mr58

What do most of you use for alignment specs? Do you go on the performance end of the factory alignment specs? This is my daily driver, but I do appreciate great handling on the road.

Thanks

'14 C2

drcollie

For maximum and even tire wear, best stay with the factory specs. Once you start tweaking for track days and autocross (and toss in some camber mods) your even tire wear goes out the window.

mr58

Can't you stay within the factory specs but go towards the performance end of the factory range? Will that cause issues/uneven tire wear?

Thanks

drcollie

What exactly is your goal? You have to have a defined parameter to tweak settings and a bias towards one will be offset by a penalty somewhere else. This is in all cars, not just a Porsche. All carmakers set their vehicles up to have some form of mild understeer from the factory. They do that because of safety concerns and that fact that the vast majority of their customers are not high performance drivers. Why do you want that mild understeer? Well, it keeps you out of trouble is why. Example:

You come off the interstate onto a de-acceleration ramp and realize you are carrying more speed into the turn than you are comfortable with. What is your reaction? Most people will let off the gas and perhaps tap the brakes, and in a car that mildly understeers that results in a car that easily complies with the driver's inputs. It slows and wants to turn into the corner gently No drama.

Now take that same scenario and lets say you cranked in some toe and camber for crisper, more dramatic steering inputs. Now you are in the corner too fast and if you let off the gas and tap the brakes the car is going to snap and spin on you, and in most cases that results in an ***-end first trip to the guardrail and a wreck. That's why you have to be careful with oversteer.

When I was actively autocrossing I used to use a very aggressive toe setting and camber plates on the car (back then it was an E36 M3). I could get marvelous snap-steering around the cones and incredible turn-in. Downside was the right home on the highway, the car would be hugely nervous and darty, especially at higher speeds. On track days, I would have the settings more aggressive than stock, but far less than autocross. The goal was a neutral handing setup, neither over or under steer. I used to have paint markings on my camber plates and also my tie rods under the car for super quick field alignments that I could so myself once the car was jacked up. With both the Track and Auto-X settings my tires would wear rapidly on the edges, but that was OK - I was good with getting one season out of a set of R-Compounds.

There is no camber adjustment on a 991, you would have to add aftermarket parts to do so. That leaves tow adjustment, which by itself is just mostly going to screw up your tire wear and make the car a little squirrelly. However you can get down under the car and after marking your stock settings with some paint, adjust away and then go take it for a ride. The paint marks will allow you to get back to the stock setting when you are done experimenting.

mr58

Hello - the tech is rcommending increasing the camber at the front to ~-1.1 on each side (outside of Porsches recommendation) but keeping the toe within Porsche recommendations. He says it will benefit the handling significantly without affecting tire wear. He says the car will handling much more neutral this way (and he says -1.1 isn't much camber even though outside of green).

Thoughts? Thanks

drcollie

If he shoves the camber all the way to the stops you likely will see slightly crisper handing and lose about 1/3 to 1/4 tire life because your inside edge of the tires will cord out before the centers. I'd not do it personally, but the worst that will happen is you have to pay for an alignment and a set of tires....