4-link/swing-arm dragster burnout

Old 05-10-2010, 03:35 AM
  #11  
johnracer
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When he lifts at the traps there's a slight vibration, but it doesn't last long. I'm pretty sure the slip yoke's causing that. Otherwise it's smooth....
Do you think a shock adjustment might help? If it was shaking on the launch, I might try stiffing the compression a little, but I don't know if it would do anything in the burnout.
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Old 05-10-2010, 01:28 PM
  #12  
hammertime
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I guess if the shocks had no compression at all it may hop on him, but they would have to go full extension to make the car hop id think.

Wish we were closer I could see exactly what its doing.
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Old 05-10-2010, 02:11 PM
  #13  
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If I can borrow a digital video cam, we'll get some video and post it. It isn't as visible as it was with the Goodyears so hopefully we can get some closeup shots of the tire & suspension when it's shaking.
The shocks are pretty stiff now, the rear of the car isn't near as springy as my Vette. In fact you really can't bounce it much at all. Of course I've never messed with a suspended dragster so maybe they're all that way....
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Old 05-10-2010, 04:53 PM
  #14  
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They normall can be moved by pushing on them a little bit, does it have a shock stuck on it ?
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Old 05-10-2010, 05:12 PM
  #15  
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I know that the rh shock is fine. We had it off Sunday, removed the spring and made sure the adjustments worked and how they work. Can't say about the left one though. You can move the rear suspension, but it takes all my weight (170lbs) and it doesn't move much no matter how hard I try to bounce it. I'm talking maybe 1/2" or less. I assume that's more than pushing on it a little bit? I'll see if I can convince him to remove both shocks tonight, move the suspension through it's travel to check for bind and check the lh shock.
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Old 05-20-2010, 04:51 PM
  #16  
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Well, wasn't able to borrow a digital cam, but we got rained out on Friday anyway. He made 2 time trials on Saturday on the stop for Supercomp and loaded up before first round. I watched as closely as possible and couldn't see any shake, and 2 others said the same, but he says it just as bad or worse. Car ran great, just can't cut a light on a pro tree yet. His lights are consistent, but slow. He ran 9.47 @ 164 on only the second run on the stop on the 9.50 SC index in Denver......personally I'd have pounded a pot of coffee and taken a shot at it!!

He's getting a pad made for the seat, and we moved the pedals and steering wheel farther away in an attempt to make him more comfortable in the car. Hopefully that'll keep him in the car so he can get seat time!

David, last fall when he got the car, I mentioned the ballast box in the nose. I'm guessing it's got 30-50 lbs of shot in it. It also has 2 batteries about 3ft back from there. I think you said that a suspended car shouldn't need any ballast. Could that account for his reaction time issues? Just a thought.

I think the car is pretty light for a swingarm dragster. Even with the additional weight, it weighs 1895lbs full of fuel and him....

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Old 05-20-2010, 06:21 PM
  #17  
hammertime
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Unless it has major power (1200hp +) it shouldnt need the weight in the front of it. When you say reaction time issues, you mean its just very slow to react or inconsistent reactions also ?

Does the driveshaft have a lot of slop in it? Like if if the car is sitting in park and your push the rear tires how far does it chuck ?
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Old 05-21-2010, 03:34 AM
  #18  
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His 565 has 970hp. His reaction times are getting more consistent as he gets used to the car, but they're slow on a .4 pro tree..in the .040-.050 range. Full tree isn't a problem, but runs 1.060-1.070 in the box to keep them decent.
With the old slipyoke, it'd roll quite a bit. In fact, he put a line lock on it to prevent it. It's wired into the box and releases with the trans brake. With the new slipyoke, very little.....we tried unhooking the line lock, but it didn't seem to help rt's much.
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Old 05-21-2010, 09:23 AM
  #19  
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Does it have a pro tree brake in it ?
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Old 05-21-2010, 10:01 AM
  #20  
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Yes it does. TCI, same as mine...
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