Cockroach Individual M3 5/4 Another String Alignment

[samthejam]

Untitled by Sam DaJam, on Flickr
Untitled by Sam DaJam, on Flickr
Untitled by Sam DaJam, on Flickr


Car has not moved too much, I am going to Road Atlanta in 2 weeks? But we are also in process of buying a house that has a detached shop, so hopefully I can finally have a space of my own to wrench in instead of borrowing someone elses.

I checked the alignment, I did not it felt like it shifted at last PCA event. It did. It went from 4mm toe out to 5mm toe in. Why? idk nothing is obviously loose or broken. Everything is paint marked, there is no smoking gun.

I hate those bimmerworld trackcabs.

I will be switching to Turner Monoballs and hopefully some new Lemforder arms. I have some takeoff ones but would like to do new, but we will see how the home goes. I have a dyno scheduled in Atlanta just to check it over, wanted to do new tires and pads but these will have to do.

[bigjae46]

They key to alignments is repeatability. The car has to be rolled to settle the suspension so if the car is sitting on wheel cribs, the cribs must be long enough to roll the tire one full rotation. Must do that even when using turn plates. That will be why you get a significantly different reading.

The wheel cribs should be laser leveled to be close. The closer to level...the alignment will be more repeatable.

I find that zeroing the SZL in a scan tool or INPA massively improves repeatability. Even if the wheel looks straight, probably is off enough to skew the toe reading. AND...when most center the wheel they are sticking their head through the window and not sitting in the driver's seat which should have ballast in it anyway using the BMW spec. Ballast in both front seats.

[samthejam]

They key to alignments is repeatability. The car has to be rolled to settle the suspension so if the car is sitting on wheel cribs, the cribs must be long enough to roll the tire one full rotation. Must do that even when using turn plates. That will be why you get a significantly different reading.

The wheel cribs should be laser leveled to be close. The closer to level...the alignment will be more repeatable.

I find that zeroing the SZL in a scan tool or INPA massively improves repeatability. Even if the wheel looks straight, probably is off enough to skew the toe reading. AND...when most center the wheel they are sticking their head through the window and not sitting in the driver's seat which should have ballast in it anyway using the BMW spec. Ballast in both front seats.

Great point on using the steering angle sensor. I'll add that to the routine. I love that. I make it a point to crawl into the car to put it straight head, but it still has human error.

The tables we use our laser leveled, and I trust the person helping me as our rear measurement was perfect. We always raise and lower the car handbrake off in neutral on the stands and repeat the measurements twice and it is usually very consistent but we are not getting the roll. The stands/tables have large casters that allow it to settle as needed, but it isn't as good as a full roll.

Car is now tracking straight again like when I headed to track Saturday.