I bought my RV-8 about 18 months ago and have struggled a little with the Vetterman crossover exhaust system. I had a crack at the number 2 cylinder attaching flange and, a few months later, a crack at the number 4 flange. Then, just a few weeks ago, a crack at the crossover tube just before the exhaust outlet on the right side. I was also repeatedly breaking the crushed tubes or the adel clamps at the attach points on either the exhaust or the engine mount.
When I got the repaired pipe back from Vetterman last week, I was determined to get the system better support to avoid future cracks! After doing a lot of reading here, and consulting Vetterman's installation package directions, I decided to rework the entire support system.
Previously, I was attaching the support system to the engine mount and the tying the two pipes together horizontally. This time, I decided to attach the supports to the engine and make no attachments to the engine mount. I attached vertical supports from the sump to both pipes. Then, I tied the two pipes together horizontally.
I have attached a link to a video which shows the new support system and my test flight. The startup and shutdown parts of the video are slowed down but the rest of the video is full speed. The indications for speed, vertical speed, and G are unreliable but I did put 5.5 positive and 2 negative on the airplane during the aerobatic portion of the flight.
As you'll see, that exhaust system has a lot of movement during startup and shutdown. For me, this video is clear evidence that attaching to the engine mount is probably not a good idea. The exhaust system moving with the engine seems to make more sense to me.
Hopefully no more cracks! Thanks to Clint at Vetterman for his help and for his quick and expert repairs of my pipes!
Enjoy - https://photos.smugmug.com/RV-8-Exha...t_mp4-1280.mp4