Holy Clutch Dust Batman!

[Mopar92]

OK.... in addition to my other thread of how to properly downshift and engage 1st or reverse gear..... Clutch 101. There are fantastic race car drivers who don't know how to use a clutch. Let me brake it down, not break it down . I want to preface that I am NOT picking on new guys or veterans. I will never point fingers at anybody, just follow the trail of smoke to find the guilty! We've been replacing wayyyyyy too many clutch packs here in the last few years. Lets go over some facts. Sorry if I mix in one of my opinions in the fact line.

Fact:
1- A clutch is a wear item, just like a brake pad.
2-You can actually over heat a clutch
3-You can actually drive a car with a slipping clutch (check that left foot to make sure it is on the dead pedal first).
4-You can absolutely still win in a car with a locked up clutch(clutch will not disengage when you push the pedal in)
5-Racing clutches can cost more than all of the brake pads and a set of tires racing tires combined.
6- MOST IMPORTANTLY- You can get the car moving and through all 5 gears at idle. You do NOT need the throttle to move the car. I'll be happy to demonstrate.
7- You can ruin a clutch that has 95% material still left on the friction pads. You can glaze the surface of both the pressure plate and the flywheel, along with pad material.


Fiction -
1- Skip Barber is given all of their clutches and they are free.
2-A clutch can be replaced quite easily (4 hours+)
3- Slipping the clutch helps get a faster jump on the start.
4-Revving the car to 6400 rpm's and dumping the clutch will help jump the start if you time it right.
5-Slipping the clutch in slow corners helps it get a better launch. Nope, only in Top Fuel does slipping a clutch make it worth while, but hey, their clutches get replaced every 1/4 miles... not bad ehh?
6- Holding the car while on a hill holds it just fine, and does not hurt the clutch since I am not revving it up.
7- If I smoked the clutch, when it cools off, she'll be just fine...


Lets start with the facts. I will never laugh or make fun of somebody that kills the car while taking off, but I'll sure maim a student who burns a clutch leaving the pits. You can ask myself or anybody who has driven pro series race cars this one. You get about 1 whiff of clutch burn before it's toast. They just can't take that abuse. They are designed for holding power, not slipping. Not only is it a good practice, but you may use the skill if you venture on into a Pro Series car, Skippy car, or even your own street car. When you get back into a race car or a street car, I want you to practice this. Start it up, let it warm up, stick it in 1st gear. Ease the clutch out with the car on level ground. Practice taking off with NO gas, then when the car is rolling at lets say 5 mph.... let the clutch all the way out, and then give it as much gas as you want... burn some dead dinosaurs. It saddens me to see a student burn up a perfectly good clutch, and see another student suffer a loss on track from it. Although it is rare, it is preventable. So from now on, impress me with your perfect and "quiet" clutch "outings" so to speak.
If a clutch starts slipping with lets say 2 laps to go and you are just trying to finish.... I personally find that if you try to short shift, it puts more bind on the clutch/drive line, and slips worse. I say shift near full rev points, but just with whatever throttle it takes to NOT slip... Most of the time when a driver pits for a clutch slip issue, it turns out to be those fancy Piloti shoes. As important as not getting gas/brake simultaneously, not getting clutch and dead pedal is equally critical. Usually clutch slippings are like alien sightings, they are human induced. When you get into a race car, and IF you do a pedal adjustment, this is also one you need to do. Make sure the dead pedal is not too low and causing clutch interference. If you feel the clutch slip with 2 laps to go..... ask your left foot what the hell is going on . That's almost always the case.... 99%. If not, resort to my personal plan B. Less gas=less slip.... Again, always use your head. If you are 15th and no chance to get in the points.... bring it in the pits, save the race from a full course yellow and shutting it down to come get you and a broken race car on top it all..... I never suggest you just stay out and hurt the car, but....






