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Author Topic:   Crazy Scaling Numbers
WesternAuto17
Member
posted May 30, 2002 10:21 AM
Here's the deal - I just scaled a brand new metric car and got some, in my opinion, weird numbers.

The only weight I added is 60lb centered, 6" behind the axle, 30lb behind the LR and 25lb in front of the LR. The ride heights are set at 9" in the LR, 8" at the RR and 8" in the front. Springs are 900 LF, 1100 RF, 175 LR and 225 RR. The total weight of the car was 2770 which is 230 lb light, but what I expected. Rear percentage is 44% which is light, but was no surprise. I'm adding the other 230lb this evening.

The weird thing is the RR was 80lb heavier than the left. The little weight I've added is on the left, I sit on the left and the cell is shifted to the left. Why am I heavier on the right? Is the jack bolt being cranked up in the RR causing this? When I run the numbers for the total right side weight, I get 53% on the left anyway.

I'm 90% sure the scales are reliable and they're all within 1/4" of ech other.

racer17j
Member
posted May 30, 2002 11:48 AM
try to switch your rear springs around i've run a heavier on the right before but thats a pretty big split as for your scales they need to be with in a .00000000000000" of each other if they are not all level with each other they will not work right if you have to get a 2x4 of something that you can run from scale to scale and get them all level with each other also how much fuel do you have in the car ?


hughes
Member
posted May 30, 2002 11:49 AM
Put the 225 in the left rear, and the 175 in RR. And you need probably a 1/2" of ride height difference in the front from the front right down to left.


WesternAuto17
Member
posted May 30, 2002 11:57 AM
I knew people would disagree with my rear spring set-up, but what I really want to know is if these numbers make sense given the springs. Do you run the stiffer LR to increase the cross weight?

I might try 175 on the RR with a 200 on the LR. I have (1) 175, (1) 225 and (2) 200's.

340duster
Member
posted May 30, 2002 01:38 PM
What is your cross weight? Sounds like your cross weight is less than 50%. That's why your RR is heavy and your left side is 53%. Keep in mind when adjusting weight jacks you are not physically moving any weight around in the car. So by cranking weight jacks your Rear%, Left%, will not change, only the cross% will change. So if you unscrew your RR jack ***** the weight in lbs (not%) will move to your RF and LR which will increase cross% , but not change anything other %'s


CLBaker25
Member
posted May 30, 2002 04:28 PM
First, you need to change rear springs. You need a 225 lr, 200 rr. I would prefer a 250 lr, but this is using springs you already have. Next, reset your ride heights. I set mine by measuring between the control arm and frame in the front, and between the top of the axle tube and the frame in the rear. To make this quick and simple, make you some measuring gauges out of bolts and nuts for the desired heights. Measure the front ride height at the front of lower control arm where the rubber stop bumper used to be. You did remove these, right? I set my cars at 2 3/4" rf, 2 1/2" lf, 4" rr. I don't worry about the left rear, because this is where I adjust to get the cross weight % I want. Is your total weight with you in the car? You need to scale the car just like is when you go on the track to race. Adding weight has little effect on cross weight, you adjust cross weight by the jack bolts. You change left side and rear weight %'s by physically adding weight to car and it's placement. You should also get your scales level to each other. Get your rear % up to 52-54%, left 52-54%, cross 49-50%. This is a starting point, track conditions and driver preference will determine the final settings you will need. If you have any questions, please feel free to call or e-mail me. http://www.coxracingchassis.50megs.com


o5racer
Member
posted June 02, 2002 10:06 PM
why is your left rear an inch higher than the rest?


WesternAuto17
Member
posted June 03, 2002 08:47 AM
owracer -

You built my chassis (#006), I'm very happy with the finished product. I'm having a little trouble getting a hold of the handeling, but otherwise, I'm happy.

I'm still fine tuning the ride heights and percentages so I'm not too surprised that she's not driving exactly perfect. The entrance and center of the turn is pretty good, I'm just having a tuff time getting off and getting good forward bite. I think part of the problem is the idiot behind the wheel. This car is so much faster than my old one, that I need a lot more brake entering the corner than I'm used to applying.

Also, I ran a 250 LR with the 225 RR and it helped somewhat.

owracer
Member
posted June 04, 2002 08:53 PM
Try the 200 lb spring in the RR. You won't have to rescale the car if you change springs, just readjust it back to what your ride heights were before you changed springs.If the track is getting pretty dry slick, don't run in stagger in the rear. If your having trouble being loose off the corner this will help to keep the rear end tucked in. I also change to a 2" offset wheel on the LR and put in a couple more rounds of bite in the LR.


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