Yes We Camber!

Now that I have a fresh new U-joint in the steering and the winter gas is all burned off, it's time to get ready for racing. This year I intend to work hard to ensure that the camber and toe are properly set, the car is corner balanced, and I hope to work out the best settings for my shocks, sway bar and tire pressures in light of the new setup.

That's about a six variable optimization (if you don't count weather & temperature), which is kind of daunting. Where does one start?

While I was doing the work on the steering, I noticed that my right side had a lot fewer camber plates than the left, so I had a strong suspicion that my side to side camber was not correct. Therefore, since this appears likely to be out of whack and since the settings are available on Lotus-Talk, I'll start there.

Over the winter, I bought a SmartCamber tool, but before I can use it I need to get the car on a level surface and equipped as if it were racing. We want to optimize for racing so the setup will be slightly off for road use, but road driving isn't a competition (despite what the folks in the urban assault vehicles seem to think).

I put on the race tires, removed the tow bar and put 150lbs of books and break rotors in the driver's seat to simulate the driver (which is around 7% of the weight of the car!). To level the car, I shimmed the wheels with linoleum tiles (available for 69 cents each in Home Depot). I measured how many each wheel needed with a 78" long level resting on a couple of sockets and the SmartCamber tool, which is really just a fancy level. After marking the point I measured the tiles, rolled the car to that point and jacked it up. After jacking the car up, and placing the tiles under the wheels I also inserted a plastic bag folded over with some motor oil between the folds. This allows the tires to slip sideways when the car comes back down and avoids the need to roll the car back and forth.

The camber measured -1.1 on the right side and -0.1 on the left side. That's a whole degree of difference, which may go a long way to explaining why my car tended to ABS earlier than it should in threshold breaking. Also, thinking back I can't remember any spins that were clockwise. I hadn't thought about it before, but I suspect that the setup I had settled on in terms of shocks/tire pressures and sway bar settings last year was flawed. Possibly, the right side of the car was slightly tail happy, but neutral on the left, which would be consistent with a better camber setting on the right that gave the front right more traction in a left turn than the front left had in a right turn.

The rear was better, -2.0 on the right, and -1.7 on the left. The latter is stock and the former is just a little bit less than the recommended setting for autocross which is -2.25.

I took out all three shims on the front left, one on the right rear and two out of the left rear. The result was -1.0/-1.1 in the front and -2.1 -2.3 in the rear. This is now within the .2 side to side tolerance recommended by Lotus (just barely for the rear). Many serious racers seek even more negative camber in the front, but to achieve more one needs to replace or mill the steering arms.

Anway, Next up... Measuring the Toe. Here are some pictures of my setup...