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Date Name Message
09/07/2005 19:59:07   Bart   Does anyone have some good ideas to reduce to vibrations of a Simons exhaust at low revs? Currently my whole interrior vibrates at low revs.  
10/07/2005 10:01:35   Rens   did you use all of the rubber mountings?
what you could do is use some rubber rings between the bolts.  
12/07/2005 12:34:10   Richard   Try loosening the system and re-clamping it. It should be clear of everything and be relaxed so when you clamp it is pretty much stays where it was pre-positioned.
The other things to look at are your engine and gearbox location. Is the engine moving alot? Are the engine mounts soft from oil contamination and is the side bar doing its job?  
14/07/2005 20:47:25   Alex   Low revs resonance is something new to me. What I know of is a resonance around 3500 rpm. The cause are the rubbers just behind the first silencer that are bolted into the cabin floor; thin sheet metal singing away nicely. When that connection point is used, whether with an original exhaust or a Simons, you'll end up with vibration. In order to cure it I put extra clamps at the front side of the pipe. One of them I bolted down in the front side of the cabin where the floorboard is joined by two layers of sheet metal; that way you avoid resonance. This extra clamping made a difference but if the flex pipes Max is speaking of were so easily available 15 years ago I would have gone for that (still an option for the Highgate under the Sonett though...).  
19/07/2005 20:24:43   Bart   Thanks for all reactions.

Rens: The exhaust is only mounted at the engine and at the back silencer. On the back I used the rubber mounting bolts which were delivered with the simons exhaust. The mounting in the middle of the car isn't used.

Richard: I'm going to try loosening and re-clamping the system anyway, because it's hanging to low at the moment which was also the reason to not use the middle mounting as this didn't fit. Maybe loosening and re-clamping helps...

Alex: I've also got the resonance around 3500 rpm, but I had that one also with the original exhaust. Both exhausts, the original and the current simons, didn't/don't use the connection point in the middle of the car. And still that resonance at 3500 rpm....  
19/07/2005 22:50:34   Alex   How come that the middle mounting didn't fit? And why is it hanging too low? Is the header positioned wrongly so that the end piece where the S-bent attaches to angles a bit downward? This could cause that everything attached to it gets to hang lower than it should. You take quite a risk in hanging all that weight on only the two rear end rubbers.  
20/07/2005 01:42:58   John   If the exhaust you have is the same as the one shown on Motorsport Sweden's Web pages then this system is similar to SAAB's Sports Kit exhaust. The central muffler should be supported at each end on four rubbers. If necessary you can shim the rubber cushions at the body side if it appears the piping is going to be too close. The rubber cushions also need to be heavy duty- see Sport & Rally Catalogue. The standard V4 cushions are too flimsy. There were two mounting kits originally - Sports and Rally. The later had lengths of rubberised webbing which were used to restrict lateral movement of the piping. Once the centre section is supported the resonance should reduce.  
22/07/2005 09:43:55   neil   Just so Bart isn't paranoid, I get this with mine too...  

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