Clutch Bell Mods

[Lyonsperf]

As many of you know i'm a old school hot rodder and have been through all the "trick part of the week" hype that usually happens when a company comes out with a new product.
That being said, I try to apply what I have learned over the last 30 years to any new project I work on.
I have been researching many of the "claims" concerning clutch bells. I see fancy patterns cut out of the face, drilled holes through the sides and even a "special" coating to make the clutch bite better.

Now I can see venting the clutch apply area to exhaust the material and gases produced during friction but they make me wonder about the fancy front and the coating.
I know that Honda coats it rotors to prevent rusting but i would think any type of coating on the friction surface is going to gum and glaze the friction material.
Also, what is the friction material comprised of? Is it asbestos based?
Knowing that chinese counterfeiters have been flooding the aftermarket auto parts with brake pads that look like brand name pads but are really just compressed cardboard makes me wonder.

I think I will modify my stock bell by adding the vent holes in the friction area. But other than that, I don't see anything gained.

[xlint89]

The one "special coating" I've seen is carbon fibre to prevent glazing.

http://sycpowersports.com/index.asp?...id=66&incid=29

Not sure how well that works, but they do make performance carbon fiber brake pads. So that does seem to have some merit as far as friction performance goes. Not too sure about the anti-glazing properties though.

I don't think the fancy cut outs have much to do with performance. More of a weight reduction and better cooling affect. Less rotational mass and less steel to retain heat are always a bonus.

And this one is supposed to have "ribs" for better heat dissipation.

http://www.shop.kidnmekarts.com/Clut...0cc-Ribbed.htm

[ckau]

I've tried a bunch of different clutches. Prodigy, NYC, Hit, and honestly I've had the best results and dependability out of the stock units. The drilled, spoked, ribbed and other such types probably do some good as far as heat dissipation and might contribute to less warping as the bell gets hot but as long as the stock clutches are not abused they will perform as well as any clutch out there. The abuse it takes to fry a stock would destroy any aftermarket out there. A bell drilled or slotted along the face would have the same benefits as a cross drilled/ slotted brake rotor.
All these different clutches with their claims and hype kinda strike me as attempts to build a better mouse trap. I've read reviews from many folks who really liked some of these clutches but I suspect they waited until the stock was so far gone, any sort of replacement would have been a improvement.
If any improvement can be done, I would like to see a ceramic composite material used on the shoes. The same stuff found in the high end disc brake pads found on some of the performance cars. I have these ceramics pads on my Infinity Q45. Once those pads warm up the grip intensifies dramatically! You would have a darn good clutch if the clutch shoes reacted the same as those disc pads

[xlint89]

As I was looking into the carbon fiber brake pads, I saw how the ceramics outperform them. Got me thinking about using that for the clutches too.

I kinda like idea of the longer pads though for performance. (more surface area)

http://www.shop.kidnmekarts.com/Clut...ngpads-150.htm

And also appears to use longer pads on the "shorty" as well.

http://www.shop.kidnmekarts.com/Shor...-Kit-150cc.htm

[Lyonsperf]

I have a vendor that makes brake pads. I'll give him a call and see what he can come up with.
The description of the coating makes it sound like it only lasts through break in.

[xlint89]

It does sound like some of the bells are "roughed up" on the inside to help bed the pads, and then smooth out for "normal" operation.

[2SlickNick]

Did you ever drill those hole Lyonsperf?
http://www.buggymasters.com/forum/showthread.php?t=4384 if you read my current problem I am thinking of sanding some rough spots in the bell and some vent holes.

[Lyonsperf]

Decided against drilling the holes. It would be very time consuming and if not done right could cause fractures in the bell. I just roughed up the interior with my air sander adding a swirl pattern to help the clutches bed in.
Our project has been on the back burner since last October due to divorce. The buggy is sitting in the shed at my new home. Never started the engine. Hopefully we can get back to is soon. But the weather is too damn hot here to work on anything!

