6 replies to this topic

[roofchoplofty]

Hi i have a 1275 mini with cooper freeflow exhaust and rc40 twin box. It has a minisparea inlet with 1"3/4 carb but with standard filter.
The problem i have is that i get a drumming noise at 3 to 3.4thou, this is wether the car is standstill or moving. The engine is fairly quite before this and after.
I have changed the exhaust ( this is my 3rd in two weeks), i have chaecked that is is not fouling anywhere. I have beefed up the soundproofing. I have swapped carbs. I have swapped dizzys. i have removed rear exhaust mounts and let the exhaust sit on a axle stand. I have removed the fan belt to make sure its not the alternator, fan or water pump. I have run it without the airfilter and still not difference.

The noise doesnt seem to be coming from the engine its more central to the car.
I have hit everything inside the car and nothing is loose that i can see.

Any help please, as its doing my head in. >

[Cerberus]

My rear bumper makes a rumbling sort of sound at certain revs.

Also, my bonnet resonates at certain rpms.


I would imagine, that as you've changed so much, that its probably just something that you'll never solve. Might be the body resonating.

[roofchoplofty]

thanks looks like i need a louder stereo

[mrbridger]

Check the clearance between the seabelt anchor bolts (which protrude through the floor) and the top of your exhaust. I had the same prob!

[cooperrodeo]

Since you say you get a drumming noise it sounds like you have some sort of body resonance. Have you got a pile of soundproofing above the headlining? The roof can resonate quite badly. Can you see the exhaust resonating?

I don't think you will find the perfect cure. They all seem to do it.

[roofchoplofty]

Hi, thanks for the replys, ive had the exhaust mounts removed and rested it on an axle stand and it still makes the same noise inside the car.
I have got some sound deadening between the headlining and the roof, but might change it to denser material.

Looks like i might have to suffer with it for now.

thanks

[roofchoplofty]

Woopeee!

Its all sorted as suggested i check the soundproofing in the roof and found no sound pads at all, so i went to the shop brought some and slapped four in there, follwed by some sound deadening and the drumming some has gone, thank god.

Thanks for your replys, im very gratefull, and the wife thinks im the bees knees!