Top-Gun

The indy I've used in the past for chassis setup isn't available, so I'm taking a crack at aligning my car myself. I'm going over everything as I had the rear coilovers out to install Tarrett clamping swaybar link brackets.

I've got the car sitting on cribbing which I've leveled, and each cribbing stand has a free floating turn plate. This way I can make adjustments without lifting the car and disturbing the suspension. I'm using string for toe, the Smartcamber tool, and the Autometrics copy of the motorsport KT tool.

So far I think I have the rear dialed in:
- 130mm ride height (about as low as I can go with the Tarrett brackets in there and two lock collars leaving a couple threads for weight adjustment)
- Toe-in at 10' per side
- Camber at -1.25 degrees
- KT set to 3 on the gauge (was previously 4.5 which made the rear feel squirmy/twitchy in fast corners)

Now I'm working on the front, I set the ride height previously to 135mm (before aligning the rear) so I'm on to caster and camber. This brings me to my questions:

- My turn plates are graduated so I'm clear on how to measure caster, but can I loosen and adjust the caster eccentrics with the car weighted?

- How do I adjust front camber properly? I presume I can't do this with the car weighted and the wheels on as I can't see accessing the strut fasteners like this. Also I presume even if I could loosen the fasteners, the weight would try to force camber towards 0. If I lift the car and remove the wheels, is it sufficient to measure camber at full droop as a reference, then adjust for the amount of change I want to make, then wheels back on, roll/bounce, measure? I also dont have the eccentric tool will I need this or does it just make things easier?

Thanks.

k722070

yes to both.
set front caster to min, go for a drive, then max and go for a drive.
the difference is a big deal and will give you a lot of information on how you like the car to feel when turning.

measure camber with car on ground, say it is -2.0 and you want -1.5.
raise the car just enough to remove the wheel, measure camber with hub in air, say it is now -1.3.
you wanted to change camber +.5 so adjust from -1.3 to -.8.
wheel on, back on ground, you should be close to your target of -1.5.
not sure if the smart camber tool will function with that method, but since you are adjusting to relative values you could try measuring off the brake rotor.
it will get close and within .1 degree is fine.
I don't use the camber eccentric tool, instead tap the brake rotor in or out to adjust.
but if you can reach under the cribbing you've made the eccentric would be very useful.
when working on front camber make sure the steering wheel is locked in place straight ahead at zero toe or whatever your setting will be.


on ride height, my experience is get it close to your target, then adjust your spring collars to exactly the same R to L.
measure from a static point on the strut, say the bottom of the threads or camber locking bolt.
set right front spring collar at 50mm(random number choice) from bottom of threads and set left front spring collar at exactly the same.
do the same for the rear, R to L exactly the same. (rear spring collar measurement has nothing to do with front)
your measured ride height might be different, like my front ride height measures exactly the same but rear ride height right to left is different by 3mm.
but using that method when I roll the car on scales it is always within .5 of being perfectly corner balanced.
so cross weight is 50.35% or 49.6%, and that is only about 1mm of spring collar adjustment.

Top-Gun

Very helpful, thank you.

Good tip with the ride height vs corner weights. I set my collars by counting number of turns from engagement so L to R started equal. Then installed coilovers, rolled/bounced, and measured ride height as per manual (ground to subframe pad/bolt head). I then tweaked the collars until the car measured the same L to R. Now that I know the car is at the height I want, sounds like I should go back and find the lowest collar, measure to a reference, and set the other side to the same disregarding actual measured height to the ground.

I can't borrow a set of scales at the moment so I just want to get it close and I can confirm corner weights later when I get an opportunity to do so.

TheOtherEric

Agreed with the above for adjusting front camber, but there's no reason to remove the wheel for that. In fact, having a big tire in place makes it much easier to push/pull to make the adjustment. If you have camber plates, you may not even need to get underneath the car, and even if you don't, you can easily loosen/tighten the bolts with the wheel on.

As an example, if you want -1.6 degrees but only have -1.0, then you need another -0.6 degrees. So raise the car and measure camber in fully drooped position. If it's now +1.5 degrees camber, then your target is +0.9 degrees. Drop the car and you should have -1.6.

k722070

I did it that way when first starting, it makes sense. but always ended up chasing ride height vs corner balance, as in my rear being 3mm difference.
finally discovered the cars are perfectly(almost) balanced as is.
getting the ride height close then making sure spring collars are exactly equal side to side has saved me hours of work.
doing it that way, street or track car, rolling on the scales is close to perfectly corner balanced.

Top-Gun

Finally got around to tackling the caster and camber. I wasn't able to set the left front caster any higher than 4.95 degrees. I could get the right side nearly to the 5.2 degree spec, but ended up setting both sides to 4.95 degrees.

I've seen many on here have achieved over 5.5 degrees of caster, any ideas why I'm limited or if theres an issue?

k722070

that is strange. what was the range of caster on the left?
being able to reach below 4.4 would be weird.
measure from center of wheel hub front to rear, make sure the length is the same R to L.
are the front ball joints in good shape?
camber plates or stock mounts?
can't think of anything else.

Top-Gun

Caster range on the left is 4.2 to 5.0, right side runs 4.5 to 5.5.

Stock upper mounts, Walrod bushings in control arms, ball joints are tight and look ok, no signs of damage anywhere.

I took a measurement from back edge of rear rim to front edge of front rim (easiest to hook a tape measure on so I could measure myself), I get 1/4" difference side to side, with left side measurement being longer.

I've started another thread as I suspect I may have some damaged suspension components. Also noticed left to right differences in rear camber and KT eccentric positions with both sides set to same measurement.

Not really sure what to do next short of blindly replacing parts as nothing shows signs of damage.

k722070

there is some space when mounting the front cross member to the tub that can account for a R to L difference in wheel base.
but 1/4" seems too much.
with car on ground, drop a plumb line through the center of each rear axle and the hex bolt in front, mark on ground and measure.
you could then loosen the front cross member and check the amount of adjustment available.
this isn't difficult, just very time consuming.

I'll comment in your other thread because it reads like the issue could be in the rear suspension.