Baseline suspension pro upper control kit

[good2win22]

Finished the install this evening along with centering the rear end and setting pinion angle to 2.5 degrees.  Here's what the calculator came up with.  I took a wild ass guess with the weight numbers as I haven't been to a scale yet.  Do these numbers look somewhere in the ballpark of making a decent launch? Questions for you suspension smart guys,  after centering the rear end, I could only get 2.5 degrees on the pinion angle as one of the upper control arms was bottomed out.  How can I fix this?

[Scoobum]

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[Charlief1]

First off, are you sure on the tire height Jason. I think you're closer to a 25.4" height. Your car also weighs more than 3200 lbs with you in it. Take it to a truck stop with a scale and drive the front wheels on, get a weight, do it with all 4, and then just the back wheels. You should be closer to 3400 or 3600. A stripped bare T will be in the 33oo+ range. Did you take the measurements with the stock arms first so you can calculate original IC location?

[Steve Wood]

I think 2.5 degs, if Negative, is perfectly adequate for a four link car with an automatic transmission.  After all, the pinion can only rise the amount that the bushing deflection will allow...that's the reason pinion snubbers are not needed on a coil spring car with a four link suspension.

At least your ic is under the car instead of out in front of the front tires.  Might be nice to have it a bit further back but most G-bodies seem to hook pretty well in this area.  It's close to the thrust line so the car should launch pretty much in a parallel line without the front end wasting motion going up instead of forward.

Pretty sure your weights are off quite a bit.  I think one of my cars was more like 2200 on the front and 1500 on the back but I may be mixing cars up.

[motorhead]

You can improve the pinion angle with longer lower control arms or offset bushings.

[good2win22]

I did not take measurements before Charlie. Add that to the list of things I've forgotten lately.  Adjusted the tire numbers and weight but didn't make much of a difference on the anti-squat.  Need to get to a scale to see what she weighs.  Offset bushing.... I was thinking of bringing the rear end ride height down another 1/2 to 1 inch.  Right now she is sitting about 1/2 to 3/4 inch higher than the front

[Charlief1]

If the IC is correct then you shouldn't have to worry about the height in the rear. The IC correction will actually help you transfer the weight better. The off set bushings are a real PITA to set properly, believe me. Since you've also got poly bushings in the lowers you should be about 1.5 degrees on the pinion angle. Rubber ones move more.

[motorhead]

No one asked for the easy answer. But, there are lots of adjustable and double-adjustable LCAs out there these days.

I do know that my car performs well for having just a set of single-adjustable uppers and poly-U/roto-joint lowers - 1.7 60' on 315/35R17 drag radial off the footbrake (the transbrake will over-power the tires so it is never used).

[Scoobum]

With everything being equal...how much torque does it take to get one of these bricks to go into the mid 1.5's for a short time?

[Charlief1]

No one asked for the easy answer. But, there are lots of adjustable and double-adjustable LCAs out there these days.

While that may be true, these arms aren't stock length or even usable in the stock location. These are designed to bolt to a bracket that mounts where the upper arm mounts on the frame. Then the arms attach.

[Steve Wood]

I guessed that was one of Kevin's set ups from the diagram...I really like the idea

[Charlief1]

It is Steve. That's how I came up with the mods I made to my "new" frame.

[good2win22]

Called the local scrap yard and they have a scale.  3 weighings later and I have some usable numbers and it only cost 5 bucks!  Anyway, total weight with me in the car and a half a bag of gas is 3560. Front is 2060 and rear is 1500.  Motörhead, I have stock length lower control arms from UMI with poly bushings.  Here are the new numbers

[motorhead]

With everything being equal...how much torque does it take to get one of these bricks to go into the mid 1.5's for a short time?

Depends a lot on weight, gearing, and torque multiplication in the torque converter.  See the attachment (pardon the Chevy... it was a custom power curve).

[Scoobum]

Thanks...need my reading glasses. Gettin' old ya' know.