Why are Clutches more fragile than Brakes?
#21
Originally Posted by Asmodeus
lol I'm a winner!! yay!! I've got mail, I've got mail!! YAY!!!
haha seriously.. the Rube Goldberg comment cracked me up, and definately applies!
haha seriously.. the Rube Goldberg comment cracked me up, and definately applies!
#24
Originally Posted by Sparetire
I am no engineer. I know. I tried mech engineering school and concluded that I would go insane looking at that many excel sread sheets.
Originally Posted by sparetire
More complex but using well developed tech: Use a clutch system similar to what some LSDs use. The clutch is surrounded by heat sensitive fluid. Fluid gets hot, clutch enages, as when slippage happens. This fluid could be used a cooling system, much as some hi-po LSDs on hard core road race apps use diff coolers. It might be perfect for slipper application on the drag strip. Might be hard to do on a street car at cruise though. Some sort of lock-up system at speed might be needed so that it acts normal after you initialy start out.
#25
I have also wondered this... especially with these high dollar clutches like Tex and Ram. I understand they are built to handle high horsepower... but a clutch only slips when you tell it to until you have full engagement. Unlike brakes which have to slow down a 3500 lb car over a very long time. And then what about automatic transmissions? They have clutch packs in them, albeit there are more than one but each clutch inside does not have much surface area and those are lasting in very high horsepower cars and they slip as well.
#27
Originally Posted by slick1851
Some awd guys add Tranmission coolers to there trannys for road racing etc...
its basically a pump, a cooler, lines/fittings that fit into the drain and fill holes..
its pretty pricey too.
#28
Originally Posted by Sparetire
More complex but using well developed tech: Use a clutch system similar to what some LSDs use. The clutch is surrounded by heat sensitive fluid. Fluid gets hot, clutch enages, as when slippage happens. This fluid could be used a cooling system, much as some hi-po LSDs on hard core road race apps use diff coolers. It might be perfect for slipper application on the drag strip. Might be hard to do on a street car at cruise though. Some sort of lock-up system at speed might be needed so that it acts normal after you initialy start out.
EDIT: Yes I am an old coot.
Last edited by GMC_DUDE; 07-28-2007 at 01:19 AM.
#29
Well I supposed it's not to hard to assume that it didn't work out exactly as planned for as far as I know there's no modern transmission that uses such "technology." Very good design theory though. I like this thread. How exactly does a tranny cooler work for a Manual transmission? I knew they had tranny coolers for auto's but not manuals. Is it air cooled or something?
#30
Another consideration - by my calculations, a 17 inch wheel is rotating at 800 RPM at 60 MPH, vs. a clutch rotating at between 1200 and 3000 RPM when you launch - the heat build up I would think is much faster and with little ventilation as stated above the window for heat damage becomes pretty short.
#32
A clutch is designed to not slip at all 99% of the time. A street car's clutch is made to grab and send the power down the drivetrain. Brakes are designed to slip and slow the wheels down by dissipating heat from friction.
Different purposes with similiar basic ideas. If a clutch was worked just like a brake then you would be spinning and losing power instead of transfering power. Pressure needs to be put down to lock it. If brakes lock then you are in trouble. That is why they are made different, last differering times and need more or less heat consideration from what I'd gather.
Kinda like brakes that are locked up would not be getting hot or being worn down, wouldn't be stopping your vehicle either tho...
I guess it is kind of a give or take thing.
Different purposes with similiar basic ideas. If a clutch was worked just like a brake then you would be spinning and losing power instead of transfering power. Pressure needs to be put down to lock it. If brakes lock then you are in trouble. That is why they are made different, last differering times and need more or less heat consideration from what I'd gather.
Kinda like brakes that are locked up would not be getting hot or being worn down, wouldn't be stopping your vehicle either tho...
I guess it is kind of a give or take thing.
#33
Originally Posted by Old SStroker
IMO, you were wise to switch majors.
That's a fairly good description of a lockup torque converter.
That's a fairly good description of a lockup torque converter.
#34
But if the clutch is NOT slipping 99% of the time... why do they not last as long as a set of brake pads when you do "slip" the brake pads QUITE a bit more than a clutch. And the flywheel acts as a heat sink as well just like a brake rotor. So it still remains why do these clutches not last as long when they operate almost on the same principles as a brake pad and rotor?
#35
Originally Posted by Jon5212
But if the clutch is NOT slipping 99% of the time... why do they not last as long as a set of brake pads when you do "slip" the brake pads QUITE a bit more than a clutch. And the flywheel acts as a heat sink as well just like a brake rotor. So it still remains why do these clutches not last as long when they operate almost on the same principles as a brake pad and rotor?
umm, read post #32 again.
clutches are not ment to slip. they are ment to grab. when they slip, they wear.. and they're only 1/8" thick.
meanwhile your brakes are MADE to slip, not to grab. when they slip, they dont wear as quickly... and they are over a half inch thick.
material composition and amounts also come into play, its not just heat dissipation.
the only "principles" they both have in common is that they use friction to transfer force.. thats it... ohh and they both rotate. lol.
#36
^^^ Ok, so why is clutch material only 1/8" thick? Why not put a thicker piece of friction on them? And i know that clutches are not meant to slip, and I know brakes are not meant to grab all the way. It just seems to me that a good performance clutch could be made to last pending all other problems are corrected, IE good master and slave cylinder, good pressure plate all that stuff.
#37
Originally Posted by Jon5212
^^^ Ok, so why is clutch material only 1/8" thick? Why not put a thicker piece of friction on them? And i know that clutches are not meant to slip, and I know brakes are not meant to grab all the way. It just seems to me that a good performance clutch could be made to last pending all other problems are corrected, IE good master and slave cylinder, good pressure plate all that stuff.
because the MATERIAL is diffrent.. once you've slipped that clutch to the point where the material thickness comes into play, it doestn matter.. its going to burn up..
now, if you had a "brakepad like" material that was ment to slip, and adjusted it so it did slip just right, and made the material thicker....
....then you've just re-invented the slipper clutch. the same kind of drag race clutch alot of race cars use.
next, you'll want to put some clutch material and plates together and stack em.. ooh, better yet, lets have these stacks "lock" together with some pins as it goes down the track...... you know.. just like the big drag cars.
#39
Originally Posted by Jon5212
No need to be a smartass, I'm just asking questions. Anyone else care to chime in?
wasnt trying to be a smartass.. just pointing out that the logical progression of ideas have already been implemented, you just have to look it up.
like the guy describing the torque converter above... lol.
#40
Originally Posted by Jon5212
Ok, so why is clutch material only 1/8" thick?
Last edited by Gary Z; 07-30-2007 at 04:05 PM.