Alignment numbers

[grannyknot]

Now that the build is finished http://forums.hybridz.org/topic/122185-m-powered-z/

I took the car for an alignment and here are the numbers,

   EDIT  Please see post #7 for the real numbers.

The shops printer was down so they wrote them out for me, the rear looks pretty good but what could account for the big differences in the front?

The springs are Eibach lowering with Illumina shocks, no provision yet for adjusting camber or caster.

Thanks,

Chris

Edited August 14, 2017 by grannyknot

[JMortensen]

Those are some crappy numbers, I hate to say. Even the rear has a significant problem, which is A LOT of toe out. That's enough toe to wear out a set of tires pretty fast, not to mention it should have a scary tendency to oversteer, if you could ever get any grip out of the front end.

Guessing this is a street car based on the Eibach lowering springs. I'd suggest you loosen the front crossmember bolts and try and shift it to the right to correct some of the camber issue. You won't get it fixed, but might be able to improve it a bit. If you want to go further you can slot the holes in the strut tower to adjust camber, do plates, or do adjustable control arms (look out though, you'll have to push so far out on that right side that you will need to be concerned with running out of length on the tie rods.

 

In the back the simplest fix is going to be camber bushings. I wouldn't try to change the camber too much, just fix that horrendous toe out situation. For street car, I'd run about 1/16 or 1/8 toe in front and rear.

 

Good luck with it!

[74_5.0L_Z]

I have to agree with Jon on this one.  Those alignment numbers need some help..

 

Jon made a good suggestion regarding loosening the bolts holding the cross member and shifting it to try and equalize the camber in the front.  You could even slot the holes in the cross member further to give more adjustment.  You could also make or purchase adjustable T/C rods to make caster adjustable.  Either way, I don't  think you will be happy with the handling with the current alignment.

 

Mine is a highly modified track car, but here are my current alignment settings:

 

 

Front:

                          L          R

Camber:         -2.0        -2.0

Caster:           5.9          5.9

Toe:               - 1/16"     -1/16'

 

Rear:

 

Camber:      -1.5        -1.5

Toe:            +1/16        +1/16

 

All readings were taken with me in the car.

[74_5.0L_Z]

Did the alignment shop give values for SAI and included angle?

 

If your SAI is very different left to right then you may have a bent strut or body damage that is making it difficult to achieve equal camber left to right.

[grannyknot]

Thanks guys,  Jon, so you are talking about moving the crossmember to the right or body to the left while the bolts are loosened?

 

Did the alignment shop give values for SAI and included angle?

 

If your SAI is very different left to right then you may have a bent strut or body damage that is making it difficult to achieve equal camber left to right.

All they gave was the hand written sheet, this was a local alignment shop. I will take the car down to Whitehead Performance this week, they deal almost exclusively with older Z cars. Strangely enough I think it handles well up to about 70 mph then it starts getting a bit squirrely, maybe I've just gotten use to it.

Thank you

[JMortensen]

Yes, you would want to move the xmember to the pass side. There isn't much room there, certainly not enough to fix it, but might make it a little better.

[grannyknot]

Okay, I've been starring at the numbers that the young guy at the alignment shop wrote down and he has made some mistakes in his arithmetic when showing the difference between sides and ALL of his numbers are negative, no positive numbers, I went back up to the shop and confirmed with him, so these are the real numbers,

 

Front

 

                    L                R                Difference

Caster        - 1.8*          - 2.9*           - 1.1*

Camber      - 0.8*          - 1.0*          - 0.2*

Toe               0.0            0.0               0.0

 

Rear

 

                    L                R                Difference

Camber      - 1.0*           - 1.1*         - 0.1*

Toe             - 0.40*         - 0.69*       - 0.29*  

 

So as I understand it the front caster is weird, wrong and I'm not sure what to do about it. I need a smidge of camber on the left front and I would be okay for a street car, same for the rear camber  and the rear toe should be equaled out. Does this look like I'm interpreting this properly?

Thanks,

Chris

 

[74_5.0L_Z]

Those number look much better than I originally thought from your hand written picture in the first post.  I thought that the front camber was -.8 on the left and +2.0 on the right.  So, you really don't have that bad of numbers for the front camber (for a street car).  You should however try to fix the caster.

 

If the T/C bushing are worn, then replace them.  You can increase the caster with adjustable T/C rods, but don't get carried away.  With stock control arms without a spherical bearing at the cross member connection, you will bind the control arm movement if you try to add too much caster.  You could however get both sides equal and get about 4 degrees of caster.

 

Were these number taken with you in the car?  Have you verified that the car sits level?  

 

I always sit in the car while measuring the alignment.  If you are in the car (left hand drive I assume) then the left front camber will become more negative.

 

If you don't verify that the car sits level before performing the alignment, then you are applying a band-aid where surgery may be required.

Edited August 14, 2017 by 74_5.0L_Z

[grannyknot]

Those number look much better than I originally thought from your hand written picture in the first post.  I thought that the front camber was -.8 on the left and +2.0 on the right.  So, you really don't have that bad of numbers for the front camber (for a street car).  You should however try to fix the caster.

 

If the T/C bushing are worn, then replace them.  You can increase the caster with adjustable T/C rods, but don't get carried away.  With stock control arms without a spherical bearing at the cross member connection, you will bind the control arm movement if you try to add too much caster.  You could however get both sides equal and get about 4 degrees of caster.

 

Were these number taken with you in the car?  Have you verified that the car sits level?  

 

I always sit in the car while measuring the alignment.  If you are in the car (left hand drive I assume) then the left front camber will become more negative.

 

If you don't verify that the car sits level before performing the alignment, then you are applying a band-aid where surgery may be required.

All 4 T/C bushings are new rubber, I wasn't sitting in the car when the alignment numbers were recorded so that might work out well for me. If the car isn't sitting perfectly level is the only option corner weights?

[74_5.0L_Z]

I don't think any of these cars ever sat perfectly level, so if it is not grossly tilted then I wouldn't worry about.  However, springs do sag with age and the rubber strut isolators do separate. So, if the springs and isolators are in good shape then the only real option for leveling (other than coil-overs) is to use spacers between the isolators and the body.

 

Again, its is more important that car is level with you in it than without you in it.  If you have stock spring rates then the ride height will change significantly with you versus without you.

[ZHoob2004]

I wouldn't be surprised if one or both of your front lower arms are just barely tweaked. I had to replace a bent arm when I got my car, and a lot can happen in 40+ years.

[grannyknot]

My worst caster setting is neg -2.9* and I have to make that at least pos 4.0*  Can anyone tell me what 7 degrees of movement translates into in inches?

[74_5.0L_Z]

Are you sure that the negative caster numbers are real?

 

If they were, the car would be almost undriveable.  A quick way to check is to jack up the car and remove the wheel.  If the strut top is behind the lower ball joint, then you have positive caster.

 

This is what 6 degrees of positive caster looks like:

 

 

Edited August 15, 2017 by 74_5.0L_Z

[74_5.0L_Z]

Also, +2.9 would be about what I would expect for a stock 240Z.

[grannyknot]

74_5.0L_Z, thank you for your help, just checked and the top of the strut is definitely behind the ball joint so I have some pos caster.

I know not to go back to that alignment shop, can't do simple arithmetic or tell positive from negative. 

[socorob]

If the shops there are like the shops here, they tend to just get things "in the green". They want to do the least possible and get you out the door.