neunelf

I have read so many times how the RSR mufflers only get better with age but I have never read what physically changes to make this happen.

What causes this metamorphosis?

jes999

There are two schools of thought on this.

The first is that the ECU adjusts to the different pressure and flow characteristics of the RSR vs standard mufflers.

The second is that through heat cycling, the steel characteristics change slightly leading to the "deeper" sound with age.

Not knowing anything about engine electronics, I cannot comment on the first theory. Knowing a little bit about materials, the second theory is probably plausible.

I do know that the "note" of my RSRs changed a noticeable amount from the time they were installed thru about the first 500 miles. Also, the car seems to be a little more responsive thru the midrange.

Flying Finn

I'd think it's mostly when the metal mesh, rockwool or whatever, burns or gets packed that causes this.

neunelf

With the Porsche mufflers wouldn't the steel and/or interior innards already have gone thru their heat cycling prior to being converted to an RSR?

I would expect new RSR's to already be broken in. I don't imagine Robin would add any new materials that need to be seasoned. <img src="confused.gif" border="0">

PramTT

[quote] With the Porsche mufflers wouldn't the steel and/or interior innards already have gone thru their heat cycling prior to being converted to an RSR? <hr></blockquote>

Yes, from my experience with my the TechEfx muffler which like the RSR is basically a reworked stock muffler, I did not notice any change in the sound with use.

However on my current Techart muffler, it is definitely noticeable that after about 500-1000 miles, the muffler definitely sounds louder

Kevin

Brad;

The interior of the mufflers do have a stainless mesh. This does not account for anything that possibly get removed in the conversion process. The inner tubes are not made out of stainless. the perferated tubing will rust through. The lower jay tube does corrode. I can post you guys a picture of the insides. As the tubes rust the sound level increases.

Mike in Switzerland

On some days my RSR's sound more like I have a blowing exhaust (ie hole) and on others it seems fine. Could this be the innards breaking down?.

I've done about 35'000 miles on my RSR's.

Regards

Mike

Kevin

Here is the picture of a 993 muffler that I have cut away. All the tubing and structures inside the mufflers are made out of mild steel. You can see the corrosion that takes place.

neunelf

Kevin,
Thank you for posting the photo. That is very interesting.

What has confused me is that I have read in some older posts that in a short time the RSR's would developed a more robust sound. I couldn't imagine that corrosion would have played a part in the sound change in such a limited time. Maybe, the process of the conversion promotes a brief acceleration but then a sustained alteration of one or both of the interior tubes.

I understand that conditions can vary widely but can anyone give an estimated life span of a Porsche muffler? Has anyone here had to replace their Porsche mufflers because of deterioration?


<img src="graemlins/yltype.gif" border="0" alt="[typing]" /> As a side note, I have had RSR mufflers on my 993 for almost a year and am pleased with their sound.

Kevin

Brad;

I had those same concerns especially when I seen all the corrosion. My solution was to purchase stainless steel mandrell bent 90's and weld them directly to the inlet and outlet openings. I then welded a 2 1/2" section of the factory perferated pipe between the 90's. Everything else was trash canned. It really sounds good.

neunelf

Kevin,
I bet that does sound Great!
Is the perforated pipe you used still mild steel?

neunelf

Kevin,
Ignore my previous post. I do see your comment above referring to the mesh as stainless.