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Discussion Starter #1
http://www.youtube.com/watch?feature...&v=BLCtVYBWyns

I've been chasing this problem for over a year. But here goes..

Suspension consists of BMR solid uppers mounted to spercial inserts on the axle, UPR lowers, maximum MS anti-roll, 4 cyl springs, and CE 50/50 shocks.

When the car is staged its ass end wants to raise. Like while being brake tq'd. If I just apply the Tbrake and build boost of the line.. as soon as I release the button the back pops up and stays up the whole way down the track.

My problem is i'm trying to keep the rear of the car down and dont know whats wrong causing this condition.

Above run is a 1.44 60 ft on 275/60 MT DR's. Its consistent but I want it to look like everyone elses car.

Pinion angle was set at -3. While browsing the net it appears -1.5 would maybe be better.. but would pinion angle cause this reaction? Bad rear shocks? motor/trans mounting angle? I'm stumped.. anyone ever had this?
 

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what angle is your lower control arm at? It would seem your IC is high to cause that condition....
 

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Discussion Starter #3
what angle is your lower control arm at? It would seem your IC is high to cause that condition....
George.. long time :) Thanks for responding.

LCA are parallel to ground. Using factory stock mounting points. The uppers I have the Wild Rides box that allows multiple point.

I guess I need to read up on instant center.. If you can think of any info i'm all ears.

Julio
 

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You need to lower your car. the control arms going up hill from rear end to car is pushing the car up when load is placed on it.

A good starting point for me has always been to get the control arm level with the ground and go from there. this is where adjustable coilover are nice.



Make sure the anti roll bar is neutralized with the driver in the car and everything at full race weight just like u were about to make a pass.

Take that sway bar off its working against ur antiroll.. while ur antiroll will ofcorse win.. its still not helping.

Your close enough on ur pinion angle to be fine.. at rest but when ur car puts on its lift kit its way WAY off.. Once you get the car to quit pushing itself up and start pushing itself forward.. the pinion wont be changing itself so much.

Pinion angle setting varies by car.. but 1.5-4 is normal.. just depends on how much your suspension moves. The goal is for it to be a 0* going down the track.. so if your rear moves 8*.. move it to -8*.. the lest drag possible the better.. pinion angle is just drag on the u joint..
 

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Oh didnt know u had the multiple location boxes up top.. you got them in too low of hole id guess. Move them up and see what happens.. Id go one hole lower than right where the stocks were and try it.

Deff read up on the instant center stuff.. The more you understand about angles and how suspension works.. the better off you'll be.

Right now you've got ur instant center set to prob about the backseat.. start with gettin it to about the firewall and adjust from there.. if it comes up to high.. bring it back some.. if it doesnt transfer enough weight.. bring it forward some..
 

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Discussion Starter #7
The bar under the axle is the anti-roll. There is no sway bar on the car front or back.

I'll need to load 300 lbs of dirt :eek: into the drivers seat and make sure there is no tension on the antiroll. :)

The rear of the car is already on top of the tires.. It has the 4 cyl notch springs.. Wouldnt bringing the body down create more issues with instant center? As the front LCA mounting point moves down?

Thanks for the replies. Just trying to learn.. Does that article that indicates front mounting point should be .375-1.5 higher than rear end lca mounting point lead true then?

Could bad rear shocks do this?
 

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Discussion Starter #9
Oh didnt know u had the multiple location boxes up top.. you got them in too low of hole id guess. Move them up and see what happens.. Id go one hole lower than right where the stocks were and try it.

Deff read up on the instant center stuff.. The more you understand about angles and how suspension works.. the better off you'll be.

Right now you've got ur instant center set to prob about the backseat.. start with gettin it to about the firewall and adjust from there.. if it comes up to high.. bring it back some.. if it doesnt transfer enough weight.. bring it forward some..
They are set in the lowest hole, last I remember. Need to read up on instant center and get educated. If you have any links.. can you post them..

Thanks.. i've posted this question on multiple sites the last few days and its been crickets. Thanks so much for taking the time..

Not that my goal is to be any faster, but to make the suspension do what its suppossed to do without tearing up parts from being misaligned under power.
 

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Gotcha.. fortunately they are not non-adjustables..

In 24 hours i've learned a lot. Now put it to practice. Funny how much stuff we take for granted.
Give Rob Wells a call at Ford Speed, he"ll get you right. He will scale the car and make adjustments
 

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You've gotten alot of good advice here, now apply it to the car and see it work.... Sorry I didn't reply earlier, we are moving the shop to our new location, so I haven't had alot of web time.
 
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