4 link 68 camaro

[camarotale]

must be 1000 camaros exact like mine just looking for a very very very close starting point.. big block, 2700 pounds empty.looking for a close intersect point.tubbed narrowed , 9 inch rear,when reading books they go on and on, I know there is a fine line of perfect, but I cant help but think there has to be an extremely close starting point of intersect. With 4 link, you should be able to set car on ground, pull some strings and see if they cross under the seat or behind the front fender or where should they be... any help would be appreciated..

[sp2816]

It really depends on how much horsepower your big block has, along with how high the crankshaft centerline is located, along with ride height of the car to where the starting point is. As with my car (a tube chassis Monte with 108" wheelbase and crankshaft centerline at 12" with about 800-850hp), a rough rule of thumb is to start with the bottom bar almost level but down a little in the front and then have the intersect point at about 45-50" out.

I take all of the measurements and plot it on the floor to calculate which hole in the top front will give me this IC. I make sure that the rear end is square in the car and then the top left bar is then adjusted to give the correct pinion angle (about 1-2 degrees) and then the top right bar is adjusted to give your preload. It is best to start at 0 preload and then if the car goes to the left you will need to lengthen the top right bar and if it moves to the right then that bar will need to be shortened just a few flats at a time.

JMHO

Bill

[camarotale]

thank you for the reply, my camaro has 724 hp. at the fly wheel, bottom bar is like you say, top bar pointed down , with an intersect point about 24 inches in front of center line of rear end,car hooks good as long as I melt the tires in the burn out box, also cant help but notice I have to burn longer than others with the same tires before they start to smoke, leterly have to abuse the thing. I have a pinion angle of 2 degrees, and the car goes straight as an arrow , not running the 60 foot of others with less power and more weight. 1.42 - 60 foot , trans brake 4500 rpm, 2 speed, 486 gears..32 x 15 x15. tires -- hoosier .. just a little back ground to see if you agree the 60 foot is slow..

[sp2816]

Your statement says 24" in front of the rear end centerline, but do you mean 42" because you would almost have to be in the same holes with 21" 4-link bars? If it is indeed about 42" then that is about right for the HP.

What is your ET and your MPH and that will help decide if the 60ft is slow?

It sounds like you might have some issues with the front suspension not letting it work and that is causing you to have to beat on the rear tires. What front springs do you have? On my car the 60fts were slow until I put some softer front springs on it (went from 400lb/in to 300lb/in on my front struts). I used to have a Nova with ladder bars with the engine moved back and stock front suspension, that I couldn't get it to hook or pull the front wheels until I changed the front springs over to the Moroso trick front springs.

Bill Mitchell

[camarotale]

my intersect point is very cloce to 24 inches, my et in the eigth is 6.18 and the quater is 9.80 at 138 mph. Thanks

[sp2816]

With your MPH, it looks like your 60ft times should be in the mid to low 1.3's, so yes it is a little slow. You should probably move the IC out to at least 42", because right now you are even shorter than what 32" ladder bars would give you. With your IC being so short, you are not getting very much weight transfer which is really hurting you.

[itsabird]

could you pull one of the slicks off? and post a pic of the bracketry.

[camarotale]

I appreciate the feed back and feel good about the things im hearing. I am putting the tranny back in this weekend, then I will put jacks under at ride height, and pull a slick and give a accurate ic and try to attach a photo, be back to you in a couple days, thanks

[sp2816]

I appreciate the feed back and feel good about the things im hearing. I am putting the tranny back in this weekend, then I will put jacks under at ride height, and pull a slick and give a accurate ic and try to attach a photo, be back to you in a couple days, thanks

Along with the picture, if you give us some measurements we can come close to calculating your IC, too.

With the car on the ground, measure from the ground (if you do this up on jack stands be sure that the car is level and to give/or subtract the distance from the ground up to the bottom of the slick) up to the center of the bottom bolt of the 4-link bar at the rear end housing, then from the ground up to the center of the rear end housing, and finally from the ground up to the center of the bolt for the top 4-link bar at the rear end housing. If you can get a measurement of how far forward from the centerline of the rear end housing that the top hole is that would be good.

Next measure at the front brackets, and give the measurement from the ground up to the center of the bolt for the bottom 4-link bar and then from the ground up to the center of the bolt of the top 4-link bars. We then will need the length of the top and bottom 4-link bars from the center of the bolt to the center of the bolt.

