in, 2 out) as well as a cap for one of the outlets, assuming it would be too loud for street use.

The verdict: after installation and driving it- I can tell you that in my opinion, the 2 in 2 out Sport muffler is NOT too loud for a street car. I would not dream of capping one of the outlets at this point- I was very pleasantly surprised at how nice sounding the muffler is WITHOUT being too obnoxious or annoying. There is a bit of drone/resonance around 2000 rpm, but it is NOT bad. The muffler IS louder than my OEM 2 in 1 out banana style muffler, but in a nice way. The M&K is significantly quieter than my old 3.2L eurospec 86 carrera with SSI's and a Dansk 2 in, 2 out sport muffler. Not sure how much of that is due to the muffler differences vs. the engine differences though.

Overall- I am very happy with the M&K. It is pefectly acceptable (and nice sounding!) for a daily driver/street car. I love it. Also- FYI- I am 36 years old and do like performance cars and the associated sounds they make, but I do not like anything too loud or attention getting. Maybe some senior citizens would find the M&K too loud, but I really don't think this would be the case.

As is posted by all of M&K's customers- the muffler build quality is first rate. Hope this post may help someone in the future who may be on the fence about buying one of these-

WK Carson
1970 911T 3.0L, webers
1982 930, modified

[sancho]

I agree with you, I think there is going to be people disagreeing with you but I think the sound is just enough before it starts being anoying.

well done you have made the right decision.

I have mine for around 12 months.

[Gillies]

I have been wondering about that myself. Now I know...thanks for the info !!!

[mickey356]

When I spoke with Ben about which route to go the "what is too loud" issue came up. I'm in the restaurant business and I told him it's like when someone askes "How spicy is it?", how do you answer that, everyone is different as far as thier tastes go. The same goes with the "loudness" of an exhaust. I bought an M&K from someone who thought it was a tad too loud, to me it's a symphony. Everyone is different and no one is right or wrong.

[deshetlr]

The gen 6 muffler is much quieter than previous generations. So loudness responses will probably reflect personal preference and which generation is being discussed. My gen 6 1 in 1 out is very quiet!

[TDHarris]

I installed the M&K 2-in 2-out sport muffler on a 3.2 Carrera 4 years ago, and I have been very unhappy with the quality. In those 4 years I have had to weld up cracks 3 times, and I just removed the muffler yesterday due to more cracks. The cracks formed around both of the inlet pipes, and around the outlets on the end plates. It appears that in an effort to make a very light muffler Ben sacrificed durability and used metal that was just too thin. The weight of my muffler is 15 pounds. Do you know the weight of your unit? He may have improved the design since then.

My other complaint was that the fit was terrible. The muffler did not even come close to matching up with the mounting bracket on the engine. Plus there were no tabs to fit into the notches in the mounting bracket to keep the muffler from shifting position. In order to get a good fit, the mounting bracket needed modification, and tabs were welded onto the muffler to lock it into position. Also, the tailpipes were too short, and didn't clear the valence. This required the addition of short extensions. I also welded gussets to the inlet pipes to reinforce them, and it looks like I will need to do the same to the outlet pipes.

On the plus side it is light - important for a track car. And it sounds great. I find your comparison of the loudness with the Dansk 2-in 2-out interesting. I have a friend with a 3.2 Carrera having SSIs and the Dansk muffler. His car is quieter than mine, and I have the tailpipe inserts which quiet mine considerably. Without those inserts I would exceed the sound limits at Mt Tremblant and Calabogie (92 dBa). Is Ben making the mufflers quieter now?

One final note. I sent Ben an email listing the defects in his design, and explaining my displeasure with the product. This was not a rant, just a polite "thought you should know" letter. I wasn't asking for anything, and he didn't offer anything. It would have been nice to get at least an apology for selling an inferior product.

[Scooter]

I could not be happier with my two in two out sport muffler. Fit is perfect, tone is perfect, look is perfect, weight is perfect, and Ben was great to work with. Outstanding product!

[Zeke]

Originally Posted by TDHarris

I installed the M&K 2-in 2-out sport muffler on a 3.2 Carrera 4 years ago, and I have been very unhappy with the quality. In those 4 years I have had to weld up cracks 3 times, and I just removed the muffler yesterday due to more cracks. The cracks formed around both of the inlet pipes, and around the outlets on the end plates. It appears that in an effort to make a very light muffler Ben sacrificed durability and used metal that was just too thin. The weight of my muffler is 15 pounds. Do you know the weight of your unit? He may have improved the design since then.

My other complaint was that the fit was terrible. The muffler did not even come close to matching up with the mounting bracket on the engine. Plus there were no tabs to fit into the notches in the mounting bracket to keep the muffler from shifting position. In order to get a good fit, the mounting bracket needed modification, and tabs were welded onto the muffler to lock it into position. Also, the tailpipes were too short, and didn't clear the valence. This required the addition of short extensions. I also welded gussets to the inlet pipes to reinforce them, and it looks like I will need to do the same to the outlet pipes.

