M3 exhaust modification

[amhobbs]

Hi Guys,

Just did mine this Sunday.
I filmed the whole process and you can see it here:
http://audittrs.wordpress.com/tuning-bmw-m3-e92/.

I did the iPhone dB comparison with an Eisenmann Race Exhaust. His is louder, but for the cost ,I much prefer mine!

Let me know your thoughts,

Andre

[HighRevM]

Nice Video, Interesting how you cut open the top of the exhaust and not the bottom like others. Might be doing this mod shortly...

[F82_SID]

Originally Posted by amhobbs

Hi Guys,

Just did mine this Sunday.
I filmed the whole process and you can see it here:
http://audittrs.wordpress.com/tuning-bmw-m3-e92/.

I did the iPhone dB comparison with an Eisenmann Race Exhaust. His is louder, but for the cost ,I much prefer mine!

Let me know your thoughts,

Andre

So you only replace one of the perforated pipes on each side? I know some people are doing both.

BTW, my name is Andre too. How weird

[snowmants]

Cut open my exhaust, took it to the muffler shop and asked the welder to cut out the perforated pipes and weld in straight pipes......the welder there said he didnt think he could do it. He felt there was not enough room to weld all the way round.
So I have gone to plan b and i have ordered 2.5 inch diameter exhaust clamps to weld in place over the 2 perforated pipes. Not sure if anyone has done this. We will see how it goes. If I dont like the way it looks when I test fit I wont weld them in and I will go some other route....I am hoping not to do the exhaust wrap as I am concerned about longevity.

[kcdude24]

Originally Posted by snowmants

Cut open my exhaust, took it to the muffler shop and asked the welder to cut out the perforated pipes and weld in straight pipes......the welder there said he didnt think he could do it. He felt there was not enough room to weld all the way round.
So I have gone to plan b and i have ordered 2.5 inch diameter exhaust clamps to weld in place over the 2 perforated pipes. Not sure if anyone has done this. We will see how it goes. If I dont like the way it looks when I test fit I wont weld them in and I will go some other route....I am hoping not to do the exhaust wrap as I am concerned about longevity.

It should not matter if they can't weld every single mm of the replacement pipe...the original has perforations in it. I had one done and just had them weld patches over the perforations. This kept the original pipe in place and just requires welding around the perimeter of the patch. Still some perforations may be open but it should not be an issue.

[JChan]

Originally Posted by jateshk

Any one in Los Angeles that has done this!?

+1 Has anyone in So Cal had this done and where!?

[snowmants]

Originally Posted by kcdude24

It should not matter if they can't weld every single mm of the replacement pipe...the original has perforations in it. I had one done and just had them weld patches over the perforations. This kept the original pipe in place and just requires welding around the perimeter of the patch. Still some perforations may be open but it should not be an issue.

What did you use for patches? You must have cut out both the top and bottom of the muffler to weld the patches over both sides of the perforated pipes....?

Well I received my test exhaust clamp made by Borla, in the mail yesterday and it looks like it will do the trick nicely. I now need to order 2 more. My plan is to cut one of them in half so that I am using 1 and a half exhaust clamps for each of the 2 heavily perforated pipes. This should cover all, or nearly all, of the holes. I am thinking about having the shop that welds the cans shut again also weld the screws on the exhaust clamps so they dont work their way loose and start vibrating. I will post some photos so you guys can see.
Here is a picture of the 2.5" diameter Borla clamps that I am using. They are $20 each and I should need 3 total:

[kcdude24]

Originally Posted by snowmants

What did you use for patches? You must have cut out both the top and bottom of the muffler to weld the patches over both sides of the perforated pipes....?

We used a thinner walled 2.5" pipe cut vertically and then slightly opened to create two sections of pipe just a shade bigger than the existing pipe. Those were sandwiched over the existing perforated pipes and welded in to place. It took a bunch of little tweaks but it only required the top cut out.

[snowmants]

Originally Posted by kcdude24

We used a thinner walled 2.5" pipe cut vertically and then slightly opened to create two sections of pipe just a shade bigger than the existing pipe. Those were sandwiched over the existing perforated pipes and welded in to place. It took a bunch of little tweaks but it only required the top cut out.

Ok understood. Well my last two clamps arrive today so I will be cutting the one in half tonight and then test fitting them all over the pipes. If I am pleased with it, I will try and get the screws welded and the muffler welded shut. I may also have them add some tack welds to the clamps just to further ensure they dont move. I will keep everyone updated and try and post photos tonight once I get the clamps in place.

