Wildncrazy

Limit your throttle modulation. Skip Barber teaches Christmas Tree. Start wide and gradually tighten your line. I tried that and it didn't really work for me, but I have noticed that as I got faster I do tend to make smaller and smaller flicks of the wheel towards the end of the slaloom so maybe that's what they meant and I was just doing it wrong before.

You can always tell the guys who are really on and off the throttle, they're the ones with the slowest times. It can unsettle the car even when you don't have lift throttle oversteer.

Race Miata

Wrong again, but wrong plus wrong makes it right!

Two wrong assumptions:
1). Mild oversteer setup = fast
2). Throttle modulation thru' slalom = slow

BUT, for a mild oversteer setup, throttle modulation DO slow you down. This is probably why you stick to both assumptions 1) and 2).

I've already pointed out why mild understeer is faster. Now why throttle modulation thru' a slalom is faster becomes clear -- because you need that extra rotation for the mild understeer setup. I'm not talking about on/off throttle trying to save a wildly fish-tailing car. I'm talking about tiny throttle modulation.

From another point of view, if you don't modulate throttle thru' a slalom, then a mild oversteer setup will be faster than a mild understeer setup thru' the slalom. But then this is exactly what I pointed out about comparing mild understeer vs mild oversteer setup. If you don't adjust your driving to optimize each setup, it's not a valid comparison.

rlaifatt

Theoretically, it seems to me that the car should be faster through a typical low-speed (tighter) corner with mild oversteer since, in theory, it will be taking a tighter line to the apex vs. the understeering car, getting to the apex in a shorter line and therefore also allowing you to get to the exit line earlier too. This would assume that you are delicate on the throttle so you don't lose the rear end where you have to "recover", but more like a very mild, controlled drift of the rear. I'm also visualizing a rally car as an extreme example where oversteer appears would be faster than understeer. I haven't compared the two myself so I'm just postulating. Where is my logic incorrect?

Iceman1

[QUOTE=rlaifatt,May 24 2006, 08:16 PM] I'm also visualizing a rally car as an extreme example where oversteer appears would be faster than understeer.

Wildncrazy

Sayin it don't make it so. The sky is falling! The sky is falling! Now that must be true.

Up until this thread I have never heard anyone say that mild understeer is faster than mild oversteer. The fact is that, contrary to what I prefer, I am faster with mild oversteer, especially in autocross where the need to rotate can overcome any inherent instability in a high speed stable state corner. Quickie polls on 2 other lists I am on also subscribe to the slight oversteer is faster theory. It seems that I am not the only one to find that so. Once again, I said go with whatever set up is faster for you. There is no perfect set up that works for everyone.

Every racing class I have taken also teaches slight oversteer (a loose set up) is faster EXCEPT in high hp/torque to weight cars that can use the throttle to rotate upon demand. Unless you are not running enough rubber the S is definitely not that kind of car.

As an example, Turbo Miatas would fall into the catagory of needing some understeer because they can rotate upon demand if they are in the right gear, but my 99 Miata also needs to have some help around the corners, more like rlaifatt was postulating.

Also notice I didn't say no throttle modulation in a slaloom I said "limit your throttle modulation" I didn't know how else to say it to make the point that the on again off again school of slalooming is upsetting to the car and slower than a balanced approach, however much fun it might be.

Balance is the key. I am not advocating a scary loose car at all. Tail out racing might look good on F&F but it is typically slower on the pavement than a more balanced set up.

Slow in fast out!

Orthonormal

If the suspension is tuned such that it understeers when accelerating, that limits how early you can get on the gas coming out of a turn.

Earlier in the year I was having trouble because I was having to lift to get the car to turn in, when I should have been able to be on the gas. With less rear toe, the I can get on the gas earlier now. The car might still get mild understeer at neutral throttle...

Orthonormal

PS - Randy Noll is an Evolution instructor and prefers mild understeer in his setups. He says it makes the car more forgiving of slight mistakes, which can be helpful when you only have three tries to turn in a good time. The cars he had been driving when he developed that preference were definitely not of the "available power oversteer" sort -- non-Turbo MR2s.

On the other hand, Michael and Kyung Wootton run a mild-oversteer setup on their Miata. They are usually extremely fast, but they seem to hit cones more often than the norm.

It seems to come down to personal preference. For most people, a mild understeer setup is probably more friendly and easy to control.

mikegarrison

Keep in mind that rally cars are driving with a much lower coef of friction than we are. In the olden days of yore, the four wheel drift was THE fast way around a corner. Now nobody uses it. What changed? Grip -- the same thing that is lacking on a dirt or gravel road, which is why extreme oversteer is still favored in rally cars.

Anyway, RM's observation that the setup you are fastest with is tied to your driving style is also valid.

Race Miata

I used to run my miata with mild oversteer at first. Then I started questioning why a RWD car "had to" wear out more rear tires than the front. Why could we not run more front roll-stiffness to shift part of the cornering load from the rear tires to the front ones so that the rear tires can focus more on accelerating the car, yielding even tire wear front to back?

So, I tried out more front roll-stiffness for the car. I didn't like it at first because I kept trying to drive the mild understeer setup like I do the previous mild oversteer setup. Eventually, I figured out the key to drive a mild understeer setup fast was to keep it mildy understeer and don't back off. It's intuitive to back off as soon as you find understeer. That's not the way to drive a mild understeer setup fast. You have to hang on and keep it mildly understeer to go fast. That means you'll have to plan further ahead than with a mild oversteer setup. You'll also need a lot of trail-braking and/or momentary lifting after turn-in (which means able to dive deep into corners) to go fast.

I finally got it right at an autoX event. People working the course were amazed that I used so little brakes thru'out the the entire course. In particular, there was a mid-speed 180 following a top-of-2nd-gear stretch where most cars had to brake for the 180. For some oversteering cars, it was even a hard braking zone. But for me, I was able to dive into the 180 at WOT with mild understeer and then lift AFTER turn-in for just a short moment to rotate the car and then get back on WOT throughout the rest of the 180. On that same course, there was also a tight gate that requires a tight 180 to go thru'. With trail-braking and good coordination between line, brake, gas, and steering, my mild understeer setup was not a burden for that tight turn. I got FTD by a big margin that day and a few other events that followed. My tire wear was quite even front to back since then.

Race Miata

In that case, it's not mild understeer. It sounds like moderate understeer. When I say mild understeer, I refer to a setup that will understeer mildly on skidpad with constant speed. Such mild understeer setup will see less understeer with trail-braking and/or lifting after turn-in because of the weight transfer to the front. When such mild understeer setup is tuned just right and the line/gas/steering coordination are perfect to match, you should feel both front and rear tires are at their traction limit at the same time while you go WOT out of corners. I know my miata did.

With a mild oversteer setup (on skidpad with constant speed), adding power out of a turn will most likely break rear traction first. And with such setup, you cannot dive deep into corners because you need to be back on the gas before max G thru' the turn.