Also see http://autocross.com/
The following is a short description of some performance driving techniques geared toward the Miata. They are mostly to be applied to autocrossing, but can be applied to other performance driving situations.
Miatas are fun cars. They do have their idiosyncracies that need to be accounted for to get good autocross times.
Miatas have relatively small, high-revving engines, at least in stock form. 90-93 cars have the 1.6L motor, 94- on have the 1.8L, offering a little bit more torque. The 1.8 motors might be able to get away with fewer revs on launch.
While it is a good idea to encourage autocross event chairpersons to design courses that have obstacles soon after the start to prevent having to place too much stress on the drivetrain and especially clutch, some courses require a drag-race start. Launching the Miata is an exercise in car abuse.
A conversation with an experienced Miata autocrosser, when borrowing his car before this author purchased his own went something like this:
"At what RPM do you launch?" "Around 6,500." "No, really, where do you launch?" "Around 6,500." Can't be.
In the first run his car was launched at 5,500 (driver couldn't imagine launching that high, especially since at the time he drove a 5.0 Mustang and anything over 2,200 RPM resulted in smoke and little forward motion). Huge bog at 5,500.
Point being, a good launch unfortunately requires either very high RPM and a clutch drop, or somewhat lower RPM but a lot of clutch slippage. DISCLAIMER: Either way, this WILL result in premature clutch wear. Judge for yourself how important that extra couple of tenths of a second are worth to you.
Slaloms are fun in a Miata. The car is narrow and nimble. Approach from pretty much straight on, and if it is an even slalom, try to keep the weight balanced; steady throttle. Where possible, accelerating slightly thru the slalom is recommended to keep the rear planted. In general, a Miata will oversteer under trailing throttle (lifting) or braking (trailing braking) while entering or in a turn.
If the slalom is decreasing, entry speed and smooth slowdown is required to eliminated aforementioned tendency to wag the tail. Try not to enter too hot, so braking won't be necessary. Try to enter at a speed that lift throttle suffices to slow the car down.
Late, late, apexes. Usually first-gear turns, requiring a slow entry and a very late apex. Careful here, since entering too quickly will result in either having to roll out of the throttle (resultant oversteer), or trying to carry too much speed through, which at slower speeds typical of a pin-turn will result in understeer.
These can be loads of fun in a Miata. Keep the weight planted on the rear to avoid oversteer. Look WAY ahead and stay ahead of the course. Use early turn-in point (NOT to be confused with early apex!). Cut the distance, as opposed to using the classic "racing line". Miatas transition left-right- left very well, so the classic racing line, swinging out wide, will result in having to make "more of a turn", and add distance to the maneuver.
This is probably the most fun in the Miata. Again, keep the weight on the rear to avoid oversteer. Try to carry as much speed into the turn as possible, without overdriving. Miatas don't have a lot of horsepower to accelerate out, so carrying speed is important. Again, the classic late apex might not be as late as other heavier, torquier cars. Carrying speed through is a bit more important.
On long, constant-radius turns, a wide entry isn't necessarily required. A wide entry generally is to increase the radius of a turn. Since it's a long turn, going wide on entry doesn't afford much of a straightening. It might allow for a slightly faster entry, but that's about it.
On a fast sweeper, it's good to turn in decisively, to get the car to take a set quicker. Don't "wheel whip", but don't take too long. If the surface of the road is bumpy, the car will bounce around a little, unloading and loading the suspension. It's best to get the car to take an early set on its springs.
On a skidpad, it's very easy to steer
with the throttle. The line can be tightened with a gentle lift, and widened
with a little throttle.
- Carry speed through turns.
- Avoid too much trailbraking unless prepared to catch the car, or if trying to rotate the car for a subsequent maneuver. Braking in a straight line is recommended until the trailbraking oversteer is understood through experience.
- Weight the nose of the car under heavy braking gradually. A Miata will stop very well if the pedal is applied progressively. Don't just mash the pedal. Transfer the weight gradually, and it'll stop very quickly.
- Use "slow" hands. Wheel whipping will result in understeer. Again, weight the outside wheels gradually by using an early turn-in point (again, not an early apex), and progressively turn in. The car will reward slow hands by gripping unbelievably by time it's at the apex.
- Try to keep the revs over 3,000. If exiting a turn below that, depending on the situation, it might be better to drop down a gear on turn entry.
If you're in too hot, and it's going to loop, don't fight it. Let it come around. Both feet in. Many a car have been trashed by trying to catch a car way out of control, and perpetuating the mistake, careening into Hard Objects.
That being said, a Miata is a very catchable car, due to its light weight. If it's oversteering, countersteering usually catches it. Don't lift or it's all over. Remember that it will try to pendulum back the other way, so be prepared to catch it in that direction too. Use good judgement. If it's really out of control, give it up and don't hit anything.
In understeer conditions, there are a few ways to correct. If it's just mildly understeering, unwinding the steering wheel will often get the front tires gripping again. If it's understeering a lot, gently rolling out of the throttle will help the nose get traction. (Lifting too much will result in the tail kicking out.) Remember, though, that due to the low horsepower and torque, that giving up throttle can't be easily made up. Again, use judgement.
The Miata requires some specific techniques, being a low-horsepower, low-torque, light, nimble car. Just do it!
Miata
Mod Spec/Size/Brand Purpose Cost Gain Impact on Street
Bodywork remove spare tire/jack changes balance 0 don't bother pain to put back
rollbar stiffens chassis somewhat 200-500 small if any, cool looking
driver restraint control $80+rollbar 1000 small to none
trailer hitch for tires 150 none
Tires BFG 230 - 205/55R14 stickier better cornering 400 2 sec have to change (small price IMHO)
Yoko A008 RSII " " "
Wheels Alloy stiffer accurate handling 400-1000 100-200 weight
Shocks GAB control body roll,settings
Koni crisper transitions 400-500 500-1000 may rattle teeth out!
Tokiko
Brakes linings don't bother
Sway bar front (size?) control body roll 100-150 some
Suspension Alignment
Toe Front - out
Toe Rear -
Camber Front - max neg
Camber Rear - max neg
Caster Front - max pos
Caster Rear
Electrical Plugs/Wires small gain in new cars
Ignition settings not much leeway with in factory
Engine/Drive train
Air filter - K&N increase air flow 2-3 hp lifetime warranty
Muffler - (various) increase in hp, range louder
Oil filter increased capacity none
Limited slip (not allowed in base model)
Driver School smoother, lines, faster! 300-1500 2-4 sec safer
Seat time ditto, but slower return 10 per safer
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14 August, 2002 |