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Question on my 4 link should the lower bar and pan hard bar be leavel at ride height? Aslo what angle should the upper bar be in?

I also noticed I went with a shorter tire went from a 33" to a 31" and I had to adjust the pan hard bar to move the rear end over to the right 3/4".

The car is used on the street mainly

thanks
 

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I'm not a mechanical engineer, but the position of the four link bars determines the IC. I make my four link adjustments based on where I want the IC location, which is based on track conditions, my launch RPMs, etc. If you are primarily running your car on the street, then it doesn't matter all that much - you might get more responses from others who run four links on the street in the Steering, Suspension and Chassis forum.

As far as a panhard bar, when setting up this type of rearend centering device for customers, I've experienced the least amount of side-to-side movement if the bar is parallel to the ground at ride height.
 

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Bottom bar should be angled pointing down towards the front of the car just a little. If its up, it will push your suspension up taking the weight off the rear wheels (bad) If its too far down it will squat too much . put 2 jacks on your car on each side...wherever the car balances (center) and then about a foot up from the frame, have the top one pointing towards it (i think) Usually right about where your shifter is. I havnt messed with my top bar much. Bottom one I have. I do know that if the bottom bar is level or pointing up my car floats all over the track. And pointing down a bit it squats and hooks on the street like a mo fo.
 

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Question on my 4 link should the lower bar and pan hard bar be leavel at ride height? Aslo what angle should the upper bar be in?

I also noticed I went with a shorter tire went from a 33" to a 31" and I had to adjust the pan hard bar to move the rear end over to the right 3/4".

The car is used on the street mainly

thanks
for 4-link a good guide line is:
street = close to parrallel for good ride, handling & less roll steer

strip = an instant center ( where the 2 links project in front of the rear end )
of around 36-54", with a height off the ground of 4" to 10"
is VERY general ball park.....a more exact point would depend on
on the combination you are working with.. as Vin63 said..

HP
torque
launch rpm
trans type
foot brake or trans brake or clutch
tire size
tire type
type of racing
type of Christmas tree (4/10 vs 5/10)
weight distribution
availalble weight transfer
etc....

Finally, the bottom bar being level thing (4-link OR ladder bar ) is really a very general guide line... unless a few of the above variables are accounted for, that guide line is almost too general to be usefull.

also... that car should have a track locator.. not a panhard bar...3/4" of an inch is alot of movement for 1" of ride height change
 

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Finally, the bottom bar being level thing (4-link OR ladder bar ) is really a very general guide line... unless a few of the above variables are accounted for, that guide line is almost too general to be usefull.

also... that car should have a track locator.. not a panhard bar...3/4" of an inch is alot of movement for 1" of ride height change
A panhard bar IS a track locator, there are different types of track locators that is one of them.
-diagonal link
-panhard
-wishbone
are all track locators.
Pan hard is more ideal for cornering...but will work fine.. lots of drag cars have them.


And I used to think having the bottom bar level was a good starting point also....NO. I have a friend who has a chassis shop, he builds all sorts of cars, 6 sec ones, And hes a racer himself. He went over it all with me and if you think about it, it makes sense. The bottom bar drives where the car is going up/down in a forward way. Lifting the rear up unloads the tires (dangerous). Loading it provides traction. Definately want the tires loaded on the street.
 

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A panhard bar IS a track locator, there are different types of track locators that is one of them.
-diagonal link
-panhard
-wishbone
are all track locators.
Pan hard is more ideal for cornering...but will work fine.. lots of drag cars have them.
Sorry for the confusion.. we use the term Track locator & diagonal link in both our catalogs & tech forums as the same.

A panhard may certainly work fine in some applicatios, but if 40buicks rear is moving 3/4" by lowering the car 1".. I don't think that's working very good .
 

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Discussion Starter #7
4 link

Actually the tire size is 2" overall so 1" lower but I did put air ride on and the struts are a bit shorter maybe overall 3 to 4"

Is it true if I jack the car up the rear end will move to the left and when its all the way down move to the right?
 

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Is it true if I jack the car up the rear end will move to the left and when its all the way down move to the right?
with a panhard bar.. yes.. it will move ..the shorter the bar , the more it moves.
If the car is narrowed Pro Street, especially with air ride.. it should not have a panhard bar.... or it will move side to side as the rear goes up & down.
 

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Is it true if I jack the car up the rear end will move to the left and when its all the way down move to the right?
I always approach using a trackbar, panhard bar, etc. type of rearend centering device as the radius of a circle. As the bar moves up or down, it will follow the arch of the circle it creates - so it depends on at what point the bar is in its vertical travel. As an engineer, you should be able to plot that arch based on the length of the panhard bar and make your measurements. Or, unbolt the bar at the rearend housing and move it up and down - you can drop a plumb line at each increment of vertical travel and measure the horizontal distance change. The shorter the bar, as Mike noted, the smaller the arch, which results in more horizontal movement per vertical distance the bar travels.
 

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Dave Morgan has stepped up his schedule of seminars around the country...a bargain deal at $85 and now has a two day deal at some locations. I'm hitting the one in Colorado Springs on the 17th & 18th of this month. If anyone wants his contact info I can provide it, or just Google it.
 
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