How to launch a 4 speed with 323 gears

[Paul_G]

I am going to the Zip Tie drags in Tucson next month. I decided to to do some practice launches, turned out to be a big fail.

The car;
1973 Charger weighs around 4000#
68 383 engine, mild cam 222/234 dur 467/494 lift, iron heads, dual plane intake, long tubes, short straight dual exhaust with turbo mufflers no X or H pipe.
Quick fuel 750 carb mechanical secondary's
4 speed manual trans
323 sure grip
29.4" rear tire

The engine is strong, the tires are sticky enough. The clutch is so so. Normal driving, throttle response is good, car runs well, shifts smooth, gets terrible mileage.

When I try to launch, staying out of the secondarys's, the car will move but not quick enough. So I tried more RPM, still not a hard launch. So I tried more rpm, in the secondary's all the way to 4500 RPM and dump the clutch, big smoke show from the tires. If I dont dump the clutch the clutch smokes.

Any ideas on how to get the car to launch better?

 

[biomedtechguy]

Upgrade the clutch disc, at least. May need a new/better pressure plate.
Look at getting this:
http://clutchtamer.com/

 

[R413]

What are the tires exactly? Size and brand. They are CRITICAL! So is the width of the tire and rim and the air pressure.

Also, you need a new clutch, it ain’t gonna work like that. Your going to have to slip the clutch to some degree, it will be hard on it.

Putting in a 727 will work a lot better for this event.

 

[Paul_G]

Rear tires are 265/45-20 Hankook Ventus S1 EVO 2, 8.7 tread width on an 8.5" wheel. I have them at 35PSI on the street.

 

[Cranky]

Don't know much about that brand of tire but a 29" tall tire with 3.23 gears means a ton of load on the clutch. You might just have to take off normally and then get on the gas hard and go from there....that is if you keep the clutch you have but even with a good clutch, imo, you're still gonna go up in smoke or bog down if you leave at a lower rpm.

 

[Jerry Hall]

You will need to have a good clutch immediately. A 4-speed in combination with your car on the track is a learning experience. Every car will act differently according to your particular setup. I can only relate my experience from years ago and it may or may not work for you.
I usually raced on street tires G-70 14 or in today's tires 8.35/70 14. 67 Satellite 383 4-speed at about 3600 pounds. Engine mods to an estimated 425-450 HP. Traction bars and Hemi springs. I found it easier to play with the gas than try slipping the clutch. I launched at about 2000 rpms by dumping the clutch. Tires were spinning and I modulated the gas for minimum spinning. Once spinning was controlled and full throttle attained, it's just a matter of shifting and not missing gears.

 

[biomedtechguy]

I had some street tires on my Conquest TSi that used to spin, some, at launch and chirp 2nd and 3rd.
Switched to drag radials and they didn't slip. Kept falling off boost because I couldn't modulate (slip) the clutch well enough, and no more tire spin.
The HitMaster launch control system would have been PERFECT for that car, which had a hydraulic clutch. I bought a Hydramax hydraulic throwout bearing for my 440+6bbl Roadrunner for several reasons, but one is so I can get the HitMaster launch control system for the Roadrunner.
Same company that makes the ClutchTamer, which I recommend you get, after you upgrade your clutch.
Another option is if you have a 8 3/4 rear axle assembly, get a 4.10 ring and pinion gearset setup in a spare chunk, use that for race duties, and swap your current 3.23 in for the rest of the time.
That way you can do what I have to, for now, until I do my upgrades, and that is to leave close to idle, as high as you can without tire spin, roll out a few feet, then floor it!

 

[Cranky]

I had some street tires on my Conquest TSi that used to spin, some, at launch and chirp 2nd and 3rd.
Switched to drag radials and they didn't slip. Kept falling off boost because I couldn't modulate (slip) the clutch well enough, and no more tire spin.
The HitMaster launch control system would have been PERFECT for that car, which had a hydraulic clutch. I bought a Hydramax hydraulic throwout bearing for my 440+6bbl Roadrunner for several reasons, but one is so I can get the HitMaster launch control system for the Roadrunner.
Same company that makes the ClutchTamer, which I recommend you get, after you upgrade your clutch.
Another option is if you have a 8 3/4 rear axle assembly, get a 4.10 ring and pinion gearset setup in a spare chunk, use that for race duties, and swap your current 3.23 in for the rest of the time.
That way you can do what I have to, for now, until I do my upgrades, and that is to leave close to idle, as high as you can without tire spin, roll out a few feet, then floor it!

Does the ClutchTamer only work with juice clutches?

