Thermal and acoustic insulation (warning - long)

[Ikom]

I am probably going to be a major pain on these forums by asking a lot of questions as I embark on my build. I promise to search the archives for prior posted information on the subject matter under discussion so as not to duplicate (similar) questions that have been satisfactorily answered.

I am starting my GTR build in the next few weeks and decided to ask our staff engineers about their thoughts on both acoustic and thermal insulation for the cockpit: (caveat - they are not automobile engineers)

The acoustics guys told me that the best I could hope for (based on their review of the frame chassis with NO isolation from the suspension or drivetrain as is now the norm on all modern passenger cars) was to have a very marginal effect on resonances. The tube frame in their opinion would transmit sound into the cockpit regardless of what I did by introducing materials like "Dynamat" (sound deadening) or other more inexpensive Bituthene or W.R.Grace peel and stick type membranes.

They in essence told me to forget membranes because these would only add weight and return very random non specific results.

They suggested that I speak to the mechanical engineers to look at more traditional thermal insulation products that posses acoustic and also radiant/convection attributes.

The mechanical engineers agreed with the acousticians but suggested that I use the following products from Design Engineering Inc or their generic equivalents for peace of mind:

1)Heat Screen Radiant Matting

2)Reflect a Cool (adhesive backed)

3)Floor and Tunnel Shield

see:

www.designengineering.com/products.html

My question to the forum -

Has anybody done any tests to confirm that materials can be used on the car that provide effective acoustic or thermal benefits within the cokpit?

Anecdotal information is equally welcome.

Thanks

[srreck]

I have fitted all the isolation mats available from the market. Mostly applied to the rear bulkhead by the inside of the cockpit and inside the engine bay. Close but...not cigar !! is like to be in the last seat of a turist class jet (just in front of the turbine). Trust me....you will be always into the noise.
Cheers,

[Stig]

My cockpit and rear bulkhead are completely insulated with thermal matting.

Sound deadening was never an issue as part of the point of having a sweet V8 behind me is to hear it!

If you looking to waft along in a serene environment with Bach tinkling away through the stereo then, errr.... why are you building an Ultima?

I still swear by the thermal insulation though. On our way to Le Mans earlier this year, we didn't use the aircon at all (blower had jammed, fixed now) but we never found the going uncomfortable even in 90 degs plus ambient!

[ultimaandy]

I used a lot of bitumen based sound deadening and backed this up with heat insulation matting (like used on rear body above exhaust).

It has reduced road noise a lot but does nothing to stop the engine noise being transmitted. At 80mph if I knock it out of gear and coast it is only wind noise you can hear and even thats not as bad as the Boxter (mines a can-am).

This added 5kgs of weight to my car and I have covered every panel on the cockpit (floor an all) with 3+layers so it doesn't have to be heavy if you use the right stuff.

However make no mistake it will never be a quite car especially if you use the right engine