Going to race my car in 6 days, I have a couple of questions.
 

I’ve decided that I’m going to race my car on Tuesday for the last time. My questions is, I’ve never had an alignment done and I’ve heard of people picking up 2-3 mph just from getting an alignment. How important is alignment in drag racing.

FYI: My car doesn’t pull to one side or the other. My question is about the wheels pointing out or in which would create resistance (Correct?).

Front end alignments are only around $60 so I would just get one to be safe. Also, does this mean that you sold your car for sure?
Anyway Good Luck,
Phil

If it was sold, I wouldn't be racing it. :)

Is this what I should run?


0* camber
0mm toe
max out the caster

That's what i have heard. Get the frount wheels as strait as possible to reduce drag.

What about my rear? I have a custom 4 link, what do the specs need to be on that?

Here is some good info. Talks about front and rear toe and so forth.
http://www.aircooled.net/gnrlsite/re.../dragsetup.htm

This is what I've found out so far.




Rear 4-link should be triangulated dead center on the front crossmember under the motor.

Front end should have 1-2 degrees camber, 0-1/2 degree TOE IN, and as much caster as you can get.

Front end of the car should be lifted 2" above standard ride height to compensate for angle of attack during the pass.

More caster will make high speed handling better.

Caster is faster.

You are correct on the front so far from what i know. Biggest problem people make with alignments and drag racing.....they set them up at ride height which makes absolutely no sense what so ever. The car doesn't go down the track at normal ride height.

So, besides me sitting it the car while it's being done. What else can be done to get the right ride height?

The triangulation of the 4 link is the thrust angle of the rear end, which is measured by the alignment machince. You can set it on the alignment rack. Just make sure you keep track of the pinion angle when your setting the thrust angle, as it will most likely change. Keep the pinion angle no less then 1/2 degree and no more then 3.5 degrees. Toe should be slightly out. Negative toe makes a car darty, out is stable.

+ or - camber, and + or - caster, which one is it on each parameter?

Great thread btw. :bigthumb:

I believe the rear should have 1-2 posotive camber for a harder hook off the line. The posotive camber will allow the tires to tuck in a degree or two during the launch allowing the tires to use 100% of their tread face for traction, instead of getting negative camber and trying to launch on the inside half of the tires.

How are my wheels going to tilt in when I have a solid axle? :redface:

Eric, make sure you have someone videotape your runs. I wanna see them. If I was still in STL I would definetaly go watch but I can't be there. Trying to reclaim your record huh?
Good Luck,
Phil

For starters NEVER put the toe out NEVER. When we setup a race car we will set the toe about 1/8 IN. Most street cars get set at about 1/4 IN. Also never zero it bc then it will follow every groove in the lane/road. The camber that can be zeroed 1/4 + or 1/4- .. as far as the caster, that just makes a car more stable at high speeds not neccesarily faster just more stable. with that you put as mush as you can within reason. If the car feels safe and stable then i wouldnt be concerned. these front ends are pretty good. And you do want to do it at +2" and you dont need to be in the car. And take the car to someone that will follow these instructions and has a clue what they are doing not some ASE asshole at pepboys who thinks they know what to do. one last the LIGHT EM UP
Greg

So, it the thrust angle of the rear end just mean "Squaring it off"?

Not exactly sure what you mean when talking about the triangulation and thrust.

Assuming you have a triangulated four link and not a parallel four link When you align the rear, you have the upper and lower arm adjustments. The upper arms keep the axle from rotating and keep ypour pinion angle in the proper alignment and also keep the axle centered under the car. The lower arms keep the axle in place front and back.

Your thrust angle is the degree at which your front end and rear end line up properly. If your thrust angle is off, your car can dog track where the rear end is toe in on one side and toe out on the other.

So when you get your alignment done, be sure that your thrust angle, the alignment between your front wheels and rear wheel geometry is zero'd out. So that your rear wheels will follow your front wheels in a perfect line. But when you are adjusting your thrust angle on the rear, don't let your pinion angle change too much or your rear end, driveshaft, tranny alignment will be offset....so you can re-adjust that with your upper arms on your 4 link setup.

When I made my comment earlier, it did not dawn on me that you are running a solid rear...I don't know why I blanked on that again. I did alignments for 3 years at my dad's shop. I am not sure on the degrees you need to be running or anything like some people have posted, but the basics of alignment are all the same.

Your 4 link is triangulated correct? You have two parallel bars and two angled bars holding your rear end in place.

I guess it's triangular........ ?

http://img.photobucket.com/albums/v2...m/DSCN0175.jpg

If you peek under your car you might find a panhard bar...

Yes, and you're attempting to say what?

That you should read more books :p:

Great, thanks for the help.

if you have a pan hard rod... then you have a standard parallel four bar and not a triangulated one

typical 4 bar with pan-hard rod

http://www.chris-longhurst.com/carbi...arparallel.jpg

triangle 4 bar variation

http://www.chris-longhurst.com/carbi...artriangle.jpg

one more thing... for the front alignment .. a little toe in is better then a little toe out. Typically the more toe in you have the straighter the car will drive if you have toe out... the car will want to drift back and forth