CLASS RACER FORUM - Clutch guys

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- - Clutch guys (https://classracer.com/classforum/showthread.php?t=83179)

Quote:

Originally Posted by Robin Lawrence (Post 668943)

Since I have raced clutch cars for most of my racing career I am always interested in the discussion. I still have a lot to learn.

In the 2000 to 2006 time frame I raced NMRA Factory Stock then Real Street classes. Both had limited rules around the clutch specs. I had a Autometer Data Logger in the car during testing as it wasn't allowed in the class.

We were limited to a 10.5" to 11" Diaphragm clutch. the Factory Stock car was a high 11 second NA car on BFG Radials at the time. the Real Street car was a Supercharged on a 26x10 M/T slick. Transmission ratios were regulated to standard offerings on OE and Street (Tremec) style boxes that could be face plated or Dog Ring style modifications.

Factory Stock was not hard , a normal rag style clutch offered enough "slip" that we had decent 60' and control of the wheel speed at the hit.
When i changed to Real Street it got interesting. I actually ran that same rag disc at first. It slipped and engaged well but it only lasted about 6 passes. I was fortunate at the time to have a clutch sponsor. Clutchmasters and Fidanza were in the import side and wanted to get deeper into the Domestic market.
They built me some very cool Diaphragm clutch plates and we experimented with various materials on the discs. Kevlar, Bronze pucks, Sintered Iron Pucks, and some weird Carbon material. They also built me a Diaphragm pressure plate that had a billet aluminum pressure ring with a steel face friction surface. That deal saved us 9 pounds on the assembly. Yes we were already using a aluminum flywheel as well.

I remember when some racers in NMRA started using the "Screen Door Closers". A good friend of mine refused to use one. After watching racers with what he thought was less ability than his he tried one. He said he will never go back. My point here is in a limited restricted clutch rule class these type of products have merit. My buddy is a super tester. Has probably 5 different pressure plates with different base pressures. He now believes.
I have tried the diaphragm discs with the weight to apply more pressure as RPM goes up. I had never seen any difference.

I currently run a twin 7" Billet clutch in my Stocker. I can tune the engagement curve with the adjustable base pressure and counter weight. It works very well.
I would think that if I was allowed to attach a hydraulic cylinder to my clutch pedal I would have a solenoid to allow it to hold the pedal on the floor so I could release a button rather than my left leg. LOL

I really hate to feed the rumor mill but I was told that there is a Stock racer who is doing that.

Interesting stuff.

To answer the OP's question. Above peak torque and below peak power.

Robin

The idea of using a solenoid to release the clutch pedal and regulate the engagement of the clutch was pretty much exactly what I proposed to Jerry Valentine several years ago, he cut me off before I even finished explaining my idea and said that absolutely there was to be nothing electronically connecting the clutch pedal to the clutch. Jerry was pretty high up the NHRA food chain so I took him at his word and didn't do it.

Don't get me wrong here.
I'm always interested in discussions that pertain to 5/10th full tree, breakout, good RT required, S/SS racing.

Also, Ken runs a tight ship. I assume he knows of 'Weedburner".
A friend, wanted to use his signature to promote real estate sales to other racers.He was not a paid sponsor. ;-)
He no longer posts here...

Quote:

Originally Posted by Mark Yacavone (Post 668932)

Seems to me this whole thread belongs in another section. Which one, I don't know.

Why?
It wasn't my intention to get into clutches and "tamers"......I didn't even ask about clutches.
My question was the consideration of the engines peak torque and power and how your launch RPM coincides with either.

Quote:

Originally Posted by joespanova (Post 668957)

To answer your question pretty basically, your best 60' will be at as high of RPM as your tires and valve springs will hold. I normally leave at 8400 but my best 60' was at 11,000, just can't cut a light at that RPM. Ever hear a Comp Elim car leave at anything below the max RPM can hold?

Quote:

Originally Posted by Jim Caughlin (Post 668948)

That's the thing with my original 'tamer, nothing electronic gets connected to either the clutch pedal or clutch. Clutch pedal is still released with your foot.

There is nothing proprietary about my original 'tamer. The first iteration was a simple hydraulic screen door closer that I bought at a hardware store and attached to the clutch pedal, also a simple sliding stop arrangement. No electronics. The version I make now is basically the same thing except with a much shorter cylinder. You can make your own for about $30 if you can fit the hardware store cylinder under your dash.

If someone had come up with it 40 years ago, I doubt you guys would be using softlok style clutches today.

Quote:

Originally Posted by joespanova (Post 668957)

Joe, I know you posted a generic question but it did Veer off from there. Just tell the people here what you do with your car and we'll probably have the answer. This is the stock super stock t e c h section

Most threads on the 1st page with more views have been up for more than a month. This thread is only 5 days old.

Here's some pics of the original Hillbilly Clutch Slipper install using the hardware store VH440BL hydraulic screen door cylinder, everything was less than $20 at the time...

https://members.tripod.com/~grannys/clutchslipper1a.jpg

https://members.tripod.com/~grannys/clutchslipper2a.jpg

https://members.tripod.com/~grannys/...lyslipper4.jpg

Like I said, the current 'tamer functions pretty much the same except with a much shorter cylinder. Just a simple, repeatable way to control throw-out bearing position during launch.

Quote:

Originally Posted by Mark Yacavone (Post 668965)

This is the stock super stock t e c h section

Which was why I asked in THIS section....
With the exception of a few reply's , there wasn't much "ON POINT" participation.
Some times the "sensitivity" or "specificity" of these forums is ridiculous. I was expecting answers on point with the question only. I never asked about clutch management.

"At the point of bogging , wheel standing or blowing the tires off how does your best "launch" RPM coincide with either peak torque or peak power?
Probably a question better directed towards the "back halved" crowd with a 13/31-14/32 tire....
Opinions?"

You can close it.

May seem simplistic, by rather than worry about what the dyno sheet says, why not just try different launch RPMs, and see what goes the quickest? A dyno pull is quite different than how a car and engine work when going down the dragstrip, especially a stick car. On my low 10 second SB Ford, with a 4 speed and Soft Lok clutch, I find dropping the clutch at 6600 RPM, and shifting at 7000 produces the best 1/4 performance. Only real way to know is to experiment.