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Discussion Starter #1
Just got an alignment at my favorite shop in Houston, Southwest Alignment.

I was worried that the process might jack up my newly refinished wheels, but this shop now has these new buckets that eliminate metal on metal contact.

Glad I got the alignment because it was off significantly after lowering the rear a little bit with the Protech coil overs.
 

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Discussion Starter #3 (Edited)
Toe was out also in the rear because of the lower stance.

Since these guys do alignments full time, he had some suitable shims to fix the toe in the rear, which was a pleasant surprise to me. I was expecting to have to order shims based on his readings, put them in myself, and go back for an alignment check.

The front was good on camber and caster because I didn't lower it, but the toe had to be adjusted to account for the steering wheel tilt after I changed to the Elise steering wheel and Bob's adapter.
 

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A1 Automotive & Smog
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That is the new design target from Hunter. The technology uses imaging system invented by FMC. FMC then bought by Snap-On. Hunter, then pay the royalty for the system and continues perfected it and has been filing over a dozen of their own patent just like the non-contact target in the pictures.
 

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Be sure those rear shims went between the frame and the INSIDE of the bushing. On my car the previous owners maintenance shop used shims between the outside of the bushing and the control arm. That extended leverage on the bushing, creating a flex I could feel as a the back end of the car moving around. The shop is a highly regarded specialist in Wisconsin, they should have known better.

The shop manual does allow some shims outside the bushing, but the thickness is very limited.
 

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Discussion Starter #6
I'll check that -- thanks. I would hope he added the shims where he saw the existing shims, but you never know.

I did show him the relevant section of the manual so he wouldn't have to guess.
 

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Can someone explain how these optical systems determine the true centerline of the car, not half the distance between the wheels (L/R) outside surfaces?
 

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Can someone explain how these optical systems determine the true centerline of the car, not half the distance between the wheels (L/R) outside surfaces?
I'm not the engineer, but I have one by John Bean Visualiner (also belong to Snap-On). And the way it sets up is unlike the older Hunter design that have to lift up the wheel for compensation reading for each wheel, this machine simply need to see the car move about 8" backwards, therefore, the wheel sensors turns approx 60-70 degrees. The eye of the camera catch it and calculate the geometry of the toe and camber. The machine only see 4 sensor, and not the car. The lenses on camera has coating like tint window. But the sensors glow so bright and you can see each sensor (sometimes I have to go to manual mode to find the sensors because not all the car are the same height)

Most car comes with non adjustable caster. But if need to measure, the machine capable to measure.
 

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To clarify, shims are allowed inside or outside the bushing, but the amount outside is limited to an extremely small amount. Its entirely possible the adjustment was within tolerance, but if no one had a service manual at the time there is no way they could have known. Its unlikely they had an inside shim sitting there that would fit as those are specific to the Esprit. Installing the inner shim also requires removing the underbody tray, and you would surely know if they took the time to do that.

You will get a rear toe change when the ride height changes, but its a fairly small amount. If your car drives well, I would not worry about it.
 

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Good to see new technology in use on our "old technology".
BUT

I didn't see any strings used in the picture....isn't that how they check alignment in NASCAR? :D
 

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Atwell is correct and that's my point. The only way to insure that the alignment is true to the centerline of the car is to find the physical centerline and "string" to it. These days you can use lasers in lieu of strings, but true centerline still has to be found. How do external optical systems on the outside of the car really know true centerline. The flange to flange widths F/R aren't necessarily perfectly referenced to the centerline, especially on a production car.
 

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Discussion Starter #13
Maybe the rolling of the car back and forth has something to do with the centerline.
 

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I think centerline you guys talking about is thrust-angle in alignment term. If so, then it depends on the rear toe (yes, after rolling back and forth and get the reading). If the rear toe let say perfectly at 0.15 left and right, thrust angle will come to 0. But let say for some reason one rear wheel of the toe maxed out at 0.25, then I have to adjust the other rear wheel to 0.05 to achieve 0.30 total toe. That's ok, just the thrust angle wont be 0. It will read 0.01. Now, the front going to compensate that 0.01 thrust angle automatically. Also, this system recognize if you park the car in the lift crooked, because still, you have to roll back and forth. Hunter system very particular about the level, therefore, they want to lower the lift to locking position. My machine doesn't, but I still do it anyway.
 

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I know I am splitting hairs here, but that's what you do for perfect race car alignment. Yes, I am talking about thrust angle, and it should be 0 degrees, relative to the centerline of the car. The front end can be set to compensate for the non-zero rear thrust angle but that will result in a small amount of "crabbing" which will upset the left-right turn in of the car. Not a big deal in a street car but for a serious track day application it can be real. I have never been convienced that the optical alignment systems can accomplish the zero thrust angle relative to the true centerline of the car. I am still not, but willing to listen. I would like to believe as it would make alignment a lot easier.
 

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Took my car into NTB, Atlanta, today; and here's their report from a Hunter device:

ImageUploadedByAutoguide1355869044.737316.jpg ImageUploadedByAutoguide1355869061.670809.jpg


The Hunter had specs preprogrammed which you can see on the image vs current "settings". Looks pretty far off; especially rear.

Anyone have particular advice as to best values? I know it depends on driving style, strategy. I'm a casual country road cruiser.

Called JAE. They're sending me a F/R shim kit.
 

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Your -2.4 to -2.6 deg rear camber will wear the tires pretty fast.
And the front toe being -.23deg wouldn't be too bad except you have positive on one side and a ton of neg on the other. Neg front toe will make it a bit darty, especially on the rutted highway.

I like a little negative front toe ~0.1deg per side, but that may be too much for some people. I have little camber in the front for tire wear and the low end of the V8 spec for rear camber, for the same reason. So -1.3 deg rear camber, -0.5 front camber, and 0.00 to -0.1 front toe. Definitely follow spec for rear toe!
 

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Thanks Travis; I just had a lot of suspension work completed, new shocks, springs, bushings, tires and figured things weren't up to snuf. Everything is nice and tight, just a bit darty; Once I receive my kit I'll have to decide if the NTB guy has the firepower and time to digest the workshop notes to do the job. There was another thread that said expect to spend a full day bringing everything into spec.

Do you find that it is an especially tricky, lengthy task?
 

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Discussion Starter #19
The front shims look painful to adjust.

The rear camber and toe is easy on the V8.

In general, most things are easy in the rear, and a complete pain in the front.


Sent from my iPhone using AutoGuide.com App
 

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Vulcan, the positive toe on one side, and negative on the other, simply means the steering wheel wasn't perfectly centered at the time the report was printed. In an Esprit you could sit in the car during the alignment, which I often do, and barely breathe on the steering wheel would see those slight variations.

The front numbers look ok, but I agree the rear camber is more than I would like. Rear camber is easy to adjust on a V8 or later 4 cyl, but doing so will change the rear toe so be prepared for that. The Lotus spec calls for more rear toe (in) than the report shows, so if camber is changed equally on both sides the toe might be ok. The rear toe is zero now, I would be ok with that, makes the car more stable. Other than the camber I like these numbers.

SE: both front and rear are very easy to adjust. The problem is that adjustments can require measuring the existing shims and replacing with others, which usually means ordering parts. No pain involved, the front shims drop in easily but require removal of the wheels. If anything the rear is a pain because you have to drop the tray to get at the rear toe-in shims.

Most alignment guys have never seen tolerances as small as an Esprit requires. A tiny change that would not be noticeable on most cars, will dramatically change an Esprit.
 
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