[2SlickNick]

Okay, thanks for responding. I was ready to drill LOl. I will just stick to sanding it too. Hope all works out for you. Jumping on a dirt bike, atv, or buggy was always the best stress releif for me. Hopefully you get it finished to relieve some stress.

[x-bird]

Originally Posted by Lyonsperf

Decided against drilling the holes. It would be very time consuming and if not done right could cause fractures in the bell. I just roughed up the interior with my air sander adding a swirl pattern to help the clutches bed in.
Our project has been on the back burner since last October due to divorce. The buggy is sitting in the shed at my new home. Never started the engine. Hopefully we can get back to is soon. But the weather is too damn hot here to work on anything!

Glad to hear you're still with us and the buggy didn't get sucked up along with whatever else! Heat, what heat? LOL ... slab in my garage stays hot all night long-- feels like I'm working in a pizza oven.

[sleepyrz]

gotta bring this back up

ok from what i know if you want more grip you want less pad

this is a clutch! not brakes kids

two completely different uses of friction material

you want te force concentrated in a small area so it grabs and does not slip

look at any performance clutch in the auto world the higher the performance the less "pucks" it has

honestly in my opinion the only clutch that looks to have any sort of added performance is the HiT clutch due to its cam which slides and locks the pads to the bell

and ive looked and seen dynos of the HiT clutch and it looks to me to have done wat its supposed to do

what are your thoughts?

just remember though brakes are not supposed to lock up, a clutch however is required to do so

[SYCARMS]

I disagree, brakes are suppose to lock up when pushed hard enough, this is why anti lock brakes are used today. In years past when you locked the brakes up you lost control of the vehicle due to all 4 brakes not locking at exact moment causing vehicle to veer off coarse and especially on wet or icy roads. In the auto world and I cannot speak much of todays import vehicles but in my days a heavy drag clutch had the same surface area on the disk except for using a different clutch material. The biggest difference in a performance clutch was the pressure plate. Now with these buggies 2 theories are used today in regards to performance clutches. Theory one is to use a longer pad and theory 2 is to use the smaller pad but use a different material. The difference in the hit clutch is both the material used and the pillow block. The material gives the clutch better grab at high temps the pillows act like a pressure plate since when the pillow is locked it applies almost 3 times the pressure on the bell then the other clutches can using the basic centrifugal force

[sleepyrz]

all the performance clutches ive used in my drag cars were 4 pucks or 3 pucks

like this


which concentrates the force on the now smaller clutch area

and you can of course upgrade the pressure plate also for even more force on those 4 pucks

i always did both

so in your opinion then

HiT clutch basically wins right?

thats what i was thinking because basically every other clutch is exactly the same except for the HiT because it employs a mechanical advantage on top of the centrifugal force of the weights being flung out

and brakes are not supposed to lock up... they just happen to be able to do so

but ive always had a sort of set of rules when it comes to brakes:
if your brakes can lock up you need wider tires
if your brakes cant lock up you need better brakes

its a line you toe to get it just right

sorry i dont know about that snow and ice stuff i live in miami lol

oh and if you have a recommendation about a clutch thats a little bit cheaper than the HiT clutch but does a good job PLEASE let me know

im not too keen on buying a clutch that costs more than the buggy does

[ckau]

Originally Posted by sleepyrz

gotta bring this back up

ok from what i know if you want more grip you want less pad

this is a clutch! not brakes kids

two completely different uses of friction material

you want te force concentrated in a small area so it grabs and does not slip

look at any performance clutch in the auto world the higher the performance the less "pucks" it has

honestly in my opinion the only clutch that looks to have any sort of added performance is the HiT clutch due to its cam which slides and locks the pads to the bell

and ive looked and seen dynos of the HiT clutch and it looks to me to have done wat its supposed to do

what are your thoughts?

just remember though brakes are not supposed to lock up, a clutch however is required to do so

