Alignment calculators online?

[ACME SS]

I own and have used my Fastrax alignment tool to align several cars with great success. The biggest drawback however is that I can not watch the changes to both caster and camber as I make them and the 2 upper eccentrics to adjust both caster and camber is causing my brain to overheat. Is anyone aware of an online calculator in which you could input the position of the eccentrics and the resulting camber caster degrees and it would suggest changes? I don't suppose there is any monetary value for anyone to have developed this but its worth asking.
I replaced my stock control arms and strut rod with QA-1 parts and while I can get much more caster and camber adjustments out of the new parts, getting the caster and camber to BOTH be in the range is killing me.

 

[Bodyperson]

I own and have used my Fastrax alignment tool to align several cars with great success. The biggest drawback however is that I can not watch the changes to both caster and camber as I make them and the 2 upper eccentrics to adjust both caster and camber is causing my brain to overheat. Is anyone aware of an online calculator in which you could input the position of the eccentrics and the resulting camber caster degrees and it would suggest changes? I don't suppose there is any monetary value for anyone to have developed this but its worth asking.
I replaced my stock control arms and strut rod with QA-1 parts and while I can get much more caster and camber adjustments out of the new parts, getting the caster and camber to BOTH be in the range is killing me.

There is a formula for shims. Maybe you could apply that somehow. The geometry of different control arms has to make that formula less than accurate.

 

[ACME SS]

There is a formula for shims. Maybe you could apply that somehow. The geometry of different control arms has to make that formula less than accurate.

Yeah its tough...I've done several cars and never had a problem. I posted another thread after I realized I may be limited due to ride height adjustment so I am curious if others concur that I need to lower the front to change the geometry.

 

[ACME SS]

I failed to mention that I am getting too much negative camber and the only time it is in specifications, the caster is way off...thinking the LCA is off due to wrong height or torsion adjustment?

 

[72bluNblu]

I addressed your car in particular in your other thread. As for an alignment calculator, no that's not really a thing.

It would have to be A-body specific to be easy to use. If it were to be generic, you'd have to input ALL of the suspension geometry points - the mounting locations of the control arms relative to the ground, ball joint heights relative to the ground, control arm lengths, the built in angles of inclination on the spindle, etc, etc, etc.

There are suspension geometry calculators out there, but they're not free and they require all the suspension geometry information in order to plot everything.

As for the eccentric bolts, that's a different story. You have two adjusters, each capable of about 2.5° of adjustment from one end of the slot to the other. Set them all the way "in", so they pull the UCA inward toward the frame and you have maximum negative camber. Set them so they're all the way "out" and you have maximum positive camber. If you move both eccentrics the same amount together, you're only adjusting camber.

Caster is the angle of an imaginary line through the ball joints. You only change the caster if you move the eccentrics different amounts. For example, maximum positive caster is when you set the front eccentric all the way "out", so it's as far away from the frame as possible. Then you move the rear eccentric all the way "in", so the rear of the UCA is sucked all the way in to the frame. Moving the front adjuster out and the rear one in rotates the balljoint rearward, increasing positive caster to its maximum.

That's actually how I start all of my Mopar alignments if I'm just using the eccentrics. I set max positive caster, and then see where the camber is. If the camber is too negative, you bring the rear eccentric out until you get to where you need for the camber (losing positive caster as you move it).

 

[ACME SS]

I addressed your car in particular in your other thread. As for an alignment calculator, no that's not really a thing.

It would have to be A-body specific to be easy to use. If it were to be generic, you'd have to input ALL of the suspension geometry points - the mounting locations of the control arms relative to the ground, ball joint heights relative to the ground, control arm lengths, the built in angles of inclination on the spindle, etc, etc, etc.

There are suspension geometry calculators out there, but they're not free and they require all the suspension geometry information in order to plot everything.

As for the eccentric bolts, that's a different story. You have two adjusters, each capable of about 2.5° of adjustment from one end of the slot to the other. Set them all the way "in", so they pull the UCA inward toward the frame and you have maximum negative camber. Set them so they're all the way "out" and you have maximum positive camber. If you move both eccentrics the same amount together, you're only adjusting camber.

Caster is the angle of an imaginary line through the ball joints. You only change the caster if you move the eccentrics different amounts. For example, maximum positive caster is when you set the front eccentric all the way "out", so it's as far away from the frame as possible. Then you move the rear eccentric all the way "in", so the rear of the UCA is sucked all the way in to the frame. Moving the front adjuster out and the rear one in rotates the balljoint rearward, increasing positive caster to its maximum.

That's actually how I start all of my Mopar alignments if I'm just using the eccentrics. I set max positive caster, and then see where the camber is. If the camber is too negative, you bring the rear eccentric out until you get to where you need for the camber (losing positive caster as you move it).

Thanks. Yeah I was doing the same but my camber was too negative when the caster was good. The ride height adjustment should put the values within the center of the adjustment spectrum as opposed to an outer edge. With the larger wheels (17"), it is difficult to know what the ride height is supposed to be since it messes up the geometry. I would not have gone with larger wheels and tires had it been my decision but it is what it is. Now it all makes sense as to why ride height is the first step in the alignment process.

 

[72bluNblu]

Thanks. Yeah I was doing the same but my camber was too negative when the caster was good. The ride height adjustment should put the values within the center of the adjustment spectrum as opposed to an outer edge. With the larger wheels (17"), it is difficult to know what the ride height is supposed to be since it messes up the geometry. I would not have gone with larger wheels and tires had it been my decision but it is what it is. Now it all makes sense as to why ride height is the first step in the alignment process.

The larger wheels don't mess up the suspension geometry. That only changes if you changed the height of the tire, and you can do that with any diameter wheels. You can run 26" tall tires with 15's or 25" tall tires with 17's.

This is the factory method and settings for setting the ride height (A-bodies are the "V and L" line, think Valiant), so A-B should be 1-7/8" for factory ride height on a 2-door

And here's a blown up version of that picture so you can see the actual "A" and "B" points to get your measurements.