Squaring upper control arm with chassis/alignment issue. **Help**

[Gatorac]

According to the alignment instructions and the GTS manual the upper control arm pivot is supposed to be square with the chassis. Mine wasn't. I squared it up and re-aligned the front end.


This ended up putting my front wheels way to far forward in the wheel opening of the body.

The LCA is also angled forward.

It's seems as if this car was supposed to have offset UCA's. Does anyone have any input on this before I invest in a set of offset UCA's?? I found some for $40 each so it's not a huge investment.

[Blue Streak 21]

I see what you mean. The tire is not centered in the wheel well, and the coil over is not centered in the upper A-arm opening. The coil over could hit the upper A-arm when driving over curbs or raised apex's. If you move the wheel to be centered in the wheel well, won't you bias the coil over farther toward the forward member of the upper A-arm? Or do UCA's fix both problems at the same time? I don't know how important this is. Maybe one of the Panoz Engr's could comment.
I used the same alignment method that you did. I positioned the upper control arm pivot to be in line with the longitundinal frame member. My positioning was similar to yours, in that I centered the bolts in the slots. The alignment was straight forward after I set the ride height and cross balanced the car. I'll have to look at how my car's suspension makes the wheel sit in the wheel well.

[Gatorac]

....and the coil over is not centered in the upper A-arm opening. The coil over could hit the upper A-arm when driving over curbs or raised apex's. If you move the wheel to be centered in the wheel well, won't you bias the coil over farther toward the forward member of the upper A-arm?

When the upper control arm moves back, the lower will need move back too. That should keep the shock in relatively the same position. That's if you keep the same caster setting.

[Blue Streak 21]

Gotcha. You'd need to move both.
I went and looked at my car. The front wheels are similarly placed in the wheel wells. I looked at the back wheels too. They are also not perfectly centered in the wheel wells. They are biased forward, like the fronts. The placement could be and artifact of the selected wheel base length for this tube chassis, verses the wheel well opening distances from the Espanante panels. Again the Panoz Engrs could settle this issue quickly.
I think that it's fine, unless you have some rubbing issues with the tires on the fender lip. I'd be more concerned with the alignment spec's and making sure the coilover doesn't hit any thing as it goes through it's range of motion.

[Gatorac]

It will take some major trimming of the hood to gain clearance as it sits now.

[Cobra4B]

Guys... I drove mine today at VIR on the full course with the "as purchased" allignment. I simply torqued everything to spec and ran the car w/ the shocks it came with and the 350lbers up front and the 200 in the rear. I put a set of Nitto R2s on the car. The car was extremely neutral w/ only slight understeer at the limit. I feel this can be adjusted with some swaybar tuning.

I like lots of positive caster... makes the car feel very tight. Also camber was perfect as the tire wore perfectly even.

Gues I'm saying is there's no need to square up the A-arm.

[Blue Streak 21]

VIR must have been great. I'd like to hear the details, especially the "S's."
My car's alignment as purchased was all over the place. Nothing was close to spec. Including toe, and camber. There was a lot of variation side to side too. We couldn't measure caster with the magic strings, so I don't know where that started. The alignment needed to be adjusted correctly. Sounds like yours must have been much closer to spec.

[panoz302]

square upper arm, 6.1 caster both sides,f/l/r -2.8 camber, 1/8 toe out total, rear r .-6 rear l -.5. My arms where off too, they should be straight. I spoke to 1. engineer, and 2. the Panoz race team/distributor. 3. Nate ( whom said the cars where give alot of caster to tighten up the steering). They had to remove the set bolts to do this and cock the arms. I replaced my bolt and had the suspension setup by one of the best shops in the country. It is fine, I am running the Koni stock springs, perilli d3 slicks in 17 inch. My wheels do not hit anything, but the lower trailing arm had some interferience issues with the lower portion of the upright, shop fixed it with a bit of grinding.

[DrBro]

I just checked my car (Series car) and it has the unequal length A arm just like the GTS cars - not at all like your picture. I guess that's why the instructions are different. The RA cars set the caster with skewing the A arm versus unequal length tubes.

[Blue Streak 21]

I checked my car, it has equal length A-arms. As mentioned before, my alignment has the upper control arm parallel with the longitudinal frame member. I guess you are calling this "square." I have the caster set at 6 degrees.
The interesting thing is that I purchased a spare upper control arm from Gary Jones, and it's an UNEQUAL A-arm. So now I'm wondering several things.
1) Does it really matter how you get caster into the alignment? Caster is caster, right?
2) If the steering is tight with the upper A-arm "squared," should I worry about it?
3) With my alignment the wheel is essentially shifted forward. Should the car be more of less stable since the wheel is biased forward? (Remember Dodge cab forward desgin????)
I guess I need to buy another unequal A-arm from Gary to have a matched set. I'll take care of that tomorrow.

[Gatorac]

Originally Posted by Blue Streak 21

I checked my car, it has equal length A-arms. As mentioned before, my alignment has the upper control arm parallel with the longitudinal frame member. I guess you are calling this "square." I have the caster set at 6 degrees.
The interesting thing is that I purchased a spare upper control arm from Gary Jones, and it's an UNEQUAL A-arm. So now I'm wondering several things.
1) Does it really matter how you get caster into the alignment? Caster is caster, right?
2) If the steering is tight with the upper A-arm "squared," should I worry about it?
3) With my alignment the wheel is essentially shifted forward. Should the car be more of less stable since the wheel is biased forward? (Remember Dodge cab forward desgin????)
I guess I need to buy another unequal A-arm from Gary to have a matched set. I'll take care of that tomorrow.

The term "square" is used in the GTS manual and the GTS alignment instructions that I have.

Without an offset control arm, you have one of two choices. First choice is to not have the UCA square. This seems to be what most of our cars ended up with. Second option is the LCA is angled forward. This also puts the tire pretty far forward in the wheel well. To make it fit it is possible that the ride height is higher then recommended. (mine was). Either of these things can result in suspension bind. (That's the reason the GTS manual says to square the UCA). While it may not be possible to have both the UCA and LCA perfectly square with the chassis, They shouldn't be this far out.

I have 1.25" offset arms on the way. I'll let you know how they work. They aren't expensive ($40 each).

[Cobra4B]

So you guys are saying that the GTS cars have shorter upper A-arms while the GTRAs have equal length? I'll have to check mine.

If you switch to unequal length arms and square it to the chassis then how do you get camber into the suspension? I don't see any other way to adjust camber other than adjusting the angle of the A-arm.

[Gatorac]

Originally Posted by Cobra4B

So you guys are saying that the GTS cars have shorter upper A-arms while the GTRAs have equal length? I'll have to check mine.

If you switch to unequal length arms and square it to the chassis then how do you get camber into the suspension? I don't see any other way to adjust camber other than adjusting the angle of the A-arm.

No. I believe when Blue Streak said "unequal" he meant "offset". See picture below.

I'm saying that it appears that the UCA should be offset. This would allow the pivot to be square with the chassis, have your caster correct and keep the wheel in the correct position.

Upper and lower control arms are not usually the same length as each other (unequal). This causes and increase in camber during suspension compression. This is beneficial in a turn.

[Cobra4B]

^ Ah I see.... I'll check mine when I futz w/ the car before the next event.

[btwog]

Here is one of the pics of a GTWC car. Obvious offset. Maybe I should unsquare the A-arms.

Where did you find the offset A-arms?
Thanks