Any way to reduce engine noise

[dcartledge]

Inside my HMMWV is really loud. Has anyone been able to reduce the noise level from the engine compartment or is that the way it is?

Any ideas appreciated,
d

[Action]

In my slantback, I had to let of the throttle to speak to the other person in the front. but, I had no insulation on the body.

You may use dynamat as others have, get the factory green pads for the tunnel and floor, get the silver insulation that mounts under the tunnel, get a 4l80e with overdrive...
maybe even some thick foam inside the rocker panels may help with road noise.
plus, there are all of those thick black pads used on the firewall of the older Humvees

Jason

[dcartledge]

I think I have some of those black pads - might try that.

Thanks!

[Ted Gates]

Use a ribberized air horn for NA engines. Seal all holes as well

I used dynamat and was able to converse with passenger at highway speeds.

[icentropy]

I sprayed the interior of my truck completely with a bedliner product and that helped some. Also cut out and layed down some 3/4" rubber horse stall mats to cover the complete bed/tunnel and that helped even more but i decided the noise reduction wasn't really worth the weight. I'll be lining the doors and roof with some perforated vinyl/foam sound insulation as soon as the slantback is installed.

I do agree with what's mentioned above though. Find all holes and plug them up.

The main thing that's helped me with a flightcom intercom system. Most places have a law that allows for the use of hearing protection when in a vehicle that requires it. I measured my truck and got a dB reading of 95dB accelerating on the highway. That's well above the 90dB rating considered dangerous long term exposure so i had some mil spec hearing protection required stickers and stuck them to the windshield frame. Now my wife and I cruise around with our headsets on, and the truck noise is just light background noise that doesn't bother us one bit and we can talk comfortably with light music in the back ground. The whole intercom system for 4 people (only got two headsets currently though) cost less than $200 used on ebay. You can still hear the truck though and any horns and sirens in the back ground, but it just dials everything down to a comfortable level is all.

I'm thinking of modifying the radio tray in the future to basically turn it into a solid sided square box and all the space between the radio tray and the engine cover be filled with foam. That should REALLY cut down on any noise coming from the engine cover. Most of the rest comes from the front foot wells and the top of the tunnel and tires.

Swapping out MTs for MTRs is supposed to help a lot with the drone and laying anything over the bare aluminum tunnel will help quiet that down.

[dunsbr]

Quietening my Humvee has beem my lifes work....

The first things are the rubberised airhorn, fitting the DWF kit rubber elbow below the mushroom cap air inlet, fitting some rubber strip between the fan solenoid (Cadillac valve). These are easy and give amazing results for the effort.

Then seal up every hole, fit insullation inside the beam under the windshield (there is a cover you remove in the engine bay under the cross beam that gives access.
Fit an Artic kit insulation package inside the truck. This gives more of that green padding and covers up the tunnel and sill plates.

Next is the harder bits, dynamat under the dog house cover and everywhere under the transmission tunnel, over that fit a barrium loaded, foam insullation with a silver mylar cover over the dynamat (this stuff is commonly used on boats as a liner for engine covers. them over that fit aluminum foil heat shield sheets to seal of the foam off from the mud and water. These sheets are secured to the cross beams on the body by screws and large washers.

After you've done all that, you can listen to music as you drive along...

But, no matter what you do, it will never be like driving a car.

cheers

[dcartledge]

Great tips!

I know it won't be like a car but it definitely has the cool factor going for it.
d

[dcartledge]

What was the model of the intercom system you are referring to?
d

[icentropy]

What was the model of the intercom system you are referring to?
d

I used a Flightcom II system like this one.
http://www.ebay.com/itm/120907489911

Though there are a few different brands that are basically the same thing. There's a small 2passenger add-on module to provide a place for the rear passengers to hook up to.

A few cheap used headsets http://www.ebay.com/itm/330727100154 and this box will make your truck way more enjoyable.

[dcartledge]

Anyone had any success with using an AM-1780 (VIC-1) setup?

Can you input music to this thing?

d

[Augi]

I use a stand alone VIC1 and it works ok. Overall I would recommend having one over not. It really saves your ears and you can also talk to people while driving! You can pipe music into it too. My ipod works well, but some smart phones cant seem to push the volume loud enough. It's a circuit impedance thing and you could probably build a transformer to fix it.

I kind of want to go to the VIC3 but its more expensive and harder to find the parts.


My gripes in rough order of importance:

1. I can't get rid of the alternator whine in the headsets. I've tried adding filters, which make it a little better, but it's still not gone. It's ok during the day, but when I turn the headlights on it gets way worse. Annoying enough that sometimes I'll shut the intercom off.

2. The bailout connectors on the H161 headsets suck. I never have 4 working headsets because one is always being finnicky and either the mic or the earphones aren't making connection. Wiggling it sometimes fixes it for a short while. Sometimes not. These are NOS units.

3. It would be nice to have the voice activation of the VIC3. Sometimes the mic's pick up wind noise or heavy breathing on the VIC1 since they are always on. Also the Bose headsets supposedly have active nose canceling and some even have talk-through (if you have ever had electronic gun mufflers with the mics that amplify voices etc into the earphones but cut out when they receive a noise louder then some threshold, it's something similar).


Augi

[dcartledge]

OK - Thanks for info.

Can you point me in the right direction for a wiring diagram, component list etc.

I know basically you would need the AM 1780 unit, power cable, interconnect cables, the four control boxes and headsets.

Anything else?

Many thanks.
d

[dcartledge]

Anyone have any experience with the Clansman intercom setups?

They appear to be less expensive......
d

[dcartledge]

It is WAY expensive to ship across the pond, evidently - I'll stay with US stuff,
d

[dunsbr]

HA!
Try owning an American truck and living in Australia!
I show you expensive shipping.

Cheers