Side Pipe(s) Hanger - stress cracks & repair

[Jester]

Roadster is back from paint and nearly ready to graduate (~2500 miles in gel-coat for shakedown this past summer before paint – no issues to report and I could have gone immediately to paint before shakedown). During final re-assembly, I polished the side pipes and I unexpectedly noticed the dreaded stress cracks at both ends of each hanger :( – on both pipes (see photo). I decided to contact my welder and design/fab a fix which consisted of stabilizing the stress cracks by welding & grinding before installing and welding a ~ 1/8th thick circular stainless plate over the area to spread the stress developed during acceleration (motor rotation). I will also only install one hanger-side pipe bolt to allow the hanger/side pipe to rotate freely during acceleration (the 2nd hanger/side pipe bolt causes unnecessary added stress to the side pipe hanger – as described in other posts).

I have attached a few photos of the cracks and repair for reference. Repair cost ~ $100. I am very happy with the repair as it looks stock and FFR should consider requesting that the manufacturer design a similar reinforcement of the hanger to eliminate this premature failure.

Comments & other fixes/ suggestions welcome

Note: I am also cutting the tips and rotating 60 deg (toward the ground) and re-installing to reduce cockpit db's.

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[NukeMMC]

When doing piping installation, it is normal practice that when attaching a pipe that is <1/2 the diameter of the parent pipe, you install a reinforcing pad around the pipe being attached. This is done to avoid the exact same stress cracks you experienced. I guess I will be making a re-pad for my bare steel pipes before I get them ceramic coated.

[skullandbones]

Jester,

Like your fix. I started out with the single bolt install. I am hoping it will delay any issue like you have experienced. I will expect to eventually have to do this patch repair on mine but at around 500 miles, I haven't seen any problems so far. If it shows any damage at around 2500 miles on mine, it will support your suggestion of the bad design. Thanks, WEK.

[Jeff Kleiner]

..I will expect to eventually have to do this patch repair on mine but at around 500 miles, I haven't seen any problems so far.

I use only one bolt---15,000 miles on one car with no cracks; 10,000 on another with no cracks.

Jeff

[Mike N]

I got to just over 3500 miles before my first one went. I checked the other side when I did the first and it too was starting to stress crack. I did a similar repair and it's been holding up fine. I agree that FFR should implement an upgrade to add a plate under the hanger and that would solve the issue very nicely. In production it would probably add less than $20 to a set of pipes but potentially save customers $100's.

[Bob Cowan]

I don't use hangers at all. After the attachment point borke 3-4 years ago, I welded on a patch and got rid of the hangers altogether.

[skullandbones]

I don't use hangers at all. After the attachment point borke 3-4 years ago, I welded on a patch and got rid of the hangers altogether.

I wondered whether that would work. Just didn't have enough nerve to try it. I think the single bolt version makes the most sense on paper and it's sounding better as the reports come in. I don't feel so bad about the potential issue. It's a little like the mods that people do to keep the door latches from failing prematurely. I think you could cut and fabricate a patch for the side pipes pretty easily and not have the car down for long. Thanks Jester. This thread is informative for those of us who don't have that many miles on our roadsters. WEK.

[CraigS]

Assuming you have 4 into 4 headers you don't need any hangers. I have 26000 miles and 6 years on mine w/o hangers and w/o any problems. I have said this in other posts but will repeat here. My pipes originally had one a little high at the tip and the other a little low at the tip. I jumped my 190 lbs up and down on the high one and managed to make it move maybe 1/4 inch at the tip. I jacked up the entire side of the car, both wheels off the ground, jacking about 3 inches forward of the low tip. I then jumped up and down in the seat. I managed to move that pipe maybe 1/4 inch higher. These pipes and headers are STRONG and have no need for hangers.

[Avalanche325]

... I jumped my 190 lbs up and down on the high one and managed to make it move maybe 1/4 inch at the tip.....

Ahhhh, the good ol' fashoned gorilla fix!!!