Clutch questions. Puck disks etc...

[vlad01]

While I have been dealing with some clutch woes on the shitbox and now have the base level Xtreme organic kit ready to install.

I started to think about the high performance options out there for that "one day"project that is the VP S


I have an NPC ceramic chushioned kit which has been great, apart from what Gareth mentioned a while ago a delay type resistance probably being the cable and I have confirmed that is the case with an identical spare new in packet cable I have in my spares, it also even with no load is very slow to push and pull the cable through by hand.

Anyone have recommendations on a brand of cable that is decently heat resistant ( most options shrivel and peel immediately to even a heat gun on low) and also has very low resistance.

I have a Dellow HD beefy cable in the shitbox at the moment and it's too long on the inner cable and I had to use a 12mm spacer and it's on the last 2 threads of adjustment. Otherwise it's low resistance and heat resistance have been the best so far since genuine factory cables were last a thing. They just made it wrong


Anyway, getting back to the clutches.

For me, a positive bite is highly desired, I don't like slippy gradual feeling clutches. Clunky engagement is a nice subjective feeling to me.

Shudder what car I have doesn't have it, so not an issue. I've learned that it's pretty much a given with a Buick v6 and the commodore chassis/driveline dynamics. Ceramic actually was by far the best in this regard.

Pedal lightness is a big criteria for me, I hate heavy pedals, I don't mind if they are heavy on the initial bit and then "pop" to become easy, the NPC one is like that. I hate clutches that have no "pop"or worse, get firmer the more you press them (cough cough... exedy ).


Another thought is, with high rpm shifting, the lighter the disk, the easier the shift is and the higher the rpm a given gearbox synchros can manage without excessive baulking and eventual burning of them. They are essentially brakes used to slow down the engine side of the gearbox rotating mass forward of the main shaft during shifting. The disk carries the majority all of this inertia.

My planned engine just slightly pushes past the rpm shift limits of the T5 and a light disk will solve this potential issue.

So I thought, to get a single plate clutch to the torque holding capacity required, estimated 330ft-lb + some margin, so lets say 30-50%. So somewhere around the 450ft-lb before slippage.

To get the lightest pedal and the hold required, can a mild to moderately upgraded pressure plate and say a 6 puck ceramic or carbotic material disk achieve this?


I recall Gareth had a 6 puck on this speedway car, stock flywheel and some lightweight billet alloy cover pressure plate. I never felt how the pedal was, but it would have similar torque output from the engine to what I am looking at. So if you chime in that would be awesome


Multiplate is an option, I do believe that is even better when it's pedal effort vs hold ratio is concerned but as for disk inertia it could be a step backwards? Or perhaps not since the diameter of them are much much smaller.

[v6bucket]

I use a 4 puck metallic clutch plate with a modified Clutch Industries pressure plate, I got this setup from from Western Clutch in NSW, they alter the pressure plate & clutch plate to suit your engine/vehicle combo. When I purchased this combo, it wasn't that much different in cost to an off the shelf unit from one of the larger auto shops. This clutch has performed great since it was fitted, 7200rpm launches in a 1200kg car on slicks with 275hp at the tyres, flat changing also tests the synchros, (which the T5 wont handle without changing to brass synchros). I'm sure there will be a clutch shop closer to you, they are the best people to talk to, it's surprising how much they can change a std pressure plate.

[vlad01]

We haven't got any good clutch places in Vic, they are all misinforming and generally don't want to deal with anything custom related I found.

I have used NPC in the past and they basically did similar to what you described. I also use Xtreme off the self kits which are very good for the money. I just installed the most basic kit in the shitbox over the weekend and boy it was a massive improvement over the junk exedy one I regrettingly installed. But even this Xtreme kit which states it's 25% heavier than stock feels pretty heavy but does have great pop and feedback and a very distinct friction/full engagement point.

Interestingly the down shift axle tramp is gone and the suspension feels like it's been upgraded which is really odd, I never knew a bad or mediocre clutch could change the seemingly unrelated dynamics of the car that much.

T5s these days use the carbon rings which are supposedly much better for high abuse and rpm loads, then the next is sintered iron but they tend to wear out. Only the factory Holden and early Ford T5s had the auto clutch paper type rings which burn if you flog them too hard at high rpm.

But I know what you mean, the brass ones can take a beating and don't seem to wear out, but are kinda slow to take up unless you force them.

What is your 4 puck like in pedal effort and is the engagement manageable?

[immortality]

So maybe this is an internet myth but I was always advised to stay away from hard engagement puck type clutches as they tend to find the weak spots in T5 gearboxes?

[immortality]

Interestingly the down shift axle tramp is gone and the suspension feels like it's been upgraded which is really odd, I never knew a bad or mediocre clutch could change the seemingly unrelated dynamics of the car that much.

I can, if the clutch engagement isn't smooth that forces aren't applied consistently and it's going to do weird shit to the driveline.

The clutch in my Subaru is worn out and it does some weird shit sometimes but not other times.

[vlad01]

Well the engagement was smooth, too smooth. The beginning of friction and the end of full engagement was 90% of the whole travel. The slipping or lack of clamp is probably what was making the drive line tramp when hard down shift, even though the clutch pedal is long fully released by that point.

It feels like the entire rear end suspension has gone to sports shocks and solid bushes, there isn't any sloppiness now despite the OEM rubber bushes I changed 6-8 months ago already failing.

[immortality]

I still can't fathom an aftermarket clutch can be that poor, I've used OEM type replacement clutches that operate much better than you describe. There must a disconnect between the clutch pedal/release bearing and the clutch pressure plate in what you had.

But on your recommendation I'm staying away from Exedy when I do look for an uprated clutch for the VT in the future.

[vlad01]

That was OEM replacement, at least for Ford but it's identical to Holden V6 with slightly more clamp.

I have the Xtreme HD lowest spec in it now and it's a world of difference!

I inspected the exedy one on Saturday as I was replacing it. The diaphragm was dead straight still, no obvious damage or problems that I could see. The fingers however had a fair bit of wear like one with 150k on it, this was probably from the bearing/pedal clanging and bouncing constantly and the excessive pressure needed to operate it due to the binding of it.

The wear pattern on the fingers show that it was all pretty well centered and the bearing itself still looked and felt fine as it was when I took it out of the packet, other than some crud on it from use.

That was about 3 weeks of use.

The creaking sound is also gone with the Xtreme. So a dud pressure plate. I am going to call exedy when I have time and see what the warranty process is like if I can even claim. Looks still brand new other than the wear on the fingers. I actually just want my money back, don't want any exedy products in return since they have all been bad for me.

[v6bucket]

I had to change to a hydraulic setup in the Torana, because of the clamp pressure, the organic clutch in my HJ ute was originally in the Torana when it had a cable clutch, it still works great, no 7000rpm launches, but plenty of "spirited" driving & towing in the 1300+kg ute.
Give Western Clutch Service (02) 9623 1233 a call, you might be surprised.

[vlad01]

How heavy is the 4 puck on the foot?

I might give them a call tomorrow for some advice and general questions.