DIY Alignment

#21

Too much negative camber in the rear may contribute to understeer, but will certainly decrease rear tire braking.

#22

E30KDG wrote:

[quote]Anyone have a solution to mahoneyj’s issue with contact to the strut tower?[/quote] Legally? :laugh: The only option is to buy one of those “donors with prior frame damage” that some guys seem to find. PS - Don’t bitch about the strut tower brace not fitting if you go that route. :wink:

[quote] What about rear, too much negative camber will cause what type of condition, understeer maybe? [/quote] Like Fish said, poor braking. Also, poor tire wear. Sub-optimal grip.

#23

E30KDG wrote:

[quote]
Now as far as the actual alignment procedure, can anyone give a little more detailed reply on how its done. I am a tech and all the alignments I do are on a Hunter laser alignment rack and it makes it quite easy. So when I attempt to do my track car how can I make the adjustments accurate?[/quote]

Front toe is set with the tie rod ends. Front camber is set by using camber plates and sliding struts inboard.

To change rear toe and camber you have to have either eccentric rtabs or a weld-on toe/camber kit.

With eccentric rtabs toe and camber are tied together. Each change of one results in a change of the other. That makes it a process of trial and error.

It helps a lot to get under the rear of the car and think about what those eccentric rtabs are doing. As you turn the nut they are tilting the wheel forward, up, back, and then down. Since the trailing-arm has two attachment points the two eccentric rtabs work in tandem. Spend enough time visualizin g this until you have a really solid understanding of how this works.

Then play with the adjusting nut on two eccentric rtabs and get your toe to zero. You can measure this while the car is still up in the air and the value will be pretty close to right. You’ll need toe plates to do this.

Once you get toe to zero, put the car back down on it’s level surface, and alignment shops can’t be depended upon to have level surfaces, and see what your camber is. Then put the car back up and see how you might be able to move your eccentric rtabs a little such that you get the camber you want without hosing up your toe too much.

I’ve not done the weld on kit before, but I imagine it’s a little easier. You adjust toe with one and camber with the other. If the kit was installed well, then the two bolts should be roughly on axis when you have your desired camber and toe. If the bolts are off axis the bolts and welded tabs are going to be under a lot of stress.

#24

Ranger thanks for the info but I wasn’t as clear as I should have been. I am an automotive Technician and I do alignments all the time, so I understand how to do them. What I am asking is how do an alignment on my track car at home without an alignment machine. Meaning how do I measure the proper angles not how do I physically adjust them. I’ve heard about using string, levels, and straight edges but I was hoping for some of you racers that do it all the time to give me some info. Thanks in advance for everyone’s reply.

#25

I put the “weld-in” adjustable camber/toe kit in the rear and adjustable camber plates up front. Make marks with white paint on them and the tie rods for “street” and “track” setups.

the rear toe is a bi*ch to adjust though, had to grind down a 18mm combo wrench.

#26

E30KDG wrote:

I use two sections of 1" electrical conduit with a hole drilled in each end. It’s very important to make sure both sections are exactly the same. I don’t remember the exact distance between holes, but the spacing should be your track width + ~4 inches. This will allow you to measure ~2 inches on each side. After drilling the conduits, you can put them on jack stands in front of and behind the car (the conduits will be perpindicular to normal direction of car travel). Then tie string between the holes (string stretches front to back parallel to the car direction of travel) on the front and back of the car. Your car should be on a platform high enough to allow you to slide underneath and make adjustments. Your strings should be at center of the wheel when stretched front to back. Using the tape measure that comes with the toe plates, measure off the wheel hub to center the strings. Start at the back; when the measurements are equal on both sides, do the same on the front. After the front, check and adjust the back, then the front, and repeat until measurements are exactly equal from side to side on the back and front. The measurements on the front may be different from the back depending on where your setup. After everything is centered, you can adjust toe on both ends using the string as a reference point. I take my measurements between the wheel edge and string. This will set your vehicle absolute toe. If your camber is too far out of whack, it could affect your toe readings. When you are complete using the strings, check your toe again using toe plates. This should give you confidence in your settings confirming it with two methods. As long as your rear toe doesn’t change (check with toe plates), you can make adjustments to your front toe using toe plates. If your rear toe looses it’s adjustment, I’d prefer to use strings to reset. Otherwise, the relative toe may be correct, but not the absolute toe may not.

