Front end setup (Drag Racing)

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The stiffness of the front end has to do with the power and how much your getting to the ground. When you make vary little, a stiff front would cause the load on the rear to release do to eng not being able to keep the torque after the launch. so you need lots of travel and a soft front suspension.

High power will whack the suspect, bottom it out(top it out) and unload the rear tires.

when you're starting out (stock and up power) you need a loose suspension with lots of travel to keep the load transfer going.
The harder you launched the stiffer/slower you want that front end coming up, to also keep the rear tires planted.

I know none of this from experience, just from reading............Which make me the "Educated Idiot".:D
 
Mopower71 said:
What's the best way to set up the front suspension on a drag car, using the the original suspension.
I already have the 6 cyl torsion bars on the front, and the suspension has all been rebuilt. I beleive the shocks are 90/10's but I'll have to double check.
The front suspension feels stiff, when pushing it down, or pulling it up by hand.
I need recomendations on how to get it loosened up for the best front end rise.
Click to expand...
What i just finished doing on my dart is the addition of some Reiley Motorsport tubular upper control arms with heim joints and also his strut rods that also use heim joints.This gets rid of the bind of rubber or polyurethane but keeps the control.
Also there is an even smaller diameter torsion bar than the /6 bar that Mopar performance used to sell. You still maybe able to find a set around.

Duane
 
Duane said:
What i just finished doing on my dart is the addition of some Reiley Motorsport tubular upper control arms with heim joints and also his strut rods that also use heim joints.This gets rid of the bind of rubber or polyurethane but keeps the control.
Also there is an even smaller diameter torsion bar than the /6 bar that Mopar performance used to sell. You still maybe able to find a set around.

Duane
Click to expand...
beware of the cut down torsion bars. I had some friends that used to have a lot of trouble w/ them breaking.
 
famous bob said:
beware of the cut down torsion bars. I had some friends that used to have a lot of trouble w/ them breaking.
Click to expand...
hello, you could ask a stock eliminator racer, with a 340 or 360 car, like e/sa. f/sa, g/sa. what they use. they leave very hard, wheels up, when wheels are up all the weight is on back tires.
 
famous bob said:
beware of the cut down torsion bars. I had some friends that used to have a lot of trouble w/ them breaking.
Click to expand...
What do you mean by cut down.
The ones I have are a Mopar performance drag race bar that is .810 diameter. I believe the /6 bars are .830. I bought these bars probably
10 years ago.
 
The "V6" bars have been the trick for a long time. Had some on the car for several years. You have to watch the hight of the front end over time they will get even weaker and the car will start to bottom out on small bumps. But for a Dragstrip only car they work. Good luck and have fun. You might want to go to a scrap yard and check the weight of your car front and back so you know and can take notes. Racing is a lot about notes.
 
/6 Torsion bars. I have my front end right down on the bump stops. That gives me 5" of front end travel which seems to work good for my power level.
Also I need to have the drivers side a little tighter so that the front comes up even.

The E.T. on the board is for 1/4 mile after I had already backed off the throttle at the 8th mile cones. 60 ft. was 1.38 and 8th mile E.T. was 6.38 @106.6mph
Here is an example of front end travel with 8th mile data on the scoreboard:
 
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moparmanestock said:
Hi I am new to FABO. I just started racing my 71 Demon. I had a similar problem an you. My car has 28 in tall front tires from MT. With car at ride height, the front end was dead stiff, with no reaction. After talking with Angelo Phillips, I checked my shocks (CE 90/10s) and they were bottomed out! They were too long even though were supposed to be for a body. I installed the CalTrak front shocks, are shorter by an inch. Now with frontend same ride height, it is loose, and lots of reaction.
Would never have thought to check that! Might want to check yours!
Chuck.
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The Caltrac front shocks are way looser than most other shocks. They claim they are a true 90/10. I believe it. They pull apart way easier than my 90/10 CE.
 
This here's a great thread to restart, I'm getting close to setting my suspension up
 
The first thing would be to change the upper control arms to the tubular. They are longer than the stock ones and can correct the bump steer. Then get a good alignment, 0 camber, as much as possible caster (3-5) and 1/16 inch toe in. Make sure they do a 4 wheel alignment and if the rear axle isn't square loosen the u bolts and give it a tweek. Expect to pay more for this kind of job and ask if they will do it first. I've seen cars pick up as much as 3 tenths if they were really off.
 
