Rattle From Lightweight Flywheel

[GTR1993]

Put a lightweight flywheel and clutch in a S15 the other day, along with a new box. Had a weird bearing noise so swapped it for another box. Same thing again, thought chances of 2 stuffed boxes would be fairly slim so started driving it around to see where the noise way, only from 2300 to 3200 ish rpm, accel and decel, worse when more throttle applied.

Thought was a resonance thing, so started reading on the net. Found a warning on Nismo clutches stating at approx 2000 rpm a bearing rumble noise will be heard because of the reduction of weight of the flywheel can not dampen the oscillations of the motors power strokes. Made sense, wondering if many other people have experienced this?

[GDZ-14R]

Don't worry too much, S15's and R34 GTR's have a dual mass flywheel that is meant to dampen the noise in the driveline. I have had both, and in my current 34 with chrome moly flywheel and button clutch it rattles its tits off under 2k. Ride it for a couple of secs when parking and it sounds like the flywheel wants to make its way into the cabin..

[StealthX]

Yeah my X-Trail had a dual mass flywheel on it, when I replaced it with a solid mass and heavy duty clutch, I noticed a tad more drivetrain noise...

I'd say its normal bro.

[sh@un]

as you've read, Nismo indicates on their performance clutch kits that you can expect 6-speed 34/S15 gearboxes to make this sort of noise. It seems to be something normal due to the gearbox. Wouldn't worry about it.

[GTR1993]

Cheers guys,

Its actually not running a 6 speed any more, its running a conversion R33 gtst box with adapter bellhousing. But it sounds exactly as nismo/other people on the net have described.

Thanks for the help.