How are you measuring front caster? Its usually done by measuring camber both at a defined angle and straight ahead and applying a multiplier. If your off on the angle you measured at our used the wrong multiplier you won't get the correct caster.

Based on my experience I believe the suspension geometry will fall to 7.5 if everything is even at the front and back of the victim arms.

 

I have been doing 4 wheel alignments with Hunter Engineering Alignment Machines for over 35 years. Doing a Wheel Alignment with strings and levels is like going back to the stone age. You can spend alot of time trying to do a alignment this way and you could be close but i will bet it is not correct. So save time and find a shop with a Hunter Alignment Machine and you tires will be Happy !!!!!

 

I think it depends on what you are trying to get out of an alignment. For my wife's jeep that doesn't see track duty and I'm only concerned with tire wear and not grabbing the crown of the road ok. For a car that I'm going to be driving on a track, I can get it better with strings. There is a reason race teams use Stone Age strings. I took my c6 to 2 different alignment shops on The same day and the machines showed 2 different sets of readings, that did it for me. Besides I can trust but verify with strings.

 

If the machines are set up correctly they give great results. Sadly most of them aren't checked regularly. Garbage in garbage out...

 

Which is why I use strings. I know they are set up and the first time is work, after you get the baseline measurements, it's simple. And if needed I can change my setup at the track. I have not been satisfied with the laser machines.

 

The owner of the company only buys the best and any spends money to keep my aligner updated and serviced. My Hunter tech lives 5 miles away from the shop. We only work on wrecked cars and it is very rare that we have a car come back for an alignment problem. And the ones that do have hit something ! When you do a alignment you start at the rear and adjust camber first then toe to get the thrust angle to 0 (zero) and is very important then do the front camber caster and then toe. Most cars that are wrecked the wheel is back (-camber) and is very important to correct. If the front wheel is back (-camber) the wheel base is short and the car will pull to that side.

The Hunter Aligner has Digital Cameras no lasers !!!!

 

I'd be interested in knowing the multiplier... But, I'm using a fastrax camber/caster gauge. On the camber side, I also add the wixley. But for caster, I'm reading the bubble level in the gauge.

 

I've paid to have my alignment done too many times for going to track and coming off. First time, they used channel locks to adjust tie rods....My tie rods are rusted chewed up sh it. AND, not once have I seen consistent results. I have print outs to back this up. That is why I've chosen to attempt this myself. Granted it would be less headache and less time involved to take it somewhere, but it is difficult to find someone willing to align to my specs.

Hell, i can't even find a place to mount tires without damaging my rims! I had winter tires mounted on base wheels at a tire shop near me, and they gouged the inside of the wheel.

I had track tires mounted at a "specialty" shop on a set of stock eBay wheels and they marred the wheel facings with their center post changer.

And, yesterday I found a great deal on ZP's at a local Firestone shop and they tore divets in the center of one of my Z51 black wheels. They called these scratches... chunks of aluminum are missing, scratches...... I get to deal with this today......

So, getting stuff done without damage in my part of the world is a joke.....therefore, I try to do it myself... At least if I screw something up, I take the responsibility! Sorry for turning this into a rant!

 

I absolutely hate to bring my cars to a shop. There is ALWAYS a issue, ALWAYS.

 

The dealership that I used to use in upstate NY sold BMWs as well as Chevy's. They had a machine that must have been recommended by BMW since all of the print outs had BMW stuff written on them. The Corvette Mechanic did the alignments and let me watch while he did them and he showed me what he was doing and why he was doing it. He told me this because he said it would be cheaper for me to do the job myself Vs coming in and having him change the alignment every time I had a bright idea about what to try next. I can say this I was never dissatisfied with what he did. If he was having problems hitting one of my targets he would show me what was happening, how he was adjusting things and how the measurements changed. It was easy to see when good enough was good enough and any more time spent was time wasted.

Bill

 

If you were trying to use the frame that clamps on to the wheel that pretty much happens with all of the manufacturers if you are using stock type wheels and street or DOT R Tires. The tire rim protector won't let the clamp get a good seat on the rim. Do that with a set of slicks without a rim protector and there is a lot of room to let the clamp seat. I found it works well if I use bungy cords to hole the frame to the wheel when attaching my Longacre frame and acculevel.