[snowmants]

Worked on the exhaust more tonight. I found that after fitting the clamps I really needed to use 2 on one side and one and a half on the other as the perforated area is longer on one side by about an inch and a quarter or so. Rather than ordering an extra clamp for the side I havent done yet I am going to try and get a small piece of stainless steel sheet metal which I will roll like a tube and put over the perforated pipe. I will then put my last remaining exhaust clamp over that to secure it all. This second pipe is straight so it should work. I think the 2 clamps work well on the side I have already done as there are more perforations and the pipe has a bit of a bend to it as you can see. There are some perforations left open but not many. I think this will work very well. Photos from my work last night:












In this one you can really see how tight the clamp is over the perforated pipe. You can see the outline of the change in diameter as well as the outline of the perforations and this is pretty beefy stainless steel. It is just a very tight fit.

[kcdude24]

I just saw an OEM unit in the for sale section that was opened up and only the white stuffing pulled with the pipes left in tact. I'd be curious to see the sound difference between that setup, a partially closed setup like yours and a fully closed set where the pipes were replaced. Maybe there is no difference at all??

My guess is that those few open perforations won't make much difference. Button it up and give us a sound clip!

[snowmants]

Originally Posted by kcdude24

My guess is that those few open perforations won't make much difference. Button it up and give us a sound clip!

That is my guess as well. I predict that on this side I have covered approximately 90% of the perforations. On the other side it will probabaly be closer to 95%. Atleast I will be keeping with the original ratio as the 90% side I did already had more perforations to begin with. I should be able to finish it up tonight as long as Lowes has a nice piece of sheet metal and then I will get it welded shut next week.

[amhobbs]

Originally Posted by snowmants

Cut open my exhaust, took it to the muffler shop and asked the welder to cut out the perforated pipes and weld in straight pipes......the welder there said he didnt think he could do it. He felt there was not enough room to weld all the way round.
So I have gone to plan b and i have ordered 2.5 inch diameter exhaust clamps to weld in place over the 2 perforated pipes. Not sure if anyone has done this. We will see how it goes. If I dont like the way it looks when I test fit I wont weld them in and I will go some other route....I am hoping not to do the exhaust wrap as I am concerned about longevity.

Buddy, find another shop. Take a loot at my video, it's an easy 3.5 hour job...

[amhobbs]

Originally Posted by E90 ZCP

Nice Video, Interesting how you cut open the top of the exhaust and not the bottom like others. Might be doing this mod shortly...

Thanks

[amhobbs]

Originally Posted by E92_SID

So you only replace one of the perforated pipes on each side? I know some people are doing both.

BTW, my name is Andre too. How weird

Yes, the one to be replaced is the fully perforated one. The other one only has a few holes so no change in sound IMO.

I have been driving the M3 with this mod for a few weeks now and I love it even more! I would call it "stealth" if I drive slowly without the M Drive. (I have an SMG tranny). But it's another story on M Drive! The car roars and people turn their heads as I give it some gas. Lot's of fun!

Ciao, Andre

[snowmants]

Originally Posted by amhobbs

Buddy, find another shop. Take a loot at my video, it's an easy 3.5 hour job...

Haha too late! Finished up tonight. I got a piece of 30 gauge galvanized steel ducting and chopped a piece out of it to wrap around the perforated pipe. Then I installed my 3rd exhaust clamp over it to hold it in place. I then used two of the steel screw clamp things to be sure the ends of the sheet metal are secure. There are only a very few holes that are not covered on this side. Probably 5% or so. Now I just need to take the exhaust on monday to be welded shut. The ducting and the screw clamps only cost $6 total at Lowes. Each of the three large borla exhaust clamps were $20 shipped, so total cost was $66 for the supplies and I paid $150 for the used exhaust, so I am at $216 right now. The final costs will be welding the cans shut and high temp flat black paint.

[GewoW]

Originally Posted by amhobbs

Yes, the one to be replaced is the fully perforated one. The other one only has a few holes so no change in sound IMO.

I have been driving the M3 with this mod for a few weeks now and I love it even more! I would call it "stealth" if I drive slowly without the M Drive. (I have an SMG tranny). But it's another story on M Drive! The car roars and people turn their heads as I give it some gas. Lot's of fun!

Ciao, Andre

[kcdude24]

That's some getto shit dude i'd weld every part of that...hate to get a loose part rattling around after you close it up.

[JCtx]

Hey man, couldn't you have photoshopped those ugly toes out? Geez . Just giving you a hard time .

Just make sure those clamps are not tighten to hell since you mixed different materials, and they expand at different rates. You don't want something breaking inside and rattling to hell. Also remove all labels man. Good luck. Looking forward to your video clip next week.

[Tomislav]

so covering up the holes helps how?

[snowmants]

It just makes the exhaust louder. Allows you to hear more of that great engine noise.

[snowmants]

Put the fiberglass stuffing back in tonight. I used mechanix gloves but still managed to get fiberglass embedded in my hands. It went through the gloves. Anyway, exhaust is going to the welder Monday. They are an old school shop and work slowly so I will probably get it back on Thursday or so. When I get it back from the welder I will spray it flat black. What is the best high temp. paint to use?