So I'm resurrecting this old thread back from the dead because of the raging debate from the
Z06 vs. F430 vs. 911TT thread that I never felt was settled. Despite the fact that the thread was hopelessly off topic, I felt there were some very good posts in there that deserved some follow-up.
When I created this thread, I had a hard time putting to words
exactly what made a good handling car. Well, it's a couple of years later, and I've finally put some of my thoughts together now that I have a moment.
Specifically, the issue of raw numbers (skidpad and slalom) vs. real world feel and communication. Someone in that thread remarked that 'feel' was something unquantifiable, and therefore his argument for a measurable approach to handling was superior.
As I stated in that thread: skidpad measures mechanical grip. This is only a small portion of the vehicle dynamics spectrum we call handling. Handling is
behavior. After years of trying to figure it out, I think I can finally put some objective qualities to what behaviors 'feel' good. Here we go:
Steering. A good handling car has steering that effectively communicates two crucial bits of information about the front tires: which way they are pointing AND (when loaded) how much slip angle is on them. It needs to do this faithfully, accurately and transparently, regardless of which way the chassis is loaded.
It also needs to have a good noise to signal ratio. This means that while it should deliver information about the road texture (which affects grip), it should not overwhelm the driver with so much information that makes it difficult for him to concentrate on the task at hand.
Stability. Not only should the car remain stable before the limits are achieved, a good handling car should maintain its composer even after mechanical grip has been exceeded. Which brings us to...
Natural transition between grip and drift. When grip has been exceeded and the tires begin to slide, the breakaway point should not be abrupt. While this quality is largely dependant on the particular tire, it is also up to the chassis design and tuning to help facilitate this transition.
Response. A good handling car needs to respond quickly and accurately to drive inputs, while allowing for a healthy margin error for 'ham-fistedness'. The chassis should load up quickly in a sharp turn, without excessive body motion.
Steady-state balance. Under steady state conditions (i.e. after the chassis has loaded up in a turn), the car should not only remain stable enough as to not go off-line, but malleable enough so that the driver can tighten up or go wider if he needs to. In other words, even after committing to a turn, the chassis should allow the driver to make small changes to the attitude of the car with the steering, brakes or throttle.
Transitional balance. When moving from one steady state to another (i.e. transitioning load), a good handling car must quickly shift loads with a minimum of instability or unpredictability.
Feedback. Finally, a good handling car is constantly feeding quality information about how it performs all of the above tasks through not only the steering, but the seats as well. A good driver should be able to sense the load moving from one part of the car to the next, and consequently be able to make full use of each of the tires.
There's probably a bit more to it, but that's the general gist of things. Feel free to comment; good, bad or indifferent.
M