Exhaust Vibration at 3-4000rpm , Anti-tizz Bracket

[SABARRAS]

I recently fitted a sports exhaust to my S2 Elise and was pleased with the meatier sound... until I went uphill on a motorway!
I could no longer hear the exhaust note because of a deafening buzz that invaded the cabin.
After a bit of research I found that sports exhausts fitted to Elises, MGFs and Rovers can cause resonance around the manifold/downpipe. Lotus produce a part called an "ANTI-TIZZ BRACKET" which connects the manifold flange to the engine block.
Has anyone fitted this to their car and does it solve the problem? Are there any other solutions?

[tupolev]

roof on or off?

even with the anti-tizz, i find i hit a noisy resonance with the roof on (think its at about 2800) just drive through it.
roof off and it all disappears,

cheers
tupolev

[Arno]

Lotus produce a part called an "ANTI-TIZZ BRACKET" which connects the manifold flange to the engine block

As far as I know this doesn't fit on the S2 as the manifold is slightly different from the S1. (for one the location of the lambda sensor is different)

But... This specific 'tizz' usually happens much sooner. Around de 2000-2200 mark. You don't have any stones trapped between the seat(s) an the floor? The undertray and diffuser bolts are all tight? Nothing 'touching' the undertray?

Bye, Arno.

[tonykart]

This happened to me and it was because one of the bolts on the undertray was not tight, and this was causing the washer to rattle at an almost unbearable pitch.

[SABARRAS]

Thank you for your replies, I tested the car without the rear undertray panels and the loud buzz was still there, but that 'tizz' that appears around 2-2500rpm disappeared. I believe that this is the handbrake cable separater that touches the undertray when it vibrates (it is worse when the engine is cold).
I am worried about Arno's comment about the anti-tizz bracket not fitting the S2, has anyone tried to fit it?

[SABARRAS]

I HAVE GOT RID OF THAT BUZZ!!!
It was caused by 2 of the wires and cables that pass beneath the engine undertray vibrating against it.
They had worn through the factory fitted foam strips, that should dampen the noise, allowing direct contact with the metal. I just put some thicker self adhesive foam on top of the destroyed strips and it worked!!!

I can hear my exhaust at last!