11" dual disc base pressue

I have a blown alcohol top sportsman car, I'm having issues getting the power to the tire. It's a AFT billet aluminum clutch, has #5 springs, 80 gram levers, 18.5 grams on each of the 6 levers. I started out at 2 turns, eng did not even change pitch when shifted, abort run. Went to 4 turns, not much different, I could use some help to get a baseline...car is 2450lbs, 3sp lenco, 4.10 rear, 33.5 tires, thanks in advance.

 

I actually had a 4sp in the car when I tested it, 2.68 first. Now it has a 2.07 first 3 sp...33.5 tall tire.

 

Put some gear in that thing! 2.19 easy with that 4.10 gear maybe more. I've had a 2.29 in my deal with a 4.56 gear legal promod engine. How old are the springs in the clutch. 890lb springs? I've had 5.5 turns of base on my 11in dual aft. But I think your gonna have problems with that gear. Try a 4.30 , would prolly solve a bunch of problems

 

I'm sure the springs are old, they measure 50lbs at 1.93, sowith 4 turns at 25lbs a turn, they should be 150lbs each...900lbs. My eng is a mild 565 25lbs boost, I haven't tried the 3sp yet. Last year on a few test passes, it wouldn't even black mark the track. Wouldn't burn out until the centrifical hit. 1.38 60ft...pitiful.

 

The clutch was fresh from Tommy at TF...gonna leave the combo alone at first, the car is brand new, 3 passes on it, just need it to get the power put down. our track isn't that good most of the time, that's why I put that gear in there, can get loose on the big end.

 

Rear gear won't affect you on big end. Your just gonna tear your clutch up with that gear. Put a 4.57 in it and stand your wicker bill up on the spoiler. You'll have to buy stock in Tf for floaters and discs, because your gonna go thru them life a fuel car.

 

if your running a ''mild'' combo i would run the 4 speed. Back the base off to around 500 lbs add 5 gms a lever launch the car @ 5000 and see what it does. To much base with a mild combo is going to pull the engine rpm down to much. I am running a 4 speed turbo deal 4.10 rear 34.5 tire with a 2.20 low gear we lock the clutch up very well.I think with your lower HP the 4 speed will be a lot happier .....what are your launch rpm shift rpm and type of motor and how much timing are you running all major factors

 

This is going to sound like a goofy question, but are you sure you're setting your ZERO height correctly? Gear ratio be damned, at some point in clutch settings you should be getting a second burnout at launch. Also make sure you've got plenty of bearing clearance in the can. if you can squeeze your fingertip between the lever tip and bearing, you should be ok. What RPM are you launching at?

 

Was just pointing out if he has a mild motor combo that makes 25 psi he will not have 35 psi at the hit and 3000 plus hp driving the flywheel also guessing he is not turning 9000 plus RPM so the 410 gear 4 speed made since i have ran similar combos on blown roots SBC and BBC

Also on the turbo car we can have 45 psi .5 into the run and leave at 6000 rpm not the same as a roots but not as far off as you would think

 

1.650 I believe....it got better as I added more base and centrifical, but not significantly...watching the burnout on video, the tires don't spin when I drop the hammer, short delay then they spin...4500-5000 launch.

 

it,s 2000hp, 8000-8500, going to put 30psi in it this year to start, I call bs on my first gear ratio not working, we have plenty of cars in my class, with similar combos....

 

Did you check it at zero with base in it to see the finger height?
Also use a vernier to measure against the depth gauge . Sometimes there it set to the number he has scribed on the plate .

 

Wish you the best on getting your deal figured out i will keep my 20 plus years of clutch car BS to myself lol i have worked on everything from blown sbc to top fuel and every other combo in between.

 

Okay, so Ring Height is 1.650... Is that from the holes near the levers or some other measurement? Springs measured 50 lbs at 1.93.. what is the free height of spring? When you zero the clutch with your current settings and without the tranny in, do the discs fall into the stands when you pull the alignment shaft? If so, you definitely have 0 lbs. of static.

Zero turns isn't really zero turns on the adjusters. With the clutch assembled and zeroed in a conventional pedal clutch with spring cups, you need to take the lock nuts totally off and spin the spring adjusters in with your fingers until you can turn it finger tight anymore. They need to be sunk in until you start feeling resistance from hitting the spring. This being a goofy AFT, you can use an allen with a light touch, but either way, you should be able to feel spring resistance against the adjuster. Visually verify you're getting the springs to compress when you use the adjuster too. If you really have 900 lbs of static, the adjusters should have some resistance when you turn them.