I wrote the following email after someone asked me some questions on racing...
> This may sound really stupid, but what makes you faster on
> some days than
> others? And what makes some guys faster? Don't you all have the same
Those are good questions, as you can see by the length of the email it took to answer them.
Yes, we all have the same engines but there are many things that can be adjusted on the car such as engine timing, suspension settings, and tire pressures. So even if driver skill is the same, good research and testing will find the right settings that can gain another second or two per lap. And the "right setup" will change depending on weather conditions, whether you're in the early stages of the race or the later stages (because the handling will change, based on things like the change in rear weight as the gas is used up, and how hot the tires get), and other factors. So a lot of how fast someone goes on a given weekend will depend on those adjustable things. Then, on top of that, there are things that vary from car to car depending on how much money you have to spend. The rules of a spec series like Spec Miata are intended to limit the amount of money you can spend on the car, in order to reduce that variance and make it about who's the best driver and not who has the most money, but you'll still never get away from people with more money having an advantage, like being able to freshen their engines (an old engine vs a new one can make a 1-2 sec/lap difference, and a "freshened" new motor can take another fraction of a second off), and then there are things like lightweight clutches and other non-stock parts that are allowed, but cost more money. On top of all that, there are people who are developing the car over and above stock but still within the rules, those who are bending the rules, and people who are downright cheating (like doing things to their engines or suspensions that are not allowed). Hopefully the last group are getting caught, but it's still another factor in why some people are faster than others.
Also, tires are a big variable. Even though we all use the same tire, the tires can be faster or slower depending on how old they are, how much tread is left, and how hard or how long they've been driven in a given session. Most people shave their tires before using them since, unless the track is very wet, they are faster with less tread. But, if the tread is too far gone the tires can "go away" and get greasy after a few laps. So ideally you want one set of tires which are at their peak to use for qualifying, and another set for the race (which have been broken in but have enough life left to not get greasy at the end of the race.) You should also have a 3rd set for practicing on, so you don't wear out your race and qual tires - or to use as spares if a tire gets damaged during practice or qualifying. You might also need a set of rain tires... And in fact, another variable that can make one driver faster than another is guessing correctly about whether it's going to rain or not in the upcoming session: you want to go out with shaved tires if it's dry, and full tread if wet - guess wrong and you'll not have as much grip as the guy who guessed right. But anyway, the condition of the tires can make a difference of up to 3 seconds a lap, even in the dry.
And note that if you have 3-4 sets of tires, you also need 3-4 sets of wheels, or be willing to unmount and mount a lot - either option takes more money. If someone is racing on a budget, they might be slower because they have fewer tire options.
But all of the above factors pale in comparison to driver skill, which makes the biggest difference. You can cheat all you want, have the best car, engine, tires, settings, etc., but if you're a mediocre driver you will still be much, much slower than a good driver. If, for example, a first time driver can do a 2:30 lap, then a mediocre driver can go out in the same car and go 15 seconds a lap faster. A good driver can go another 5-10 sec faster than a mediocre driver. An excellent driver (like the guys who are winning races) can go another 1-3 seconds faster than a good driver. (Typically, the majority of the Spec Miata field is usually separated by 6-8 seconds.)
Driving the car well involves a lot of factors: The ability to find the cornering and braking limits of the car, the ability to be *at* those limits constantly, the ability to find the fastest line through every corner and/or series of corners, the ability to read and adjust to changing track conditions, to monitor the gauges to make sure you're not losing oil pressure or overheating, and to monitor the changing handling characteristics of the car. And even if you can do all that for a couple corners, if you mess up one corner: brake too early or too late, turn in too early or too late, enter the corner too fast or too slow, fail to be smooth on the steering and throttle inputs and end up getting the car sideways, *succeed* in being smooth on the steering and throttle inputs but *still* stepping out the back end anyway simply because you were asking the car to do to much, miss a shift... Get any *one* of those things wrong in any *one* corner and you just blew a chance at a good lap time. It takes a lot of concentration.
But I haven't even got to the best part. I haven't talked about actual racing yet, which is where the fast *racers* are separated from the fast *drivers*. All of the above only speaks to how fast a driver you are - i.e., how fast you can get around the track one time without worrying about any other cars or having any strategy (other than maybe finding some clear space in qualifying.) Once the race starts, everything I wrote above still applies to how fast or slow you will be, but now you *also* need to think about not getting caught napping on the start, your strategy for how you're going to pass the car in front of you and not let the car behind you pass you... You need to often change your line through the corners because you're inches away from another car, or you're taking a defensive line, but you can't defend too much because that slows you down so even if you keep the car behind you, it might allow other cars to catch both of you (plus you're losing contact with the cars in front of you.) You have to be aware of how much race is left in order to judge how aggressive you should be. You have to be setting up passes many corners in advance, sometimes laps in advance, because you need to watch the guy in front of you to see where on the track you're faster than they are, and time it so you get a good run on them at that point. You have to know the other drivers and their tendencies, so you can know whether they're likely to take the bait if you try to fake a pass on them, or whether you can go side-by-side through a corner without them turning down on you and taking you out. And you have to do all that lap after lap for about 30 minutes, in a typical race. The ability to do all of the above is called "racecraft". Someone who has good racecraft and is consistent over the course of the whole race can often beat drivers who may have been able to put together one faster lap in qualifying but can't maintain that pace the whole race. Anyway, the only way to get top 5 in a race, let alone win, (at least in this region, which is probably the most competitive Spec Miata region in the country: The first 3 finishers at the Nationals this year, and 5 of the top 10, were all from the west coast) is to drive darn near perfectly (both strategically and with respect to car control) the whole time.
So basically, the reason I'm faster on some days than others is that this is a sport like any other - it takes a fair amount of skill and concentration, and some days I'm dialed in more than others mentally, physically, and car settings-wise.
And luck plays a factor too: maybe in how well the car is running (things wear down and/or break without necessarily being noticeable or fixable, which can make the car slower - a good example is the issue with my differential in the final race of 2004, which was still functioning but the added friction from it slowly breaking down might be enough to cost me a car length on the straightaway, and hence make the difference between being able to pass a car or not)... or with respect to getting my settings dialed in, or with respect to not hitting that patch of oil that the car in front of me just dropped, or the patch of dirt or sand that was just brought onto the track from some car going off and coming back on. Luck will almost always come into play at some point during the race, like when I finish higher than I otherwise would because someone faster than me made a mistake, or when I get taken out of the race at the start as a result of a chain reaction.
To some extent, the above also applies to the question of why some drivers are faster than others (i.e. some drivers are better at being dialed in, or at maintaining focus, or are luckier on a given day), but the biggest factor here is difference in skill levels, plain and simple. Some guys (and girls) are just better drivers than others. Sometimes it's because they have more experience, sometimes it's because they are more naturally talented, sometimes it's because they put more effort into becoming better (like analyzing on-track data and in-car video, reading books, staying in shape), sometimes one driver is just more consistent than another, and sometimes the difference might be one driver has less fear than another and is willing to push the car a little bit harder and be more on the edge of losing it.
Hope that helps clear things up,