Turn 1: Banked, it is wide enough to turn a truck and trailer around. Normal apex. Some low HP cars will choose to stay low to avoid climbing the banking.
Turn 2: Roughly the same radius as T#1, but no banking. Normal apex. Most will want to brake or slow going into T#2, although many cars can go flat, warm up to it. If one must brake or lift, do it on the straight before entering T#2, there is an access road on the outside, use that as your "End of Braking" point and return to full throttle at that road so the car is stable through the turn. Most cars will be doing around 100mph here.
Turn 3: Most cars will require two down shifts. It is very easy over brake into and have too slow of an exit speed, only doing a single down shit forces one to keep momentum up. Others commonly lock up the brakes off and go shooting straight off the track, or carry too much speed and shoot off between T3 & T4. Speaking of which, the dirt around BIR is very soft sand.....if one goes off, don't fight to save it, drive straight, if you turn the wheels while in the dirt there is a good chance the wheel will dig in and flip the car! Going into T3 is a popular spot for late-brake passing...aka dive bombing. Very late apex, the curbing on the apex and track out are very smooth. Use all of the track, track out should be very near the end of track out curbing. Feel free to guard the inside against dive bombers going into T3, because the passing car will undoubtly steal the track out point away from you and compromise your line twice. If it is an out of class car you are better off lifting early and letting them pass you in the middle of the braking zone vs the end of it.
Turn 4: Most cars that did two downshifts into T3 will run out of gear before entering T4, so a short shift into the next gear and down shifting again for T4. IMHO the apex curbing is way to early. This is a sucker corner, late apex, but don't track out fully, come out only 1/2. If one tracks all the way out it makes T5 too difficult.
Turn 5: Momentum corner. A Miata can usually be full throttle from the exit of T4 all the way to the braking point for T6 and just a slight lift before turning in. Normal to late apex.
Turn 6: Scrub some speed before turning in, I commonly over slow for this one. Normal to late apex. IMHO the track out curbing stops too soon, the last foot or so is my track out point.
Turn 7: Just cut it shorten the track and enter the carousel wider. One can carry a lot of speed in and through T7 but requires dumping some of it before entering T8. It can get quite harry to dump speed, enter the carousel and down shift all in the exit of T7. Use a few inches of curbing, as they are smooth and it straightens out the approach to T8.
Turn 8: The carousel, debatable.....the "school" line is to enter it wide and tighten as one goes around it, touching the curbing one nearly completely around. Good handling cars can ride the inside all the way around but it does scrub the tires. No matter what approach is chosen, look for the curbing on the exit and use it. Holding the inside line tends have cars massively under-steer all the way around others will spin. Look for the old signage on the walls of the exit. Make faster cars pass you on the outside, the longer line, but be mindful of wanting to be on the driver side of the track for T9.
Turn 9: There is a corner that is formed by the track side walls, aim to basically take your driver's mirror off on that wall. Track out and clip T10. Get the car to lined up parallel with the wall.
Turn 10: Cut distance. The exit of T10 determines the approach to T11 and the pit straight. Apex normal and track all the way out if one wants the shortest line. Or apex late and don't track all the way out for a slightly safer line.
Turn 11: This turn seems to cause the most accidents of any turn, myself included. People will carry too much speed and fall off the track exit or catch it and shoot off to the inside. Others will clip the inside curbing getting the chassis upset and end up in a spin. An all to common mistake is for people to lift or brake in the turn, which obviously ends up poorly. There are two bumps that can upset the chassis. One bump is driver's left, there is an only access road there at turn. The other is near the apex.
Turn 12: Common place for dive bombing, protecting the inside is doable but it will be a compromised line. Many people will attempt to "hero brake" into the turn, and often end up locking up tires and go sliding off. It is possible to go so far off and hit a wall! The curbing on the inside is smooth for like the first 12 inches but don't go beyond that. Down shifting to 2nd gear usually isn't necessary. I recommend not tracking all the way out....only go 2/3rd's because the straight going to T13 comes all to quickly and there isn't enough time to go all the way track right on exit of T12 to get all the way track left in order to enter T13. Track entrance is on the exit of T12, so be mindful of cars entering.
Turn 13: Clip the inside apex curbing and track all the way out. There is plenty of run out room. T13 is the most important turn of the entire track. Your exit speed on T13 compounds all the way into T3. One can just go straight through T12 to T13 and exit the track, there is an access road behind the corner station. So....if there is a mechanical/crash issue it is closer to exit the track there vs. limping around the entire track.
