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DIY Alignment: Lessons Learned

 
Old 10-23-2017, 09:55 PM
  #61  
Kaged
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Default Track experience with revised toe?

Getting ready to install the AMT blocks and Granetelli rear links on my car and get it re-aligned. Did the change to 1 mm toe in on the rear work as expected on the track?
TIA,
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Originally Posted by Poor-sha View Post
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.
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Old 10-23-2017, 10:56 PM
  #62  
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I'm not Poor-sha, but take a look at this post he made:

https://www.corvetteforum.com/forums...post1595723486


In there you can read:

As best I could understand Mike, the Granatelli toe links changed the distance from the end of the toe link to the back of the upright. That changed the geometry of the suspension. Since I was at DSC/TPC we decided to measure the toe curve with the toe links and found that you don't get the toe changes with it that you do with the stock toe links. So we went with 1.0 or 1.5mm (can't remember which) of toe-in on the rear instead of the DSC recommended 0.5 toe-out with the stock setup.

All I know is that getting the rear toe right totally transformed the car. It's amazing what a difference such a small thing can make. The fact that I was able to turn a 1:59.0 at VIR on Cup 2 tires is good enough indication for me that the car is working well.
Sounds like it works great!! I've got the Granatelli links and I need to change my rear toe to that 1.0 mm toe-in setting before my next event!!

.
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Old 10-24-2017, 06:08 AM
  #63  
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Originally Posted by Kaged View Post
Getting ready to install the AMT blocks and Granetelli rear links on my car and get it re-aligned. Did the change to 1 mm toe in on the rear work as expected on the track?
TIA,
Bill
Change it to 1.5mm toe in the rear. That's what Mike and Sean both said was correct. I changed mine and it makes a lot of difference. Be sure to get the caster right. Sean's suggestion to put an extra washer in the fore end of the rear uca's was almost dead on in my car as well. I had to add and extra 1/16th on the right side but the left was perfect.
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Old 10-24-2017, 06:40 PM
  #64  
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Originally Posted by badhabit_wb View Post
Change it to 1.5mm toe in the rear. That's what Mike and Sean both said was correct....
Hmmm...I need to get this nailed down because I'm ready to change my rear toe!!

Is it 1.0 or 1.5 mm toe-in???

In post# 55 in this thread Sean says:

Given this new information we decided to go to 1.0 mm of toe-in at the rear on my car.

So....0.5 mm isn't much, but I'd like to get the target I'm aiming for confirmed before I get to work on it!!

.
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Old 10-24-2017, 06:50 PM
  #65  
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I'll be honest, I don't know and will have to setup the strings to measure. We went back and forth and I thought we agreed on 1.0 but Mike says it was 1.5mm. In the end neither of us made the actual adjustment though so I have no idea what Marco with the spanner heard

I was saying 1.0 mm as we were already swinging from toe out to toe in. I don't know if you'd be able to tell a difference between 1.0 and 1.5 but I will try to string the car up this weekend and see what my ruler says.
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Old 10-24-2017, 07:24 PM
  #66  
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Originally Posted by Poor-sha View Post
I'll be honest, I don't know and will have to setup the strings to measure. We went back and forth and I thought we agreed on 1.0 but Mike says it was 1.5mm. In the end neither of us made the actual adjustment though so I have no idea what Marco with the spanner heard

I was saying 1.0 mm as we were already swinging from toe out to toe in. I don't know if you'd be able to tell a difference between 1.0 and 1.5 but I will try to string the car up this weekend and see what my ruler says.
Is that total toe of +1.0 mm or toe per wheel for a total toe of +2.0 mm?

Bill
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Old 10-24-2017, 07:31 PM
  #67  
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Originally Posted by Bill Dearborn View Post
Is that total toe of +1.0 mm or toe per wheel for a total toe of +2.0 mm?

Bill
Whichever it is it's per wheel. I used 1.5 and it worked great for me last weekend at VIR. The last time out it was -.05 so for me it was a big difference.

Last edited by badhabit_wb; 10-24-2017 at 07:33 PM.
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Old 10-24-2017, 08:58 PM
  #68  
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Originally Posted by badhabit_wb View Post
Whichever it is it's per wheel. I used 1.5 and it worked great for me last weekend at VIR. The last time out it was -.05 so for me it was a big difference.
So can you quantify the improvement going toe in vs toe out i.e. tracked better, less twitchy, or....?
Bill
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Old 10-24-2017, 09:09 PM
  #69  
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Originally Posted by Kaged View Post
So can you quantify the improvement going toe in vs toe out i.e. tracked better, less twitchy, or....?
Bill
It was twitchy and loose feeling but part of it was because the caster was off as well. I'd replaced the street tires and got a bad alignment then got it all straightened out when I got the Granitelli links.
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Old 11-07-2017, 08:52 PM
  #70  
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Default Did you get a chance to measure the toe?

Sean,
Just finishing putting in the Granatelli links in the rear and was curious if you had a chance to verify your current rear toe settings.
TIA,
Bill
Originally Posted by Poor-sha View Post
I'll be honest, I don't know and will have to setup the strings to measure. We went back and forth and I thought we agreed on 1.0 but Mike says it was 1.5mm. In the end neither of us made the actual adjustment though so I have no idea what Marco with the spanner heard

I was saying 1.0 mm as we were already swinging from toe out to toe in. I don't know if you'd be able to tell a difference between 1.0 and 1.5 but I will try to string the car up this weekend and see what my ruler says.
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Old 08-18-2018, 07:54 AM
  #71  
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Poor-Sha,

I'm revisiting this thread. Have you made any changes since this was posted?
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Old 08-18-2018, 09:35 AM
  #72  
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Originally Posted by AKKutz View Post
Poor-Sha,

I'm revisiting this thread. Have you made any changes since this was posted?
Not from me. The car worked well and then I traded it for a ZR1. On the ZR1 we went with the stock eccentrics and rear toe links and aligned it according to DSC track recommendations.
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Old 08-18-2018, 10:32 AM
  #73  
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Originally Posted by Poor-sha View Post
Not from me. The car worked well and then I traded it for a ZR1. On the ZR1 we went with the stock eccentrics and rear toe links and aligned it according to DSC track recommendations.
I believe I would do the same. Thanks for the reply!
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Old 12-09-2018, 06:30 PM
  #74  
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I know this post is a bit old, but wante to clarify something...

On the rear UCAs - to have the correct caster, you want washers on each of the FRONT ONLY dogbone bolts and no washers installed on the rear bogbone bolts, correct?

Heading to he track this coming weekend and want to get the alignment setup properly to settle the car a bit. THanks for any insights!

Sean
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Old 12-09-2018, 06:36 PM
  #75  
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If it helps I think the front leg is shimmed out more than the rear on the uca. Once you get that set correctly it will stay set as long as you keep the front and rear amt plates the same. Even if you go from 1 to 3 or more.
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Old 07-08-2019, 08:56 PM
  #76  
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Do you thread the AMT bolts all the way until they stop on/in the frame? Thanks for the pic.

Originally Posted by BEZ06 View Post
Here's my Harbor Freight shim kit:






And below you can see some installed on car - I have the AMT Motorsport Stud Kit, as well as their Camber Plate Kit and Granatelli adjustable rear toe link:

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Old 07-08-2019, 08:59 PM
  #77  
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I didn't thread them all the way in. Not sure how to explain it but you can see how deep the holes are and screw them in based on that. Be sure to put loctite on them and let them set so the loctite holds the studs in.
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