I have a theory that much of the NVH (noise vibration harshness) people complain about in the Infiniti / Nissan's with manual transmissions is due to poor balancing of the clutch / flywheel assembly. I had an IS300 I inadvertently put an unbalanced flywheel into, and it felt a lot like my G35 sedan does (clutch pedal and shifter vibrate a lot at high RPM). My clutch is fine, but I'm very tempted to by a JWT clutch / flywheel kit and have it balanced before putting it in. I think it cost me ~$100 to have the assembly balanced by a drive line shop the last time I did it and it made a big difference in the IS.

Has anyone already tried this with the G35?

Thanks!

 

not heard of anyone try that in the G, but i dont have any vibration in the clutch or shifter at higher rpms from what i recall, i do get a bit at idle just on the shifter but just as much as any other manual iv had, the noise/chatter which i dont get as much as many other owners will only get worse imo if u get JWT since it does not have dual mass flywheel.

However if u try this and it works out, it will make many owners happy who are suffering with the "noise vibration"

 

+1

The noise and chatter comes from the transmission and has little to do with the balance of the engine/fly/clutch assy. The dual mass fly significantly dampens it; without dampening, it's left to rage on.

Also, the engine NVH at high rpms presents in the automatics as well.

 

I was hoping to hear from someone that actually used the JWT flywheel / clutch combo, and went to the trouble of balancing the flywheel & pressure plate as a unit before installing them. I've had a couple of Fidanza flywheels in past cars, and my experience is that they do not come very well balanced. I believe the Fidanza site even recommends having the flywheel and pressure plate balanced as a unit. I don't have any experience with JWT.

Sorry, I just don't buy that it's the transmission. It doesn't make any sense to me that the NVH is from the trans.:

1. The manual (FS6R31A) and automatic (Jatco RE5R05A) are radically different designs that do not share a single part, so the fact that the NVH is present regardless of either being present doesn't support the transmission as the source of the NVH.

2. The dual-mass flywheel is obviously in front of the transmission, so any vibration created in the transmission would be free to transmit to both the shifter and the rear wheels regardless of whether the flywheel was dual mass or not. In general, dual-mass flywheels are supposed to smooth out torque pulsations inherent in the engine at low RPM, not mask any vibration from the trans.

3. If I place my trans. in neutral and rev the engine, I get the same vibration that I get when it is is gear. You could argue that the input shaft is still spining in neutral, and you'd be right, but:

4. The same vibration is present with the clutch disengaged and the car in gear, when the input shaft is not spinning.

 

I think we might be talking at cross purposes; particularly about just what NVH is and what "noise and chatter" from the transmission is.

I've always regarded the common NVH gripes about the VQ's as purely being a function of the engine, so when I say that the autos do it too, I'm fully aware that it's totally different from the manuals . . .THAT was my point. If they both do it, it's only the engine they have in common. The NVH I refer to is that raw, labored harshness and droning sounds and vibrations produced when the VQ is revved into the higher rpm's. It feels wonderfully full of torque, but it is anything but smooth and refined when compared to other engines.

That being said, NVH is totally different from the rattling and clanking cement mixer/bucket of bolts sounds you get from the manual trannys when you eliminate the dual mass fly. THAT is a function of the manual tranny (autos don't do that) and is mitigated by the oem fly.

It is certainly a good idea to balance your fly and clutch if you can. Some manufacturers do it at the factory and require that you match-mark and reorient them correctly when R&Ring them for service issues. Obviously, it can never hurt, but I think you're chasing your tail if you expect it to "cure" the NVH characteristics of the VQ.

.02

 

spot on! should not take many searches to see how moving to JWT will give you more of the "cement mixer/bucket" sound...