dizwiz24

ok,

I installed a spunghub spec stage II clutch / lightweight Al. flywheel and long tube headers w/o EGR /AIR or cats.

What extra noise from the flywheel should I be hearing? Right now I hear a knocking at idle (in neutral, clutch pedal up...) Put the clutch pedal in and it disappears. My old dualmass flywheel did that too. No big deal.

At low RPM (1500 or so, 6th gear) I might be hearing a small amount of gear whine, but the noise from my headers and the raddio drowns that out almos completely.

HERE IS THE KICKER: Do any of you guys with the lightweight flywheel get any extra noises when the car is under load in between 1500-3000 RPM.

For example, you are going up a hill at 40 MPH in 3rd no noises yet until you push the accelerator down a little more. You give it gas and do any of you hear a trememendous rattling/vibration noise like I am hearing - note its fine until you give it a little gas?

or maybe its engine knock....

jsaunde2

Here is a summary of the noise I get with a similar setup, camaro FW and Mcleod clutch with sprung hub.

At idle with clutch engaged (up) trans in neutral, a slow rock tumbler like rattle/clanking noise. This goes away if RPM's are raise to approx. 1k. This is caused by lack of the dual mass FW.

Low RPM clutch engaged in gear as load is applied, rattle that doesn't sound good like you described. This is apparently caused by the springs in the clutch disk. I guess this is caused by the springs bottoming out and then rebounding repeatedly as it only happens at low RPM's.

I believe the sounds you are hearing are probably "normal" and nothing to worry about. This is why I am more cautious about recommending a single mass FW than those who recommended it to me were. The noises are fine for the driver but don't exactly impress the unwashed mases. :D

Jason


[Modified by jsaunde2, 11:18 AM 10/11/2002]

dizwiz24

These noises are very very severe. Its nothing you can drown out with radio. They are accompanied by a vibration, and it is only under load.

It doesn't happen if you slip the clutch for a gear change at these RPMS either. It happens with the clutch fully engaged, and ONLY under load. high gears are worse. (ie. if you sit in your driveway and rev it, you won't get that rattle I describe between 1500 and 3000 RPM).

It is so severe, I think if the lightweight flywheel was causing it, nobody would be selling lightweight flywheels.

jsaunde2

It is difficult to communicate the severity of a sound but given the conditions under which it happens it is almost certainly the standard noise form a sprung hub clutch. I wish someone else wouls corroborate my reassurance to you.

Like I said, this is not a good noise and people will downplay how bad the various noises, from a SM flywheel setup like this, are.

MSR

the sprung hub actually alleviates the noise somewhat. without the springs, the engine pulses vibrate the tranny pretty hard.

dizwiz, is your clutch disk sprung, or like the stock one?

i kept the stock disk, and the noise is very severe.

SPD DMN

The noise should not be real severe. The SPEC satge 3 I am now running does have considerable noise under 2500-300 under WOT loads. It sounds like loud stress gear whine, but it normal for this clutch. The only other noise I have is at idle with the clutch released in neutral. The McCleod I ran had a very quiet rattle, but the SPEC is 5 times louder.

The Stage 2 should be considerably quieter. Not sure about how the aluminum flywheel makes much difference over the steel flywheel I am using. I did ride with a friend with the Spec Stage 2 and aluminum flywheel and did not notice much difference to mine though.

Everything is probably fine. With the lightweight components you can not lug the engine like with a stock dual mass flywheel. It can make the tranny sound like a box of rocks when lugging the motor. I usually have to drive above 1500-1600 RPM in higher gears if I give it any gas. I can coast at highway speeds without noise as long as I do not give more than 25-30% throttle.

mikey

i have the aluminum flywheel and stock clutch setup on my '94 383..

the rattling in neutral is normal gear chatter from the zf6

i get what i would describe as a "buzzing" type noise under load.. have always assumed this is due to the single mass lightweight flywheel's inability to absorb normal gear noise..

but, be careful that you are not out of balance.. LT1's are externally balanced via the flywheel.. your new flywheel/clutch/pressure plate should be balanced matched to your old flywheel/clutch/pressure plate.. you should not be feeling any vibrations..

put the car in neutral and keep your foot off the clutch pedal.. very slowly depress the gas to slowly sweep through the rpm range.. go up through the rpm's slowly all the way to 5000 rpm and take note if there are any vibrations.. an off balance flywheel/pressure plate setup will often have prominent vibrations only in a specific rpm range, depending on the severity of the improper balance..

good luck,

dizwiz24

had a mechanic ride in it. He says its not knock. But likely the flywheel. My noise seems consistent with what you all are describing while under load.

I should mention I had the new flywheel balance double checked against the old flywheels balance jsut to make sure it was balanced right. It was balanced exactly like the old.

Its bad, but I'm getting used to it. But just like a loud exhaust, you can drive it 'quietly' by being in the right gear when going uphills, etc.

I just wanted to make sure it wasn't knock.

