First things first. P4 is extremely hot after riding around for awhile. I’m planning on purchasing the insulation kit next week. I’m sure it will help with the heat and may even may it a little quieter. Now, I’m considering a muffler silencer. My question or my 2 questions are; 1. Will the insulation help much with the motor noise? 2. Anyone install the silencer and if so did it rob you of any power?
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IMO, the bulk of the noise in the 700 comes from sources other than the exhaust note. If all I heard was the exhaust, I'd be quite happy.
The engine...yes, but the main noise maker to me is the rear diff growl and clunking, which will be hard to do anything about other than thicker gear oil. Then you get doors and bed rattling. The insulation will help to some degree, but I don't know what this insulation kit includes. That roof (I'm assuming you have one) is a big factor and an area where a 4 seater is at a big disadvantage to my 2 seater, while the extra floorboards, etc may help in keeping engine noise under the machine a bit better.
No way of knowing, but I'd bet I have
maybe the quietest P2 around. How? A lot of work...
1. I have 2-3 layers of heat shielding in some places. This was done in stages.
Directly under the seat is a vinyl cargo matt cut to fit and extended about 1/2 up the seat back.
@trigger may be making these for 700's now. Prior to that, I had a cheap car windshield sun screen also cut to fit, so I decided just to leave both. Both are trimmed over the PCM to prevent retaining too much heat in it. Additionally, some DEI fabric type heat shielding is in the opening just over the cylinder head in the center span of the seat frame under the plastic. Pay attention to keeping gaps around seat buckles as tight as possible.
Directly in front of the exhaust pipe, next to where your calves rest, is another piece of the fabric in the frame span in that area. Later, that whole "firewall" behind your legs got an additional layer of cheap stick on heat shielding from Amazon (the frame/chassis helps hold this in place, even if the adhesive fails, which it hasn't thus far). It actually extends a bit up under the floor boards.
All this was done for heat control more than anything, but it obviously helps with noise. You may want to do this to stuff in the rear of a 4 seater as well.
2. Add something like a pool noodle between the dump bed and front seats. A lot of noise comes up from that area...though maybe no so much on a 4 seater. Test it by stuffing a jacket or something down in it on the next ride. Obviously, you don't want this falling on the engine or exhaust, so use some sense.
3. De rattle/squeak. Doors and dumpbed will rattle and squeak. Even if the latch on the doors doesn't rattle, the hinges probably still will unless you adjust the stops very tight.
@RB3offroad makes tighter busings. They will all eventually start to squeak. I use electrical tape on the door latches, and sections of plastic gas line in the dump bed latches. Stuff in the glovebox will rattle as well...along with the door sometimes.
4.The top. I have a soft top, which doesn't reflect as much noise. The top reflecting noise is a BIG factor in what you hear. Take it off and go for a spin if you want an eye opener. Any windshields, etc, will also add to this. Everything thus far has concentrated on keeping noise from getting to the top, so now, I'd add some acoustic foam, glued...or maybe using Velcro (to make it removable for cleaning) to the WHOLE top. I've never done it, but that might do the most to keep things quiet in the cab.
I seem to recall a few trying the silent rider type exhaust on a 700, and most didn't like it. It WILL kill some power...and let's be honest, the 700 doesn't have much to give up. Maybe others will chime in, but I'm sure you could send it back if it disappointed...but like I said, the exhaust, to me, is well down the list of culprits.
