Serious Vibration Rumbles @ 1800 Rpm

[richaney]

Anyone suffered from this on an S1 Elise?:

 

Yesterday, whilst driving through Loughborough (as it happens) my 2000 S1 started suddenly making a god-awful rattle/buzz at 1800 revs only, powering up and coasting down. I already have the recognised 2500 rpm 'tizz' and was due to get the bracket fitted on my next service in October, but this seems to be a much more violent variety.

 

I thought the exhaust had blown at first, but it is only @ the 1800 rpm point, and echoes all around the cabin. It is hardly present when the engine is cold, increases with temperature, but continues to increase once my usual 84C has been reached - as if a part in the engine compartment is slowly being warmed by indirect proximity to the engine. It cannot be easily heard from outside the cabin, and still only marginally from either above with the boot lid up or from underneath.

 

Any pointers gratefully received - otherwise its off to the garage for them to spend several days of fruitless (? - and expensive!) searching. At the moment my gear choices are set to stay above 2000 revs whenever possible to avoid exaserbating the situation whilst keeping the car on the road.

 

Cheers for any help.

[ally]

Not sure about that one, thought it could be your exhaust mounting but you say that has been checked, so i am at a loss. Try posting this on SELOC as well, there are loads of people who could hopefully help on there

[Scott_Mac]

Floor pan vibrating? Exhaust catching bodywork? Combo of both?

 

I hvae had both of the above cause serious vibrations at ~ 1800 rpm.

[steve]

Could it be the baffle inside the exhaust coming loose?

 

Or the the little "fill-in" piece between the outer and inner tubes on the tailpipe itself? Mine has come loose and although it doesnt sound like it was as noisy as yours, it was very noticeable.

 

Maybe it could be part of the downpipe touching the bulkhead... or more likely the heatshield or its bracket touching the bulkhead or the downpipe (mine also broke and it needs doing because lotus kindly put some flammable sound proofing right behind the breakable heatshield!!!).

 

Sorry i cant point to anything definite but theres a few leads.

 

Steve

[Ladders]

Could be the flexy section of the manifold coming apart, the bits then rub against the undertray

 

Try taking the engine tray off and having a look!

[Scott_Mac]

Also sounds familiar....

[JohnnyM]

i had the floor under the seats rattle like a nutter. fixed it by wedging a cut off of black carpet under there. went away when i had the full carpet set in the car.

 

although i dont have that or the rattle on the s160

[ipanter]

loose change under seats?

[richaney]

Thanks for the replies so far. I had the speakers changed a month or so back, and they took out the passeger seat to do it - could this be part of the culprit?!?

[steve]

Possibly.... will keep you busy for a while though!!!

 

Nice choice of colour by the way - it's good to see another person with taste on here.

 

[richaney]

I took the engine tray off this weekend (a first for me!) No obvious rattly bits, or loose shielding - so that's good.

 

But still don't know where the rattle is coming from - how do you check under the floor pans under the seats?