Next, if the clutch locks up on you and when you push it in, the car keeps moving. You ALWAYS have the right to drive it, or get out of it. It is a little hard on CV's but if it's race time, and you like the car..... well.... What I recommend a driver do if the race is underway, and this happens.... start braking a tad lighter and a tad earlier and watch over revving the motor. I suggest braking lighter because it transfers less weight off of the rear of the car. With no clutch, it's not exactly going to be smooth. You stand a pretty good chance of locking up the rears, or making the car very loose with these mismatched downshifts. I also suggest doing the downshifts at a slower speed to further decrease the risk of getting in car control trouble. It's not easy on the car, but you CAN still finish the race. Blipping the throttle will really not help it, because you are technically blipping a car that is in gear. Blip with it in gear and tell me what it feels like... it would be the same sensation as riding along with tester Kris Wilson...

If this happens and you are on a lapping day or practice.... PLEASE come in the pits or don't leave the pits if this happens on start up (rare). If this happens on the grid prior to a race... I will absolutely get you a new car with warm up if you so desire. I am not here to encourage driving a wounded car, but sometime you may be subjected to this . And, now you have a plan A. If my opinion strikes somebody wrong, I am sorry, these are my opinions off the clock with care of You and then the car, and in that order. Safety and good judgement will always be priority. Not only do I want you guys to take good care of Skip's equipment, I want you to FINISH the race. Be it the 24 Hours of Daytona, or 24 hours of de Lemon. (Yes, I said Lemon, not Le mans.)

[dalyduo]

At my second race weekend, a Feb. Sebring regional 4 years ago, they had a batch of bad clutches that were failing prematurely. Had never heard of clutchless shifting until I overheard Chris Wilcox mention that his clutch had gone away during qualifying and that he'd finished the session shifting clutchless. This was news to me.

Qualified P2 (sportsman) and slotted in behind P1 with P3 on my gear box after the start. We stayed that way for the first two laps and on the 3rd pass into the hairpin the clutch, that had become reluctant on lap 2, gave up the ghost completely. Figured there was no time like the present to try the Chris Wilcox clutchless shifting method and began snicking down and up through the gears without the clutch while holding onto P2. Discovered that less was more in terms of lever pressure and throttle to get the engine and drivetrain to match up. It wasn't pretty or smooth at the beginning and we lost some ground to P1 but after a couple of laps I got the hang of things and by the last lap was almost caught back up to P1. Gained a lot of ground through turn 1 and was no longer grateful for just holding onto P2... The red mist smell of victory was now filling my helmet.
Turn 3 took a couple of extra fervent tries to get the downshift done and P1 was pulling away. The sequence into the carousel was to breathe the throttle and then turn in but my over-focus on P1 allowed me to lose my mind and turn in first and then lift... Inducing a perfect Mr. Bill "OOOOOOHHHHHHHH NNNNNOOOOOOOO" TTO spin. With no clutch the motor stalled and I couldn't refire it. We'd gapped the field by at least 20 seconds so I sat there with enough time to smoke a cigarette before the rest of the field passed by.

It was a disappointing ending but a great race because I learned to clutchless shift by managing throttle and shift lever pressure with the sequential box. It does make you acutely aware of the relationship between engine and drivetrain speed as they really don't like to work together at wildly differing speeds.

In this case the failure wasn't my fault but I've always found that if you're nice to your clutch, your clutch will be nice to you.

[rgreist]

What is "clutch"?

[rgreist]

Just kidding! Thanks, Keith, for these primers on shifting and clutching. Both are important aspects of the craft of race driving.

Driving the Formula Continental, we actually use a 4-speed, H-pattern Hewland gearbox that we shift without the clutch. It was challenging re-learning to drive a racecar with a "normal" gearbox again, and this from a guy who was weaned on the Skippy Formula Ford, 4-speed race car. Shifting is an important part of driving well, and most of the best drivers know how to do it properly.

[GEORGE]

When I teach a first time standard shifter, my rule is; "There are only 2 places for a Clutch pedal, all the way in or all the way out"
The hill hold clutch slipping method has made many a mechanic rub his hands in glee as he looks forward to a profitable job.

[Rosso]

Hey Keith - I'm guessing (from operation) that Skippy clutches are single disk?

I once drove a Healy vintage racer with a small diameter, low-inertia, multi-disc metalic clutch at IRP. Car owner must have told me 10 times "...and don't slip the clutch..." That thing was like a light switch, full-on or full-off. It was difficult to get it out of the paddock without stalling the engine or spewing gravel. Once underway, no problems.

