Drag Racing Discussions > Front Engine Dragsters
How to properly launch a FED?
dreracecar:
To easily verify what the wheelie bar is doing is by painting the wheel with shoe polish and to have someone on the crew veryfi the marks left on the track. you can pick up notes on ---
when the bar hit at launch and for how long, is the wheel steering the car?
JrFuel Hayden:
Mr Fitz, I agree with Bruce, shoe polish on the wheelie bar wheel, and look at marks on the track after you take off. You can also use VHT wheelie bar spray, or I use kids side walk chauk. Also if you have a crew member video your runs have them shoot your wheelie bar tracks so you can watch.
I have run into a FED pulling to the right when I had one of my motors in a B/ND running in NHRA Comp, we fixed it for that event until we got the slick company to give us another pair, by running 1/2 pound more in the right slick.
Another good idea is to check rear end location by measuring wheel base on both sides, keeping in mind if your chassis has an offset front axle [ NHRA allows 2" offset]. I know a famous JrFuel driver that always commented on how much he had to "drive" the dragster that was built in the 80's, but when they had the car "front halfed " the chassis guy found the rear end was not square in the frame, so Don was very happy afterward that the car went straight. The very best thing to do if you think your race car is not plum is get it on a chassis jig.
The reason the wheelie bar height is important is if your bar is too high, and you have a tight converter, at launch you could be jerking you front end up hitting the wheelie bar hard thus unloading your slicks and maybe unloading your right slick more. Bruce is right about 2 1/2" height. It could also add to your problem if your wheelie bar is too stiff, thus adding to the unloading of your slicks. We use a 3 bar CM 5 feet long with no supports between the 3 tubes so it works like a spring and more gently pushes the front end down.
Another crazy thing that might be going on is since you are new to this FED deal is right after launch you may be looking for your shifter [ on the right ?] thus going to the right. After all you will go to where you are looking.
Have Fun with your new project !
Jon Hansen, Hayden Wheels, and Hammer-Hansen-Hook JrFuel
dreracecar:
A simple way of a quick check on the chassie is to string it
Both tires equal air pressure
String/cord from Home Depot/hardware store
Tie lenght to 2 heavy jackstands per side(3-4 feet longer than WB)
place 1 JS behind rear slick and adjust front JS so that the string "JUST TOUCHES" the front/rear sidewall,
Do that on both sides
Stand back to see what you have
Is 1 wheel towed in more? is the whole RE cocked? at this point you can check the front end toe by measureing each rim to the string. Front ends can be off , the import measurment is the difference between the front and rear of the rim be the same for both sides. 4 7/16 & 4 1/2 and 5 7/16 & 5 1/2 is still 1/8 toe and not dealing with 2" offset or the front axle off to one side
ricardo1967:
All great input here, I'm following this thread very close.
I think one way to eliminate any chance of being tires' at fault is swapping their positions in the rear axle. Agree?
masracingtd1167:
--- Quote from: ricardo1967 on June 02, 2014, 11:26:53 AM ---All great input here, I'm following this thread very close.
I think one way to eliminate any chance of being tires' at fault is swapping their positions in the rear axle. Agree?
--- End quote ---
Very good idea !!
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