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Clutches and Fly Wheels.


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Guest Terry S

Ashley, my stock clutch only started slipping when I added cams to my lairy hybrid set-up. I think you'd be fine with stock. If you ever get enough power to make that slip then buy a modified pressure plate for more clamping force. I made the intial mistake of going from a stock clutch to an RPS 6 puck which I hated. I am much happier now with my dual friction Kevlar/Metallic but even this would be overkill for 95% of the cars in this Country. Leon sells a full Kevlar which will hold more power than stock & have similar engagement ( modified PP make the effort/engagement harder). Also, Chris Wilson was doing a great deal on his own modified set-up a while back.

 

There is no reason you can't run a LW flywheel with a stock clutch. The set up will chatter though unless you raise your idle to 1200 rpm. What evr check the FW when doing the clutch as the stock dampers seem to give up after a while. Mine was completely shafted when it was pulled.

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Originally posted by HardHead42

Lightened flywheels are great, I ignored all the comments and myths that others (who had never had one) banded about and got one anyway and have never looked back.

 

Interesting article http://www.pumaracing.co.uk/flywheel.htm

 

Rich, just read that, shit me, thats takes reading a few times, but yeah I can see why you would want a lightened fly wheel, thats why I want one as they do increase exceleration at low gears, due to less wheight having to be shifted. But for me its a minefield of which one, as I dont know the difference between a sprung or non. And wheather I caould run this with a standard clutch, and if not not then minefield no.2.

 

But interesting reading, nice one, hows the Honda, havent seen you about....

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Originally posted by Terry S

What evr check the FW when doing the clutch as the stock dampers seem to give up after a while. Mine was completely shafted when it was pulled.

 

Terry, Sorry mate, what was that, ha, ha. You have to remember who your talking to, but I will pass this onto the chap who will be doing the work.

 

I think this sounds the best option for me to keep in drivable round town.

 

So I just have to find myself a fly wheel.........:thumbs:

 

PS, Is that the only reason I need to raise the RPM, so stop the noise of the fly wheel, or is it not good for it to rattle.

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Guest Terry S

Ashley, the stock flywheel has a damper on it to reduce driveline shock. These wear after a while. They can be tested by trying to twist the flywheel against the damper. If there is significant movement then it's probably on it's way out. Yes the only reason to raise the idle is the noise, but it won't harm the car, just make you sound like a knob at traffic lights.

 

Eyefi the car had Hybrids for about 6 Months before the clutch started slipping. I put the slipping down to the additional injectors & the addition of higher lift cams, but it could have been just general wear.

 

If it were me all over, I would do the full Kevlar set up, but it's your money guys.;)

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Guest Martin F
Originally posted by Terry S

There is no reason you can't run a LW flywheel with a stock clutch.

 

 

Nope there isn't, but not a good idea as there would be absolutely no damping and the life expectency of your gearbox would be serverely shortened.

 

I'm not aware of any sprung lightweight flywheels. Have you found one Terry ?

 

As far as i know for a decent life span of your gearbox one of the components needs to dampen the take up force (i.e. be sprung) either the flywheel as in the stock system or the clutch plate.

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Guest Terry S

No Martin, I don't know of a sprung LW flywheel. That is why I said the full Kevlar would be my choice. You can have it as a 6 paddle with a sprung hub. IMHO it would be the ultimate BPU set up.

 

I have heard like Paul said that the new RPS is supposed to stop chatter but unless it's dampened I can't see howit's possible. BTW the chatter gets worse the hotter the box gets.

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Yep, my RPS flywheel doesn't chatter at all, mine ticks over at 840rpm so not particularly high. But then I've heard Zac's RPS flywheel and that rattles like a c**t. May be they fitted it wrongly, all I know if mine is quiet as a mouse. 6 puck clutch is a bit of a bitch though for everyday use, luckily that doesn't matter to me as I only use me motor for nice days. OH and I was at Donington Sunday and it didn't get any noisier when warm, may be I have a freak one!

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Guest Terry S

You'd need to call Leon. 01908 367100.I Think the whole Kevlar set-up is about £500 - 550 but reading between the lines you could just get the Kevlar disc, & if you wanted more clamping force just get the PP machined a bit. This could save loads. If not I have a used RPS PP that would work well if you had the face machined a bit.

