That's where we differ, Diz... I am not that concerned about shaving off a tenth, if it means sacrificing the drive quality. It just ain't worth it.

If I was that concerned, I would build a dedicated track car...

 

Thanx for the story neat. Pretty interesting stuff.
Those dirt car crankshafts amaze me. 36 lber's!
Our cranks are like 50 some odd lbs.


....and so goes on the never-ending saga of single mass noise and dual mass cost/weight.......

 

I do remember hearing that you should go to a 'sprung' hub clutch if you go with the lightweight flywheel to reduce noise.

I went with a SPEC stage II sprung hub clutch at the same time. So maybe noise on my setup isnt as much an issue.

Theres only 2 real areas of driveability that are affected.
1. Noise. But only under high gear, high load acceleration. Freeway noise, coasting noise is unchanged. Sometimes theres a slight rattle during initial clutch disengagement from a dead stop. However, its not as loud as the noise experienced during high gear, high load (up hill) acceleration.

2. Sometimes, I have to downshift more often to tackle slight hills (which you should anyways).

You make it sound loud when you want to make it sound loud. Lugging an engine is rough on it and this flywheel lets you know when you are doing that and should downshift.

Its all about opinions. Different strokes, different folks.

I would recommend going to a CF get-together and ride along with someone that has it in their C4.

 

or for a real treat, just stand outside next to one while its idling. mine used to turn heads from other lanes with crinkled expressions at 4 way stop lights, it was so insanely loud. engaging the clutch for sanity relief proved to be just another pita. the fidanza (and yes it was mated with a stage II setup which included a modified sprung hub disc from carolina clutch) was by far the worst decision i ever made for the car, bar none.

 

David Vizard is one of my favorite authors. If you want a really good primer on timing, combustion, and other such topics, try his Volume 1 on horsepower. Excellent read in my opinion.

dlmeyers 90 coupe zf6 3speed shocks

 

I have a distinct feeling that you don't know exactly what is going on inside a clutch.

The sprung hub friction disk is needed because it is actually 2 halves that will absorb the torque loading during a shift. The DM does this on the stock setup.

If you didn't have this, the driveline shock would be astounding.

 

quote:

or for a real treat, just stand outside next to one while its idling. mine used to turn heads from other lanes with crinkled expressions at 4 way stop lights, it was so insanely loud. engaging the clutch for sanity relief proved to be just another pita. the fidanza (and yes it was mated with a stage II setup which included a modified sprung hub disc from carolina clutch) was by far the worst decision i ever made for the car, bar none.

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Thats where I got my setup from. I'm surprised to hear about your experiences. Mine made no extra noise whatsoever at idle. I get a rattle only under load. Its not the rocks-in-a-can noise I hear everyone talk about. Its a metallic rattle when accelerating.

Maybe a light tap-ing if you had it in neutral, clutch engaged. Thats it.

In my case, it was one of the absolute best decisions I made for my car.

If it made my car sound as bad as some of you have reported, then I would have taken it off.

It sounds like our experiences are different for some reason.

But then again there was forum members saying that every SPEC clutch is garbage and here I am having great luck with my stage II many miles later.

 

Parked next to a wall, or in a drive thru, it sounds like it's falling apart. I keep the clutch in. And that's with a cast iron SM flywheel.

 

Tom Haus did say this up front, although I had to begin that part of the conversation. And he sort of glossed it over. The sales pitch was all about revving and transfer of extra 10-15hp to the wheels. Its a roll of the dice. And you'll never find out until its all installed. I was one of the unlucky ones. And the ridiculous noise could be distinctly heard from quite a distance, out in the clear wide open.

For a person like me who doesn't care a hoot about timeslips, numbers, 15hp (I've got plenty from the engine mods), and bragging rights, the 1/4 mile, that thing had to go. There was absolutely no doubt about it. The ultra light aluminum fidanza is for racers, not for the 99.5999% of the rest of the world.

 

100%. That is exactly what Tom said/did... he glided over the reality of both potential vibration and noise.

 

I don't have that at all. I had some with the stock dual mass, but it's completely gone now.

I guess different set-ups are going to respond differently.

My point is that just because your single mass was noisy as hell, doesn't mean they all will be. Condemning all single mass set-ups to someone trying to make the decision on which way to go is incorrect, IMO. I just think you guys that can't stand the noise from the single mass should try to point out that it is only your specific opinion and experience. Stating that 99% of the people out there will be happier with a dual mass set-up is just wrong, IMO. Saying that single mass set-ups are only for race cars is wrong, IMO. My single mass is daily driven, and is so marginally louder than the stock set-up it's almost not worth mentioning. At idle, it's quieter, and I don't get the weird looks from people when I sit at lights because the loud clanking I got with the stocker is gone. Maybe I lucked out, I don't know; but my experience with the single mass set-up has been great. I'd recommend it to anyone, even my mother.

I just hate to see a new guy replace the clutch in his C4 with the stock dual mass, when it might not be the best choice for him, all because a ton of people told him that single mass set-ups are for race cars only. Pointing out that your single mass is unbearably loud to you is great, share your experiences. Don't try to make it sound like everyone's experience with the single mass is identical to yours though. Like I said, I couldn't be happier with mine.

 

neat, pretty much true points.

however, noise is a well known fact, and it generally does apply. i've done reading too. and based on what i've read, backed up by my experience, i could not sleep at night recommending a SMF to anyone who doesn't tear it up at he track as their main, or semi-main, passion.

therefore, i respectfully submit that what i said, and others in regards to noise, racing, et al, is not wrong. it will generally be correct. most people do not like that kind of noise. perhaps the biggest point to make to would-doers is to drive it home that its a roll of the dice. THAT's a biggie

 

Plenty of guys out there running SMs on the street without unbearable noise.

It comes down to how much vibration you have at the crank, and how effectively you can damp it.

There are a number of steps you can take to reduce the noise (increase idle rpm, for example)...

...but I suspect the "roll of the dice" factor comes down to how well the engine is balanced internally. ie. "sans flywheel"

 

I have a black tag ZF with a stage 2 SPEC clutch/alum SM FW in it and I don't find it loud at all under throtle under 2200RPM ( who drives under 2200RPM?? ) although I do hear it.

After driving for about half an hour you can hear it quite a bit at idle but if you hold the clutch pedal down, it's dead silent.

That's good enough for me and I'm keeping it for my next engine, coming soon.

 

Lemme try again... there are more than one noise to contend with... and the killer isn't the increase at idle, it's THE DAMNED RESONANCE!!!!

It hits between 1700 and 2000 RPM, right in the meat of the crusing band (contrary to your opinion, many of us run below 2200 RPM, it SAVES GAS and wear and tear on the engine).

It is boomy, it resonates everywhere... and gives me a ****ing headache. I hate it.

I am going to get a DM again... SOON. I will swap it out over a weekend...

 

I guess the point here then is.... your miles may vary. It might be loud as hell, it might be bearable. And you might get typhoid fever. And the guys who recommended it might have a different idea of "loud" than you do.

All I know is, I'll avoid the subject if it comes up. I know what a single mass 1985 grey iron flywheel sounds like on a black tag transmission with a oem clutch, so that's all I'll comment on.

 

Beats getting VD, I guess...

The thing is, I know how the Fidenza sounds on a LT1 with a black tag... and it ain't pretty.

 

Lol, the debate rages on!

 

No doubt. Kill this thread like I kill DM corvettes.

 

One thing that helps SM gear rattle is raising your idle rpm if possible. It gets better with a higher idle around 900+ rpm. Also... for some reason, the dual discs don't seem to have the gear rattle the single discs have.

Some good info Josh