4dr Scrap car going full restore + 3,2 24V engine

the_whip said

I don't want to give you advice as I am only going on what I have read, but the science seems to make sense…

A heavy object attached to the metal would pass the sound on, but because it is decoupled by the foam it can move and absorb the sound energy. Some of things I have read say that the foam does nothing on its own, but some methods just use foam I can tell you this: it's bloody heavy and a pain in the butt to fit behind the fuse box. I envy you your blank canvas.

That why I want to fix the sound issue now And not later on with everything on it…

The first layer is like a rubber mat that should, in theory, transform vibrations in the metal (noise) to heat by absorving the vibration and thereby not transfer it. The rest of the noise could then be absorbed in the foam. But I am i doubt if I need another layer on top, I know in never cars there is a heavy outer layer, could be what you are talking about (MLV).

MLV doesn't seems to be something easy to get in my local shops   

As you say, the first layer (CLD, Dynamat, whatever) will dampen vibrations. But as it is attached to the metal it affects structural borne vibrations (such as engine noise). As the MLV is not attached to the metal it affects airborne noise (tyre noise).

I like this analogy…
"If you take a baseball and throw it at a bed sheet hanging from a clothes line, what happens to the ball? In a very short distance the ball loses energy and drops to the ground. The sheet “bled” off the energy by being able to move in 3-Dimensional space.  If the sheet could not move, the ball would bounce, and whatever net energy left in the sheet would result in vibration of the sheet.

Now, think about that in terms of sound. Sound hits wall, bounces, net energy in wall causes vibration, vibration in wall vibrates air on other side of wall, vibration in air on other side of wall hits your ears and you hear it. Now imagine that the wall is floppy like the sheet hanging from the clothes line"

Here is a very basic example. It's a recording of my laptop playing music (airborne sound). First normal, then with CCF, then with MLV as well, then removing MLV, then removing CCF:
Dropbox - File Deleted - Simplify your life
As you can hear, the CCF does very little on its own - only absorbing some high frequencies. The effect is far more pronounced in real life compared to the recording.

Thanks for the sound clip and the explaination. I hear what you say, and will try to find some MLV to put on top on my CCF.

Would you suggest this in the whole car ? Bulkhead, floor, rear, roof ?

That's the question I'm asking myself. I'm guessing doing the whole car would add about 50Kg. I only have 110bhp, and have the added weight of a cabi. I've started on the bulkhead so will finish that then go for a test drive. Definitely gonna do the wheel arches, doors, floor too I guess. I haven't done much investigation into the roof. I think people don't do it because of the weight. Maybe just the foam isolating the headliner?

I'm guessing the most important about the roof is to stop the vibrations… even though I have 250 hp, I dont like the idea of 50kg ekstra weight. That will put me over the magic 1000 kg

When I did my test drive, with absolutly no sound proofing, I notice the engine wasn't that noisy, but the tires and exhaust was really annoying, so wheel arches and trunk I find to be the places to be most concerned..

Think I will drive the car and add more sound proofing where needed to save the most weight.

Hummel said

I'm guessing the most important about the roof is to stop the vibrations… even though I have 250 hp, I dont like the idea of 50kg ekstra weight. That will put me over the magic 1000 kg When I did my test drive, with absolutly no sound proofing, I notice the engine wasn't that noisy, but the tires and exhaust was really annoying, so wheel arches and trunk I find to be the places to be most concerned..

Think I will drive the car and add more sound proofing where needed to save the most weight.

Or where you need weight to keep traction Yeah target noisy areas such as wheel arches, bulkhead and rear seat bench.

How loud is the exhaust by the way? You running 2 silencers?

I'm hoping the Wavetrac will sort the traction issue

How loud? Mmm it is loud, but not like extreme annoying noise, Yes I runn two silencer, the middle one is a straight through though…

What bore is it? 2.5" or 2.25"

I have a milltek classic and had a resonator and silencer. Straight through though :/

And how is yours sound ? To loud ? Isn't the Miltek 2.25" ? Mine is 2.5".

Hummel said

And how is yours sound ? To loud ? Isn't the Miltek 2.25" ? Mine is 2.5".

Don't know yet. Very close to a start up. Waiting for a fuel fitting and then she will be fired up. I'll get a video up when it's running .

Yeah 2.25", can't be louder than the g60. That was loud all the time lol

Looking forward for that mate Bet it sounds awesome! I was stunned over the sound when I fired mine up the first time

Rich, do you know if it is possible to get a Coolant temperatur sensor to fit in the R32 that also works like a fan switch ? So I both send temp to gauge, but also works like a switch for the fan ?

Hummel said

I'm hoping the Wavetrac will sort the traction issue

How loud? Mmm it is loud, but not like extreme annoying noise, Yes I runn two silencer, the middle one is a straight through though…

I've got a Quaiffe front LSD in mine and it certainly helps, but 270hp is still too much to put down with FWD in the car when it's this light. I can get the wheels spinning in 3rd gear easy.

But like you, it's not crazy noisy. Sounds good in a tunnel, but only really gets loud when you hit 3.5krpm.

I was also expecting a bit on wheel spin 270 Hp ? Also from a R32 ? What tuning have you done to it ?

Hummel said

Rich, do you know if it is possible to get a Coolant temperatur sensor to fit in the R32 that also works like a fan switch ? So I both send temp to gauge, but also works like a switch for the fan ?

No not that I'm aware of. Is your thermo switch the same as mine, 3/8 NPT?

I was trying to find an adapter to take it from 3/8 NPT to M22 x 1.5 but with no joy as this would've made the fan system simple using the mk1 set-up rather than run a separate relay.

I'm running a black 20mm 2 pin water sensor I have installed in to the blank space on my thermo stat housing for water temperature on instrument cluster

I was just to clean the bay a little more, instead of that sensor pointing out of the side of the radiator, I supposed we have the same eurowise radiator and the sensor setup. I would run a relay on the fan no mather what. But the wiring annoys me, so if I could mount a sensor on the thermo housing that could handle both, that could be awesome

rubjonny might be able to help  

Hummel said

I was also expecting a bit on wheel spin 270 Hp ? Also from a R32 ? What tuning have you done to it ?

Oh I thought you said yours was gonna be 270. Mine's a stock R32 lump. Air filter and exhaust re-done, but that's it. So I expect stock power basically.

Maybe 270, at least thats what the program in the ECU should give. But a Dyno test will show me later on

Even with all that power I still want the car to be light, so all this sound proofing is a bit, what do you call it, evil need I want a driveable car but as light as possible

Hummel said

Maybe 270, at least thats what the program in the ECU should give. But a Dyno test will show me later on

Even with all that power I still want the car to be light, so all this sound proofing is a bit, what do you call it, evil need I want a driveable car but as light as possible

I've been driving mine for a good year now without any sound proofing at all and I don't care. I'm putting some in soon simply because I'm replacing the carpets and probably doing some welding, but if I didn't need to, I wouldn't have thought it "required" unless you plan to be driving it every day for a whole host of miles.

Just my opinion, I don't find mine loud really at all. "shrug"