Lock Up clutch info for blown cars

I just talked to a local Outlaw Pro Mod guy and quizzed him on the lock up clutch many of them are running. I was amazed at how simple this was. He said he made the swap for around $300. I'm sure such a swap kit from a mfg will go for more, but even if it's $1000, that's still cheap for what it can do for the car.

Basically all they're doing is putting two fingers in that have a different profile than the other 4 conventional fingers. An electric solenoid on the opposite side of the pedal shaft limits the travel of the throwout bearing much like a fuel car's cannon does. At a preset point, the solenoid releases the bearing to let the lock up fingers engage.

While I don't have much time playing with the higher OD, I was heavily involved with the tuneup on Jason Cannon's TAD a few years back.

Judging from my experience of running different ratios vs the clutch programs to go with them is that when you run more ratio (numerically higher) you can't run as much clutch. It's harder to get enough weight on the clutch to lock it up good in high gear without getting into wheelspeed trouble early. So you go to a taller gear, get to run more clutch, but you have the challenge of getting it on the tire quick, and you definitely sacrifice some 60' et to gain the benefits of more clutch downtrack. In any instance the fine line on clutch weight you have to walk definitely makes revving the motor up to lock the clutch up hard a necessity to go fast.

There's various models of mechanical lock up clutches, but none of those models could allow you to go from sliding the hell out of the clutch to a very locked up clutch. In theory, a true lockup clutch, either controlled pneumatically or electronically could allow you to really slip the clutch early while having it locked up hard in high gear.

That's where on paper I think such a device might be worth a nickel or more. By just replacing your current gear ratio/clutch program to a manual lock up, there probably isn't much performance vs just consistency. If you are getting true clutch lock up at say, 2 seconds, whether you do it mechanically or manually, it's going to run the same.

I would think the perfomance gain would be in getting away with throwing more ratio at it in low gear, using ratio and less counterweight/static to move the car to a preset lock up point somewhere near the top of low, depending on track conditions. You could really make it a 60' monster and get away with it. You could also run enough clutch in the lock up stage to get it locked up, running more mph, and if you can get it in high gear sooner, it will run more mph to boot.

I'd like to hear from some more racers besides myself on this. I think it's cheap and easy enough to implement, and I'd really like to hear a good argument why not at this point.

The racer I talked to converted his 3 disc clutch with 2 new fingers, an old Lenco air pod he had around the shop and a solenoid....

If anyone has some contacts with some of the Pro Mod racers running this, I'd invite their experiences on this.

This is all theory, but it might be a realistic option for the blown cars to get some help.

 

gains

mike-

If you ran .930 60' on a 5.30 run, if you could get it down to .890-.900 do you think it would equate to a 5.26-5.27?

Question for all BAD's out there -

With the added hp of the new od and a lockup clutch, wouldn't it stand to reason you could pull a 36" tire. Use more gear ratio to get the car to 60', lock the clutch up good to pull the tire, and possibly some mph gain due to gearing?

This is just my personal theory, but I think .890's are about the best you're going to get out of a 34.5" tire in great conditions. Maybe .880's. I can't reconcile why you couldn't get better 60's out of a bigger tire, if you can pull it in high gear. Maybe in bad air you still run the small tire...I don't know. You can make the car think it still has 34.5's back there with gear ratio, but a bigger tire should be able to handle more, lending to quicker 60 fts.

In my opinion the gains would be primarily in the front half, maybe .03 to .05 in 60' and maybe .005 to .02 out the back due to potential mph increase.

I think the lockup clutch is something that if everyone lobbies for, they could institute this year. I don't look for NHRA to allow more cid or the C blower this season.

 

60 hero

Unless you're on a double throwdown super good track, the gear ratios you have to run to be a 60' hero usually gets you in trouble in the 60 to 330 area. So then you have to back off on the counterweight enough that it doesn't lock up good in high gear. More gear ratio, the counterweight comes in quicker because the motor is going up quicker. When you have one set up like that, they are on the ragged edge and tend to shake alot, not to mention inconsistent.

With a manual lockup clutch, you don't have to run as much counterweight to achieve lock up. So in theory, you could use some ratio and less counterweight to get the car going. I'm sure it could also be developed to pull a really tall gear by locking the clutch up earlier.

Bottom line, I think it could open enough windows to pick up the blown cars around a nickel. It's realistic, economical, and I think NHRA would go for it. Is it enough? No. But, it is an improvement.