adding lead and where?

[bluemod]

I need to add 40 pounds to car the drive was 260 and now 220 so where is the best place to place this weight to keep the %s the same. Under driver seat or high on left side where do i need to place this?

[LITE-INN]

same place you lost it lol

[bluemod]

same place you lost it lol

Better not never get in the car now. Wheres the best place to mount the weight.

[Racer111]

between driver and drive shaft.thats a neutral area.

[istock11m]

Around the drive shaft loop or in that area.

[autoshop]

high for wet track low for dry

[bluemod]

thanks for pointing me in the direction i needed ill be puting it on the scales soon.

[Confused?]

Find the center of gravity for the car and mount it as close to that as possible. This won't change the precentages.Depending on the rear and left side numbers, it may be mounted around the dash bar, above the transmission.

[juice87]

high for wet track low for dry

thats backwards.

[drtrkr244]

Mount it beside the driver, to his right.That will be as close to the center of gravity, for a dirt car,as you can get.

[DaveBauerSS6]

Put the car on scales, note the rear %, and the left side %. Get a 20# chunk, lay it on the roof move the weight front to rear until the rear % is the same as you started. Then move it right to left until the left is the same. That is the CG, and will have the least amount of change to the car. Vertical is something to tune with.

[speedbuggy]

To my knowledge, Dave is correct.

The only reason you have to do the raising of the car is to be able to calculate the true CoG height. Most just say your CoG is about the same height as the camshaft and it's close enough.

Another way to do it is take the wheelbase and track of the car. Let's say the wheelbase is 100 inches, and the track is 60 inches (just to make the numbers round). If your percentages say you have 55% left and 58% rear, then your CoG is (100%-55%) x 60 = 27 inches from the center of the left-side track and (100%-58%) x 100 = 42 inches from the rear axle centerline.

Dave's method should give the same result and a lot less math...

[speedbuggy]

thats backwards.

Agree....that sounds backwards to me, too.

[DaveBauerSS6]

Agree....that sounds backwards to me, too.

Agreed, High ballast for slow , slick tracks. Low ballast for tacky tracks.

[DaveBauerSS6]

That isnt how you locate CG. That would be neutral to left and rear but nothing to do with CG.

CG can be calculated on scales, mine came with directions which said something about raising the rear of the car 14 inches on the scales etc. Ive never done it.

When you add lead to the CG, the rear and left % will not change. That proves its in the center of CG. Longacre has that procedure for lifting the car on scales to find the CG height.

http://www.longacreracing.com/articles/art.asp?ARTID=22