LO23M8B said:
The first thing would be to change the upper control arms to the tubular. They are longer than the stock ones and can correct the bump steer. Then get a good alignment, 0 camber, as much as possible caster (3-5) and 1/16 inch toe in. Make sure they do a 4 wheel alignment and if the rear axle isn't square loosen the u bolts and give it a tweek. Expect to pay more for this kind of job and ask if they will do it first. I've seen cars pick up as much as 3 tenths if they were really off.
Click to expand...
What brand of uca are you using ?
 
I think so. I had a little issue with them and called them and they sent me another set right away and told me to send the old ones back in the box. They didn't even wait for me to return them. GREAT SERVICE. They can power coat too. They look great.
 
LO23M8B said:
I think so. I had a little issue with them and called them and they sent me another set right away and told me to send the old ones back in the box. They didn't even wait for me to return them. GREAT SERVICE. They can power coat too. They look great.
Click to expand...
Great, yeah I think I'll get myself a bare set and paint them.
 
O but they look so pretty, and they are more durable. I got the bright red ones and they match the car.
 
LO23M8B said:
O but they look so pretty, and they are more durable. I got the bright red ones and they match the car.
Click to expand...
Yeah it does, I'm running out of money though since my engine which was running 4 months ago and got hurt on the Dyno and other things were just not right.
So that refresh and upgrades was unexpected
 
Mopower71 said:
What's the best way to set up the front suspension on a drag car, using the the original suspension.
I already have the 6 cyl torsion bars on the front, and the suspension has all been rebuilt. I beleive the shocks are 90/10's but I'll have to double check.
The front suspension feels stiff, when pushing it down, or pulling it up by hand.
I need recomendations on how to get it loosened up for the best front end rise.
Click to expand...
When you get the alignment done, have the front of the car lifted to the approximate height it will be at the 660 foot mark and have the alignment set to factory specs at that lift height. It is worth .25 to .50 of a second. You can also take the third leaf out of the rear spring pack and put them in backwards. This acts like a traction bar for Mopars and aids in lifting the front end, and can be used in conjunction to a pinion snubber if one like, but I never have.
 
Just something to consider....
Watch this video from about half way threw.


And the after video here.
 
Cudafever said:
Just something to consider....
Watch this video from about half way threw.


And the after video here.
Click to expand...

I watched your videos, what are you showing?
I see your suspension is free without torsion bar and it still won't drop fully.
I'm a suspension rookie and want to make sense of what's going on here.
Thank you
 
The torsion bar in out in both videos. The video i had to push the suspension down was with the stock suspension.
The 2nt video shows, how much less resistance aka, Free the suspension was with the new setup.
I need the front suspension to rise, much faster at launch, to keep the back tire planted.
It also took some weight of the front end, as a bonus.
 
Cudafever said:
The torsion bar in out in both videos. The video i had to push the suspension down was with the stock suspension.
The 2nt video shows, how much less resistance aka, Free the suspension was with the new setup.
I need the front suspension to rise, much faster at launch, to keep the back tire planted.
It also took some weight of the front end, as a bonus.
Click to expand...
Oh okay, got it. I rewatced after reading and It makes sense
 
Two schools of thought, control wheel movement through REALLY stiff springs or minimal spring strength and control wheel movement with the shock. MUCH easier to adjust a shock than change spring rate. I have /6 bars, no bump stops, QA-1R’s front shocks single adjustables. The real hurdle to front wheel travel is the stock control arm hitting the bump stop mount. Go aftermarket and/or a taller ball joint and now the stock strut rod and is binding up. Aftermarket strut rods and other than the upper a arm pivots not being in plane. You have about as much drop as you’re going to get. Remember the timing of the rise is just as important as the amount. Were it tops out and how is crucial. Also, be very careful with aftermarket shocks, because they tend to be larger in diameter the body of the shock can hit the bump stop pad on the frame. I have seen multiple B bodies and mine hit.
 
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