[Mopar92]

Originally Posted by rgreist

Just kidding! Thanks, Keith, for these primers on shifting and clutching. Both are important aspects of the craft of race driving.

Driving the Formula Continental, we actually use a 4-speed, H-pattern Hewland gearbox that we shift without the clutch. It was challenging re-learning to drive a racecar with a "normal" gearbox again, and this from a guy who was weaned on the Skippy Formula Ford, 4-speed race car. Shifting is an important part of driving well, and most of the best drivers know how to do it properly.

Would it not be cool if we got the old 4 speeds back

[dalyduo]

Way cool... It's a dying art form. Won't be long before there won't be any crash boxes left.
From a parallel universe. Walked into an appliance store over the holidays to discover that with a few minor exceptions there weren't any cathode ray tube television sets being sold anymore. There weren't even color sets when I was a kid. Now there's a new iPhone that does everything but make you dinner.

Originally Posted by Mopar92

Would it not be cool if we got the old 4 speeds back

[Tireman]

Originally Posted by dalyduo

......Now there's a new iPhone that does everything but make you dinner......

Wasn't that feature included in todays iPhone announcement ???

Viz

[dalyduo]

Ohh right. They're introducing virtual food that downloads into and dispenses out of the phone and calling it a Giga-bite.

Originally Posted by Tireman

Wasn't that feature included in todays iPhone announcement ???

Viz

[LimeRockRacer]

Originally Posted by dalyduo

There weren't even color sets when I was a kid.

Those were radios DD. You sat around the living room to listen to the RADIO. When you get to be a certain age you also confuse the facts some times....I know from experience....

[Mopar92]

What does me eating a gigabite fixed by my cell phone have to do with students burning clutches up?

[GT-Subject]

Once again a brilliant technical thread hijacked by the mysterious thread disturbers!!! I have only one question, do you feel full after eating a gigabyte?

[cooleyjb]

Originally Posted by Mopar92

Fact:
1- A clutch is a wear item, just like a brake pad.
2-You can actually over heat a clutch
3-You can actually drive a car with a slipping clutch (check that left foot to make sure it is on the dead pedal first).
4-You can absolutely still win in a car with a locked up clutch(clutch will not disengage when you push the pedal in)
5-Racing clutches can cost more than all of the brake pads and a set of tires racing tires combined.
6- MOST IMPORTANTLY- You can get the car moving and through all 5 gears at idle. You do NOT need the throttle to move the car. I'll be happy to demonstrate.
7- You can ruin a clutch that has 95% material still left on the friction pads. You can glaze the surface of both the pressure plate and the flywheel, along with pad material.


Fiction -
1- Skip Barber is given all of their clutches and they are free.
2-A clutch can be replaced quite easily (4 hours+)
3- Slipping the clutch helps get a faster jump on the start.
4-Revving the car to 6400 rpm's and dumping the clutch will help jump the start if you time it right.
5-Slipping the clutch in slow corners helps it get a better launch. Nope, only in Top Fuel does slipping a clutch make it worth while, but hey, their clutches get replaced every 1/4 miles... not bad ehh?
6- Holding the car while on a hill holds it just fine, and does not hurt the clutch since I am not revving it up.
7- If I smoked the clutch, when it cools off, she'll be just fine...

It takes longer than that to change a clutch on these cars? I wouldn't have guessed that.

It's an easy job on FC and FF cars. That's why I am shocked it's so tough on a car that is built roughly the same. We did it twice to the same car in one day chasing down a bad seal inside the master cylinder.

[dalyduo]

Absolutely nothing... It's a jazz riff of hijacking in a short attention span theatre kind of way. (Did I say that out loud?!) Like you've never had an (Ohhh Look.... Cows!) A.D.D. moment? Sometimes I just can't help myself.
Should have said the Giga-bite would be seasoned with clutch dust and served on a clutch plate made in China. :-/ A blue clutch plate special as it were... OK I'll stop now.

Originally Posted by Mopar92

What does me eating a gigabite fixed by my cell phone have to do with students burning clutches up?