As many know the teryx is quite loud in the cabin area under load, loud enough that if you are not wearing a helmet your ears will be ringing in a short time. When I first got mine I tried several things to attempt to quiet it down with mixed results. I was able to quiet the machine but the cost for all I did wasnt justifiable.
My parents purchased on a few weeks ago 08 leftover and this was also their biggest concern. So I spent all weekend soundproofing theirs with some feedback from other posts here and I can say it made a HUGE difference.
Here is what I did.
On mine I bought a bunch
and Damplifier - Acoustic Vibration Dampening Mat
I covered all the plastic in the engine bay and under the bed. I was not really happy with the results and now that i have done the standard bore kit it is louder than a stock machine without any sound proofing.
Now on theirs this is what I did. I should have taken photos but it is pretty easy to describe.
I coverd the the enging housing and in all the aread that were not HOT i peeled the reflective foil off from the material as it seamed that noise would bounce off from it. I then placed a section against the bed behind the intake to absorbe sound. I also covered the intake cover both inside and out with the same material less foil.
I took an innertube and cut it and mounted over the intake runners around to the back and cut out holes for the seat belts to go through. It is trilled so it covers everything except the engine (I didnt want it to touch and melt)
under the seats I placed the foam on the innder sides about 4 inches wide.
Under the intake on the back there is a opening where the catch plug is for the intake housing. You will see push pin holes not being used. I bolted another peice of innertube to this opening (Does not block any of the intake just the void underneath.
Results are dramatic. Now at WOT you can talk with your passender and the majority of the noise is from the exhaust wich is fine. Very happy with the Results.