BCZR1

Did u replace the pilot bushing?
Reason i ask is u mentioned "it did it before w/ the dual mass" If the pilot was worn and moving around in the housing, it would make a "knocking"/clunking type of noise, there would be no question. BUt i would bet if u have everything in order, it is just your hearing the more noise from the tranny, as u have less damping material there now than with the dual mass. Noise out of gear, engaged clutch(up), and just easy out is normal and expected. I run a sprung hub also on my Z. I guess it depend a little on the clutch set up as to what degree the noise is, but should be most prevalent in the cases mentioned here and previously.

Brian

Red Rocket

Have the Camaro Steel Flywheel/Mcleod stage II clutch and the noise is not bad at all. There was a lengthy discussion two years ago on the real lite weight flywheels versus the steel ones like the Camaro flywheel. My flywheel weighs 20 LBS the spec aluminum weighs about 9-11LBS I believe.
Do not want to start a flywheel debate but the discussion two years ago concluded that the heavier the better from a noise standpoint. The knocking noise can also be a problem with the clutch fork banging. There is a cheap clip that holds it in place as I remember. Mine kept breaking off with multiple runs at the track.

The Dingo

Sounds normal to me. I have a DRM single mass (f-body flywheel) and an unsprung OEM clutch disc and OEM pressure plate. As has been said here already, your sprung clutch disc should lessen this noise if anything.

It seems as though not many people mention this particular noise in single mass flywheel discussions though, do a search if you haven't already and you'll see what I mean.

When I installed my flywheel I had the same concerns as you, despite doing alot of homework on the flywheels before I did it nobody mentioned this issue - I wrote to DRM after I first drove the car after the install to ask if the noise was normal and they said something along the lines that as long as I didn't have any heavy vibrations it the noise should have been fine.

I have had my single mass on my car for about two years now and covered more than a few miles over that time (highway, normal driving, roadcourse & dragstrip) and so far everything is fine - I expect it to stay that way (touch wood :)).

edit: The dual mass in my understanding was used to quiet noise in the ZF - going to the single mass is automatically going to introduce alot more noise to the party... I used to have a similar noise from my old dual mass only much, much quieter when I pulled sixth gear too early, now I have the same thing in more gears only much louder. HTH


[Modified by Red 90 L98 Coupe, 12:31 AM 10/13/2002]

dizwiz24

in response to Red 90 L98 coupe's comment....yeah there is definitely some vibration that occurs in addition to the rattle. But kind of like a loud exhaust, you can avoid it all if you use the right gear for hills, etc.

I might try putting Castrol 10W-60 synthetic (the bmw stuff) in my ZF-6. Maybe since its a slightly heavier weight it will absorb some noise.

jsaunde2

I'm switching to the Castol TSW tomorrow and will let you know if it helps the noise etc. I actually drained my tranny today and was suprised at how good the fluid looked. Anyway, I'll repost once I give it a test drive.

Jason

Vette Threat

What about the DRM aluminum dual mass flywheel. Would that also make more noise than stock because it is lighter? Anyone running one of these or heard what they're like?

I'll be doing my clutch/flywheel over the winter and I was considering getting it over the single mass.

ericcer

I have the same setup and it is not broken in quite yet. I have the same noise. It is the tranny buzzing and vibrating. It is amazing how much that dual mass flywheel hides. My mechanic thought that was normal for the setup I have.

The ZF Doc said the BMW oil would quiet the noise down a bit.



[Modified by ericcer, 7:14 AM 10/13/2002]

R23HTC

I have the same setup and had the same noises as I was breaking it in. It's got around 4500 miles on it now and it is noticabley quieter. It's still noisey, don't get me wrong, it's just not near as noisey as it started off being.

ered95

DRM aluminum dual mass flywheel????????? tell me more. :cheers:

Vette Threat

I wish I could tell you more. All I know is that DRM sells it for $400 and that it's aluminum. Some time over the winter I'll be putting one in and I was wondering if anyone else has tried them?

On the surface it sounds like you get the weight advantage of a single mass yet the noise advantage of a dual mass but I'm not sure.

Hopefully someone out there has one and they can chime in with personal exeriance.

The Dingo

dwiz, In my opinion, if you only get a mild vibration when lugging the car around in a higher gear that is normal. A thicker weight oil will quite likely lessen the noise to a degree.

With the aluminium flywheels, I read in the ZR1 forum that someone (GTB/ZR1 I think) said in a thread that he had run a few different SM flywheels and found the alumnium to be a little quieter. Do a search for under single mass flywheel in the ZR1 section and you might find the coments I am thinking of. Even if an aluminium single mass is quieter the other types of single mass flywheels, I definitely wouldn't expect to acheive dual mass levels of smoothness and quietness with one in my opinion.

dizwiz24

I have the aluminum one with steel friction surface, and steel starter teeth around the outer edge

I just feel dumb that I thought the noise from it was knock.

To tell you the truth, I am used to it now. I notice I slip the clutch more when leaving a light.

One thing I don't like is that I don't get that tire chirp when downshifting into 3rd at highway speeds when I had the other flywheel.

But the combo with my long tube headers....wow...I got more acceleration.

I don't know whether its due to the flywheel, or headers, or both though.