#27

“I take my measurements between the wheel edge and string”

outer rim or tire? i’ve heard the tire.

#28

Get some toe plates to get relative toe. Easy. Strings are too hard.

Absolute toe. Go to Harbor Freight and get a laser level. Put the toe plate against the rear wheel and put the laser level against it with the laser pointing forward. If the laser is 1" outboard of the rear wheel, it will be 1" out from the front wheel at 0 absolute toe.

If the laser misses your target 1" (or whatever) use a 1:6 ratio to figure out how much of a problem you have. For example, if the laser misses it’s mark at the front hub by 24mm, your rear toe is off by about 4mm.

If it takes you longer than 60secs to check your toe at all 4 corners you need to put your beer down and use both hands.

For camber you can either get a real camber gauge for ~$300, or you can get a digital level for a lot less. Some guys have been able to get pretty good accuracy out of a digital level but you might have to put some time and energy into that before you could really trust it.

#29

E30KDG wrote:

Why not take the car to work and do it there?:blink:

If that’s too simple, you and Ranger are going to get along just fine. :laugh:

#30

Ranger wrote:

Strings are not too hard! It’s important to get your absolute toe straight for a baseline… Toe plates are great for checking and making quick changes but can’t help with absolute measurements…

Too hard? Paleeeeeeease!

#31

If you have a diving board car it is easy enough to make “string rods” that fasten to the front and rear bumpers. The really nice thing about having the string supports attached to the car is that you can set it on the ground to check alignment, raise it to to make and adjustment, and roll it to unload the tires, without disturbing the strings. The best string is monofilament fishing line. You get bonus points for attaching a cheap fishing reel to one end of the “string rods”.

Something a bit fancier can be fabricated for plastic bumper cars. For ideas, watch the Bimmerworld crew (or other pro teams) check alignment.

#32

Steve D wrote:

[quote]E30KDG wrote:

Why not take the car to work and do it there?:blink:

If that’s too simple, you and Ranger are going to get along just fine. :laugh:[/quote]

I am one of 30 techs with one alignment rack at a dealership and the bosses don’t care much for track cars tying up lift time. Plus I need to learn how to do this often to make adjustments so I can really feel the slight differences.

Thanks for all the info though, racers are very creative to say the least.

#33

I barrow my buddy Smart Stings set up to do mine. Hanging the strings off the car makes life a lot easier. You can fab up a much cheaper way to do if you are only planing on using it for one type of car. I am glad I only need to drive a few miles to get it.

My major issue is my garage floor is a slight low spot at one of the wheels and it took a long time to create some correction figures to get it close to right.

#34

mahoneyj wrote:

[quote]I barrow my buddy Smart Stings set up to do mine. Hanging the strings off the car makes life a lot easier. You can fab up a much cheaper way to do if you are only planing on using it for one type of car. I am glad I only need to drive a few miles to get it.

My major issue is my garage floor is a slight low spot at one of the wheels and it took a long time to create some correction figures to get it close to right.[/quote]

Screw correction factors. Put something on the floor that is the correct thickness to level everything up. I found that 1/4" is worth about 0.2deg.

Re. Strings are easy. When you can get absolute toe at all 4 corners in 60sec with no prep at all, then I’ll agree.

#35

Man, its been a while since I’ve had to do this…

Start with jack stands. Grab some kite string. Put each jack stand in front and behind the car, and a couple of inches away from the body, while leaving some slack between the width of the car. The strings from front to back should be tight and wrapped around the jackstand a few times.

Once you have this set up, you need to make a “box.”

You need to have the strings equidistant from the left front and right front, and from the left rear to right rear. Then, you need to pick a spot at the center of the hub of the front and rear of the rims. When you pick that spot, you measure the distance and make sure that the distances from the front hubs are equal, the rear hub distances are equal, and the strings from side to side are also equal.

Once you get the box set up, write down those numbers. Then you have an easy setup for the next time you want to make “the box.”

I typically measure from a rim lip (assuming I don’t have bent rims) from front to back to measure toe. That is typically what I’m measuring for the most part. If I have stuff moving around on me at the track without hitting things, there are other issues to address.

