Re: Got the dart on the scales! How do the numbers look?
[Re: 440charger500]
#1457541
06/24/13 05:31 PM
06/24/13 05:31 PM
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Joined: Aug 2003
Posts: 43,205
Bend,OR USA
Cab_Burge
I Win
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I Win
Joined: Aug 2003
Posts: 43,205
Bend,OR USA
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Quote:
I borrowed some really nice scales, these things are cool. Here's what we got 67 dart eddy headed 340, dana 60 rearend w/1 inch drop+ 2 degree shim, battery in trunk, 3/4 tank of gas, caltracs w/bar in lower hole and preload, torsion bars set on rubber bumpers. Think it still needs more tuning.
Heres numbers after adjustments to caltracs & torsion bars with me in it!
Left Front 805 Right Front 763
Left rear 751 Right Rear 731
Front 51.41% Rear 48.59%
Those percentage numbers are common on most A bodys with both BB and SB in them  Do you have the battery mounted in the trunk? If not do that next I mounted two of the group 27 batterys behind the right rear wheel tub as far back as I could get them and as close to the taillights as possible and still get the bulbs out on my Duster  I did keep the stock gas tank full at the track also, I would make three runs and top it off That weight can act like a teeter tooter, especailly on the launch  Weight mounted behind the rear axle tends to help move the front suspension up easier than if the same battery weight is mounted up front 
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
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Re: Got the dart on the scales! How do the numbers look?
[Re: 440charger500]
#1457543
06/24/13 06:28 PM
06/24/13 06:28 PM
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Joined: Nov 2003
Posts: 7,348
Mt.Vernon ,Ohio
VernMotor
master
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master
Joined: Nov 2003
Posts: 7,348
Mt.Vernon ,Ohio
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Quote:
. Only thing that was a bit weird is we were almost 100 pds light on the Right rear so we turned caltrac bar until weight came in closer to left rear.
You should not of adjusted it like that. You should of use the torsion bar to ajust and get that weight with the caltrac with no pre load on them. and then ajust then ajust the caltracs. I run no pre load in mine. Right side touch and .060 gap on left.
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Re: Got the dart on the scales! How do the numbers look?
[Re: Cab_Burge]
#1457549
06/25/13 07:22 AM
06/25/13 07:22 AM
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Joined: Mar 2006
Posts: 9,844
MI, usa
dvw
master
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master
Joined: Mar 2006
Posts: 9,844
MI, usa
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When scaleing my car I made the mistake on my car of using the torsion bar to set preload on the RR. RR ended up #20 heavy after adjustment. All was well until it started leaving hard and carrying the front wheels. Now it drove to the right. My bet is with the wheels in the air It lost it's preload. Adding preload with the RR ladder bar fixed it. Obviously I don't have Caltracks but load is load. I came within 12" of the wall last weekend before the adjustment. It was close enough that I thought "don't let it hit to hard".
Doug
Last edited by dvw; 06/25/13 07:25 AM.
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Re: Got the dart on the scales! How do the numbers look?
[Re: Cab_Burge]
#1457550
06/25/13 10:34 AM
06/25/13 10:34 AM
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Joined: Jun 2003
Posts: 52,972
Romeo MI
MR_P_BODY
Master
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Master
Joined: Jun 2003
Posts: 52,972
Romeo MI
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Quote:
Quote:
Couldnt stand it rainy night had to play with scales some more. This time we set torsion bars first with caltracs backed way off then slow adjusted the caltrac bars in & set extra battery in rear corner. Here what we ended up with.
Left Front 785 Right Front 767
Left Rear 754 Right Rear 776
Front 50.36% Rear 49.64% total weight with driver & extra optima 3083 lbs
I likey it a lot  That should work real well, I was told years ago by a very sucessful modified racer to try for 30 lbs more preload weight on the right rear versus the left rear Time to go try it Let us know how it does
There isnt any set number for the RR weight but 30#
is in the ball park... as engine torque goes up you
will tend to add more pre-load... that is what counter
acts the torque.. some dont understand that the axle
is trying to roll around the drive shaft... the right
side is going UP and is giving the LR tire more bite
which drives the car to the right
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