Drag Racing Discussions > Front Engine Dragsters

How to properly launch a FED?

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dreracecar:
Years ago when cars had torsion suspension, the front axle would drop thus moving the spindle pivot and turning the wheel all while the driver had the steering straight. Driver would look at the turned front wheels and would correct the situation by turning the steering wheel- but when the car came back down the front would correct itself and head towards the wall. Look at some old dragster wheelstand pics. The Good drivers would turn the front wheels even further for the reverse action when the car would come down and the wheels would go the other way.

Mister_Fitz:
My car has a torsion suspension at front, I will have to check for any "bump steer" effect when the axle unloads/loads.

I made some measurements on my wheelie bar today. It seams like it is about 2" off to the left. I guess it is to the right direction, to help unload the left wheel since the right one will be unloaded by the engine applying torque on the rear axle?
I will make the wheelie bar adjustable side ways asap. Is it a good idea to decrease the offset a bit since the car is pulling to the right?
One other thing I saw was that when the single wheelie bar is offset the wheelie bar wheel is no longer parallel to the car. Is this a problem? I have not seen any wheelie bars that is adjustable to compensate for this.


--- Quote from: gregm784 on June 02, 2014, 03:37:15 PM ---Tire speed is easy, start dropping tire pressure in 1/2# increments.  It'll eventually give you tire speed.  If i dead hook my tires on my 200" car, it'll drive the car in a random direction.

--- End quote ---

I do not really follow you on this one. Shouldn't I be adding pressure to eventually loose some traction with the harder tires and then get some tire speed?

How big is the window from starting to get tire speed to smoking the tires?

Mister_Fitz:
Or...
Am I doing it the hard way now... Is it better to just leave the wheelie bar as it is, since it probably is fairly right. Pick a fixed launch rpm and only experiment with the tire pressure until I get some tire speed at the launch and see if the problem is gone?

Dolmetsch:
If it were mine before I did anything else I would pull the axles and look at the splines. Even a fairly bad alignment should not cause a side launch  because in the car has any suds at all it is basically on the rear wheels at that moment. Only other possibility is you are correcting the steering during wheels up instead of letting it do its thing. Wheels flop to one side on most conventional steered cars. When I have a guest shoe in the car I always tell them Do Not correct steering on the launch. car will run straight on its own. Any back talk and their ride is cancelled. on mine when the front wheels come up the wheels flop left however when the car settles they are perfectly straight again with no correction.
Have a video of it that shows it very well.
don

wideopen231:
I am assuming you have been over the whole car and looked for craked welds? Spool are all spline in good shape? About everytime I have had a car launch to one side or other more than once I found something broken Or had let someone work on chassis that caused it to bind up and act stupid,long story lots of cussing.
]Went from DNQ to number 2 (4th qualify round)on early shutoff after cutting 2 bars that we had been told was new rule.Before cutting the car acted like it was on crack,jumping all over the place. Just throwing thoughts out there since most other have been hit upon.

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