56 replies to this topic

[MRA]

My wife just told me she doesn't know what I'm complaining about and I need to grow a set.
Love my wife and her honest yet vicious tongue..... haha
No poly bushes, all standard mounts on exhaust and engine.
I should just shut up and drive it!

 

Sounds like we love your wife as well

 

What you are hearing is possibly due to lack of calibration, has it been on a rolling road ?  as Moke says if the timing is not at optimum you will get more harshness, however it could be very well tuned and you are just more worried about the noise than it warrants.  sound deadening is not like it is on a modern car.
 

Edited by MRA, 29 May 2017 - 08:49 PM.

[Chris.Williams]

My dyno "rolling road" session is booked for the 16th of June.

[racingbob]

Mines been dyno tuned and everything spot on but can't get rid of the drone at around 3500 putting a larger mid silencer did help some. My car has no inner wings as it's got a carbon fibre front and brace bars so doesn't help probably with road noise . The drones not there before or after around the 3500 mark

[vx220]

Unsure if this is possible given the limited space and length under a mini, but there is a formula for working out a bend in an exhaust to reduce drone at certain frequencies, I'll see if I can find it.

Obviously it'll only work if it's exhaust noise, not induction or road noise.

[Dusky]

The drone can come from resonation in the shell too, that's where the dynamat type of stuff really helps

[vx220]

Unsure if this is possible given the limited space and length under a mini, but there is a formula for working out a bend in an exhaust to reduce drone at certain frequencies, I'll see if I can find it.

Obviously it'll only work if it's exhaust noise, not induction or road noise.

https://www.performa...e-drone-489463/

[vx220]

The drone can come from resonation in the shell too, that's where the dynamat type of stuff really helps

If the sheet metal is drumming along with the noise, Dynamat etc will help. If not, a layer of closed cell foam followed by a complete seamless layer of Mass Loaded Vinyl is a better barrier than Dynamat-style product. A lot more work than Dynamat, though

[Dusky]

The drone can come from resonation in the shell too, that's where the dynamat type of stuff really helps

If the sheet metal is drumming along with the noise, Dynamat etc will help. If not, a layer of closed cell foam followed by a complete seamless layer of Mass Loaded Vinyl is a better barrier than Dynamat-style product. A lot more work than Dynamat, though

Yeah, that's how I do mine :)
I first got some rubber to the big panels, then cover large and hollow areas with acoustic foam (as a musician I have loads of this leftover from insulating my room).
The mini almost feels modern now. ;)

[blackbelt1990]

I'm just about to read through this thread as I have a similar issue. At 3000 rpm it's touching 100 decibels inside, I drive it with ear plugs in and rarely go above 60 on the motorway. It's a real chore to drive now...

[Northernpower]

I'm just about to read through this thread as I have a similar issue. At 3000 rpm it's touching 100 decibels inside, I drive it with ear plugs in and rarely go above 60 on the motorway. It's a real chore to drive now...

Do you have straight cut drops?

[vx220]

The drone can come from resonation in the shell too, that's where the dynamat type of stuff really helps

If the sheet metal is drumming along with the noise, Dynamat etc will help. If not, a layer of closed cell foam followed by a complete seamless layer of Mass Loaded Vinyl is a better barrier than Dynamat-style product. A lot more work than Dynamat, though

Yeah, that's how I do mine :)
I first got some rubber to the big panels, then cover large and hollow areas with acoustic foam (as a musician I have loads of this leftover from insulating my room).
The mini almost feels modern now. ;)

A lot of acoustic foams are open cell, so will absorb and hold water...

[blackbelt1990]

I'm just about to read through this thread as I have a similar issue. At 3000 rpm it's touching 100 decibels inside, I drive it with ear plugs in and rarely go above 60 on the motorway. It's a real chore to drive now...

Do you have straight cut drops?

Nope, I don't even have as extreme a spec as the op.
1380, STG 3 Head, SW5 Cam, 1.5 Rockers, Standard Airbox and Maniflow LCB into a Twin Box Side Exit.

[SolarB]

Same situation here.

Similar spec. to the OPs but with a single 1 3/4 HIF and an MG Metro air filer case. Will be pulling the car off the road this autumn for a major refurb and sound deadening campaign. I have a solid mounted front subframe and no anti-vibration pads on the panels.

[tiger99]

As people have been suggesting, damper pads in the middle of all large flattish areas of bodywork help. That includes doorskins and roof, and the stuff that you may have removed from the floor during restoration. (Nothing wrong with bitumen based material, except that it was applied UNDER the paint in the factory. Prime and paint to a good standard, then fit the bitumen, and finish coat over the top if needed, and it doesn't cause rust.)

I seriously doubt that solid subframe mounts are making it noticeably louder. The rubber mounted horrors were greatly overrated by the Rover management at the time and killed the handling while hardly touching the noise.

You could try changing parts of the exhaust. As has been suggested, lengths and positions matter, and you could try putting a dent or crease into bits like the silencer to make them stiffer.

I expect that this thread will rumble on until some of the suggestions work for you. Hopefully soon! Have fun and at least enjoy the driving experience while the summer lasts!

[Chris.Williams]

Ok, after some more extensive testing.......Thrashing around the country side.......I have narrowed my problem down to only one thing, induction noise.
I drove, must have looked like a bloody idiot, but I was cruzing at the dreaded 4K moving my head around the cabin, trying to deduce where the sound was originating......yip from the carbs.
When I moved my head into the back seat area......thinking it would get louder from the exhaust......quite the opposite.
Guess I'm stuck with it.......not much to complain about really, at least I don't need to replace my exhaust.
I made a video and on play back you can't even hear it,