It does really help to have slip plates for this, or something makeshift.

Once you have “the box” it can bet set up on a flat piece of ground in about 10 minutes. Toe and go, check camber and leave.

#36

Ranger wrote:

[quote]Screw correction factors. Put something on the floor that is the correct thickness to level everything up. I found that 1/4" is worth about 0.2deg.
[/quote]

What approach do you use to determine level for the floor?

#37

I am bringing this back from the partial dead to give a procedure I used this week when doing a detailed alignment on my SE30. I found a website that showed some Honda guys running string around the car and the string resting on the tires. Basically start at the front of the car with one of those small short bungee cords and hook it to the screen over the oil cooler. Tie a loop in one end of the string (I use fishing line) and run it around the spoiler, across the center-line of the front and rear driver’s side tires, around the spare tire well, across the center-line of the passenger side tires and back to the bungee at the front. Tie another loop in the string and hook it to the other end of the bungee. Make sure the string is at the center line of each tire and that the string is tight with tension from the bungee. Now, adjust the steering wheel so that there is equal gap at the rear of each front tire (assuming toe-out in front). You can now look at the back and see how the rear tires are tracking with the front. In my case the left rear had both front and rear of the tire touching the string and the right rear hand over ½” of perceived toe-in. I know the total toe-in in the rear was around 3/8” in by using the toe plates. I now lifted the car (I have a lift) and let the wheels hang free. I adjusted the strings a little and surprisingly the measurements were basically the same for the rear. I kept checking the front to make sure there was equal distance from the rear of the tire to the string on both sides. I now adjusted the eccentric trailing arm bushings to where the left and right side each had about 1/32” of toe-in. I let the car back down and adjusted the strings again to the center-line of the wheels and it still showed just slight toe-in in the rear and the toe-out in the front. I used my toe plates to confirm the total toe and had 1/32” toe-in in the rear but this time I know the rear is tracking with the front. My rear camber ended up at around 2.25* neg each side so not too bad.

I know in theory that the strings should be measured from the center-line of the car and equal distance from this center-line. I also know that according to the specs I found on the web that the front track is 1407mm and the rear track is 1415mm. This difference in track and the toe-out of the front and toe-in of the rear pretty much tell me that there is no way that these strings were parallel to each other from side to side. I guess it really did not matter as it was able to give me the rear wheels alignment relative to the front which was the objective anyway. The toe plates tell the story of what the total toe is. I am also wondering if this left rear toe-out and right rear toe-in was why my car liked to dart left under very heavy braking from high speed (back straight at Mid-Ohio).

Anyway, it is worth a try and a lot easier then stringing the car with jack stands or smart strings. The strings are not in the way and as long as you check to make sure they are in the center-line of the wheels it is no big deal if you hit them or move them. This would also be very easy to do at the track to check things after an off or hitting a big curb.

As a side note, I built some adjustable alignment stands that hold my scales and are set in place using a lazer level and adjusting the feet. I then use the heavy duty thick contractor garbage bags folded over numerous times for slip plates.

Michael

#38

my local race shop guy (wally’s race cars) told me that toe should be measured from the outer edge of the tire, not the rim. he said to take a pc of chaulk, spin the tire and mark. then pull your measurments from that line to the string.
after thinking… deosn’t really seem to matter where you measure from, right? wouldn’t the degree be the same?

#39

[quote=“NASA144” post=55648]my local race shop guy (wally’s race cars) told me that toe should be measured from the outer edge of the tire, not the rim. he said to take a pc of chaulk, spin the tire and mark. then pull your measurments from that line to the string.
after thinking… deosn’t really seem to matter where you measure from, right? wouldn’t the degree be the same?[/quote]
Does Wally think you are mean, too? I think the dude is messing with ya. :blink:

Using toe plates, the measurement is taken against the tire.

Regarding strings, if you are going to rig up something like Smart Strings, my recommendation is NOT to use the bumpers or anything else that might get tweaked in a bump (i.e. when you will likely be checking your alignment at the track). Try to mount the standards somewhere inboard far enough that only the biggest tub-screwing hit would prevent them from staying the same.

YMMV

#40

You’ve met me… don’t you think I’m mean :evil: