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Author Topic:   Scale help
RACEINMUD
Dirt Freak

Total posts: 323
posted May 05, 2003 12:32 PM  
First run last Sat. Loose in (bad)on 1/4 mile semi bank dirt. Track dry slick. Going to scale car the week. 72 buick 4/dr skylark needing to be min 3200lbs. 1100 lf 1250 rf 225 lr 200 rr. 225/70/15 rf on 8in w/ 2in offset . 215/70/15 lf on 7 in 3 1/2 offset. 205/70/15 lr 8 in w 2 in offset. 215/75/15 rr on 7 in 3 1/2 off. Please let me know what you think corners should weight and what tire press. would be good starting point. Thanks! Race

rico 08
Dirt Forum Champ
Total posts: 1139
posted May 05, 2003 01:41 PM  
Looks like you have way too much tire stagger on the rear,try to keep the rear's close on size.

RACEINMUD
Dirt Freak

Total posts: 323
posted May 07, 2003 09:40 AM  
Ok, scaled car, this is what I have: LR 576 RR 792 LF 1000 RF 648. Where would you add weight to get my % right? Thanks. Race

flywheel
Dirt Full Roller

Total posts: 28
posted May 07, 2003 11:40 AM  
You have to get the weight down on the left front or your gonna be adding 500 lbs or better to get close. lower the left front frame height or raise the right front frame height. Cause your WAY off. Definately explains a LOOSE condition. Maybe just maybe you can put a smaller(lots) tire on the left front to help some.

twleach2
Dirt Full Roller

Total posts: 53
posted May 07, 2003 11:54 AM  
I would have to agree with flywheel. If the wieghts you listed are correct, you have 40% cross and 45 % rear. What you should have is 51% cross with at least 50% rear. Make all your tires the same and rescale the car. Use your tire sizes to get the scale percentages you need. Once the car goes into the corners, then change stagger to help with exit if needed. I actually run more air pressure (increase in tire radius) in my LR to add a little negative stagger.

Eljojo
Dirt Forum Champ
Total posts: 968
posted May 07, 2003 04:13 PM  
You'd better make that right front spring a little longer! Put a shim under it up in the pocket. Then throw yourself some lead in the trunk! Mine works best at 49% cross and 52.5 rear. I have a shipload of lead in it to get it that to that rear % but it really grabs up the track out of the corner. Load up the LEFT REAR of the trunk way back by the bumper--forget about that "pendulem " BS about having the weight behind the axle.

RACEINMUD
Dirt Freak

Total posts: 323
posted May 07, 2003 04:53 PM  
Eljojo, I have 3in spacers on the 9 1/2 springs. Should I just cut the LF down a couple of inches? Thanks.

Eljojo
Dirt Forum Champ
Total posts: 968
posted May 07, 2003 08:27 PM  
You got to remember that your springs are rated 1100 and 1250 in the front. If you took a half inch off the lf wouldn't that effectivly be half the rate of the spring? ...so -550 lbs off the left which would put a half inch more on the right front spring or 625lbs....follow me? You better be working with quarters of inches! Watch the ride heights! Work with all four corners. Try to get the right side up an inch over the left and the rear the same as the right--or more. Ya want the car to tilt when you're into the turn / tilt back to and a little past level. Think about it. If the shocks travel three inches and the car is level you have changed the car past that whole amount,but if it wer tilted an inch to begin with you've shifted the left side weight without upsetting the whole car.

RACEINMUD
Dirt Freak

Total posts: 323
posted May 09, 2003 09:33 AM  
OK, added 370 lbs to lf rear and got my back to 52% but cross stayed at 42%. Put on my smallest rf tire I have 205/50/15. LF still saye at a 1000lbs. Is my only option to add more spacer to RF? Can I got to a 255/70/15 (87 roll)for any help? Thanks! Race

twleach2
Dirt Full Roller

Total posts: 53
posted May 09, 2003 11:38 AM  
Do not put the smallest tire on the right front. The right front should have the tallest tire. This will create the same effect as adding more spring spacer. Another thing I noticed earlier this season is that moving weight around in the trunk with the cars on the scales, is that with a stiffer left rear spring putting weight on the right rear side increased my cross weight. By putting more weight on the left rear the cross weight went down. My springs were 900 rf 800 lf 250 (13 inch pigtail both ends) lR and stock (13 inch unsure of spring rate) on RR.

RACEINMUD
Dirt Freak

Total posts: 323
posted May 09, 2003 11:46 AM  
I ment LF on the small tire. SInce the car is so loose on entry and exit doesnt that mean my rr is to heavy, so is it OK to add more to rr to get my cross %. Thanks for the help! 1 man show with my wife and 4 little helpers. They like to "paint" the car while I'm at work.

Eljojo
Dirt Forum Champ
Total posts: 968
posted May 09, 2003 04:12 PM  
Lookit Mud, Cut yourseld a "donut" spacer out of 3/4" plywood and put it on top of the right front spring. That's simple as pie...then give me your scale numbers and your frame heights (with you- or your weight)in the car. I'll try to help you figure this out.

OppendikeRacing29
Dirt Maniac

Total posts: 135
posted May 15, 2003 02:11 PM  
Also when u cut that right front spacer you could cut one for the left rear, that wont mess up your ride heights to much and its the way you should put in cross weight. it will be like putting 4 turns in rf and 4 in lf and ride heights will be better then just jackin up the rf

NYhick
Dirt Maniac

Total posts: 130
posted May 18, 2003 10:11 PM  
Instead of running all those spacers you could just buy the right spring and forget the spacers. They make 12 and 11 inch springs that would eliminate the need for spacers, or at least 3 1/2 inches worth...

CrazyT
Dirt Forum Racer

Total posts: 79
posted June 30, 2005 07:38 PM  
Raceinmud i would like to know if you ever figured your car out, i have the same problem with mine. My car is fast the way it is but it just looks terrible on the scales. LF983 RF673 LR880 RR770 springs lf1250 rf1400 lr225 rr200 ride height are good. The car is really fast on entry and through the middle but lacks forward bite coming off.

Thanks for any help

mfcracing
Dirt Full Roller

Total posts: 30
posted July 01, 2005 06:38 AM  
quote:
Originally posted by CrazyT:
The car is really fast on entry and through the middle but lacks forward bite coming off.

Thanks for any help


What's the pinion angle on your rear-end??? A 4 to 5* angle will really help coming out of the corners (TRACTION)....


CrazyT
Dirt Forum Racer

Total posts: 79
posted July 01, 2005 10:00 AM  
I dont remember what the pinion angle is but i changed it last year and you are right that helped a ton with traction.

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