I have an '82 911, stock engine and intake, with SSIs and a 2-in 1-out Monty SS muffler. From what I have read, there are a few hp to gain and some weight to lose by going to a two-muffler race setup. This is a track only car, although I will sometimes drive it to a shop for alignment/corner balance. My car must be the quietest 911 at our track - other drivers say they can't hear me coming I think I'm giving up some high-rpm power with the current setup too.

I need to keep the heat and thus the SSIs - no headers for me.

What is my best option? So far I have seen:

Phase 9 - These seem to be very popular on 911SC and Carrera track cars with headers. Stainless steel. They are $285 each (need 2) and it's not clear to me if they come with mounting flanges. Do these even work with SSIs? Are they bolt-on or would some fabrication be necessary to get them to connect? Do they require support besides just the attachment to the SSIs?

Coast Fabrication Ultralight Racing Mufflers. Nice looking, stainless steel, come in different diameters and lengths. Around $250 each (need 2) depending on length and diameter. Again, based on the photos in their web page, these don't seem to come with flanges (or even exhuast tips). Anyone have experience with them? Do they need support other than the SSI flange attachment?

Supertrapps - don't know much about these and their web page lists a wide array of different models, some mild steel and some stainless. Not sure which model would be appropriate for my car. Do they need support other than the SSI flange attachment? Anyone running these?

M&K 911 Race / Track Mufflers - stainless steel, great price ($250 for both). It appears that these are light enough to just bolt up to the SSI flange without any additional support. How would these compare in terms of performance to the more common race mufflers mentioned above? (picture here)

Thanks,

Jeff

 

Jeff,

I also have SSI with a 2-in, 1- Monty, and was looking for a replacement for track use. My car was too quiet (approx 87 db), and I couldn't hear it when I was in traffic, so I wanted something a little louder.

I also looked at the phase 9, but was told by my mechanic that the Phase-9 will work the the SSI since the SSI are too long and the Phase 9 will stick out too far. I was told I would need to switch to race headers to make the Phase9 fit properly. I needed to keep driver's side heat however, so I didn't get them.

I ended up going with the M&K dual out. It is a fair bit louder than the single out Monty, and give a really cool sound. No noticable power difference though. Installation was a simple bolt on. Unfortunatly, my M&K cracked after my first track event, so I put the Monty back on. I called Ben at M&K and he suggested I get it welded locally (at his expense), and if that doesn't work, he'd replace it. So, although I had a problem with his product, I would recommend M&K since Ben was very good to deal with and responsive to solving problems.

Do you have any sound restrictions at your local tracks? I couldn't run the M&K mufflers you are looking since they would be too loud for the two tracks I drive at the most. The Phase-9's just get through sound.

 

Thanks sjanes, that's very helpful!

I have the same issues in traffic - can't hear my car.

No sound restrictions at our track (yet).

Ok, so Phase9 is out with my SSIs.

Where did the M&K crack? I assume this was the 2-in, 2-out?

I'm considering the M&K "shorties":



Cheers,

Jeff

 

Yes, mine was the dual-in-dual-out. It cracked where one of the inputs was welded to the muffler. You may want to confirm on the Phase9 wrt the SSI, but that's what I was told. There are a few guys on the 911 Pelican board that have Ben's shorties and appear happy with them. Ben told me they were too loud for the street, but fine for a track only car.

 

I have some M&K race mufflers on order myself. Ben said they will be around 108 dB with the 3.4 engine we are running them on. He also recommended a bracket similar to what is used on megaphones to support them.

I thought about the same options as you have listed but selected the M&K's for a few reasons #1 being that my engine builder recommended them. Cost is also key and they are very reasonably priced for the pair. They are basically a bolt on and don't require me to make flanges like the Coast Fab or Burns Stainless ones would (I already have a megaphone bracket). Phase 9 looks good but is over double the price, and I haven't really heard anything good about Supertrapps on 911's. I think they will be pretty loud but I've already got a quiet system for tracks with noise restrictions.

FYI- the price you listed is for unpolished, polished like in your picture is another $40 or so

 

Thanks Corey!

Regarding a bracket - I may have to give that some thought. Seems like 3.5 lbs out to be all right hanging off the SSI flange. Are you running headers with an extension tube between the end of the header and Ben's shorty muffler? Perhaps that's why a bracket is needed?

Thanks for the info on the price - still a great deal compared to the other options.

Cheers,

Jeff

 

I'm not worried about the effects on the header, the bracket would be there to prevent the muffler from failing at the flange. All of the weight of the muffler is cantilevered off of the flange where the weld is, the high temperatures combined with all of the vibrations and shock loads can cause it to fail at the weld. I have seen a few megaphones (which are lighter than the M&K's) fail this way. The bracket doesn't weigh much and will help support the muffler. Maybe it isn't neccesary but Ben said it was a good idea and I agree.

 

Thanks for the advise about the bracket. I assume that is something that you made yourself?

 

I got it with a bunch of used parts I bought, it is pretty simple. Mine looks homemade from sheetmetal but they are available from a few shops (see below). The mufflers are then secured to the bracket using large hoseclamps or springs, I'm going with springs so the system is free to expand and contract but is still supported.

http://www.patrickmotorsports.com/cg...6%20Conversion

 

I have the M&K Shorties pictured above on a 914-6. They are loud. Nice units. I have the Coast Muffler on a FC. Also very nice unit, but loud. If you have sound restrictions, do lots of research. I'm not sure either of these would pass.

 

I have the Bursch Headers and Supertrapps. I have no problem hearing the engine at all. Very loud. I have not experimented with the disks yet. Very simple set up though. I hope to be able to tone it down a bit for noise requirements at some tracks. The engine seems to really like this set up. But what do I know .

 

A company I do work for has "race" mufflers. They are technically a muffler and may work for you. Full stainless, and classed as a muffler for racing.

http://vibrantperformance.com/catalo...c3c43949f9545f