I've been curious for a while about the effect a 2" rear drop has on L weight distribution, so I hauled out the old trig books and came up with the below:

1: The angle of drop is figured to be about 57 minutes (about a degree) by dividing the drop by the wheelbase, assuming the drop is downward toward the right angle in a right triangle formed by the nose of the truck (most acute angle), the tail of the truck (least acute angle) and the final position of the rear axle after drop (the right angle).

2. Assuming that the weight of the truck was uniformly distributed throughout it's length,
the change in weight distribution to the rear axle attributed to a drop would be

sin 57' * 4670/2 = 38 lbs.

However, the %^&* truck is not weighted uniformly throughout its length; it is 57% front and 43% rear at the angle in #1 above. Based on that, the starting weight on the rear axle is about 2008 lbs. An approximation that gets near the actual weight transfer due to a 2" drop is therefor sin57' * 2008 = 33.5 lbs. The rear axle weight (unsprung) can't be counted as part of the 2008 lbs, so it is likely a mite less than 33.5 lbs, but let's stick with 33.5 for now.

33.5 lbs is about .7% of 4670, so a 2" drop would change the weight distribution from 57/43 to -about- 56.3/43.7. Any gurus out there, now is the time to complain if this doesn't add up.

What is more interesting to me on about this is the potential weight distribution improvement for dumping the spare tire and moving the battery to the spare tire area, this would be a clear 1% (battery weighs about 50 lbs.) shift from front to rear. That combined with the 2" drop is nearly 2% change, and that has -got- to be noticeable in handling and at launch time.

-tvw


[This message has been edited by tvw (edited 03-31-2000).]

 

asfeasf

 

I wouldn't add sandbags over the axle... every hundred pounds you add is about .1 on your quarter mile time.. kinda of counter productive if you ask me.



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Injection is nice, but I'd rather be blown. 99 Lightning, the best of both worlds!

 

Not having traction hurts your ET pretty bad too. I think that the payoff for either would be equal in the end result.

Definately a good thing moving weight to the rear though. I think I'll leave the trig to you guys. hehe

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JB
JDBURKE@ball.com
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• 91 GMC Syclone (Red)
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"Still waiting for lightning to strike"

 

Nice job tvw
I will let you know how the extra weight effect the Launch / ET. I believe the truck can handle the load, its just getting it started thats such a bummer right now. To much power for the weight and tires. Gone try softer shocks both front and rear to see if the weight will transfer first then start adding sand.

 

One thing on the weight tranfer though is that by lowering the truck you move the center of gravity closer to the axles. Therefore, I think you'd have less of a transfer by lowering it because the truck's weight center is more in-line with the axle doing the pushing. A good weight transfer seems like it would rely on the center being higher than the axle providing a lift-and-sit kind of motion.