 

This is a mail I was sent by a MKIV guy that basically sold me on the Kevlar idea. It's very long so take a deep breath or just skip the mail;):

 

"The alleged advantages of the kevlar is that it wears like iron,

doesn't create much heat when slipped, and makes for a very nice slippable clutch, not an on/off type clutch at all. By keeping heat down, you don't warp the crap out of the flywheel and pressure plate, or weaken the pressure plate diaphram, or turn the clutch disc lining into ash. If you warp the flywheel and pressure plate you can end up with 0 clamping force even if the

disc is brand new. That is what happened to my RPS stage II clutch, the one with a "tweaked" or shaved pressure plate to increase clamping force and the stock clutch disc, after 12 passes.

My setup drove just like stock. Same pedal effort and slip as stock. Very nice for an everyday driver. Break-in is about 50 miles.

For the 1st 50 miles the clutch would break loose when #2 turbo kicked in. I definitely had my doubts, after break-in it would hook and stay hooked.

 

For the last couple passes the clutch would slip about 1000-1500rpm when dumping the clutch in 4th gear. It would then hook and stay hooked. IMO I just needed a bit more clamping force. It wasn't breaking loose after engagement like a clutch does in 4th gear when it is failing. I don't lift much on shifts so I wasn't babying the clutch at all.

 

I'm putting in a T88 now so I'm installing a OS Giken triple so it was time for the single disc to come out. This was probably just about the best time to pull the clutch and check out how it did anyway. I had over 50 passes on it, which people seem to think is a reasonable measurement of success for a clutch, and it wasn't quite hooking up as I'd like in 4th gear. Basically if I kept drag racing with it and allowing the slipping in 4th to continue there might not be much to evaluate.

 

Now, I hope that is enough background. If there is something I should elaborate on I'm sure you'll will let me know. I'm reluctant to even tell you what I found and I think you will see why.

 

The flywheel, upon inspection looks perfectly flat. There is no

blueing from heat, cracking, or warpage at all. There is an area of brown marking, like shoepolish where the kevlar disc made contact. The flywheel had been resurfaced using a spinning stone which left c-shaped marks on the flywheel mating surface. You could probably make deeper grooves with 80 grit sandpaper. Well, in the browned area of contact the grooves were still visible, smoothed down a bit but still visible. So, there was virtually no wear to the flywheel at all. It was essentially smoothed, polished, but not worn or deeply glazed. We surfaced the flywheel just to freshen up the mating surface and took off about .003 of an inch.

 

The kevlar disc had a slight bit of glazing, if you want to call it that, to less than 1/2 the width of each puck. The inside 1/2 of each puck looked like new. The outside 1/2 of each puck was more polished looking. Now, when the kevlar is bonded to the disc it is glued and pressed in place. The press makes grooved indentations in the kevlar. They are extremely shallow and you have to look very closely to see them. I guess they are called tool

marks. These tool marks can barely be felt with your fingernail. The grooves could still be felt in the kevlar. When we mic'd the disc it was the same thickness as brand new! So, there is virtually no wear to the disc at all! We sandblasted the disc to roughen up the smoothed area and it is just like new.

 

Okay, this is getting a little long winded I know, but I'm almost

done. :)

 

The pressure plate was essentially the same as the flywheel. No

blueing from heat, cracking, or warpage, etc. I'm told that there is a slight taper to the stock casting; I don't know why. But to knock off the polishing and increase clamping force a bit we took off .005 inch of material. It looks like new. So, at the end of a season of hard drag racing launches you could pull this out, sand-blast the kevlar, and probably just rough up the flywheel and

pressure plate with sandpaper and be ready to go. How does that sound? If there still isn't enough clamping force you could take another .010 inch off the pressure plate. I can't be certain if clamping force wasn't quite enough with the stock pressure plate or if the "glazing" had reduced the coefficient of friction enough to cause my slight lack of hook-up in 4th gear. The only way to really tell is to drop it in and see how well it hooks in 4th gear as it is right now. If it doesn't hook after a re-break-in in 4th gear then the pressure plate would need to be tweaked a bit. If it only starts to not hook up in 4th after 50+ passes then it is probably time to roughen up the kevlar and perhaps the flywheel and pressure "

 

Sorry that was so long guys but in sumary I went fora Kevlar/Metallic clutch & have been more than happy with it.

