SWelsch

When measured from top of rim to bottom of fender/ wheel well I get the exact same reading on each wheel yet the settings via OBD are quite different. Why?

MP4.2+6.0

Start with, be sure the parking surface you are using is very flat. Check with a long level (or long straight board with a shorter level on top) in both directions. If it isn't level, car is essentially tweaked in the corners ride height wise to deal with unevenness. Won't matter much if there is a slight slope in only one direction, but if it rolls off to one side in the second direction at same time, that's sort of like sticking a little jack under one tire.

After that, expect some is build tolerance.

the_duke

I think I understand what you're saying. When you physically measure them they are the same but your scan tool shows different measurements at each wheel? If that is what you are saying then the answer is simple. There is a slight variance between all the sensors at the wheels. When the ride height is set up they adjust the setting at each wheel to make sure the physical measurements are equal at all wheels.

SWelsch

Gotcha, thnx!

MP4.2+6.0

Agreed with this. You are trying to set the actual measured height (with a physical ruler) to be the same side to side, even with some variances in the readout. I found it took several tries to get it pretty close--it can undershoot or overshoot on each attempt. Also be sure you relaize the sway bars effectively tie the two sides of either axle together to some good extent, especially in front where the bar is very substantial. Thus, the four corners do not truly move independently, not are they controlled just by that corner's ride height setting. I actually ended up sticking pieces of blue tape at each corner and writing down the as measured numbers each time--until I got down to about 1/8" (3mm or so) of some back and forth inconsistency after each adjustment that was not really wringing out. Be careful though about a few things as explained below. I find easiest way to keep starting point settings with VCDS is just snap some shots with your camera phone as you go. Then you can always reverse, and have an easy record longer term too.

Again, the floor/surface car is parked on has got to be consistent in both dimensions. Don't assume that on a home garage floor, which is often sloped one way for some drainage to start with. When I checked ours, I knew it was sloped toward the doors for general drainage. I found one of the two sides was pretty consistent left to right as well, but the side I park my S8 on usually was not. There was probably a good half inch of discrepancy side to side at the axles. That discrepancy would have meant I was trying to set things effectively with a half inch block of wood under one of the four tires had I proceeded. Maybe said another way, if you find yourself adding different amounts to the right and left sides of either axle from the factory original settings, be suspicious something may be wrong with the floor the car is sitting on. In the end, I decided to stick to the same relative difference I started with left to right when I changed overall height. Thus if left the left front said 408 (made up #), and right front said 402 to start, and I wanted to go down 10 mm, I moved both by the same 10mm and maintained that 6mm delta in the changed settings. Since my car was almost new when I got it CPO and there were no service records about an alignment, I figured I was starting from factory settings and calibrations and their rack was far better than my garage floor even on the more consistently level side.

Different front to back numbers are expected. You can alter the rake slightly if you adjust them differentially front to back. As another heads up, realize though if you do it, that is tweaking headlight settings, and maybe more critically the calibration of a variety of sensors. Be careful in this regard (rake changes), and likely keep a good record of the starting settings in case something goes wrong and you later get sensor errors. This last point is really not something you would find in the older posts and then cribbed ride height instructions from when the mod was first developed for the D3--about ten years ago now. Most D3's didn't even have adaptive cruise, let alone side assist, lane change, cameras, etc.

SWelsch

I used the scanner settings I got when I wss getting ready to lower the car. Added 10mm to each setting as the car looked and felt level from the factory. Not sure I would notice a mm or 2. Was just curious about difference in original setting. Build tolerances I guess