^ word! ^

 

Pictures of my failed U-bolt clamp configuration. I had about 3 of those things fall off even after double nutting them. The U-bolt clamp looks the same Geometry. Even if you tried not to over tighten it would loosen up even without the nuts turning on the U-bolt. Usually it would start rattleing after some hard use. Hot pipe, thermal expansion, and external loading is just too much for the small contact area the U-bolt puts on the pipe.

Vs. my current setup which has been on the car over 2 years driven long road trips and a large number of track days running significantly below spec Miata lap records. It has never come loose or had any problems. large contact area and the clamp ends up the pretty close to the same temperature as the pipe so they expand and contract together.

I haven’t figured out how to post big pictures that you don’t have to click on?

Bob

 

I'm definitely purchasing the exhaust brace for my whip.

I'm still like every time I see that v-band setup. Time machine! aha... FM is the **** though.

 

Pardon the thread necromancy but hustler's pics are worth emphasizing. I really like turbo hangers to take the load off the manifold and the turbine joint. They don't however increase the resonant frequency of the system so its smart to also add a rigid brace between the turbo and the block. Otherwise vibration cracks everything to hell. Ask me how I know.

 

I always thought this would work as it ties motor/tranny/hotside together as a unit...but it was discounted for same reasons Bob posted the one other time it came up here.

Wouldn't the point that the clamp is applied make the difference in whether resonance was a factor or not? I'm thinking the distance from clamp to downpipe flange, and distance in other direction from clamp to first flex section would be critical, and need to be similar.

 

Wouldn't worm-gear-clamping (or something better) the exhaust to the mounting points (3 at muffler, one a little north) help? Basically tying the exhaust to the frame at those points? NVH be damned?

 

if you did that, the engine would still move and vibrate about on it's mounts - the exhaust wouldnt --> death to turbo/manifold joint

the entire drivetrain / all moving parts are suspended seperately from the body of the car in one way or another. The exhaust is a 'moving part' even though it might not move very much.

 

A datum point for everyone: I just ran a track day with the FM exhaust brace and the manifold bolts are still tight. Seems to work as advertised.

 

Have you participated in a similar track event without said brace with loosened manifold bolts as a result?

 

I have, but fuel pump issues prevented me from running for any extended period. Pre-brace, the nuts did come loose during some spirited backroad bombing, so I know I wasn't immune.

 

What fuel pump issues?

 

I installed a TRE high-pressure pump before FM figured out they suck hard. The problem was intermittent and we chased our tails for a long while before it started happening to other customer cars as well, which confirmed the actual cause. I now have a Walbro and all is fine.

 

BFTD.

Any more experiences w/ this, regarding stud stretching/loosening?

 

I'm also in for updates since I just bolted one of these up last night.

 

I actually plan on ordering on of these today myself. Seems it cant hurt to have the extra support. I have no idea if it'll work with my ARTech 3" dp, but I can always make it work if need be.

 

I used .051" safety wire to hold my exhaust at the clamp to the rear subframe to stop left/right movement. I definitely felt the shift pattern improvement at the last race, and my bumper ceased melting.