Author Topic: FED bounce problem.  (Read 1337 times)

Offline Scott Krieger

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Re: FED bounce problem.
« Reply #15 on: July 23, 2020, 10:43:15 AM »
Your trying to use her as a rifle and not a hand gun, using only one hand to hold the gun to hit the target

Flex fades away over time. eliminate any flex from front motor mount to rearend.

Top rail in front of motor likes a slip joint to plant the rear tire, while forcing the fronts to stay planted in the beams every pass never lifting out.

Slipping the top front rail allows the car to eat up the track and hard top end breaking.

A lot of arch makes the front tires pull to the right on the launch. no give in the steering rod. we use clamps on the chassis to control movement.

She will be happy

Enjoy

Offline Curly1

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Re: FED bounce problem.
« Reply #16 on: July 30, 2020, 08:09:43 PM »
New Tires are in going to try that and see if helps before I start welding in more bars. Right now I think tires are only a small part of the problem but anything helps and I think chassis needs to be stiffer. I am trying to get this car to where it will go down any track under any conditions and be competitive all the time.

As for bounce in the shut down I find on this car it stops best if I just let off on the gas and then let it slow a little before I ease into the brakes. When I do that it stops faster and smoother. Sometimes that is hard to do on short tracks with rough shut down areas. If I try to hit brakes hard same time I kill gas it does not like it at all. Also I have been using the parachute more and it helps. For stopping once again I think it would stop better if chassis was stiffer.

Problem here is not many people have a combination like mine so what works on your car may not work on mine. A typical Rear Engine Four link dragster has a much stiffer chassis and suspension to make it work. FED are more flexible and no suspension so we have to work with weight, tires, chassis flex, engine angle etc.

Offline Scott Krieger

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Re: FED bounce problem.
« Reply #17 on: July 31, 2020, 08:43:38 AM »
Curly,
My daughters car is a 174" fed, triple slip joint top rail, BBC 600 HP, turbo 400. Runs 5.60 at 124 & 8.75 at 150 mph 3000 rpm launch in 2nd gear nice and calm bracket mode 4000 D.A. Chassis has 6.00 cert

I will try to get my daughter to post a run or two, watch over the tops of valve covers & see how much the of front tires come & go from sight under launch, settling down and hard braking on the top end, all controlled by amount of slippage at each joint to let car run free & easy. I do not like chassis flex as it goes away, I have some that will show itself over time and I readjust the slip joints to raise her back up.

Enjoy

Offline Curly1

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Re: FED bounce problem.
« Reply #18 on: August 01, 2020, 05:43:55 PM »
My new tires are here will mount them tomorrow and then try to test soon. Still considering a way to "Tie" the chassis down to make it stiffer to test before I start welding in more diagonals. I do feel part of the problem is this chassis is too flexible but hard to prove with out taking a chance and welding in more bars.

Offline jeff/21

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Re: FED bounce problem.
« Reply #19 on: August 02, 2020, 01:55:20 PM »
If really think that just make some bars that will clamp-on, make collars and weld or bolt bars to them( bolted you could move them up and down the frame)

Offline afaulk

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Re: FED bounce problem.
« Reply #20 on: August 04, 2020, 12:46:43 PM »
You beat me to it...I was going to suggest the same thing.

Offline BK

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Re: FED bounce problem.
« Reply #21 on: August 04, 2020, 06:39:29 PM »
To expand on Jeff/21s idea.
Clamshells on the end of a tube and hose clamp them on.
Should be good enough for a test.
Especially if you could come up with aircraft style clamps.

Offline jeff/21

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Re: FED bounce problem.
« Reply #22 on: August 05, 2020, 05:38:04 PM »
clamps could be  simple tubing that is cut length wise, into two halves  before cutting you weld pieces of tubing across so you could insert small  bolts to clamp  i would use 4 bolts for better clamping and they could be smaller, there are so many ways you could do it keep it simple

Offline Curly1

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Re: FED bounce problem.
« Reply #23 on: August 05, 2020, 07:39:57 PM »
I will try to pull the body off soon and see if there is a way I can do that.