I have to disagree with your logic here somewhat. Not to say your wrong but the clutch disc shown ( small contact area) was not designed for our application here. This unit is intended to reduce weight and reciprocating mass thus allowing the motor to spin up faster. These discs do grip extremely well but that's due to a softer pad composition used in conjunction with a clutch plate with a 3,500 to 4,000 lb. or more spring rate in a car weighing, on average under 3,200 lbs. Longevity and heat transfer is not a primary concern. How many passes do you get out of this plate? If I were to use this plate in my daily driver or under off road/ dirt conditions I'd be lucky to see a hundred miles at best. Under off road conditions that clutch is used more in one day than a drag car uses it in a season. Pad contact area plays a important role in every aspect but there's always a trade off. In our application, less is not best.
In drag racing the ability to lock the brakes is of no real concern. You only need to stop the car before hitting the sand. Brake lock at the end of a run could spell disaster for you. In off road the ability to lock the brakes plays an very important roll in order to negotiate a tight coarse.
You stated you've seen dyno results of a hit clutch? I'd enjoy seeing these. got a link or can you post them up?

[Masteryota]

Ok, let me take a stab at this. As for clutch disc upgrades, if you were to do just the disc, then yes, you want the smaller puck design. This creates more clamping force between the flywheel and pressure plate due to all of the force is now held in 1/2-1/3 of the applied area. This can, however, create uneven surfaces in the flywheel and pressure plate if using the stock components.

This was done for many years due to cable driven clutches, and the force needed to move a harder pressure plate. With everything going to hydraulic, you can now run almost what ever pressure plate you want, and feel almost no change in the pedal effort. This is what I see being used now, stock disc with a heavy pressure plate. The main reason for this is to reduce chatter and keep replacement costs low, as the disc is considered a wear item and normally cheaper than the race pressure plate, and keeps the flywheel damage to a minimum.

As for the brakes, normal design calls for lock up at extreme braking force, but under lock up, control is sacrificed. ABS provides the advantage of regaining that control but releasing the pressure from the locked wheels resulting in regained traction. Tire upgrades, not necessarily wider, also help reduce lock up. Wider tires essentially spread the weight of the vehicle over a larger area, resulting in an easier loss of traction at the tire surface. Softer compounds are better in this respect, but wear faster. It is a fine line to tread, but everything is a see-saw when you start moving away from stock components.

As for the HiT clutch, the mechanical side of my brain is actually concerned about the mechanical portion of the clutch hanging up and not allowing it to disengage. In the case of centrifugal clutches, smaller pad area would in theory hold better, but the material is also important due to the increased heat from not being able to radiate the amount of heat the larger pads are capable of. From what I gather from these sites, is that the stock clutch holds up just as well to the 'race' clutches.

[sleepyrz]

Originally Posted by ckau

I have to disagree with your logic here somewhat. Not to say your wrong but the clutch disc shown ( small contact area) was not designed for our application here. This unit is intended to reduce weight and reciprocating mass thus allowing the motor to spin up faster. These discs do grip extremely well but that's due to a softer pad composition used in conjunction with a clutch plate with a 3,500 to 4,000 lb. or more spring rate in a car weighing, on average under 3,200 lbs. Longevity and heat transfer is not a primary concern. How many passes do you get out of this plate? If I were to use this plate in my daily driver or under off road/ dirt conditions I'd be lucky to see a hundred miles at best. Under off road conditions that clutch is used more in one day than a drag car uses it in a season. Pad contact area plays a important role in every aspect but there's always a trade off. In our application, less is not best.
In drag racing the ability to lock the brakes is of no real concern. You only need to stop the car before hitting the sand. Brake lock at the end of a run could spell disaster for you. In off road the ability to lock the brakes plays an very important roll in order to negotiate a tight coarse.
You stated you've seen dyno results of a hit clutch? I'd enjoy seeing these. got a link or can you post them up?

