Lasers and Computers… Chassis Measurement Part 1

Conducted a test day with AST support on the 29th of April in the hopes of addressing our “lift” issue on the inside rear tire.  We made great progress on the handling of the car but couldn’t replicate the issue when running up at A&M.

Still, feeling good about the car we loaded up and ran the Houston SCCA Regional at GGP.  1st and 3rd overall in PAX but still unloading the inside rear tire!!

Convinced it was time to get serious.  Took the car to our shop and was time to break out the laser levels, WinGeo3 and Suspension Analyzer 2.0!!

First step is to lay down some paper on which to mark some marks.  Make sure this is on a fairly level spot on your floor.



Next measure and mark some reference points from the chassis and the suspensiom onto your paper.  Jot these down as you’ll need them later.

Jack the car up, put jackstands under the chassis and measure your reference points.  You want the car as level as possible, so this may take some shims under your jackstands.  Once level, take the wheels off and remove the shocks and springs as you need the suspension to be able to move and be set at ride height easily.

Put the suspension at ride height using a jack.  Now take a plumb bob (we used a laser one from Bosch which worked great) and mark all the pickup points, ball joints, sway bar attachment points, etc.  This is time consuming and the more accurate you are, the better.  Make a dot on the paper at each point and label it so you know what it is later.  Same time as you’re doing this, measure the height of each point and keep a log.  Most suspension software will let you print out a blank worksheet to use for this.  Sometimes you need some additional help finding points if they’re obsured by the chassis or something else in the way.  We used a laser level to line up the point from outside the car and then used the laser plumb bob under the chassis and lined it up as best as we could.  At the intersection of the laser points is where we made our mark.

Take your time on these steps and do them right.  The last thing you want to do is take the car off jackstands and realize you have more measurements to make…

Stay tuned for the next post.  This will cover transfering the measurements from the paper to the computer!

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