Clutch work between rounds-Pro Mod vs TAFC

If the top running teams in Pro Mod go 12 rounds before they change the clutch discs and floaters, why is it necessary to change them every round on a TAFC?

 

#1 - the Sheik's Pro Mod gets the clutch pulled every round

#2 - Some aren't as anal about overall flatness in the pack, but the less flat it is, the more chance you chunk a disc.

#3 - Bronze Floaters

#4 - Roots PM's with steel are usually only slipping for .5 to .75 seconds, compared to the screw car where dust is flying for quite a ways. (Just covering Roots too).

In all honesty, if you want an apples to apples comparison on changes, pulling the clutch, changing/grinding steel floaters and surfacing the discs helps maintain consistency in the can. Those Pro Mod guys pull the clutch and the disc has a mirror finish on it.. Some guys have done it long enough they know how much more clutch to put on it for a 3rd, 4th or 5th run disc/floater pack. Probably the biggest reasons those guys don't pull it every round is ease of access, manpower and time constraints. It's fairly simple to pull the driveshaft and tranny out on a TAFC or TAD, not so easy when you take the same tranny, longer driveshaft and put it all in a small cage and give 30-40 minutes for turnaround.

 

Frankie Taylor switched to a Lencodrive set up this year in his ADRL PM and the main reason he gave was lack of time and hands between rounds to work on the clutch . He has since set the ADRL record at 3.60 in the 1/8th .

 

i'm talking about nhra legal pro mods going 12 rounds. would you be just as consistent if you ran a tafc in the 70's or 80's? a person once told me that there is a "red dot theory". If frank manzo has a red dot on his car, you need to get one!

 

Using the word consistent and NHRA legal Pro Mod in the same statement is kind of funny.. Its about consistency in the can. If you're running 70's and 80's and are satisfied with that, well then try whatever you like. Discs get hard and glazed, which usually means adding more clutch. If you aren't trying to squeeze every last bit out of it, it works fine. Keep an eye on your floaters though. They will warp and can cause chunking on discs just from heat sink from the crank.

 

Do bronze floaters help much in terms of being able to go multiple runs, versus plain steel?.....

 

good question.

 

It has been my experience that as long as the tune-up is close, bronze bonded floaters stay flatter longer. They also have less of a tendancy to weld themselves to the discs because they don't smear like the bare steel does, leaving all those rough spots. Not saying they're bulletproof by any means, but outside of making them out of a different steel that would lose aggression, they are the best suited floaters for repeated abuse without service. The only downside is you could buy 4-5 steels @ $70/each for the price of 1 Bronze.

A really good racer told me once that you can make anything work for you with enough testing and learning. Same holds true here I think with leaving the clutch in.

 

Pulling the clutch on any car is a pain. I guess I'm just lazy. Like I said in another post-my clutch has about 20 runs on it, and the last 3 were within 5 hundredths of each other. It takes right at 10 thousands off each pass so if the discs were "glazing up" it shouldn't wear that evenly. I guess if you want to go to the trouble of taking it out every pass, go ahead but untill I lose consistency I will leave it in. I will relace it soon as the discs are getting thin.Like I said, I'm just lazy.

Dale Hill

 

i'm just thinking that maybe for the cars that run... say in the 5.70 area, that it may not be an absolute necessity - like it seems to be - to change the clutch after each pass, provided it's cooled before going out, again like the pro mods.

 

We can put 3-4 runs on the clutch in our car and get away with it. We wear about 2-3 thou off every run, except the 1st run.(obviously) We run the clutch very "heavy" on the base and counter and it works well for us. There is minimal separation on the 1-2 and none on the 2-3. We just cool it, check the air gap, and reset the 2 step switch and it works like a charm.

This is on a Pro Mod car, roots setup. Clutch is a Triple-Crower 10" and Friction Unlimited disks.

 

Bronze Floaters

Does anyone know what material the bronze floaters are made from? I keep seeing the word "bonded" when refering to bronze floaters. Are they not machined from some billet material such as Ampco Alloy Bronze?

 

No, they are not machined from a special alloy. Its made similar to a clutch disc. It has a steel core that is copper plated and then bonded/sintered to a material in the same family as cerametallic buttons on street clutches. The difference in the sintering.. normally that material is bonded with just heat when making buttons, but when you apply multiple tons of pressure while heating, it does some neat stuff.

P.S. Jason, thanks! I knew you guys ran them tight, but DAMN.

 

No that comment is misleading Bonifante told me they are sintered and the sintering bonds everything together same as a disc. It's a blend of powders and a steel center.
I was also told the chunking has nothing to do with heat sink from a crank or anywhere else but it comes from a bad bond in the mix particle to particle or particle to the steel plate period! I went and got the 10cent tour of thier factory it is something to see they have meatalergy lab, multiple dynos, unit and disc, cnc machines eveywhere, and alot of other very impressive stuff if you can go see and if you have any questions and want to know for sure call there and try to talk to them they will give you the straight story. I never have a problem they always answer thier phone