I bought a used Evolution Motorsports exhaust from petert on the board. He's a good guy. He gave me a smoking deal on the exhaust because it had some 'issues'. It had a horrible buzzing or rattling noise. Beyond horrible, according to peter. The vibration caused the silencer shell to spilt wide open along the weld. I should add that this was one of Evo's old systems and I believe their current system is different. Also, I don't think this old system had any inherent problems; this one was just not right.

I happen to be a mechanical engineer and I do some freelance work for some motocross accessory manufacturers. One of them makes exhausts and they weld stainless all day long. So...after looking at it, I think I found the source of the rattling and I had it rewelded and added some supplemental welds as well. We also opened it up to see what was inside. It was the same as a motoX exhaust basically; just a perforated tube (perf core) with some packing material around it. Steel wool in this case. Probably stainless steel wool.

This exhaust is pretty cool in that it has some flexible tubes going from the cats to the silencer. I can't see how you would mount a rigid one piece system. The chances of it fitting every car would be very slim. In fact, petert had to modify his new system to get it to mount successfully. Even with these flex tubes, it was still a ***** of a job for one person. I'm friggin' sore today. Especially the back of my head from the garage floor

The sound is pretty cool. Very different than an exhaust for a normally aspirated Carrera. On startup, it's got a nice, deep growl. It sounds pissed. While driving, I didn't detect any resonance on my way into work. Need some more driving to experiment at different RPM's and speeds. When you hit the launch pedal, the turbos are barking like a couple of rabid dogs. Sounds like a $100K sports car now. No more sewing machine. Hopefully, it'll hold together. I'm keeping my fingers crossed.

 

That's a great story and it's always good to see someone put som real effort in You'll have to make a video clip... You've got one of the last ones since I believe EVO stopped making them

 

Thanks. Too bad they stopped making them. Its a good design that could have been great with a few modifications. I wonder why they stopped? Maybe the issue this exhaust had, or maybe just business reasons with who was making it for them. Who knows. I guess its pretty cool that I'll have an exhaust that not many others have.

It did mount a little crooked too. The straps on the can need to be moved a bit. For me its fine. I'm not that ****.

 

Jack, do you have anymore pictures of your car? Or possibly a video clip of it with the new exhaust?

And good job doing some fabrication work.

 

Here's a pic of the car before exhaust. Nothing to see but stock tips though. They do stick out too far like others I've seen also. I wish it looked more like stock.

No video clip with sound.....sorry.

 

Above pic is at Irvine Spectrum...Jake we should hook up and check out the rides. Would love to hear the exhaust.

T

 

Well....the exhaust held together for about a week. The weld split again. This time, I'm going to weld an additional stainless sheet over the entire side of the exhaust can. I think the problem is that the wall thickness they chose was too thin and the weld location is lengthwise right in the middle of the flat area of the oval cross section of the exhaust can. If the weld were near the top or bottom, it might have helped. I think there's a certain PRM range that causes this think wall to vibrate and it just tears the weld apart. I figure if I change the thickness (mass) of the wall, it will have a different resonant frequency and it should hold together.

The ****ty part is that these exhausts are a pain in the *** to put on and off. In fact, taking it off last night, I screwed up one of the studs coming out of the turbos. The studs are replaceable because one of them came right out. They're threaded on both ends. It's so hard to fit a 13mm socket in there because of the diameter of the cats. I'm going to try and get some replacement studs and nuts from my local Newport Beach dealership today. I hope they have them.

 

Got the exhaust back on again last night. This time, we rewelded the original weld, and drilled holes in the overlapping portion and then plug welded the holes. We also added a 3" wide patch over the entire weld and welded the perimeter of the patch as well as plug welded some holes in it. We also purged the area with inert gas for a clean weld.

I think the problem that caused the failed weld was one of the following items:

1. The original weld, and the first weld that my guy did, may not have been purged adequately with inert gas. Any contaminants present while welded stainless will cause a weak weld.

2. The location of the weld is right on the flat of the oval shaped can. This flat is a point of vibration that may have just destroyed the weld. Ideally, the location of the weld should have been closer the the top or bottom of the can.

3. The material they used may be too thin. The thin material has a resonant frequency through a section of the RPM range and the vibration from this resonance may have torn the weld apart.

I just drove to work and its sounding great. Only time will tell if it holds up. We'll see.

 

Hey JakeMate,

How's about welding a pair of CF Jardin race pipes on instead... wonder how that would sound!

 

I had that old system on my 01 TT - one of the best sounding exhuasts I thought

 

StephenTi: My buddy works over at Jardine. Maybe I'll ask him to send a few shells my way

Darren: Yep....it sure sounds sweet. A nice deep, low growl. Until the weld breaks....then its more of a rattlling, cat-in-heat, kind of a sound.

 

I solved the clearance problem by grinding a little off a 13mm open end/box wrench. Also took a ball peen hammer and set it on the cat where the studs protrude and gently hit the ball peen with another hammer to indent that area. No more clearance problems and the welds have held up fine.

 

Does it look like this setup ?

 

Great idea. When the weld breaks again, I'll have to do that.


Darren: Yep....that's it.

 

The exhaust blew apart again. Luckily I was 2 hours from home on the way back from an Open Road Race in Nevada. I put the stock exhaust back on (just what I felt like doing after a 10 hour drive).

I'm convinced that the resonation at around 3800 RPM is is so strong that it's just tearing the exhaust welds apart. I'm not sure what to do now. Maybe that's why Evolution Motorsports stopped making this system.