The final measurement would be the distance from the center of one hole to the center of the next hole in your front 4-link brackets.

Thanks,
Bill

[camarotale]

heres some measurments, 15.125 center of axle to floor,10.625 back bottom bolt to floor--back top bar bolt center to floor is 18.5 -- front bottom bolt to floor is9.875 --top front is 15.375,--- top bolt to axel center is 1.125 -- top bar is 19.625 - bottom bar is 20.375 also balanced the car with me in it and it balances at 63 inches from center of rear axel. thanks Eric

[camarotale]

how do attach photos

[DirkaDirka]

You have to put them on an photosharing website. i use photobucket. Then you would have ot take the url for ht epic from there and copy and paste it on here.

[camarotale]

http://s879.photobucket.com/albums/ab357/zin4ny/
hope this is right

[DirkaDirka]

Here ya go man......

http://i879.photobucket.com/albums/ab357/zin4ny/donation8609006.jpg

http://i879.photobucket.com/albums/ab357/zin4ny/donation8609007.jpg

http://i879.photobucket.com/albums/ab357/zin4ny/donation8609008.jpg

[camarotale]

hey, thanks

[sp2816]

Those are good measurements and an excellent picture to let us see your setup. When I do the calculations, your IC is actually about 61" out and about 8 1/4" up. The IC is the intersect point of the two bars if you continue them both out in a straight line forward. So that along with having the bars in the holes closest to the rear end housing is what is causing your less than favorable 60fts.

If you move the top bar up 1 hole in the rear that would move your IC to about 49" and about 8 3/4" up. But it would be best if you could also lower the rear of the car down about 1 1/2" to 2" and then move the bottom bar down one hole at the rear end housing. This would move the IC out to about 43", but would give a little bit more leverage from the rear end housing onto the chassis.

That would be the adjustments that I would do first and if I wanted to move the IC back out to about 49", I would then move the top bar up one hole in the front.

Bill Mitchell

[camarotale]

Now that I have your idea of plotting on the floor, I tried it and come close to your measurments. Mine were 8.250 up and intersect at 65. Now I wonder if my cg is at 63 inches from center of rear axel, where does this come in to the equation when trying to establish the point of the intersect and the height off the floor that one would want. I see numbers of 49 or 43 or46 etc, in some different things I read, also when finding my current intersect of about 61 to 65 it looks like I am reaching to far forward, so what is this probably making my camaro do that it shouldnt . thanks

[sp2816]

Yes, your IC is out way too far for the HP that the car is making at this time. Also, the spread at the rear of the 4-link bars is too close. One way to think about this, is try to lift a sledgehammer out horizontal with your elbows together vs with your elbows apart. When your elbows are farther apart, you can put more leverage on the handle to raise the head. Now lengthen where your grip is at on the handle and shorten where your grip is at. When you get closer to the head of the sledgehammer, you can lift it easier. This is similar forces that the rear end is trying to transmit through the IC.

The CG of the car is at 63" forward (as you balanced) and is roughly located at about the height of the camshaft. If you plot from this point to the bottom of your rear slicks this is your squat/anti-squat line. If when you plot out your IC from the rear end and it falls below this line, the car body will try to squat down over the rear tires. If the IC falls on this line, then the car will not try to squat or raise in the rear. If the IC is above this line, then the car will raise up in the rear. I have my car set up to squat a little in the rear, so the IC is below the squat/anti-squat line.

I use this for an initial start, but I really adjust to what the car wants. Every car is different, so you will have to adjust on the bars and the shock settings, and even possibly the springs. The rear springs only need to be stout enough to hold your car up to the correct height on your shocks. My shocks are supposed to be set to a compressed ride height of about 14.5". So you adjust the spanners on the coil springs to get to this height and then you adjust the shock mounts to get the ride height on the car. This allows for the shock to be close to the middle of its range to allow for compression and rebound.

JMO
Bill Mitchell

[camarotale]

Im finally learning what some of the mechanics are , when toying with the 4 link. I thankyou for the time you spent helping me. I live in ND. so wont be able to try this untill the end of may. I will make the adjustments and give it a whirl. Bill, thanks again. Eric