On the plus side it is light - important for a track car. And it sounds great. I find your comparison of the loudness with the Dansk 2-in 2-out interesting. I have a friend with a 3.2 Carrera having SSIs and the Dansk muffler. His car is quieter than mine, and I have the tailpipe inserts which quiet mine considerably. Without those inserts I would exceed the sound limits at Mt Tremblant and Calabogie (92 dBa). Is Ben making the mufflers quieter now?

One final note. I sent Ben an email listing the defects in his design, and explaining my displeasure with the product. This was not a rant, just a polite "thought you should know" letter. I wasn't asking for anything, and he didn't offer anything. It would have been nice to get at least an apology for selling an inferior product.

A rare complaint and even rarer that Ben did not offer more. I can only think that he figures you can't please all the people all the time. Ben's background in designing the M&K product is aircraft muffler design. The crossover to sutomobiles has not been seamless for M&k products. When I bought my muffler there was no talk about gen 2 much less gen 6.

That tells me he keeps working at a better product line.

Fours years ago I don't think the M&K married up to the stock muffler bracket all that well, but I thought Ben had a mounting kit that made for a better hook up. Do you have that kit installed?

[tcar]

Originally Posted by milt

A rare complaint and even rarer that Ben did not offer more.
I can only think that he figures you can't please all the people all the time.

If TD's complaints are true, it's WAY beyond not "pleasing all the people all the time".

Bad product, non-existent follow-up?

That particular muffler would please "NONE of the people NONE of the time".

I know a lot of people have good experiences with them, but...

[356RS]

WOW, very surprising to hear a possible lack of response from Ben. I had Ben make a modified version of the Sport Muffler for my 2.7 Short Stroke that was fitted into my 356A coupe. Ben had to make it about 3 inches shorter at each end so to fit between the rear bumper brackets. Lots of communication and a perfect fit. I was very happy.
I hope your situation can be worked out.

[Zeke]

Originally Posted by tcar

If TD's complaints are true, it's WAY beyond not "pleasing all the people all the time".

Bad product, non-existent follow-up?

That particular muffler would please "NONE of the people NONE of the time".

I know a lot of people have good experiences with them, but...

OK, let me be a little more succinct and be the way I really am.
First, I did not say Ben didn't reply to the guy. In the OP's words, "....he didn't offer anything."

Second, the OP is using this muffler for racing. I wouldn't guarantee anything I made for racing.

Third (from the OP), "Plus there were no tabs to fit into the notches in the mounting bracket to keep the muffler from shifting position." I've never seen any 911 muffler with tabs to the mounting bracket. And "shifting?" What kind of headers move that much? Maybe during an off-track excursion.

And forth (this is where "me" is really me), I would have quietly sent the purchase price back to the OP in return for the muffler. I would do this for a couple or three obvious reasons that I'll let you figure out for yourselves.

I recommend that Ben still do that and let the OP find a better product.

And now I'll notify Ben about this thread.

[brads911sc]

I have the Dansk 2 in, 1 out, stainless. Its great. Would consider nothing else for a street car...

[whiterabbit]

I just put on an M&K 2 in 1 out last week bought brand new from Pelican. It is a little louder than my Dansk sport but still acceptable to me at idle and it sounds great above 4k. It was easy to fit and I am very happy with the quality so far. It weighed 9lbs less than my Dansk sport.

[snbush67]

I have the M&K Gen 5, 2in 2 out on a 3.2 Short Stroke with SSIs.

Excellent Sound !
Excellent Performance !
Excellent Fit !
Excellent Service !

I have had this muffler on and off about four times for maintenance of the car and an engine displacement increase. There are no flaws the welds are perfect, the material is light.

I had a bit of a drone at 2300 rpms when it was new and on my 3.0 but since I increased displacement it seems to have gone away.

Shane

[Jeff Alton]

We have sold about a dozen of these over the last few years. The only complaint is that a couple of folks found them a bit louder than they were expecting. None of these were gen 6 mufflers. On our track car we run sport with dual out (straight out under the bumper) on our 300hp motor. No drone, no problem making sound at our local track (93db).......

We have also found Ben very responsive to our needs.

Cheers

[TDHarris]

Let me clarify a few things concerning my original post. As milt has already pointed out Ben did respond to my email, acknowledging some shortcomings in the early versions of the muffler. Given the generally high praise given to M&K products I suspect these shortcomings have been addressed. But this is the only M&K product I have experience with and my post was intended to: 1) Gather additional feedback from users. (I may still buy another M&K muffler if I could be convinced it is a quality product); 2) For what it’s worth, add the experiences of one user to the thread.

