project triangulated 4-link

i'm trying to use this 4-link calculator and have a few questions. here's the link

not sure how to get these numbers, CoGX,CoGY. i know how to get my CoG Height but don't know how to measure for the other 2.

and the links X, Y and Z.
X says foward from rear axle centerline? from centerline foward to what?

Y says 1/2 horizontal seperation at frame. does that mean if links at frame were 6" apart my number would be 3"? half seperation.

Z is height from ground. so is that the distance to center of link bar? or to the top or bottom.

got a couple more but i'll wait. this should get me started.
thanks.

link not found

how about this.

it's in the first paragraph second link.

i finally found a link to all the anwsers to my questions. there's a couple center of gravity measurements i can't do because i don't have a scale. wondering if someone could help me out. the truck is a 91 b2600 std cab. i think most std cabs should be about the same weight. i need to find out total weight of truck if anyone knows, weight of passenger side of truck, weight of front 1/2 of truck.

as for the center of gravity measurment, i can take that off the top of the bellhousing? or can i use the bolt on the side of the housing so i can measure off the ground to it? going to be kind of hard to get a measurement to the top. ride height is 4" if it matters.

i hope i'm makeing sence. i've never done this before and trying to set up this 4-link as right as i can. all this is coming of sites i've read. if it looks like i'm going in the wrong direction please let me know.

thanks.

someone has to have something to say??

I got your PM. Really, don't worry about the COG height. I found that it is'nt too important to know when building the 4-link. Only because our trucks are so low and there is'nt much to them except drag it on a road...

Put your COG height at 20" high and in the middle of the truck. The weight you add on to the back is going to about equalize it...

BTW, give these links a read over...

toshay my friend

thanks again!! that will get me going. i want to take all these measurements on my existing 4-link and see if it's in right or not. i'm kind of thinking it's not. when i sat the back of the truck on the ground axle would rotate up quite a bit and bag was really smashed on it's side.

y didnt ya leave it like this

i wish i could have left it that way, probably would have been done by now. i had a guy start the truck for me and i think he didn't know exactly what he was doing. but he claimed he's done 4-links before. all he got done was the 4-link, and shaved one door handle then he moved.
well, the spider web on the back he should have made the middle tube more arched because the fitting for the air line was hitting it, so i cut the spider web off. then when i tried lay the truck out the axle was hitting bottom of C notch and the frame was about 1/2 off the ground at the crossmember and thats with 17's and i want to put 20's on the back, so i fixed the C notches for 20's. then i got the probablem of the axle rolling up when i set the back down. plus i'm wasn't gettin very much lift.
so i figured i would check his setup and that 4-link calculator and see what happens plus it would be good practice for me. i'll probably gusset lower bars and put the bags on them.
i've read through all those links a few times and bought the book Chassis Engineering by Herb Adams and read through that to. it's kind of weird reading about jacked up jeeps with 4-links compared to little mini trucks. reading there tec guides and comparing it to my truck. but i guess the concept is the same. what makes this project kind of diffcult is that i live in a small town on the coast with no one around to ask. i've never even seen a bagged truck that can drag frame around here. all my learning is comming from the internet and the people on this site which i appreciate a lot. my finger hurts from typing. i'm one of those one finger typers. LOL.