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Originally posted by Ashley Willis

Rich, just read that, shit me, thats takes reading a few times,

 

Yes it's interesting reading, don't understand the maths though.

 

But interesting reading, nice one, hows the Honda, havent seen you about....

The BAD news:

The Honda is currently running with low compression on one cylinder and bad oil comsumption, So I am only using it part of the time (basically days Teresa has to use a car)

 

The GOOD news

Its going in to get fixed next Tuesday

 

The BAD news

It's going to need reboring and oversized pistons used

 

The GOOD News

I will be installing oversized Civic Type R (EK9 the older version) pistons which are a direct fit and raise the static compression ratio from 11.1:1 to 12.4:1

 

The BAD news

It's all going to cost

 

The GOOD news

I am also having the topend rebuilt including uprated springs, Titanium retainers, adjustable verier pullies, and a nice pair of TODA 'B' cams (12mm lift / 295 duration on VTEC lobe)

 

The BAD news

Teresa is going to kill me when the bills arrive.

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Originally posted by Terry S

Ashley, the stock flywheel has a damper on it to reduce driveline shock. These wear after a while. They can be tested by trying to twist the flywheel against the damper. If there is significant movement then it's probably on it's way out.

 

Agreed. And has no-one read my earlier mail...;)

 

As for lightened flywheels increasing acceleration, I really find it difficult to subscribe to the fact that an engine capable of pushing a ton and a half of mass up to 60mph in 5.5 seconds is going to be overly troubled by an extra 6 pounds on a flywheel....

 

Throttle response though, yes.

 

Nathan

TDI PLC

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Guest Terry S

That Jun one is an excellent price!

 

Dual friction is just two types of material alternated on the paddles. The metallic will hold more power but they grab making it more on/off han just organic or Kevlar. No need unless you are running big power really.

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Can I just confirm, Terry, that your set up is not sprung in anyway?

 

What is the weight of the stock sprung flyweel?

 

This kevlar clutch does by that account sound like a good option.

 

To slightly digress when shifting on the drag strip are you supposed to over rev the engine and drop the clutch and let it try and bite?

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Well guys, this has been hard, thanks Terry, Eyefi, Nathan and Rich. Its hard to take in everyones point of view, and I know nothing on this which doesnt help. I spoke to Leon yesturday and we are discussing it at the moment, but he has said that he cant see a problem running a lightened flywheel with a stock clutch.

 

I will of course let you all know what happens....

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Guest Terry S
Originally posted by Alex Holdroyd

Can I just confirm, Terry, that your set up is not sprung in anyway?

 

What is the weight of the stock sprung flyweel?

 

This kevlar clutch does by that account sound like a good option.

 

To slightly digress when shifting on the drag strip are you supposed to over rev the engine and drop the clutch and let it try and bite?

 

No Alex I am running a disc with a sprung hub.

 

Ash I don't think Leon's head was in gear when you spoke to him. Whilst technically you could run a stock clutch with a LW flywheel, all the driveline shock would go directly to the box. This would not help the longevity of the box at all. If you want to run a LW flywheel get a disc with a sprung hub. Cheapest way would be a stock PP & a Kevlar 6 paddle spung disc.

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C-one do a flywheel here

 

http://home.catv.ne.jp/dd/checker/overseas/o-jza80.htm

 

Its 39,000 yen - £210 rounded up - which says its for a Turbo.

 

I'll do a search on it but can anyone find

a) a picture

b) a better price :eek: :p

c) a dealer we can trust.

 

EDIT -

found this to

AASCO Flywheel

 

Am I right in thinking that Aluminium is not wanted and that a chromolysteel is better??

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Fidanza flywheel for £300ish landed from the states.

+ an uprated PP and sprung kevlar clutch from Leon sounds like a nice setup...

 

Being able to do over-revved gear changes for a kick from every gear on the strip would be nice :D :cool: and should shave some time of a BPU car's 1/4 without being undrivable on the street.

 

Hmmm getting a bonus at the end of the month...clutch or fuel system...or replenish the bank account :(

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