Weight bias and c of g height - Lateral-g Forums

stonebreaker · #1 02-06-2008, 10:59 PM

Anyone know off the top of their heads what the front/rear weight bias is for a 91 S-10/Sonoma regular cab short bed?

Same for the height of the center of gravity?

I'm narrowing a caprice 8.5" rear end to fit under the truck, and since I'm going to have to fab up the suspension anyway, I figured a nice 3-link would be just the ticket for an autocross setup. I want to set the truck up with 100% antisquat, and to do that I need to know what the cg height is.

I know I can figure it out with scales and a jack, but I don't have a set of wheel scales and the truck currently does not run.

Thanks in advance,

stonebreaker · #2 02-24-2008, 07:05 PM

Well, since you guys don't seem to know anything, I guess it's up to me to update my own post. I found one guy who has weighed his truck, and he says the short bed regular cab truck is 42/58% front/rear weight bias.

Still haven't determined the height of the c of g, though.

ccracin · #3 02-24-2008, 09:14 PM

Quote:

Originally Posted by stonebreaker

Well, since you guys don't seem to know anything, I guess it's up to me to update my own post. I found one guy who has weighed his truck, and he says the short bed regular cab truck is 42/58% front/rear weight bias.

Still haven't determined the height of the c of g, though.

I think you got your numbers backwards. Without measuring, a good rule of thumb for cg is the height from the ground to the cam centerline.

stonebreaker · #4 02-24-2008, 10:20 PM

Quote:

Originally Posted by ccracin

I think you got your numbers backwards. Without measuring, a good rule of thumb for cg is the height from the ground to the cam centerline.

You're right, it's 58/42, not 42/58. As far as the cg height, I need it to be exact. I'm trying to design a 3-link for the truck, so I need to know the exact height of the cg in order to develop the correct amount of anti-squat.

ccracin · #5 02-25-2008, 11:14 AM

If you really want all these numbers exact, hook up with someone that has scales and start checking. You really need to do it after all the mods are done. The key to the build is giving yourself adjustability. This is key for the three link. I have run 3 links for years in stock cars. To me the way to get the 3 link angle or anti-squat correct is driving. Put in as much downward angle to the front as the truck will handle without hopping the rear end under hard braking. Our stock cars had about 15deg. Again, get in the ballpark on paper and give yourself room to move with your brackets. Then tune from there. JMO Goodluck!

stonebreaker · #6 02-25-2008, 12:25 PM

Quote:

Originally Posted by ccracin

If you really want all these numbers exact, hook up with someone that has scales and start checking. You really need to do it after all the mods are done. The key to the build is giving yourself adjustability. This is key for the three link. I have run 3 links for years in stock cars. To me the way to get the 3 link angle or anti-squat correct is driving. Put in as much downward angle to the front as the truck will handle without hopping the rear end under hard braking. Our stock cars had about 15deg. Again, get in the ballpark on paper and give yourself room to move with your brackets. Then tune from there. JMO Goodluck!

OK, when you say "downward angle to the front", do you mean having the front trailing arm link lower than the rear link? And is this for all three trailing arms, or just the bottom two? I'm trying to picture where the instant center would be...

ccracin · #7 02-25-2008, 04:05 PM

The 2 lower trailing arms on each side of the rear should be kept level when the truck is at ride height. The 3rd bar or the one mounted in the center on top of the rear is the one to angle down to the chassis.

ccracin · #8 02-25-2008, 04:06 PM

By the way, what does your screen name mean? Are you in the quarry bussiness?

stonebreaker · #9 02-25-2008, 06:21 PM

Quote:

Originally Posted by ccracin

By the way, what does your screen name mean? Are you in the quarry bussiness?

No, my last name is Stone, and I used to be a prison guard at the juvenile detention center in Manassas, VA. I got into a tight situation one time, and the way I convinced the inmates I was too tough to mess with was I slapped a cinderblock wall as hard as I could. Just through dumb luck, the cinderblock I hit broke - I knocked a hole in it - so they backed down. I took a couple of weeks off to let my hand heal up, and when I came back to work, all of a sudden I was Mr. Stonebreaker. I never had any trouble with the kids after that.

stonebreaker · #10 02-25-2008, 06:29 PM

Quote:

Originally Posted by ccracin

The 2 lower trailing arms on each side of the rear should be kept level when the truck is at ride height. The 3rd bar or the one mounted in the center on top of the rear is the one to angle down to the chassis.

Thanks, that's the same thing Dr Shope said. Always good to have independent confirmation.