Belly Pan noise reduction - Sound Proof
 

I was wondering if you remove the sound deadening (proofing) from the vehicle.
Would you compensate the majority of the loss of sound proof by installing a belly pan (Full).?

You could save potential 40 lbs and still have more or less noise in cabin?

Maybe a very thin layer of a sound proof material (light weight of course) stuck on the belly pan. At the same time this material could be heat resistant.

? acoustic foam thin , lightweight. Not sure if they are fire proof.

Solve two problems at once maybe.

If you make significant improvement in the aerodynamic drag, then you don't have to worry so much about a 40 pound change. Forty pounds is not significant for virtually any car on the road. But if you can improve the Cd by even 0.01 you will notice a improvement in the efficiency.

Thanks for that advice although with a little road car with lower bhp, you would be surprised that 40 lbs would make a difference.

But would be nice to know the answer if you can substitute it with belly pan. 4mm corex with 6 mm acoustic foam layer.

Please prove how 40lb of removal would be a 'surprise' ?

maybe you should read some more before you question Niel's answer........

and imho, there isnt 40 lb of material in the average car sold in england.
secong, if you are dismantling the interior to find '40lbs' why not put the new isulation back on the interior? you are just creating a tin can with insulation on the outside.....there is a reason they put the sound deadening material on the inside.
And how will this insulation on the outside react to water.......?

When you drive a low powered low weight car, 40lbs is something you can feel when driving. In acceleration, braking and other handling aspects. If 40lbs was nothing to be bothered with, manufacturers wouldn't use lightweight metals to shed 40lbs. But they do.

He's not saying that 40lbs is worth 5% better gas mileage or anything like that.

I can't offer anything more than an anecdote, but when I tried the belly pan on my car, I was sure I noticed a decrease in road noise. Debatable how much was from the sound insulation properties vs. improved aerodynamics (better aero = less wind noise).

And about that 40 lbs: If I could easily take out 40 lbs from any of my vehicles without affecting my own criteria for keeping it practical, I sure would.

Perhaps surprising, but PaleMelanesian has documented a small but measurable benefit of driving with a nearly empty fuel tank vs. a full one from his vast collection of commuting data. That's in the range of ~40 lbs.

I have driven quite a few small cars and the first thing you notice is it is quite zippy when you are alone, take on a passenger and it becomes a slug, so I'm in with the 40lb weight reduction benefit, but unless you do something like pull out the rear seats I think you will have trouble finding 40lb in insulation.

@Mcrews. Please read fusion210 post.

"When you drive a low powered low weight car, 40lbs is something you can feel when driving. In acceleration, braking and other handling aspects. If 40lbs was nothing to be bothered with, manufacturers wouldn't use lightweight metals to shed 40lbs. But they do.

He's not saying that 40lbs is worth 5% better gas mileage or anything like that."

Of course weight reduction in un-sprung weight (i.e wheel/alloys) is more noticeable but every lbs counts in a smaller vehicle (75-100bhp).

But having now seen what it takes to remove some of the deadening I think it is best left. Worth questioning.

hummmmm.....
You said that there was 40lbs of deadening material.

That is just a little different than "removing 40 lbs"
maybe YOU should re-read what you wrote.
so to be clear....PLEASE SHOW ME 40lb of deadening material you can remove from YOUR car..
Let's stay on topic and not re-invent the discussion.

After all, I have documented the removal of my spare tire ('40 lbs+ of removal) from my 02 Infiniti Q45 5 yrs ago. So I am familiar with the concept of OVERALL weight removal.

I stand by my original statement.

reminds me of a management training exersice I run.

You whisper in the first persons ear a sentence. By the 6th person it has changed dramaticly.
It only took 8 posts here to change the point!