Aftermarket Flywheel?
 

Hey all, so I recently purchased a '10 Touring Z from a dealer, and they had no idea what had been done to it from the previous owner. I can tell it has G3 Intakes, Stillen Catback exhaust, and looks like sway bars and Eibach Lowering Springs on it. I've noticed that i have this rattling in lower rpms (louder with ac on), that goes away when i press the clutch in. My buddy says it kind of sounds like a flywheel, but i've never had an aftermarket flywheel and don't know what the chatter sounds like. So my question is, is it possible to even see if its an aftermarket flywheel without opening the tranny? I'm also kind of curious as to if the CSC has been replaced with the Z1 CSC as well...

That is typical of the stock clutch.
A lightweight flywheel, which I have, is more noticeable when accelerating, not when depressing the clutch.

Yup. The rattle is par for the course with these platforms. An upgraded ZSpeed HD CSC would be difficult, if not impossible, to tell without dropping the tranny. The Z1 would be easy, get under the car and see if has the elimination kit on the outside of the tranny. If not then it's not there.

Check the link for pictures of the installed elimination kit.

https://www.z1motorsports.com/z1-pro...it-p-7340.html

A lightweight flywheel will kinda sound like someone is lightly shaking rocks in an aluminum can. The sound should be noticeable from idle till 1500-2000 rpm or so. There is no way to be 100% certain what flywheel is on the car without pulling the trans. However, I suggest go test drive a stock Z at the dealer. Focus primarily on the throttle response and how quickly your rpms increase relative to throttle position. Your car will feel more "peppy" with your additional modifications, but you should be able to tell a difference between a factory flywheel and a lightweight flywheel. A lightweight flywheel will rev significantly faster than an oem flywheel.

As for the CSC, Z1 uses an elimination method. If you have a Z1 elimination kit you will be able to tell visually with the extra components mounted outside the transmission. Pictures for reference in the link below. If you have a Zspeed HD CSC, the only way to really know is to pull the transmission. The only other indication of possible CSC/clutch/flywheel replacement would be a heavy duty clutch line outside the transmission. This is generally always replaced when upgrading components.

https://www.z1motorsports.com/z1-pro...it-p-7340.html

Go for a long drive and drive the car hard to get the flywheel hot. Pull over and let the car idle in neutral, make sure the AC is off. With a single mass flywheel you will hear chattering and a weird metallic resonance that sort of drifts in and out. Another way to check is to short shift at low speed and low rpm. Shift into 3rd gear at 20 mph. You will hear a very loud deep resonance through the cabin if you are single mass. It is very noticeable. If you have single mass installed, you are lucky...one of the best mods.

Hmmm. Well i know when i shift from 2nd to 3rd in my neighborhood and am at under 1300rpms, there is a sound that sound exactly what your describing. I'm going to try to get a video tommorrow.

If your revs are that low, the sound you are hearing is engine lugging. Get your revs higher than that.
A lightweight flywheel will have a warbling sound. Kind of like a pigeon on steroids.

On the lower left hand side of the transmission bellhousing there is a large black rubber grommet where the clutch fluid lines enter the area.

If the lines are stainless braided flexible hoses, you have a CSC upgrade. If the CSC is stock, there will metal pipes going in there instead.

You can use a small tool to expand the openings in the rubber grommet and you should be able to peer in at the clutch/flywheel with a flashlight.

What cj said or you can pull the little inspection plate in the back of the oil pan and shine flashlite and stick one of those telescoping mirrors in there but it is a mother bitch to get at in the car.