Drag Racing Discussions > Front Engine Dragsters

How to properly launch a FED?

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Supercat:
Mr. Fitz. When you do your burnout and then back up how far do you go behind the starting line? The reason I ask is that "MANY" people back up to short and make track alignment corrections in a very short/too short a distance as they stage.
We back our 200" up to a crew member standing on the track side of the waterbox. We then make any alignment corrections in the first few feet as we pull forward, rolling as straight as possible for as long as possible to center the tires and chassis to the track.
When you make a moderate to strong correction durring final staging you put a twist or side load in the tires, lift the front and the car will center to the last big correction.

I too am chasing a wheel speed issue now but that should be corrected on the next time out. If the new convertor gets here in time. We launch at about 2500 rpm which is just too low for our combo.
Have fun and let us know what you find.

BK:

--- Quote from: Mister_Fitz on June 03, 2014, 01:06:16 PM ---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?

That's how it was explained to me. Engine torque unloading the right rear tire. My experience was bar to left, moves weight to right, car goes straight. Also I agree more air more wheel speed. But more air raises the wheelie bar. My guess is you weren't on the wheelie bar. 2" offset on bar sounds like plenty but not too much.
--- End quote ---

slingshot383:
A softer (lower rpm) launch will make it easier to climb the ring gear.  You want to launch at 600 - 400 rpm under the converters stall speed.  And yes, it raise slicks air pressure @ 5 psi. increments until you start slipping the tire.  You really need somebody watching the car to help with that, shorter wheelie bar contact with pavement, less than 4 wrinkles of the slick at launch movement.  Those wrinkles are important clues also, they need to be in the lower front of the tire, and not behind axle centerline.   

GlennLever:
Take a look, remember I am a low  HP dragster only running 8.00

Comments

slingshot383:
Glen, your car looked good at Gateway, and that picture has the crush right where it's supposed to be low and in front of axle centerline.

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