Rotaryphil

I've been researching clutchs and am confused. There are many different types, stage 1,2,3, some with 4 finger surfaces, some with 6 and some that are all the way around. some are street, racing clutchs etc.. some have lots of springs, some have little and some have none. Anyone have a good explanation of what all of these clutch options mean and how they affect driving, horspower, price?
I have driven a car with a racing clutch and know how that is, ON/OFF no in between, pain in the *** lol

redbstd

its all about the surface of the clutch disc
how grabby it is and how much heat it can take, and how well it dissipates said heat
and the pressure plate springs
more springs/stiffer springs more pressure better clamping force

Heat is the major killer in clutches so the less friction you produce (ie engaging and disengaging faster) the longer the clutch will last. Also as a clutch gets hot it looses its clamping force. Thats why race clutches are like that. You'll also notice the aren't torsional dampening (ie springs and hub in clutch plate missing) they are solid hub discs

steve84GS TII

Basics here,since it could go on forever.......

Facings......
Full face clutch will engauge smoother than a clutch with 4 or 6 "pucks".
The pucks will concentrate the holding force into smaller areas,making the the unit grip better, but also grip faster.The full faced clutch will slip and slide easier upon engagment since there are less leading edges grabbing into the flywheel.But,it will require more clamping force from the pressure plate to hold a given amount of torque from the engine.Sintered metal (brass-copper) discs will tolerate lots of abuse and heat,but tend to be very grabby and cause lots of wear to the pressure plate and flywheel.Organic discs will engage smoother and not wear the flywheel out,but are also less tolerant of heat and abuse.Pop the clutch too many times and they can explode or tear right off their backings.

Springs......
Marcel springs are little leaf springs that are under the friction material.They make the dics thicker and compress when you let the clutch out.This eases the contact of the disc into the flywheel and makes things smooth.But,they also make the disc weaker since the firction material is no affixed securely to the disc anymore,they "ride" atop the marcel springs.I always skip marcel clutches.They only make a marginal difference in driveabilty,but create a large weak point in the disc.
Drive cushion springs are the coil springs around the hub of the clutch.They absorb shock and sudden changes in torque into or from the engine.They do induce a small amount of driveline lash,but they also protect the drivetrain aft of the clutch from damage, by absorbing shock.The sprung hub does make the disc slighly weaker since the hub is now made of multiple pieces,but there are lots of very high HP clutches out there that are sprung hub.The number of springs is less important than whether or not you actually have them and the rating of the springs is more important than the number of springs.Unsprung clutches tend to be just for all out racing when getting every bit of power and strength out of a car is the most important thing.

Pressure plate.....
This is the steel cover and diaphram spring that pushes the disc into contact with the flywheel.The higher the "torque holding" rating of the clutch,the stiffer the spring typically is, and so the clutch pedal will be harder to push.You will also see shorter throwout bearing and clutch hydraulic lifespans since these parts will have to work harder to bear down on the stiff pressure plate.


Stages typically indicate the torque holding power of a clutch.The higher the rating,the more power it can hold without slipping......but its also a good indicator of how hard it will be to drive on the street.My personal taste is to choose the highest rated full face organic disc with a sprung hub and no marcel springs.The stiffness of the pressure plate is totally subjective as to what it TOO much,but I preffer the street/strip units for my car.The RB unit has proven to be VERY streetable and feels right at home in traffic,yet has held my 300HP TII engine solidly for many years.

Rotaryphil

Awsome! that clears up alot! I'll probably lean towards a stage 3
6 puck clutch as opposed to the stage 2 full faced clutch.
I like a clutch that engages clean and has a "crisp" feel to it.

Just doin some reasearch on a future T2 project. I'm going to be using the SE tranny so thats why i've been looking into clutch's. I need a second gen n/a clutch and a (smaller and/or lighter??) flywheel to bolt onto the
S5 T2 motor so it clears the SE tranny bellhousing.

steve84GS TII

Youll have to run a rear counterweight thats appropriate for the year TII engine your running.This will keep the engine balanced.
Then get a GSL-SE light flywheel and clutch.This will assure mating to the GSL-SE tranny and starter.

You cannot bolt any other factory flywheel to the TII engine, except one that is for the correct weight rotors in your engine.That would be either the stock TII unit or an N/A unit from the same series.The N/A flywheel would allow for use of the GSL-SE sized N/A clutch,but I dont know if the SE starter will mesh,or if an FC starter will mount up.Youll definately want to not go too aggresive with the clutch,since the N/A trannies arent nearly as robust as the TII units.

trochoid

iTrader: (6)

If you want to preserve your SE tranny behind a TII engine, go with a organic disc or one of the ceramics. A puck disc will impart much harsher shock loads on the tranny. I have a ceramic disc with a very odd face pattern in the widebody. It has nearly the same engagement feel as a stock clutch with a slightly stiffer pedal, yet holds the 245/50/15" tires without any slippage.

