Muffler identify please, plug one side for noise reduction?

octanemaestro · 12:50 PM

Can anyone help me identify what exhaust system I have in the picture...are these SSI headers with a Dansk or M&K? You can't really see in the picture but this is a dual exhaust output setup, two tailpipes proportionally placed coming out of the rear underside.

For a variety of reasons in my jurisdiction changing this muffler and/or headers to another (let's say stock muffler, for example) is absolutely not an option, and not worth comments -- it's just an absolute non-starter, impossible. I saw a YouTube video where a guy with a Japanese car JB welds in a metal can into one side of his dual exhaust to get the car to be less loud. It did work and he was satisfied with the result. He made it invisible to the person looking at the rear of his car by putting the vegetable can way in the pipe and painting it black inside. Simple enough, it seemed. He supposed it might have made the "plugged" side and its tailpipe act as a resonator. Regardless of why it worked, it did work in his case. It cut down his volume to 70% of what he had and he was satisfied

I took my shoe and covered one of my tailpipe ends for 30 seconds. The car seemed to run perfectly happily and healthily, and it also did reduce the loudness of the exhaust.

Be that all as it may be, would it seem to you that JB welding in a can would be a safe thing to do from a mechanical perspective for the rest of the engine and its operability? I have no idea what the additional backpressure may do...is that a concern, or any other mechanical repercussion of the restricted exhaust? Would all the exhaust just get forced out the opened pipe like in the original muffler setup and have no effect on the engine?

Maybe som oldtimer enthusiasts are familiar with cars from the early 1900s (especially with raceabouts and runabouts) that had factory "exhaust cut offs" so the driver could select to use the remainder of the pipe with its muffler or just have the exhaust be loud for extra power. This could be selected from the driver's position. Packard is one example of this. At Hershey some time ago there was a grey 1910 Packard runabout with this feature...very very fast car for the period, and very gutsy sounding (with the cut out selected). Has such a selectable exhaust ever been done on a 911?

Any help would be appreciated.

RarlyL8 · RarlyL8's Garage

Definitely not an M&K, looks looks like a 4 pipe MagnaFlow type can with inlets on top and exit below. Typically these are mixed flow so you can cap one side with no engine safety issue, you'll need a positive ID on the can to be sure.
Do NOT use JB-weld on a muffler, it will melt at those temperatures. YouTube mechanics need 911 on their speed dial.
We have an active exhaust for the 911 but haven't brought it to market yet as it is fairly expensive to produce (correctly).

JohnJL · 12-11-2016, 05:35 PM

Quote:

Originally Posted by octanemaestro

I took my shoe and covered one of my tailpipe ends for 30 seconds.

Come again? I need to see video of this to answer your question.

Whats the matter, you couldnt find any bananas or potatoes?

octanemaestro · 12-11-2016, 11:46 PM

Quote:

Originally Posted by RarlyL8

Definitely not an M&K, looks looks like a 4 pipe MagnaFlow type can with inlets on top and exit below. Typically these are mixed flow so you can cap one side with no engine safety issue, you'll need a positive ID on the can to be sure.
Do NOT use JB-weld on a muffler, it will melt at those temperatures. YouTube mechanics need 911 on their speed dial.
We have an active exhaust for the 911 but haven't brought it to market yet as it is fairly expensive to produce (correctly).

How would you recommend effectively capping the one side in the least costly and most cosmetically attractive fashion?

Elombard · 12-12-2016, 06:00 AM

I had a local exhaust shop cut a short piece of pipe and weld a flat piece on the end. Then I drilled a hole through the "cap" and the tail pipe and put a long bolt and nut. It dropped the noise and drone a little. looks kinda racy.

If you search there has been several threads with lots of solutions. Some are much more elegant and expensive.

Those headers you have look like B&B. I think that may be the B&B muffler that came with the system. I think B&B makes a 2 in 1 out for that system now that you can buy that supposedly cuts the noise and drone down quite a bit. B&B is $$$

Looking forward to RarlyL8s active system when it is released!

octanemaestro · 12-12-2016, 06:19 AM

Hmm...it does like B&B now that I've Googled that...you're right, $1,700:

Porsche 911 SC Performance Parts | B&B Headers | LM Performance

Yes, maybe RarlyL8 can give us a picture or diagram? Will that have a servo or actuator or be manual cable driven like with a choke style finger pull?

JohnJL · 12-12-2016, 07:23 AM

The most economical and invisible way to do it is like m+k does it...cut out a circle, fold the edges in so the outside diameter of the cup you form fits the inside of one tailpipe. Then slip that cup down inside the tailpipe so you cant see it and put two screws through the outside of the tailpipe to secure the cup in place.

RarlyL8 · RarlyL8's Garage

^^^
What he said. Put a cap up in the pipe and secure with a set screw.

Active exhaust is still being tested for longevity. Valve(s) will be vac operated like modern systems. Biggest challenge has been valve durability. Our mufflers are lifetime performance parts, valves must be as well.