 

[BSB67]

Have you tried to hold an rpm, maybe 2500. Dump the clutch, but don't hit the gas, just hold the throttle in the same place long enough to let the car lurch forward, then drop the hammer. It will feel slow but will probably be better than a spin. When you drop the hammer after the initial lurch, it should pull slowly, but smoothly away like it would from a 5 mph roll. If it bogs, up the squirter size. If this works out, I would guess a 2.1 sec. 60' might be possible. Experiment with the rpm in maybe 200 rpm increments.

If you cannot do this without the clutch slipping, you'll have a hard way to go until you replace it.

Have fun.

 

[biomedtechguy]

Does the ClutchTamer only work with juice clutches?

ClutchTamer for MANUAL clutch mechanism
HitMaster for hydraulic clutch mechanism
I was going to get the ClutchTamer but there are other reasons why I want a hydraulic clutch, and I think the HitMaster is more flexible in that you can program different clutch release/total pressure and time factors.
For example, my understanding of the ClutchTamer is to avoid a soft clutch on the shifts other than the launch, you have to have a spacer drop out of the lever that actuates the clutch. That way it's fully engaged for all the following shifts (other than the launch, which is the only engagement that I would want "softened"
The HitMaster allows for the slip to be programmed in.

 

[biomedtechguy]

Lots of details on the ClutchTamer here:
http://grannys.tripod.com/clutchtamertuning.html
HitMaster info here:
http://grannys.tripod.com/hitmaster.html
Reviews by actual users have been great.
(I can't wait to report on my experiences here!)
More reviews:
https://www.racepagesdigital.com/ta...rans-racers-dial-in-a-dead-hook-off-the-line/

 

[Paul_G]

My neighbors must think I am crazy. Up and down the street all afternoon.

I have been trying different things in the set up to stop the bogging. My base timing was at 18°, tried upping it to 20°, little help if any. Raised the primary floats to a little above half glass. Helped little if any. The bog felt like a rich bog. Changed the squirters to 25's from the stock 31's. That seemed to help the most. Or maybe a combination of it all. Tomorrow I going to try moving base timing down to 15° and see how it responds.

 

[68 HEMI GTS]

Fix the clutch, add a gear, add some sticky tires. Be my first 3 moves.

 

[BSB67]

If you're willing to try stuff, go up on squirters. Smaller motors, taller gears usually need more fuel to cover up the poorer signal/bigger hole. Keep move in a direction until you know its better. FWIW, I've never experienced a rich bog. Usually the richer the squirter is above ideal, it just keeps getting softer and softer, but does not bog.

You should be able to idle in first gear and drop the hammer and no bog or hesitation.

 

[65Fury440]

Practice keeping your rpms constant,while you let your clutch out all the way, then let her eat.
Maybe get some 26" slicks to give you a better launch.

 

[68 HEMI GTS]

I know whenever I’ve ran a stick car at the track that’s not gonna come off the line due to lack of gear, tires, whatever my goal is just to get the clutch out and then wood it. That’ll all be in the carb/distributor tuning. It’s not ideal but it’s reality. If you wanna pull any real ET you’ll have to do some work and spend some money.

 

[Paul_G]

If you're willing to try stuff, go up on squirters. Smaller motors, taller gears usually need more fuel to cover up the poorer signal/bigger hole. Keep move in a direction until you know its better. FWIW, I've never experienced a rich bog. Usually the richer the squirter is above ideal, it just keeps getting softer and softer, but does not bog.

You should be able to idle in first gear and drop the hammer and no bog or hesitation.

Let me define what is my bog. Car not moving, engine at 3000 RPM, Letting the clutch out slowly as I apply more gas. As the clutch starts to engage car begins to move, as the clutch fully engages the engine rpm's decrease as engine labors to catch up.

Practice keeping your rpms constant,while you let your clutch out all the way, then let her eat.
Maybe get some 26" slicks to give you a better launch.

That will take practice. I have the natural urge to fully press the throttle.



My 72 has shorter tires on it. Cooper Cobra 275/60-15, 28" tire. Would the 1" shorter tire help me that much?

 

[65Fury440]

My car was similar in weight to yours, also with 3.23s and a 28" tires. It 60d in the 1.90s. Going to the 26s helped launching off the line.
Going from 29.4-26 will be like gearing down to a 3.39 according to Wallace.
Sounds like you have a carb issue as well, but the help the shorter tires will be noticeable.
Getting a heavy car off the line is a lesson in clutch feathering, AMHIK.
Sounds like a cool event, go have fun!

 

[kiwigtx]

How to launch a 4 speed with 323 gears ?


Like this...... (skip to 15 sec)

 

[biomedtechguy]

How to launch a 4 speed with 323 gears ?
Like this...... (skip to 15 sec)