Weasel497

I'm running a Sheepey hot side kit with a 6262 and I keep having my downpipe crack at the lowest point where it snakes under the oil filter. First time it happened, I thought the rest of my exhaust was putting stress on it, even though it has a flex joint. So I decided to run open downpipe. Got it welded back by a local fab shop, and that lasted maybe 2 months, then it cracked fully in half around the same area. Had a welding inspector weld it up and x-ray the pipe and he assured me that it's as solid as it's going to get. Lasted me maybe 4 months, then cracked again. Has anyone else run into this problem? I have the downpipe braced to the trans at the end, but it broke that brace once too. I can only think it's caused by this gnarly vibration I get at 3k which is pretty unavoidable because that's cruising speed in 6th for me. Would bracing the end of the manifold make any difference? Maybe having the downpipe made out of a thicker material? I'm at a loss and don't want to keep throwing money at this stupid problem. Makes me scared to drive the car any further than a few minutes from home.

Jaspah

Does the downpipe have a flexible piece and a mount after the flex?
This is key in not killing your downpipe

Weasel497

Yes, the downpipe has a flex joint near the end, and I have the exhaust brace mounted after the flex piece.

2004TurboS

What engine mounts do you have ? Are they in good condition?

Spoolin

I think the problem may lie with where you have the DP brace. Having it after the flex pipe may be allowing the pipe before the flex to resonate off the turbo a lot. Try moving the mount to before the flex pipe or move the flex pipe to behind your mount.

nguyen365

that's a big downpipe. 2.5 to 3inch or 4? Have a muffler shop weld some braces?

Weasel497

The problem is that there's not really anywhere to brace the dopwnpipe closer to the turbo or before the flex joint. It's a 3" pipe btw. I guess I'm going to get new motor mounts and have a new pipe made and hope for the best.

Spoolin

If you can, when you have the new one made, have it be a solid pipe from the turbo to the mount and then put a flex pipe on after so the rest of the exhaust can move since it's rubber mounted. What you want is the manifold and DP to be stationary to the engine and move with it and the rest of the exhaust move with the body. Vibratechnics are the best mount IMO.

spectacle

Add another brace before your trans mount and that should fix the problem. You need two on this motor because of the vibrations.

jzz30

My downpipe used to crack every so often. Added a flex and it helped. Then found my motor mounts were trashed and ever since I changed them out to innovate mounts my downpipe hasn't cracked since. I do want to go back to stock mounts though vibration sucks