Since I have a 1/2 bp engine, I need to feather any clutch more than a stock port needs from a dead stop, which this clutch does quite well. ReSpeeds sells a ceramic clutch similiar to mine for around 400, iirc. I bought mine through eBay for around 300.

Rotaryphil

what about using the stock SE flywheel on the T2 engine? or do i have to get the lighter one? and the counter wieght that bolts on will still work with the different clutch setup? isn't it a turbo clutch and flywheel counter wieght? the 6 puck will still be to harsh even if i don't slam the clutch out.? Friend of myne is using a 6 puck with his GSL S5 T2 250rwhp and slams the **** out of it and seems to have no problem

steve84GS TII

TII trans can take the abuse.
They are quite overbuilt, wheras the N/A boxes are pretty weak.FD guys regularly use the TII box,its built tougher than the 3rd gen tranny!

The stock SE flywheel CANNOT be used on any 2nd gen engine.The rear counter weight on all 5 speed engines,is cast into the flywheel itself.Even if you put the SE front counterweight on to match the SE flywheel,they are not weighted right to balance the TII rotors.
The S4 N/A and TII engines all had the same weight rotors.
The S5 N/A and TII engines all had the same weight rotors.
All S4 and S5 N/A engines have the same 225MM clutch as the GSL-SE had.That means you can use an N/A factory flywheel from the proper series,on your TII engine with no problems.A GSL-SE clutch and tranny will bolt right up and youll be in balance.The only thing I cant say for sure is if the GSL-SE starter will mesh with a 2nd gen flywheel.

The only alternative is to run an A/T rear counterweight correct for the engine you have,then an aftermarket light flywheel correct for the clutch and tranny you are using.

Rotaryphil

Awsome! thats good info . That'll save me some money on a flywheel. I'll just buy a better N/A clutch to take the HP. I'll Resurface the TII flywheel if it needs it, install the N/A clutch on the T2 motor and Bolt the SE tranny to the T2 motor. I can update to a lighter flywheel later on. Now just have to figure out starter options, shouldn't be a big deal,Ii'm sure one or the other will work

steve84GS TII

The TII has a bigger clutch,so the N/A clutch and pressure plate are unlikely to bolt to the TII flywheel.
There is also no garuantee that the GSL-SE starter will mesh with the TII ring gear.

Thats why when you combine unlike engines and trannies its easiest to match an AT rear counterweight with the engine,and match an aftermarket light flywheel with the tranny.
When you try to use all factory parts,there will always be issues with clutch size,spline count,counterweights,starters and ring gears.If anyone has tried the combination you want to try,I hope they speak up,since I have always preffered to just use a light flywheel so that I know things will alighn.

elwood

iTrader: (1)

Good info -- you obviously understand clutches very well.

As for the drive cushion springs, I've been counseled that the most important reason OEMs use them is to damp the pulsations from each power cycle in the engine so the driveline components aren't constantly loaded and unloaded, creating backlash (clutch rattle) and pounding the components. The end result is enhanced durability, as you stated, but the real reason is the reduction in hammering of components during light load conditions, not during high power situations. During high power applications, the springs immediately compress and become ineffective, which is why most racecars don't use them (not driven much at light loads).

I've used and driven both sprung and solid hubs, and I can't tell much of a difference behind a rotary engine. I'm currently using a solid hub 6-puck. But then, my car isn't exactly stock anymore, so YMMV.

Rotaryphil

anyone use the clutch/flywheel setup i am talking about ? someone on here must have used the SE tranny in there T2 swap!

trochoid

iTrader: (6)

You can't use the TII flywheel with an NA trany, period. If you insist on using the SE tranny, find the NA flywheel that matches your series on TII. If you need an S4 NA one, I have several collecting dust.

Rotaryphil

Hmm i'll need a S5 N/A flywheel in the spring then. shouldn't be to hard to come by. I can't seem to find a new one on ebay, do they even make new N/A flwheels?

steve84GS TII

It should be easy to find a used one and machine it flat.

New flywheels are common now at parts houses since most flywheels are quite simple.The rotary flywheel is a heavy chunk with some unique characteristics like a tapered mounting seat,integrated counter balance,unique applications based on engine model and heavy overall weight.It wouldnt be a surprise if no one is making new ones except Mazda.

trochoid

iTrader: (6)

Post a WTB in the 2nd gen parts section, that will net you a flywheel. Other option is spending the extra cash and going with a light weight flywheel and matching counter weight. That can get spendy, near 5oo for the flywheel cw and shipping.

PM Midwest7s, I know he part an S5 NA and may have a flywheel.

Rotaryphil

Cool guys. Thanks for all the info, much appreciated! Where might i see more pics of your car Trochiod?, looks pretty cool from your avator pic.