34 replies to this topic

[jeffster06]

I have this in my mini to reduce the noise of the SC drops. Worked well, although got rid of the sc drops now.

https://www.nkgroup....dwich-material/

 

Might have to give that a try. Guessing you stuck that to the engine side of the bulkhead?

 

I am also looking into getting an acoustic foam block (maybe a 4 inch thickness) to put in place where the rear seat base would be. had the sudden thought that the muffler is basically half under the rear seat and me not having one is probably not doing me any favors, plus my dog may appreciate some extra cushion when he rides with me so win win I guess lol. 

[stoneface]

I fitted it to the inside of the car from the top rail behind the dash to the floor cross member.

Also fitted in the engine bay from the bulkhead cross member up to under the scuttle.

I didn't stick down. It's fitted in place with the metal tabs already on the body work. I wanted to be able to remove it if needed.

It's fairly weighty but easily moulded to shape.

[coopertaz]

you will not be able to get rid of all the noise you want. you can reduce intake noise with drilled plastic air filter housing but with exhaust fit a twin box rc40 and it will be quiet inside. minis are so small loud outside uaually equates to droning inside

[jeffster06]

Been driving the car the past few days trying to listen to pin point where most of my noise may be coming from. It seems I may be getting a lot of engine noise because when I turn my head I hear more from that direction than I do the rear. I guess I will start there and see where I get. I know its a mini and it wont be silent just trying to dial it back a little. 

 

I see a lot of votes for the rc40 exhaust, its definitely on my radar now. I just figure before I crawl under the car and mess with slip joints (god I hate those), I can try to get some deadening on the engine side of the bulkhead. who knows maybe that will get me to a happy level. 

[nicklouse]

If you have a filter that does not use the original housing you will not reduce the noise much.

[fokko]

Been driving the car the past few days trying to listen to pin point where most of my noise may be coming from. It seems I may be getting a lot of engine noise because when I turn my head I hear more from that direction than I do the rear. I guess I will start there and see where I get. I know its a mini and it wont be silent just trying to dial it back a little. 

 

I see a lot of votes for the rc40 exhaust, its definitely on my radar now. I just figure before I crawl under the car and mess with slip joints (god I hate those), I can try to get some deadening on the engine side of the bulkhead. who knows maybe that will get me to a happy level. 

 

Sounds good! Hope you get some results from it, as it is hard to get it right

[jeffster06]

If you have a filter that does not use the original housing you will not reduce the noise much.

I have a med stub stack with a foam filter... and I run a center speedo... guessing the odds are stacked against me huh. 

[nicklouse]

 

If you have a filter that does not use the original housing you will not reduce the noise much.

I have a med stub stack with a foam filter... and I run a center speedo... guessing the odds are stacked against me huh. 

 

Yes. As that is pointing all the induction noise straight at you. That is your issue. That is what you need the quieten.

[jeffster06]

Yes. As that is pointing all the induction noise straight at you. That is your issue. That is what you need the quieten.

 

 

I actually stacked some strips of closed cell foam intended for a window AC unit and packed them around the backside of the speedo housing. This helped a lot with the suction sounds and a bit of engine noise. I'm wondering if I do something like the bulkhead sound deadening from an MPI if that would help because it looks like it will completely cover the hole in the bulkhead. 

[nicklouse]

But the MPi had the opening pointing up. So had much less work to do.

[timmy850]

I bought a nice thick insulation blanket from a local shop. It’s what you can get from a decent car audio shop, a textured vinyl on the front and a heavy foam on the back. It makes a huge difference to the induction noise

[jeffster06]

I bought a nice thick insulation blanket from a local shop. It’s what you can get from a decent car audio shop, a textured vinyl on the front and a heavy foam on the back. It makes a huge difference to the induction noise

I've been looking for foam that is suitable for the engine bay. Just worried about melting it if it can't take the heat from the manifold area. Kind of curious how hot that area gets

[Spherix]

I have a med stub stack with a foam filter... and I run a center speedo... guessing the odds are stacked against me huh.

Is the firewall open behind the speedo, or covered?

[jeffster06]

 

I have a med stub stack with a foam filter... and I run a center speedo... guessing the odds are stacked against me huh.

Is the firewall open behind the speedo, or covered?

 

its is open, but I packed what I could in the back of the housing with some foam, it helps but I guess not enough. 

[Clip]

Not sure if you got your noise issue sorted, but for what it’s worth now, I had the same problem. My ‘62 850 with 1310 maniflow header, custom exhaust, HIF4 with K&N filter was noisy for me. What I found was:

• after using Dynamt equivalent on floors, rear parcel shelf, behind rear seat and inside firewall made little to no difference. This stuff is only for limiting resonance from large areas, and other the floor and roof, the mini doesn’t have a lot. 
• I then added foam to inside firewall and behind and under rear seat. Made little difference.
• Lined inside of bonnet with a 10mm self adhesive closed cell foam with aluminium foil over the top and this made a slight  but noticeable difference to induction and engine noise inside the cabin.
• Added old fashioned felt type insulation covered in heavy vinyl (similar to what you can buy ready made for mini) to the engine side of the firewall (just the top area behind the speedo). This made a big difference.
• Added this type of insulation to the inside of the firewall from behind the speedo and down to the floor, and again made good improvement.
• Added more of this type to rear parcel shelf from underneath (as Cooper S spec), and to the rear seat panel from the boot side, and this also made good difference with exhaust noise. 

So I guess it’s all about stopping the noise before it gets into the cabin, rather than insulating the inside of the cabin. I’d love to fully line the firewall from the engine bay side because I reckon that would also make big difference with the right stuff.

I read up a lot about acoustics and there are some big misconceptions that I had. Dense foam type is hopeless at stopping sound - it may help with reducing resonance, but not “noise”. Looser, soft, thick materials are​ best at reducing noise, and that’s exactly what I found. I can actually have a conversation now, but still pointless having a radio etc.

Only problem is I’ve probably added around 10kilos of weight with all this stuff. 

Edited by Clip, 01 November 2022 - 08:50 AM.