Concerning milt’s comment about the tabs that fit into the notches on the muffler bracket. Perhaps I used the wrong terminology, but EVERY stock Porsche Carrera muffler has what are essentially tabs – it’s the raised weld seam that runs around the entire muffler. This seam fits into two grooves on the muffler-mounting bracket, locking it into place. My headers are copies of the SSIs, but without the heater boxes. They are, therefore, more flexible than headers with heater boxes, and prior to my addition of mounting tabs to the muffler, the entire assembly could shift by more than 0.5”. Unfortunately, this was only discovered after the cracks appeared. I suspect this movement is what led to the original cracks around the inlets. Since modifying the muffler (mounting tabs and reinforcing gussets), these cracks have not reappeared. Tomorrow I’m off to my welder to see if there is any hope of doing the same to the end plates, or if I would just be throwing good money after bad.

And as milt has pointed out the 911 is dual purpose – street and DE in about equal amounts. Anyone out there using M&K products on a DE or racecar?

Thanks for reading,
Tom

[mb911]

Thanks for those that gave me a heads up to this thread.

1st I do appoligize if I did not respond to Toms email. I get so many emails that sometimes they can be missed or go right to spam it just depends on how it comes in.

2nd over the last 6 years our company has developed and grew considerably. with that the product has evolved as we have learned from designs thus you see the different generation mufflers. We have also refined the muffler in its fittment to compensate for different headers/ssi's etc. Though the tabs have never been a consideration it may be something to look at in the future. I just have never really seen a need for them but may be worth revisitng should the community feel there is a need for them.

now to comment on replacement of "inferior" product. This is not common place for us as we simply do not run into this very often but to say it never happens would be a lie. What we do on a one on one basis is determine 1st how the muffler was installed for example did the customer loosen the heat exchangers/ headers so that there is no stress on the inlet pipes per our instructions? Does the customer use this exclusivly for racing? did the customer use the mounting straps? did the customer have a rear ender with the system installed? If everything was done properly we ask the customer to send the muffler to us for inspection(at the customers expense) and 99% of the time the customer will get a new one at no charge. If we find that the customer is partially to blame then we do whats called a goodwill warranty and that is simply a prorated system replacement.


It must be kept in mind that how this business started was by posting picture of one I built for myself because I was unhappy with options out there. This went on my 914-6 conversion and then on a few of my local friends cars and pretty soon people wanted them. I would explain myself as an enthusiats first and a business owner second. When its all said and done it was about the cars. I try my best to make ever customer happy and build a quality product. this can't be done without feedback and I thank all of you for that.

If I can help any further answer questions please let me know

[TDHarris]

Originally Posted by mb911

Thanks for those that gave me a heads up to this thread.

1st I do appoligize if I did not respond to Toms email. I get so many emails that sometimes they can be missed or go right to spam it just depends on how it comes in.

2nd over the last 6 years our company has developed and grew considerably. with that the product has evolved as we have learned from designs thus you see the different generation mufflers. We have also refined the muffler in its fittment to compensate for different headers/ssi's etc. Though the tabs have never been a consideration it may be something to look at in the future. I just have never really seen a need for them but may be worth revisitng should the community feel there is a need for them.

now to comment on replacement of "inferior" product. This is not common place for us as we simply do not run into this very often but to say it never happens would be a lie. What we do on a one on one basis is determine 1st how the muffler was installed for example did the customer loosen the heat exchangers/ headers so that there is no stress on the inlet pipes per our instructions? Does the customer use this exclusivly for racing? did the customer use the mounting straps? did the customer have a rear ender with the system installed? If everything was done properly we ask the customer to send the muffler to us for inspection(at the customers expense) and 99% of the time the customer will get a new one at no charge. If we find that the customer is partially to blame then we do whats called a goodwill warranty and that is simply a prorated system replacement.


It must be kept in mind that how this business started was by posting picture of one I built for myself because I was unhappy with options out there. This went on my 914-6 conversion and then on a few of my local friends cars and pretty soon people wanted them. I would explain myself as an enthusiats first and a business owner second. When its all said and done it was about the cars. I try my best to make ever customer happy and build a quality product. this can't be done without feedback and I thank all of you for that.

If I can help any further answer questions please let me know

Ben,

Email can be overwhelming at times and my email probably fell through the cracks after an initial quick read. I've included the images I originally sent you, and will use them to answer some of the questions raised in this thread.

Yes, the headers were loosened to allow the system to "relax" during installation.
The supplied straps were used. The marks left by the straps can be seen in the image below.
The car is used 50% DE and 50% street.
No collisions of any kind.
Off-track excursions were always on smooth surfaces - no gravel traps or rocky fields.

The first image below shows the section that contacts the muffler mounting bracket. Ignoring the two small tabs that I added, it is a very flat and smooth surface. There is very little friction to prevent the muffler from shifting position. The image also shows the gussets added to the inlet pipes. Once these two modifications were made, cracking around the inlet pipes did not reappear.

