Outer Limits 4x4 Board

Hi guys

Considering selling the rocky because it's getting too noisy. It's around 100bdA or 85bdC going down the highway, so it's doin me some damage.
Before I make a silly decision and sell, are there any suggestions that you guys can offer to prevent me doing this travesty?
It's an 1985 f75 non turbo diesel. I spoke to a fella in an exhaust shop and he wasn't too helpful.

Any suggestions would be appreciated!

Cheers

Alex

my sierra is very noisy as well so i just wear ear muffs. problem solved.

get a muffler that works? Got mine for $350, from headers back, 2" straight thru, and was quiet enough on my NA.

Wack a turbo on it for the exhaust noise, sadly unlike new cars they are bloody noisey, especially after upgrading tyres etc.

I spoke to a fella from an exhaust shop, and he tretty much told me to suck it up, as a new one wouldn't help much.
Where abouts did you get your new one from?

Would putting carpet under the bonnet help?

Got mine done in Blacktown Sydney, Charleston exhaust.

Are you sure its the exhaust thats noisy?? If there's no holes/cracks and the muffler is actually there, then it shouldn't be so bad that you would notice? Rocky's aren't the most refined 4x4's by far so are you sure its not a combination of road noise? Are you running mud terrains?? Hows your gearbox? - I had a worn bearing in 5th and the noise was tremendous by the time I finally got sick of it.

don't put carpet under the bonnet but I'd look at spraying some for of sound deadener in the cab under the carpet.

Yeah I have muddies, so it could be that, but it does sound more mechanical though. The exhaust should be alright too, and each gear is roughly as loud as eachother.

Is this sound spray hard to use or expensive?

do a bit of googling. The matting type stuff that you glue on isn't too dear, and then there's heaps of different spray on stuff with varrying price ranges and effectiveness. Or at least there was when I looked into it.

Never did bother with it though.

RockyF75 wrote:do a bit of googling. The matting type stuff that you glue on isn't too dear, and then there's heaps of different spray on stuff with varrying price ranges and effectiveness. Or at least there was when I looked into it.

Never did bother with it though.

Your best bet would be some aluminium backed bitumen - stick it on bitumen side down and put some neutral cure silicone over the edges where the bitumen is exposed so the car doesn't smell like turps on a warm day. Cover that with some closed cell foam type sound insulation and it should be fairly quiet. You'll still get noise transferred through the gearstick holes, and the firewall. The firewall is easy as you can just add the bitumen/foam to it, I can't advise on the gearsticks though...

Stick the bitumen to the doors/walls/roof too and this will reduce the amount of heat transferred into the vehicle on warm days...

I put some raammat in covered with some ensolite closed cell foam. Got the tranny and floor bed. Made a little difference but probably not worth the cost, as I reckon most if the sound is still emu sting through the firewall.
Will spray foam work if I apply it to the engine bay side of the firewall? Will it make much difference or will it just be a waste of time and money?

just make sure anything you put near something that gets hot is not flammable otherwise it might catch alight and be very hard to put out. if you havent done the doors you might be getting some noise thru them, also are your engine mounts still good and also the gear box and the secondary mount on the transfer still there and nothing is metal on metal etc.
cheers brenton

brush on body deadening works wonders inside doors and under carpets on the floor etc.