heres four of them on this channel
http://www.youtube.com/user/drpulley/videos

heres another few in this video
http://www.youtube.com/watch?v=8cSt5xaMreU

i think i saw maybe 2 more ill keep looking

[Johnny 5]

I have found that the stock clutch works great until the pads wear down and it takes more force to grab the bell. The clutch in my red buggie has thicker pads not longer and it works awesome. The clutch in my wife's blue buggy with the 183cc motor slips on take off on the street with no tire spin and the variator upshifts faster and then bogs down when the clutch hooks up. The next clutch Im getting is a http://www.ebay.com/itm/SCOOTER-GY6-...item27d7f1eaca

[SYCARMS]

Originally Posted by sleepyrz

all the performance clutches ive used in my drag cars were 4 pucks or 3 pucks

like this


which concentrates the force on the now smaller clutch area

and you can of course upgrade the pressure plate also for even more force on those 4 pucks

i always did both

so in your opinion then

HiT clutch basically wins right?

thats what i was thinking because basically every other clutch is exactly the same except for the HiT because it employs a mechanical advantage on top of the centrifugal force of the weights being flung out

and brakes are not supposed to lock up... they just happen to be able to do so

but ive always had a sort of set of rules when it comes to brakes:
if your brakes can lock up you need wider tires
if your brakes cant lock up you need better brakes

its a line you toe to get it just right

sorry i dont know about that snow and ice stuff i live in miami lol

oh and if you have a recommendation about a clutch thats a little bit cheaper than the HiT clutch but does a good job PLEASE let me know

im not too keen on buying a clutch that costs more than the buggy does

What is the application of the clutch pictured?

[SYCARMS]

One more thing about the clutches we use. One must consider the reason the factory used the clutches they do, is due to the fact that they put in all reality a 5hp engine in a 4-5 hundred pound buggy. The clutch has to slip a good bit or it would bog down the engine. Now I know someone will correct me by saying their manual says their engine is 12-14 hp. This is a true statement when tested on a bench dyno but when you add all the drive gear horse power drops to about 5hp. Also when looking at a clutch just because it say's performance does not necessarily indicate it will work well in our buggies since they are all designed for scooters which are 350-400 pounds lighter then our buggies. This is why the DP hit clutch uses a different setup for scooters and buggies. Ask one who used a Hit clutch for a scooter in their buggy and they will tell you they won't last long at all. I mean hours to weeks and it is destroyed. The scooter uses a different degree pillow block then our buggies call for.

[sleepyrz]

O REALLY! did not know there was a difference in the HiT clutch pillow blocks

and that clutch is for a toyota tercel they are super light so 300 hp makes em stupid fast

im rebuilding the block all forged now since the old stock block finally decided to give out after 2 years at about 25 psi

like the intake headers?(thats what i call that type of equal length intake manifold)

[SYCARMS]

That type of clutch you showed will work in a light car but would not work in say a Nova or Camaro with say a 350 or 427. Yes the Tercell may make 300HP but it will not have anywhere the torque as a V* would have. The only difference I see in todays clutches is that none use an asbestos disc since its use has been banned in this country, and dissipated heat very well. Todays clutches use a different material with more metal so they will get hotter and heat destroys clutched. Now severe duty or racing clutched need a way to dissipate heat quicker so instead of the clutch disk using a one piece material around all 10" or 12" discs surface area they will use multiple pieces of friction material which are spaced apart from one another to better dissipate the heat. What you have to remember is the clutch plate is made of friction material so with less friction material you have less grab and not more. The clutches used on imports which incorporate many American cars as well since they are using much smaller displacements , much smaller and lighter cars producing high horsepower but much less torque due to displacement.

[sleepyrz]

which angle? pillowblock is for the buggies???

or wait are you saying we shouldnt use the hit clutch because they dont make one with the correct pillowblock angle?

[SYCARMS]

60 degree