Clutch-Counterweight Distribution

Using Crower 10.7" Pedal Clutch in NHRA TAFC. Question: When distributing counterweight, is there any benefit/negative impact to distributing the weight to only 3 fingers (every other finger) vs all 6 fingers? If so, what is the impact?(good or bad) Is it abolutely necessary to distribute the counterweight evenly to all fingers in use? Why?

 

Total weight is total weight, period.
You must work in 180 degree though.
You can work two levers (every third)
or three (every other) or four.
I used to number stamp each spring area, so it was easy to remember where you were. I tried to get Molinari to just stamp the new ones, but he said "well what if you turn the motor backward" ??
I'm old, but I can still count backward from six!

 

Hehe

 

Mike; you are certainly correct.
I guess I should have clarified my statment by including the fact that you probably should not stagger more than three grams per finger from each other.
It finally dawned on me that that question could be conscrewed to be "can I put 16 grams on every other finger ?"

 

First, thanks for the discussion thus far.

Second, we have been running all of our weight on only 3 fingers so far, regardless of counterweight amount (not exceeding 40 grams-as high end let's say). We're a relatively new team and we're just starting to really let the clutch work. We've been very conservative in our clutch settings to establish baselines on other components. We've run a minimal amount of weight, especially at the Div races. As we have gotten more agressive in adding counterweight just recently, we are now able to distribute the weight to more or all of the fingers and we are looking at the best way to do that, be it 2, 3, 4 or 6 fingers. I gather from the earlier posts that whenever possible, distribute to all 6 fingers evenly.

Our minimum counterweight using all 6 fingers and the parts we currently use is between 20 and 26 grams-is this in the same ballpark as others?

Clarifying Questions: When applying minimum counterweight, should we find a way to distribute to all six fingers or is 2, 3, or 4 fingers sufficient? One bolt/nut minmum counterweight for us is around 4 grams-is this too much/too little? (We also use washers for counterweight) Are their counterweight components and materials that we should be looking at that we aren't beyond basic aluminum bolts, nuts, washers?

Again, thanks for the discussion.

 

you got it, basic nuts, bolts and washers. i have staggered the weight on many occasions with no adverse effects noted. your minimum is very much int the ball park, we try to not go below about 25 grams otherwise a ratio change is likely in order. if you get it too low it will not lock up at all

 

Does anyone know what weights the IHRA cars are running. We have a Kobelco blower, and have been smoking the tires right at the hit for the last three races. We had way too much weight, 11-12gr per finger. At shreveport we took it all the way down to 16gr total(4gr on 4), and the car took off, but pretty much didn't go anywhere, and slid the clutch the entire run. We're moving in the right direction, but trying to get closer without have to slowly move up the weight run by run. That could take forever.
thanks
bryan brown

 

25 to 35 is what we use. crower 10.7

 

If you guys are really interested in Clutch set-up or application you would be smart to listen when Bob Meyer speaks......Not only from his experience here but also from across the Oceans................Not only an excellent chassis builder, but as far as a Clutch guy he IS the man....................!Don't put all of your faith in Guido although he does know a lot..

 

A brilliant chassis builder Uncle Bob is, and as a
clutch guru,well, he always tells me not to let him near the bellhousing, all the while mumbling something about only just being a welder.........., but I wished I would have listened to his advice about this time three years ago, might still have had a race car in one piece...........!!!!!!!!!!!!! Remember, he's been around for a while, and he still knows his stuff. Listen to Mr Wade's advice!!!!

 

Mark T
are you going to the IHRA motor city nationals at Milan Mi. next month??
should be testing the new car in a couple weeks

stop by the Gerardot-Hart camp and say Hi

 

John,If things go well at grandbend its possible will be there. Good luck testing the new ride!

 

Aw pashawwww, humble-mumble..........
Sorry I missed you at Indy Larry.

You just have to be smarter than a bunch of nuts and bolts! The computer is a great thing, but the car itself will talk to you. As I tell my grandkids now, you have to be a good listener!

The biggest point to remember is that the driver must be like a robot and do the same thing EVERY time to get a handle on the clutch. I had to walk away from a deal where on one run both feet would lift at the same time, and the next run the throttle would go down before the clutch pedal came up (making about 1500 RPM more) and on and on.

And I'll surely get some crap over this statement, but I'm no fan of grinding the shit out of a high dollar clutch every run just because it's the fad of the year. If you get it right to begin with, it'll stay more consistant and a hell of lot less work! Here's something for the grinder lovers to try. Rockwell your plates at the end of a run. Write it down. Do your grinding, put it in, go do a burnout and shut it off. Now pull your plates back out and Rockwell them again. You don't have to write it this time because it's already on the paper!

The ol' guy

 

Mark,
What static pressure are you running. We've always used 2 - 2 1/2 turns. Will that still be okay with more power and less counterweight?
thanks,
bryan brown

 

Thats hard to say Bryan , depending on trans ratio chassis and tire pressure and how much leaner you use in low gear.

[ June 01, 2005, 10:02 PM: Message edited by: M Tigges ]

 

We have a 1.64 low, 4.10 rear gear, 34.5 tires at 6 1/2 pounds (beadlock). We have a high speed that starts to lean out at 6500 rpm, which should be about 30 feet out, according to the computer. I can see it either way, needing more static to hold it, or less to let it get to the fingers quicker. I guess starting at 2 turns probably wouldn't be bad, now that we have a better idea of how much weight to put on it, and then move from there. You've been a big help,
thanks
bryan brown

 

A 4:10 rear gear...wow...why so mellow?

 

It's a 4.30, I have no idea what I was thinking about.

 

Bryan; Gerry is trying to give you a hint here.
1.64 x 4.10 =6.724 launch ratio = WOW !

With very little clutch in the car the motor goes to the moon right now, slamming in the levers and the tires spin because of the advantage. You must control the RPM. More static and counterweight both will load the motor more than you think, keeping the RPM from zooming.

Play with some numbers of trans ratio being careful with the second gear drop, and my guess is you'll be happier with something in the 1.80+ range. The clutch will then be more responsive to changes.