Without seeing the installation first hand the skeptic can always say (with some justification), "was the system REALLY aligned properly?" The second image shows cracks around one of the end plates. There is no alignment here. The tail pipes do not touch anything! You can see a major crack following the weld seam and radiating outward. On the far right is a smaller crack working its way in from the outer weld seam. Metal too thin? Excessive harmonic vibrations?

In retrospect, I should have sent the mufffler back at the first sign of trouble. But I thought I had identified what caused the problem and how to prevent it from reoccuring. That was only partially correct - the original problem WAS corrected, but the problem moved somewhere else, and we were now on a slippery slope.

So to restate my original reasons for posting to the thread. I am looking for answers to the following questions.
1) Has anyone successfully used M&K mufflers on a DE car?
2) What is the sound level produced by current M&K mufflers? Tracks are becomming more and more restrictive. Lime Rock Park, for example, has a maximum permissible noise level of 84 dBa for cars made prior to 1979, and 81 dBa for cars made after 1979. That is not very loud. Mt. Tremblant and Calabogie are currently at 92 dBa, but are always under pressure to lower them.

Thanks again,
Tom Harris

[TimT]

1) Has anyone successfully used M&K mufflers on a DE car?

Yes..and has been on my car for a few years now

I have used a Gen 1 M&K on my racer for years..

I do have a selection of turn downs/baffles etc to install in the pipes fool the sound man ( supplied by M&K per my request) Lime Rock... no problem...

I can run my car from the shorty RSR headers, to a full quiet M&K system...

Heck I have a Gen 1 RSR and have none of the issues mentioned...

Trying to avoid sounding like a M&K circle jerk... but he makes good stuff

I have used my M&K exhaust on the end of Narbel headers..

and M&K headers

and OEM

ALL Miles are track miles

[mb911]

Originally Posted by TDHarris

Ben,

Email can be overwhelming at times and my email probably fell through the cracks after an initial quick read. I've included the images I originally sent you, and will use them to answer some of the questions raised in this thread.

Yes, the headers were loosened to allow the system to "relax" during installation.
The supplied straps were used. The marks left by the straps can be seen in the image below.
The car is used 50% DE and 50% street.
No collisions of any kind.
Off-track excursions were always on smooth surfaces - no gravel traps or rocky fields.

The first image below shows the section that contacts the muffler mounting bracket. Ignoring the two small tabs that I added, it is a very flat and smooth surface. There is very little friction to prevent the muffler from shifting position. The image also shows the gussets added to the inlet pipes. Once these two modifications were made, cracking around the inlet pipes did not reappear.

Without seeing the installation first hand the skeptic can always say (with some justification), "was the system REALLY aligned properly?" The second image shows cracks around one of the end plates. There is no alignment here. The tail pipes do not touch anything! You can see a major crack following the weld seam and radiating outward. On the far right is a smaller crack working its way in from the outer weld seam. Metal too thin? Excessive harmonic vibrations?

In retrospect, I should have sent the mufffler back at the first sign of trouble. But I thought I had identified what caused the problem and how to prevent it from reoccuring. That was only partially correct - the original problem WAS corrected, but the problem moved somewhere else, and we were now on a slippery slope.

So to restate my original reasons for posting to the thread. I am looking for answers to the following questions.
1) Has anyone successfully used M&K mufflers on a DE car?
2) What is the sound level produced by current M&K mufflers? Tracks are becomming more and more restrictive. Lime Rock Park, for example, has a maximum permissible noise level of 84 dBa for cars made prior to 1979, and 81 dBa for cars made after 1979. That is not very loud. Mt. Tremblant and Calabogie are currently at 92 dBa, but are always under pressure to lower them.

Thanks again,
Tom Harris

It looks very clear to me that there are some strange harmonics going on there. That being said you should have sent it back to me before you had it modded I could have updated it to the gen 4 and up specs. That included inlet overlays and rear patch reinforcment. Though no tabs.

As to thickness etc. I have built 1000's of these mufflers all .040 wall on the shells and all .055 on the endplates. We have also added strengthing to the inlets as I stated and have even shortend the newest gen6 mufflers to keep weights downs as we have reinforced them. in that time only a handful have been returned for issues. as I stated before 99% of them were fixed and problem solve. The funny thing is you look at any other manufacturer and no one will warranty a part that has been on a track why people ask? well the heat cycling is the big thing. track use no matter 50% or 100% there is some extreme heat being produced.

that said back on topic or to answer your questions is that our latest gens are quieter then the 1st etc and even daniel jacobs is using our mufflers on his 3.6 conversions because they will meet dbs for lime rock etc. now thats not everycar but it is somewhat convincing.

Tom,

Should you want to try one of our systems again give us a call we will take care of you.