Super Sports Exhaust Vibration?

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I have just bought s/s super sports exhaust with a silenced cat by-pass pipe.It is not the official Lotus item but the twin pipe as fitted by Haydons.Initial impresions, the car can breath! The low - mid range is much smother, more power at the top end. Noise levels are slightly lower than standard with the silenced bypass pipe and it now has a deeper note over all. But best of all I now get stabs of flames out the back! (even though it is only 177 bhp).Anyway, back to my original question, dose this exhaust cause vibration through out the car particularly at idel?

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NickI have recently fitted cat bypass and SS Exhaust - No vibration at idle, but it has always had a “tizzing” noise when on overrun at aprrox 2000 rpm. I think this is a known problem (that can be cured) as my previous Elise also used to do itHave you checked that the exhaust is not fouling on anything by wobbling the tailpipe without the engine runningGiles

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I have this exhaust too, and its just fine.Not very helpful really…Cheers

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I’ve got the Lotus stainless steel sports exhaust and occasionally I used to get a resonating noise at low revs as if the exhaust was just touching something. I believe it’s down to the care taken to fit the exhaust - it’s very tight underneath the car but it can be fitted so that it won’t knock against anything. SGT fitted mine… 'nuff said.However, my car is at B&C at the moment and the head has had to come off so I’m hoping they’ll line it all nicely and the vibration will have disappeared.I’d take it back to Haydons and ask them to check the exhaust isn’t rattling against something - it won’t need to be by much to make a lot of noise inside the car.

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I had the same exhaust fitted by Haydons about 15 months ago and had the same problem. Turned out to be a large bolt roughly in the centre of the rear underpanel was not properly tightened.

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Thanks for all your replies, judging by what you all say it sounds like there is definitely something wrong. The amount of vibration is quite extraordinary! You can even it feel on the external bodywork and right through the seats too! I am going to take it back and have it checked over, I will post the result.In the mean time if anybody has any further suggestions post them up.Thanks Nick.

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nick c or anyone:Can you describe the silenced cat by-pass pipe. I assume that this is a correctly sized by-pass pipe unit with a straight-through “bullet” type silencer.Also do you have an email address of someone at Haydons I could contact about this.ThanksSJP

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quote:Originally posted by NAL190S:Can you describe the silenced cat by-pass pipe.Not quite sure what you mean, but the cat replacement pipe is just that - a piece of straight-thru exhaust pipe the length of the cat with the same three-bolt (IIRC) flanges on each end. You can use it with a standard exhaust if you want - the silencer box is seperate.HTH.Ian [image]http://www.exiges.com/ubb/NonCGI/images/icons/smile.gif[/image]

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IPJ:Not sure what I (or he) mean(s) either. Please refer to the original post by nick c. Repeated below. Part in question has been placed in quotations. My car came standard from lotus motorsport with the cat replacement pipe. Nick C seems to be describing a different part.*********************I have just bought s/s super sports exhaust with a ““silenced cat by-pass pipe.”” It is not the official Lotus item but the twin pipe as fitted by Haydons.Initial impresions, the car can breath! The low - mid range is much smother, more power at the top end. Noise levels are slightly lower than standard with the ““silenced bypass pipe”” and it now has a deeper note over all. But best of all I now get stabs of flames out the back! (even though it is only 177 bhp).

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I’ve given up trying to stop resonance, rattles and vibration. The car seems to permenantly sound like a bag of spanners!

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I have a “Standard” 177 bhp car and I live in London and found the low speed running rough and jumpy in traffic. From what I read on this site I gathered that removing the kat would improve the overall performance (which it has see above). I found the cabin noise just about bearable in standard form, and by replacing the kat with just a pipe would increase it. My original plan was to just replace the kat and keep the standard Janspeed box, so I contacted Torque Technique Nr Salisbury (who make the s/s twin pipe systems for Haydons) Tel: 01722-744747. They made me s/s silenced kat replacement pipe, this is basically a straight through small oval silencer box with flanges at each end and slots in where the kat goes.When I got to Torque Technique the owner Mick Poulten showed me round his workshop and I was very impressed with the quality of his work (his wife who made me tea describes him as a “perfectionist”). When he dropped the belly pan he showed me how crap the standard Janspeed system is, the exhaust gasses go in one end and are left to swirl around the baffles and then find their own way out via the two exit pipes. It is also made of tinny mild steel which Mick joked is only good if you know someone with “Steel Band”! Mick’s own system is straight through design so the gasses are guided out. It made from high quality s/s with proper sound deadening material in the box. So it was a case …might as well have it fitted at the same time.I am very pleased with the performance result as my original posting…it’s just the vibration /resonation through the car. I have dropped the car back to Torque Technique and Mick is looking into the problem. I am planing to pick it up this weekend and will post up a report.