Going up in smoke off the line

Discussion in 'PSI Superchargers Tech Questions' started by Wildcatracing, Feb 6, 2011.

  1. Wildcatracing

    Wildcatracing Member

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    Hi all, we are running a heavy doorslammer type car (3,300lb) with a 3 stage auto and 1600BHP BB Chevy. We need to get more weight transfer to the rear on launch and want to drop the front of the top 4 bars as they are currently parallel with the lower bars. Is this the correct way to go? Cheers
     
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  2. Moparious Maximus

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    I dont know jack about 4 link cars, but I will tell you launching a heavy blower car can be a real pain.

    You need to video the launches so you can study what the car is really doing and look at the tire track patterns, going off of what the driver or crew guy thinks is goin on might work, but you are still shooting in the dark more or less.

    Whats your tire size, gear ratio's, shock settings, % of wieght on rear/front, stall rpm? To get a good answer from the really smart ones on here they really need more info.

    We run a 3250 lb door car on 10.5W's at around 1500hp, this spring will be our 3rd season and we still dont have a 60' for shit, we did go up in smoke a few times and we played with tire pressure and swapped converters and it went away for the most part, on a crappy track it'll still smoke the tires sometimes. Our main problem now is when we go to a good track we cant keep the damn front end down.
     
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    Last edited: Feb 7, 2011
  3. Mike Canter

    Mike Canter Top Dragster
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    Wildcatracing.....do you have any launch retard control? What tires are you using at what pressure? What rear shocks are on the car and are they double adjustable?
     
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  4. Wildcatracing

    Wildcatracing Member

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    Hi guys, no we dont have any retard devices, we are running MT slicks 32x16x15 with stiff side walls) set at between 5 1/2-6lb, the shocks are single adjustable only. The set up is fairly basic but we used to have issues with pulling huge wheelstands, we changed the 4 bar set up several years ago and now have the opposite issue so I just wanted to make sure I didnt go the wrong way with the 4 bars. Cheers Graham
     
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  5. Mike Canter

    Mike Canter Top Dragster
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    Graham, that is real hard to say on the bars. Do you know where the IC is. Keeping the bottom bars level with the ground and dropping the front of the upper bars appears to be the right direction. Do you know how to map out a 4-link on a wall or a large sheet of wrapping paper on a table to find the IC?
     
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  6. Wildcatracing

    Wildcatracing Member

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    Hi Mike, no I dont know the IC but I have worked it our before. I think I will try dropping the front of the top bars and see how I go as it cant get much worse !! I used to hate wheelstands but now pray for them !! Thanks for your help Mike and take care. Cheers Graham
     
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  7. Mike Canter

    Mike Canter Top Dragster
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    Graham, you really should work out the IC. If you do then adjust it to around 48-49" out about 6-7" up and then work from there. I believe you are just going to be chasing your tail by random moving of the bars. At least if you know where the IC is and what the car is or is not doing then it is more logical how to change it.
     
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  8. Wildcatracing

    Wildcatracing Member

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    OK, great advise and thanks again for taking the time to help out. Cheers
     
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