86 carpet install debate

[The Bloody Panda]

How much does installing the carpet in the front of the 86 quiet down the interior?

I'm on the fence about installing carpet from the firewall to the rear seats in my 86. The drivetrain is pretty noisy and I hear gear noise coming from the transmission. I'm sure the carpet would help but I don't know if it would really make a big difference like I'm hoping for. Does anybody have any first hand experience with going from no carpet to no carpet and vice versa. My car has never had carpet so I have no idea how much it would change.

I'm also curious about the weight on those front two pieces of carpet since this is a track day car. Oh, and if you happen to have some really nice black carpet laying around and for sale, I'm interested.

[SidekickChuck]

I cant say with 100% certainty, but the fact that there is a carpet barrier between the drive train and you, along with the fact that it may absorb resonating noise in the cabin, I would think that it would make a difference. It wont be quiet, but will dampen the noise some. I think of it like having a bare room with hardwood in a new house. Its very hollow with lots of echo from sound frequencies bouncing off all the walls and floor. Put carpet and furniture in, and the echo goes away along with some of the reverberating sound.

[The Bloody Panda]

It will definitely make a difference, but I would like to get some opinions on how much of a difference, followed by me being subjective about them. Currently I'm leaning towards no carpet since I don't have any. But I do wear ear plugs while I drive and it's still pretty loud, it would be nice to get a big reduction in noise.

[SidekickChuck]

Is your entire interior gutted?

[The Bloody Panda]

The roof is gutted, the dash and door panels are on. There is no interior in the back and there is nothing behind the dash. The carpet is the only thing I could see putting back in at this point, and only in the front. The factory sound deadening on the floor has been removed and replaced with rubberized undercoating.

[SidekickChuck]

In that case, I can not see carpet providing a big reduction in noise levels in the cabin. Youre still going to have lots of gear noise coming as well as exhaust noise coming from the bottom of the vehicle and bouncing around the mostly gutted interior. Without anything to absorb the sound as it bounces around in there, carpet would have a very small effect on noise levels I feel.

[The Bloody Panda]

Yeah, that's what I'm afraid of. It could just be adding weight.

[Jimmee1990]

Adding carpet will do hardly anything, I tried this with my last car. No sound deadening and sprayed with undersealer underneath with no interior. Is it mechanical noise or exhaust noise that's making you need earplugs though? I've been in heaps of serious track cars and only ever needed earplugs for cars with unmuffled exhausts.

[The Bloody Panda]

I value your opinion highly since your setup was so similar. Just to clarify, in your old setup you actually did add carpet and experienced an insignificant difference?

The mechanical noise is the real issue and not at the track, but on the way to the track. I don't have a trailer so when I'm driving on the highway I'm cruising over 5000 RPM in 5th gear just to go 65 MPH because of my final drive.

My exhaust isn't quite as loud as my velocity stacks and neither of those are bothersome. I'm going to try out some Bose Quiet Comfort noise canceling headphones and see if those can reduce the gear noise. After I get my windows tinted black as midnight anyway.

[Deuce Cam]

The carpet does help a little even if you removed the sound deadening, but don't expect a night and day difference. However, if you still don't have full interior (i.e. deleted rear seats, panels, headliner, etc.) the affect of the carpet will minimal since the rest of the inside won't be fully insulated.

Your trans. and/or r&p might just be noisy. I have a similar setup to you with the 4.77's. I also have increased gear noise due to upgrade mount ans shifter bushings. Although my car is really loud at highway speeds it's nowhere close to unbearable or ear piercing. However, I still have full interior even though I removed all the sound deadening material.

[The Bloody Panda]

Yeah, I'm thinking it would be pretty cool to have the carpet. I think it would just be nice for aesthetics if nothing else.

[The Bloody Panda]

Anybody know how much the front 2 pieces of carpet weigh?

[Deuce Cam]

5 lbs. give or take. They're pretty light.

[The Bloody Panda]

No wonder the noise reduction from it is so low.

[cedu]

does not help with noise. for me it just gets annoying when trying to reach the pedals.

[The Bloody Panda]

For me I just think it would look nicer. 5 pounds is pretty light so why not.

[The Bloody Panda]

Wish I could find some nice carpet...

[RuizXIII]

I never understood the infatuation with driving around with a gutted interior UNLESS it is a race car, but, hey, to each their own. I'd be chuffed to have fresh, plush carpet and interior in my car.

[jondee86]

The guys that install high end car audio know what it takes to quieten
down a car interior. The fundamentals are adding mass to all panels that
can vibrate and transmit noise (this is the sound deadening that you have
removed). Closing off all opening that can allow airbourne noise to leak
into the interior (includes having good door and hatch seals). Minimising
hard, reflective surfaces inside the car. And isolating the cabin from
chassis and drive train noise/vibration with rubber mounts (these are the
ones you replaced with poly bushes or heims).

Once you have gone to a lot of expense and effort to make the inside of
your car as noisy as possible, you can't expect a bit of carpet to have any
worthwhile effect on quietening it down. But it will make you feel better,
and there are a couple of businesses around that make carpets for the AE86.

Here is one http://www.knoxautocarpets.com.au/

Their carpet is for RHD but it looks as if they could sew another heel pad
on the other side for LHD. And there are others, probably in the US also.
Otherwise, find one of those places that make custom moulded earplugs
for shooting sports

Cheers... jondee86

[The Bloody Panda]

Over the winter I've decided I'll be going from completely gutted interior to full interior minus the back seats, original floor sound deadening, and roof liner. I hope it makes a significant improvement.

[SidekickChuck]

specs on your car?

If its a dedicated track day car, and you have performance mods, and its a loud car overall... It will still be loud, but should make a difference vs. what you are used to. Having to use ear muffs is something I cant imagine. My car is too loud for a radio (though a high powered one would work) but not loud to the point that its annoying to drive since it is not a daily. Just loud enough to enjoy the tones out of the ITBs and some from the exhaust (mostly ITBs)

[jondee86]

Noise, vibration, and harshness (NVH), is the study and modification of the
noise and vibration characteristics of vehicles. So, like with a lot of things, you
really need to define the problem before you go looking for a solution. You need to
identify where the objectionable noise/vibration is coming from, and then look at
possible ways of reducing the problem.

For example, you will have road noise (tires on the road), and this can be reduced
by making sure door and window seals are in good condition, and windows are wound
up (eliminating gaps and openings). Mechanical vibration is generated by the engine,
gearbox and differential, transmitted by conduction, and amplified by attachment to
sheetmetal. Same principal as listening to bearings with a screwdriver pressed
against your ear. Exhaust and induction noise are a bonus

Examine any modern car and you will see how the factory minimises NVH to keep
the interior of the car as quiet as possible. They use a combination of techniques
designed to contain, attenuate, isolate and absorb noise and vibration before
it reaches the cabin. Once noise is in the cabin, the only available remedy is soft,
textured surfaces to absorb sound energy.

You may find by experimentation, that on your car there is one particular source of
noise that is vastly more annoying than all others. Elimination or reducing that one
dominant source may be all that is needed to turn unbearable into bearable

Cheers... jondee86

[The Bloody Panda]

I'm hoping to be able to better pinpoint where the most objectionable noises are coming from after driving it with most of the interior back in. The current loudness seems to make it more difficult to isolate the sounds.