Sound deadening project bonnet

[AdamG]

Following on from a previous thread regarding Stp standartPlast.

I bought a gold bulk pack and have started installing it in my w220 s320cdi.

First I put some of it under the bonnet




I can't say I have notice any difference to engine noise inside or outside the car

 

[AdamG]

The bulkhead

Next step was the engine side of the bulkhead.

Later I will have a go at the inside. Also just behind the engine a will fit a spaced layer bulkhead blanket.







With the wipers removed and plastic trim there is quite a bit of bare metal.

Covering this area in the mat has definitely made a difference. It is particularly noticeable when the engine is cold.

Adam

 

[sasha091]

vey informative will try on mine


thanks

 

[dog68]

Good work.

 

[prc]

Nice job. Have been tempted to do the bulkhead myself. Just looks like a big job.

 

[AdamG]

Thanks for the comments.

It is actually quite easy to get to. Remove wipers, scuttle cover and wiper mechanism. The plenum chamber is only held in with a few bolts.

It's a good opportunity to clean the area out.

I've ordered some acoustic foam that together with the stp mat I'll fit in the cabin.

Adam

 

[jonnyboy]

Superb post

 

[FasterThanSound]

I want to explain something regarding sound deadening / proofing.
Adam did a good job but he didn't understand sound deadening process in full in the beginning. We had a little chat about it later on.
StP Gold he used as other butyl (not bitumen) based products has unique feature to convert rattles to low level heat, relfect heat, kill vibrations and sound proof as well.
Just to make it clear sound proofing features are best in sound barriers but sound deadeners do good job in certain places in the car.
To make an engine more quiet you should apply sound barrier for the engine (i.e. StP Hood solution).
When it's applied to the bonnet rest can be applied in varies places under the bonnet to not let the sound being reflected inside the engine compartment.
StP gold used on the doors, floor or firewall will give much more difference.
It kills vibrations and kills low frequency noise so does he job you expected.
To kill the noise you have to adjust best sound barrier for the noise frequency. I know it sounds complicated but in fact it's not. If Adam would apply sound barrier on top of StP Gold on the bonnet he would feel the difference. Equally important is to apply some sound dampers as Adam did on the firewall as once bonnet is soundproofed that's another place where sound goes into the passenger compartment.
I hope it helps and don't confuse too much