I plan on using a R200 differential (technically out of a 370Z) for a project car. But regardless, I see the differential has these thin rubber bushings on the front mounts. Of course I'm missing one. It's not technically the bushing I suppose, but I can't find this OEM part #. Does anyone have one I could buy off of them? Or know where I could look to find one?

 

I think that is called a differential bushing.
I would call Z1 to get the part, they have them for their rebuilds.

https://www.z1motorsports.com/z1-pro...l-p-11644.html

 

You won't need it if you run poly bushings, which you should

 

This is true, but trying to avoid as much NVH on this build as possible

 

The rear diff will still be insulated from the chassis by the rear subframe bushings and doesn't add any discernible NVH.

It makes torque delivery on/off throttle MUCH more responsive but the biggest reason people swap them for poly is the stock rubber is absolutely **** design and degrades after 60k miles. Once the rear section tears it will quickly cost you another rear differential.

In conjunction with the rear subframe yes, transmission yes, engine DEFINITELY. However the V35 chassis was loud and clunky to begin with and definitely didn't have much of a "luxury" feel compared to the V36 chassis so most people feel absolutely zero NVH difference with poly diff bushings.

To reduce NVH over stock I would put a huge focus on pulling up the factory carpet and lining the transmission tunnel with better sound deadening, same with the firewall down to the footwell. Same with backing the door cards with better sound deadening. The floor pans are surprisingly thick so it's not as big of an issue but the tunnel has fewer layers plus the gear whine from the CD00X transmission and the diff is quite noticeable in the cabin, the RE5R05A is less discernable. More deadening under the rear seats over the top of the gas tank as well. The VQ35DE is a loud engine so deadening the firewall would help substantially.

This can MOSTLY be done with just the seats and the console removed, you don't need to completely peel the carpet up. You can reach in from the front at the firewall and peel back the carpet, in around the center console, same for where the carpet meets the rear seats.

This will quiet the powertrain enough that your loudest source is road noise from the tires.

 

Yup ..same story with the mustang cobra with IRS.
Short of delrin bushings , poly is best..

Prothane poly is stiffer than energy suspension.
Greasing the poly/metal sleeve with synthetic grease is supposedly important to eliminate squeaking.

As mentioned above by cleric, The IRS cradle (my mustang language) bushings insulate you from nvh.

Yes to all the sound deadening, same story for the mustang.

I think there is a vendor that sells stiffer IRS cradle bushings as well...white horse?

IMO You have a driver's sports car.
Screw the comfort.
The G35 is all about handling and the "all car" experience...everyday.

 

Whiteline Performance

There's a few vendors for poly bushings, personally I use the Z1 Motorsports diff bushings.

 

I maybe should have mentioned that the differential is going into an S30 I did go the poly route all around on my G35 and didn't notice much more NVH, and completely agree with the 19"s on the G being a huge contributor to road noise.

But the rear suspension kit I'm going with for the S30 is from apexengineered: https://www.apexengineered.com/store...nsion_Kit.html

Many parts of it are solid mounted to the body. The rear bolt on the diff has to get solid mounted to this kit with no bushing at all I believe. So I figured for the front diff mounts, the more rubber (or poly I suppose), the better. But I hear ya on sound deadening. The S30 body is a tin can, so it'll definitely be getting as much sound deadening as reasonably possible/within budget. With heavy focus on trans tunnel, firewall, floor pans.