Launch techniques with stick

I was just reading Zapo's thread on the transbrake/stick delima and wanted to ask some of you guys how you launch your manual car. I have had pretty good success with mine, but still can't seem to nail the consistency of the launch. The main questions are as follows:

1. Is it better (lowest 60 ft) to dead hook?

2. Is is better to run more air in the tires and let it spin?

3. Is is better to slip the clutch?

4. When all of these things are considered and the car does not 60 ft right when do you know the slicks are going away?

5. What does it mean when the car hooks off the line and slips the clutch in second but not high gear?

6. What about when the track seems good but the car spins in second or third down the track.

7. How do you guys think stiffening the shocks effect the launch on a manual.

8. When do you just say, "hey, I don't have enough horsepower/torque to get any better 60 times".

9. Calvert racing says you can't really have "to stiff" of a rear leaf spring, but to me it seems that if the springs (5 leaf) were too stiff some of the rotational energy that should be transferred to the Caltracs is spent pressing on the leaf springs without rotating the pinion and thus allowing the bars to work. (do you copy?)

Look, I know there are a lot of questions and I know there is not one singular answer, but I want some feedback on your search for the perfect launch.

Thanks for the therapy.

I don't have time write a detailed explaination right now (maybe later) but I do know you run nitrous with a stick, just like me. What helps me the most, is to make sure the nitrous doesn't kick in before the clutch! If it does, traction goes away.

I have a throttle switch, and try to have the clutch engaged -right- before the foot hits WOT taking off. If your foot hits the wood and engages the nitrous before the clutch is fully engaged, it hits too hard and spins.

I haven't had many issues going down track, but don't -quite- powershift on the bottle.

As for a stiff rear suspension... If you've got a sintered iron clutch, and have it designed to slip on launch, stiff is good. If the car isn't set up that way, the shock from the initial clutch engagement needs to be absorbed -somewhere- and a looser suspension can help.

Good Luck!

Originally Posted by n2omike

As for a stiff rear suspension... If you've got a sintered iron clutch, and have it designed to slip on launch, stiff is good. If the car isn't set up that way, the shock from the initial clutch engagement needs to be absorbed -somewhere- and a looser suspension can help.

+1

This looks like it'll be a great discussion...looking forward to it.

Cris

I'm no expert but I'll tell you what I feel works with my car.Mine has a non adjustable clutch and very little adjustment in the suspension(that I know how to utilize anyway).
Basically,the highest possible RPMs I can leave at without destroying the tires,but have a trace of wheelspin,is where its going to 60 ft and ET the best.
If I back off of it enough to get it to "dead hook",it pulls the engine down and doesn't 60 ft or ET as well.

Gee Cahorne, with times like you have I would think that you would be here teaching us the ins and outs of how to launch an old Mustang.

I'll touch on a couple of things that I found last year. Take it for what its worth, as last year was my first time of being a regular at the track.

Initially I tried the dead hook many, many times and it never resulted in the same 60's as when I added more RPM. As long as I didn't blow the tires away, my 60's improved with some spin off the line. Dead hook was around 3000RPM and I was getting my best 60's launching at 4900RPM on a cold track. Videos of my car bogging with lesser RPM's prompted the increase in launch RPM. I use a 2 step so my launch technique has fewer variables.

I used 3 different rear springs last year. First I tried 5 leafs, but with one leaf removed. Car hooked well and I used that as a baseline. The rear was somewhat springy without the 5th leaf. Added the 5th leaf and I couldn't 60 as well as when I had the leaf removed. I then installed the Calvert split mono rear springs and immediately my 60's dropped down to where they were with the "4" leafs.

Funny that Calvert says to use the stiffest springs since the Calvert split mono springs are not that stiff at all--I would almost call them spongy. They are a big riding improvement over the 5 leafs when on the street, especially when coupled with low settings on the Rancho shocks.

When I first installed the split mono springs, I tried to keep the rear shocks set somewhat stiff (5-6). A conversation with Dave Zimmerman (team Z) led me to try setting the Rancho's to just 2 or 3. He said the loose setting would let the Caltracs and mono springs do their thing better and that the stiff shocks were acting counter productive. I have to agree with him as my car liked the softer shock settings and gave me the best and most consistent 60's of the year, even as my ET Drags are near there disposal point.

This year to better my 1.60-1.65 average 60's, I've added the new Calvert 90/10 front shocks (to further improve weigh transfer) and I am going to go with a wider 9.6" tread slick (last year was 8" wide.) That should allow me to add even more RPM off the line. I am also going to be running a sintered iron clutch and will see what advantage it will have over the Center DF and Spec 2+ I that ran last year.

Since each car seems to act different at the track, there doesn't seem to be just one recipe for success. A lot of that probably has to do with driver experience as well.

Wow.. you guys are rocket scientists compared to me...
I simply rev my motor to 5000 rpm, close my eyes and scream like a little girl when I dump the clutch. LOL

Ok, seriously, Im with 68stang... I dump the clutch at an RPM that wont obliterate the tires... and what Mike said is important too... no NOS outa the box... its just too much for the tires.

Originally Posted by Thordane65

. . . . close my eyes and scream like a little girl . . . . . LOL

I tend to do that after I powershift 2nd gear and then go broadside down the track. LOL

Has anyone ever calculated how fast they are going at the end of 60'? I used the Wallace calculator and it says that I went from 0 to 51.55mph in just 1.60 seconds!!!!!!!

Sorry, back on track.

Originally Posted by Thordane65

and what Mike said is important too... no NOS outa the box... its just too much for the tires.

Oh, I DO use the nitrous out of the hole! It's the KEY to good 60ft times. I just try to engage the nitrous a couple milliseconds after the clutch engages.

My car is set up for nitrous. Right now, it has a 28" tall tire and a 4.33 rear gear. To optimize off the bottle performance, a shorter tire or 4.56 gear would work better. Therefore, off the bottle, I launch the car as hard as possible to get it to 60ft. Off the bottle, it will NOT blow the tires off, so I launch it as high as possible. Going for broke, I'll launch it at 7000 or 7200 rpm, even though it is shifted at 6800. That's how I got my best n/a 1/8 mile time of 7.48 with the old 289 headed engine. Still, the 60ft's are in the mid 1.6's. With it's current gearing, the little 306 just doesn't seem to have enough torque to launch the 3300lb car that hard without the assistance of the bottle.

I only got the car to the track twice last summer with the new engine. I only made one run off the bottle, and it went 7.46 @ 93. However, on the bottle, it went 6.68 @ 105.4, which is a pretty good improvement in mph. The last engine's best was 102.98. This is with a 200hp plate, and slicks that were at least six years old. They had to be heated HARD to work, and liked a smooth launch, where the clutch had time to fully engage before full throttle kicked in the nitrous switch. (takes practice)

I also recently found the driver's front shock that had broken. The bracket where it bolts on at the bottom broke off. One of the rear Ranchos is also dead. It looks like the car will need new front and rear shocks and a new set of slicks before it goes back to battle. I'd also like to replace the stiff 5-leaf springs, but that probably isn't going to happen any time soon.

Sorry for 'thinking out loud' and rambling... Back to your regularly scheduled program.

Good Luck!

Th e weight of your flywheel has more to do with the 60 foot times than anything else. When I was a kid ( years ago) just going to an aluminum flywheel let me floor the gas pedle before I let out the clutch. This was worth a full three tenths of a second on an 11.6 to 11.7 big old 409 Chevy. It dropped down to 11.15 or 11.27 with the lighter flywheel/ With the heavy steel wheel, 5000 was the mosyt I could come off the line. After the alu wheel, I could just floor it and dump the clutch( about 7000-7500)Plus it is MUCH easier to drive, you done even have to look at the tach.

JOE SHERMAN RACING ENGINES

BigJoe and others. Let's elaborate on flywheel weight.

My 3500lb Fairlane with 420hp at the crank is running a 40lb Hays with a Hays street strip clutch. At the time I built the car I was 15 or 16 and driving it on the street several days a week. Now the car is getting more and more hardcore every month (roll cage, no heat, etc..). I still want it to be a street/strip but can I decrease my flywheel weight and improve et? Current set up is at 12.28