Roll bar noise

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simonjrwinter
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Roll bar noise

Post by simonjrwinter »

In the new year I’m going to be replacing my MGB axle with a Jaguar IRS. On one of my previous cars, the whining caused by the solidly mounted diff reverberating through the roll bar drove me nuts. I attempted to quell it with expanded foam but it never really worked. I was wondering about filling the roll bar with rubber crumb?
(eBay) I’m pretty sure this would stop the roll bar acting as a conduit for sound.....anybody tried anything similar?
Simon
TR6 (V8) Hawk 289 FIA (V8) Doing my bit for global warming.
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Migge
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Re: Roll bar noise

Post by Migge »

Your exhaust pipes are too quiet.
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peterc
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Re: Roll bar noise

Post by peterc »

Initially sounds a good idea but not sure how you would get the crumb in. Both hoop and brace are sealed units. Any cutting would need re welding and as such not desirable if filled with foam. You could possibly squirt in expanding foam through one of the bolts holes but not sure how far you would succeed in filling it.
The only noise I have noticed is the hissing noise of the pads brushing the discs when traveling slowly otherwise engine and gearbox are dominant. Insulation under the carpet helps but not that successful.
Peter C
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clive
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Re: Roll bar noise

Post by clive »

I use earplugs! To be honest I haven't heard of anything that is successful in addressing the issue. The only time that it actually bothers me is driving with the hood up. Using in-ear headphones is also a good solution to the problem.
Cheers, Clive.

(If I'm not here I'm in my workshop or on the golf course!)
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simonjrwinter
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Re: Roll bar noise

Post by simonjrwinter »

I’m obviously too fussy! :lol:
TR6 (V8) Hawk 289 FIA (V8) Doing my bit for global warming.
SiJackson
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Re: Roll bar noise

Post by SiJackson »

Migge wrote: Tue Dec 17, 2019 9:24 am Your exhaust pipes are too quiet.
This is your answer ^^
allan horsfall
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Re: Roll bar noise

Post by allan horsfall »

Simon,

I dont have a roll bar! No roll bar, no noise, no problem. Simples.
But seriously as Clive pointed out, its all a lot worse with the hood up. I have a Jag diff and with the hood up my wife wears my strimming ear defenders in the car, 'What did you say' !
However it promotes the joy of open air driving?

Ps. Would a rubber pad between the chassis and roll bar mounting help?

Allan
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StewbieC
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Re: Roll bar noise

Post by StewbieC »

I used to get diff noise from the Jag Diff along the roll bar and then I had a new exhaust and the problem is solved.
Car sounds awesome now and even when not driving through tunnels! 8)
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Stu
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simonjrwinter
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Re: Roll bar noise

Post by simonjrwinter »

Now I’ve got my car just how I want it, I’m going to address the issue of roll bar noise. I’ve got sound proofing in the car and silenced exhausts (that’s how I like it) but the newly installed IRS is making itself heard. I’ve read LOTS of theories, expanding foam, rolled up carpet etc, but the only one that seems truly successful is pouring in moulding rubber. A cobra owner on the cobra club site achieved what he said was a “98%” improvement in noise transmission and that he could only hear any noise at all when turning his head to place his ear closer to the hoop. I’ll see what’s available, give it a go and report back. He reported the cost to be under a tenner!
Simon
TR6 (V8) Hawk 289 FIA (V8) Doing my bit for global warming.
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Roger King
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Re: Roll bar noise

Post by Roger King »

My Hawk had no roll bar, and a Jag diff. There was always a 'zizz' from the diff audible through the rear of the car even without the roll bar. This applied to three different diffs when I was fiddling with ratios. The reason is that the diff is mounted directly to the frame of the car, unlike in the original Jaguar mounting or the original AC mounting, for that matter. Not much point in filling the roll bar with anything when the diff is mounted to the main frame behind you. As suggested, just turn the exhaust up.
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