Get my car to launch better...

[crackedback]

Pinion angle is the difference between the centerline of the transmission output shaft and the centerline of the pinion gear UNDER LOAD. Meaning when you're accelerating they should be parallel. This does not mean pointed at one another. It means parallel.

As an example or a typical drag car...If your trans output is pointed down from parallel to the ground say 4°(big block and motor plate) and the pinion as measured is 2° down from parallel with the ground(SS springs w/ the shorter from segment), that means you need to shim the leaf spring perches or cut and relocate them to get the pinion down far enough to get proper pinion angle under load. In this example's case that would be 2°. Leaving the pinion "down" 4° from the trans output at rest.

In the example wouldn't the pinion need to be angled up 4* to be a 0 pinion angle related to trans output? Because you want it parallel. Thus, if you had the pinion pointed at 2* up it would be 2* down angle, and at 2* down it would be 6 down angle. If you had pinion at 0, perpendicular to the ground, it would be 4* down in relation to tailshaft.

If you meant having to roll the pinion up 2* to get it perpendicular to the ground, that looks right to me at 4* down.

I do it the same way. Parallel planes then roll it down whatever number you desire.

Here's a visual of the way moper and I set pinion angle.
http://www.rosslertrans.com/Pinion Angle.htm

 

[juvat]

Here's an update from my last post. I moved the battery to the trunk, drag shocks front and rear, installed a mallory hyfire with 2 step limiter and a line lock. While going down the strip, I was unable to keep the throttle to the floor the entire time, since I ended up having problems shifting the tranny doing that (wouldn't go into gear sometimes). I finally got decent at burnouts and I tried launching at different RPMs. At first I tried launching at 2500 (using the 2-step) and the tires hooked, engine bogged and took off. 60' time was 2.00. Kept bumping up the 2-step and kept improving times slightly. On my last pass I set the 2-step to 4000, dumped the clutch, tires hooked, bogged slightly and made a 12.97 pass with 1.91 60' time (Previous best was 13.19 and 106MPH). My MPH was 107.17, also the fastest of the night. I think I'm going to try bumping up my 2-step RPM even more next time, I don't want to break anything, but I don't think I'm at the power level right now to start destroying u-joints or the rear end anyway. Thanks for the help everyone. I finally got my tires to hook off the line, and I've got my street car into the 12s.

Best part of all I beat my buddy in his attempt to get his AWD Jeep SRT8 into the 12s (his best was 13.01 despite all of his money spent on computer tuning and car payments). You should have seen his frustration!

 

[Longgone]

It sounds like you picked up a couple tenths without spending too much money. Good job! With some more practice at the burnout box, the tree, and speed shifting I bet you`ll knock off another tenth or two. Congratulations!

 

[turbodart68]

Hey Juvat, Great job on the 12 second pass! Race cars take patience and a one thing at a time approach. You are doing a great job of doing just that. I would like to mention the front suspension. The front end is more important to a cars ability to hook than the rear suspension. I loose suspension will help a marginal car hook in a car wash. For example, low friction bushings such as poly or heim joints. Low friction ball joints and a good drag shock and spring. Without the ability to transfer weight to the rear of the car via the center of gravity a car will have limited success hooking. I ran a stick car for a few years with a small block and I left on the high chip (shift RPM) and even though it spun a little bit, it made its fastest 60 foots doing that. When launching a stick car something has to give. Either the car accelerates immediately and pulls a big wheel stand or it spins the tires or it slips the clutch. The best way to control that situation is with a slipper clutch. Since you dont have one and they suck on the street, a little tire spin is welcome.

The 2 step is a great tool since you leave the line WOT. Otherwise you have to open the throttle and the motor has to recover from the throttle change. Getting a stick car to work efficiently is difficult, sounds like you are well on your way. Congrats, that 12 second timeslip feels good dont it?!

 

[mshred]

Hey Juvat, Great job on the 12 second pass! Race cars take patience and a one thing at a time approach. You are doing a great job of doing just that. I would like to mention the front suspension. The front end is more important to a cars ability to hook than the rear suspension. I loose suspension will help a marginal car hook in a car wash. For example, low friction bushings such as poly or heim joints. Low friction ball joints and a good drag shock and spring. Without the ability to transfer weight to the rear of the car via the center of gravity a car will have limited success hooking. I ran a stick car for a few years with a small block and I left on the high chip (shift RPM) and even though it spun a little bit, it made its fastest 60 foots doing that. When launching a stick car something has to give. Either the car accelerates immediately and pulls a big wheel stand or it spins the tires or it slips the clutch. The best way to control that situation is with a slipper clutch. Since you dont have one and they suck on the street, a little tire spin is welcome.

The 2 step is a great tool since you leave the line WOT. Otherwise you have to open the throttle and the motor has to recover from the throttle change. Getting a stick car to work efficiently is difficult, sounds like you are well on your way. Congrats, that 12 second timeslip feels good dont it?!

adjustable clutches work fine on the street if you know how to adjust them properly

 

[pettybludart]

Congrats on your goal of reaching 12,s!I to ran a 4 speed at the track with a Lakewood bell(safety),4.10,s,Centerforce clutch and CE slide-a-link(similar to Caltracs)but has a big neoprene bushing to soften impact at lauch.It has lots of adjustment to play with.My best run was 12.82@108mph,60 ft was 1.80.At this mph I should have been in the low 12,s,but with some slippage(clutch)and wheel spin off launch(M/T drag radials)Good luck with your goals,my 4 speed car is now retired from the track.Now I have my 66 Dart(410)to punish at the track.Shooting for mid 10,s,with a 408,904,4500 Coan stall and 4.30 gear with a 26 inch tire.:clock:
Vid is with 9 inch slicks
[ame="http://www.youtube.com/watch?v=INeu1MhFdnM"]YouTube- 73 Dart Sport 340,4 speed Cayuga/09[/ame]

 

[turbodart68]

adjustable clutches work fine on the street if you know how to adjust them properly

I have run a McLeod cintered iron adjustable clutch on the street. Cintered iron disc is necessary for an adjustable clutch due to heat. Its miserable, its noisy and harsh. Have you ever had squeeling brakes? Sounds just like it. Its doable but its not fun. Plus those clutches are expensive to reface.


Pettybluedart, Nice pass man. Its hard to run a stick car at the track, looks like your doing good with it.

 

[pettybludart]

I have run a McLeod cintered iron adjustable clutch on the street. Cintered iron disc is necessary for an adjustable clutch due to heat. Its miserable, its noisy and harsh. Have you ever had squeeling brakes? Sounds just like it. Its doable but its not fun. Plus those clutches are expensive to reface.


Pettybluedart, Nice pass man. Its hard to run a stick car at the track, looks like your doing good with it.

Was doing fine,turbodart68.I,ve now retired the 4 speed car and am in the process of building a 10 sec. car outta my 66 Dart:cheers:

 

[mshred]

I have run a McLeod cintered iron adjustable clutch on the street. Cintered iron disc is necessary for an adjustable clutch due to heat. Its miserable, its noisy and harsh. Have you ever had squeeling brakes? Sounds just like it. Its doable but its not fun. Plus those clutches are expensive to reface.


Pettybluedart, Nice pass man. Its hard to run a stick car at the track, looks like your doing good with it.

I realize what running an adjustable entails (although i cant speak from personal preference) and i know the sintered iron does chatter quite a bit...but like you said it is doable...everyone's idea of streetable is different though right, so i guess thats what makes us individuals lol8)