Bill

 

Based on what I've read it's 15 degrees and you multiply by 2 or 20 degrees and you multiply by 1.5. Tenhulzen instructions are here but they don't specify the angle, just how to use the bracket.
https://static.summitracing.com/glob...nh-3300_us.pdf

I used this thread to figure out the angle for the turn plates:
http://specracer.com/forums/viewtopic.php?f=5&t=2504

I'm going to put my car on the alignment rack at TPC this weekend to check my work. I also want to check my thrust angle as I buggered that up when one of the toe link jam nuts came loose.

 

At TPC Racing / DSC Sport having them check how close I got with the alignment at home. First though Mike is using this rig to calibrate the alignment machine. I bet he's the only shop that goes through this effort to perfection.

 

Most shops don't. When I got mine aligned in Raleigh Gabe spent close to an hour just getting everything level to make sure the alignment was perfect. It was not a quick process.

 

Some more data. We had slightly less fuel in the car (~4 gallons) and about 30 fewer pounds of ballast in the drivers seat than when I aligned the car at home. The camber on the DSC rig matched what I had at home which was -2.5F and -2.0R. The LF caster was right at 7.5 and for some reason the RF caster was at 7.1 which was unexpected since they both measured the same at home but not concerning enough to change.

The rear caster also measured a little off from what I saw at home (0.6 laid back) with their measurements showing 0.5 and 0.9. I found this surprising given that we both were using the GM bracket and a digital level, but they did have a much better digital level with a remote display.

My toe was totally out of whack but I knew that after I had the issue with the rear toe link coming lose and me adjusting both sides throwing off the thrust angle. Mike and Marco got it squared away though.

I also noticed that they had a much easier time getting the suspension to settle on their rack after we lifted the car. I need to revisit how I'm using my slip plates and bouncing the car (they did it from underneath which I never thought of) to see if I can get the same effect.

Mike was actually a bit concerned about the fact that I shimmed one side of the UCA to get caster and also about the fact that I changed to toe links. We decided to measure the toe sweep with these changes and sure enough it was different. We weren't seeing the toe-in under compression that the stock setup has. That toe under compression is why DSC normally recommends a very slight 0.5 mm rear toe out at rest. Given this new information we decided to go to 1.0 mm of toe-in at the rear on my car.

It's amazing what a difference these little changes make. You could immediately tell on the street that the car put power down better than when I arrived. I'm hoping to get to the track soon to validate how the car feels at the limit.

Big thanks to Mike and the DSC crew. It's great to have the opportunity to learn from the best.

 

Yeah, this is odd. I know quite a few folks, myself included, have installed the Granatelli rear toe links and set the toe to the DSC specs. I guess I don't understand why there would be a difference.

 

Trying to finish my at home alignment. Be nice if I lived closer to TPC....
I made the changes to the front LCA as per Mark from AMT suggestions. Making my measurements, looks like I've idecreased my positive caster in the front by only 1 degree. I'm using SPS's Fastrax bubble gauge to take the readings. Caster is reading around +9.5 degrees now with camber -2.5 in the front. Camber plates at 2 in front LCA and 3 in rear position. Still roughly stock shims at UCA.

In the rear, I tried Poor-Sha's shimming on the rear UCA and am getting the .7 caster both sides.

 

I am glad you and Mike measured the rear toe with the Grantelli links! I just installed the toe bars with AMT plates and it was set up with rear toe in, which I was initially concerned about as I knew Mike recommended .5mm out. Makes me feel much better about my rear settings knowing that!

 

Hey I'm in Raleigh as well. What shop did you take your car? And is it a Z06? I have a Grandsport and my problem with shops have been that I couldn't get on their lift without damage and/or my tires (325mm) wouldn't fit.

 

GT Performance. Ask for Gabe.(919) 412-2534. He does the alignment with strings. I have the tool for the rear castor so we used mine. I have a z06. He is very meticulous. It's not a fancy shop but he does great work.