cant get down the track

Discussion in 'PSI Superchargers Tech Questions' started by 37hemi, Nov 7, 2010.

  1. 37hemi

    37hemi New Member

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    the lenco ratios are 2.60, 1.81, 1.31, 1.

    Also found today that 3rd gear has an issue. The roller bearing that the folk pushs on to put the car in gear has broken. The folk had fallen sideways in the housing and looks as if it may have been pushing on the clutch pack. The clutchs are burnt out. What would this do to the car
     
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  2. 37hemi

    37hemi New Member

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    Havnt had the car out much at all. Finally got the car weighed today. Here are the corner weights. LHF 631 RHF 674 LHR 745 RHR 598. Is that close?
     
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  3. Comax Racing

    Comax Racing Member

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    Chassis settings

    Scaling the car for weights is good but you really need to know the center of gravity, as it was stated the car looks like it is porpoising (spelling in know). This is basically when your IC and your center of gravity are close to the same spot.(car rocks forward and backward down the track) If you can find your center of gravity the rest is just mapping the IC's and the rest is testing.

    The procedure for checking center of gravity is too long to state here but there is procedures on the net, it's a pain but it helps you pinpoint your proper chassis settings fast.

    2 cents

    corey
     
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  4. GTPerf

    GTPerf Member

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    I use to run a combo close 20 years ago and to what I remember I think if you had a 3 speed it will help alot so here is an easy way leave in 2nd gear. I think we ran a 1.80 with a 4.56 rear gear if I remember right , try it (2nd gear) I think it will like it : )
     
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  5. rotory26

    rotory26 New Member

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    Maybe try getting 20lbs on the right rear. You have 147lbs on the left + axle rotation big bags on the rear and low air. Just even it up, should help heaps.
     
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  6. secondwindracing

    secondwindracing top alcohol

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    your motor is hunting..bring your idel up some..Dave
     
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  7. Dale H.

    Dale H. Member

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    Find someone that has some liner wheels and tires you could borrow and try that. We have a altered that had the same problem and fought it for a couple years, put some liner type wheels on and it went straight.I have talked to some other racers that have had similar experiance.

    Dale
     
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  8. rotory26

    rotory26 New Member

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    (Like I said when it happens it dosnt go up in smoke or shake me to peices(cant actually feel shake) it just sends the car in the wrong direction.) This is what you stated. From what you can see from YouTube the car looked fine untill the left rear weight drove you to the centre line. Have seen this many times, all you need do is screw the weight into your right rear which will then balance the drive across both tyres. You may need as much as 100lbs on the right depending on you front and rear spring rates. If you are soft on the front the right rear will unload as you go down the track and you will turn right.
     
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  9. 37hemi

    37hemi New Member

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    i took the car 2 when of our top doorslammer guys over here, u set the 4 link up and we went 2 a hoosies slick. Car is like an arrow. I think the original scales we used were off
     
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  10. rotory26

    rotory26 New Member

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    You can get the car balanced also by placing a piece of small angle with the pointy end facing up on top of your trolley jack. Place it in the dead centre of the rear axle, you should know this spot as part of your setup sheet. Once you have that point place the driver and fuel in the car as ready to race. Now jack the car up until the left rear starts to leave the ground. A good starting point would be about a inch of the ground with the LRW before the RRW starts to show some day light. That should place maybe 20-30 LBS on the right rear to help even the drive. You will have to play with the adjusters on the shocks to get it were you want. Also measure the roll out of both tyres. If one is 10-20 bigger stick it on the right side. Last place a cable tie around your shock shaft so you can tell how much travel you have in the car. 2 inchs is all you need in my opion. As you make more power and apply more clutch the drive effect will make the LRW dive harder and so the ballance needs to be work on all the time. Also the lane you are running will change this as well.
     
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    Last edited: Jan 11, 2012
  11. Wild Bill

    Wild Bill Member

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    I would preload the upper passenger side 4 link bar and see how that works out. That would be shorten it up I would go 1 flat @ a time
     
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  12. Creech

    Creech Member

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    The cross weights were backwards. the right to left front and rear weights.
     
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    Last edited: Jan 13, 2012
  13. BlownBantam

    BlownBantam New Member

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    Maybe its the M/T tires, I know its a completely different car but we have a 125 inch altered adn had the same exact problems. Car left great then got around 60 feet then shook and spun the tires. Went back to hoosiers and now have goodear. No more issue. We are running a 15 inch wheel and couldnt jump to a different M/T rubber compund through them without changing the wheel. Not knocking M/T, I think they are great but only for certain types of cars. I could be completely wrong but thats what we did and its all good now.
     
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  14. Creech

    Creech Member

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    I believe 37hemi has the problem solved. It is fairly common to tighten the right rear springs spanner 1/2" to 3/4" more than the left this helps prevent the rearend from rolling up and undloading the right tire and having the left tire drive it to the right guardrail. Then we crank the left front springs spanner to square the car. Shorten the right upper 4 link bar if it drives right and lengthen the right upper 4 link bar if it drives left.On higher horsepower cars especially without sway bars the body roll tends to move the instant center on the right side and give that tire more bite which drives the car left unless its so severe that its picking the right rear tire up and unloading it. This is what I think was happening to 37hemi's car. On my 106" wheelbase blown alky TA I pull the bottom right 4 link bars in 1/16" top out 1/16 to prevent it from driving left and give it a little dog track, it makes it more predictable when it spins the tires instead of going left right left or right left right it always fishtails the back to the left and points me toward the right if it spins.But not as dramatic as 37hemi's


    Marty
     
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    Last edited: Jan 13, 2012

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