I found this to be pretty helpful when coming to the track
Turn-By-Turn Description of Donnybrooke Road Course
The 3.1-mile Donnybrooke Road Course has 10 turns and is considered wide – the main straight is 60 feet wide. There is essentially no elevation change. BIR is a very high-speed course; vehicles can reach speeds of nearly 160 mph and take the slowest corners around 80 mph. There are wide runoff areas at most of the corners, which makes BIR’s road course extremely safe.The ground off the edge of the track is generally smooth, except for rutted runoff areas at the exit of Turns 2 and 3, curbs on the outsides of the exits of Turns 4 through 8, and ditches and low (two- to three-foot) banks six or eight feet off the right-hand edge of the track coming into Turns 4 and 7. The mile-long straightaway, which doubles as BIR’s drag strip, was replaced in 2004 and is now one of the flattest and fastest pieces of pavement on the planet. The entire track is extremely smooth, except for the straight from Turn 9 into Turn 10, which remains somewhat abrasive. The track is otherwise remarkably free of other bumps, frost heaves, holes and pavement flaws.
What follows is a generic description of the track, describing its features without defining speeds, gears or shift points, all of which will vary widely between vehicle types.
Most of the turns at BIR are separated by straight segments, allowing them to be treated as isolated turns. Only Turns 7 and 8 can be considered as clustered turns (where your line through or out of a turn must be modified to accommodate the requirements of the next turn or the one after it).
The starter’s stand is about halfway down the drag strip and is clearly visible from the last turn. The front straight is extremely wide and leads into the narrower but very high-speed banked right-hand 60-degree Turn 1, which is intended be taken flat out by all vehicles. You can go through Turn 1 pretty much anywhere on the width of the track, although you will scrub off less speed if you are alone and can take the “classic” maximum-radius line through the corner. Following Turn 1 is a straight that’s long enough for you to regain most or all of the speed you scrubbed off in Turn 1. Turn 2 is a flat (but wider radius than Turn 1) and very high-speed right-hand 80-degree sweeper that can be taken flat out by many vehicles. The track is widened at the exit of Turn 2 but only for a short distance. There is a long, generally flat runoff area at the exit of 2, with a robust tire wall just short of the trees. Following Turn 2 is another straight, again long enough for you to regain much of the speed you scrubbed off on 2.
Your car’s top speed at BIR will be limited by aerodynamics and power, rather than by torque and weight as at slower tracks. You should be able to attain your top speed before entering Turn 1, and may be able to reach it again coming into Turn 2 and possibly into Turn 3. Maintaining a high speed in this part of the course is crucial to good lap times. Just be sure not to overstress your engine. You will be spending a lot of time at max revs, and turning hard right, so be sure your oil pickup is properly located.
Turn 3 is slow only by comparison with the two previous turns, but many drivers don’t brake properly for it (after all, it’s your first chance to use the brakes for over a mile, and they will be well cooled). Turn 3 is a 130-degree right-hand turn with a curb at the exit, with a following short straight leading into the left-hand Turn 4. Turns 4, 5 and 6 are a set of esses with progressively longer straight stretches following them, and curbs at the exits of all three. Turn 4 is about a 100-degree left-hand turn, slightly faster then Turn 3. Turns 5 and 6 are 90-degree right and left turns, respectively, both a little slower than Turn 4. The turns in the esses are far enough apart that you can easily get back across the track each time, and you may even recover enough speed that you need to change gears up and down between them (this more likely coming out of 5 and 6, if you change up and back down between 4 and 5 you may be geared wrong).
Look for slightly widened track surfaces at the entrance to all these turns. They may help you but watch out for Turn 6, where using the widened entry will likely cause you to apex too early.
Turn 7 is a higher-speed left-hand 45-degree turn that is followed very closely by Turn 8. You must make a very late apex in Turn 7 and stay to the left edge of the track at the exit to be set up properly for Turn 8. The track surface is substantially widened at the entry to Turn 7, and again at the entry to Turn 8, which is a 75-degree right-hand turn that’s followed by a short straight leading into the fast 60-degree right-hand Turn 9, under the vehicle access bridge. Taking the Turn 9 apex too early can put you into the bridge abutment, and you will be going fast enough here for that to be most undesirable.
The straight following Turn 9 runs past the drag strip paddock area down into Turn 10, which is a fast and very wide 120-degree right-hand turn leading out onto the front straight. There is a little dip on the inside that gives the effect of a slight banking, but it may be too early for practical use as an apex. You can swing wide coming out of Turn 10 but check this out carefully since the track surface appears to fall off camber on the outside half of the pavement (it feels as if it does but doesn’t look like it). Don’t go too wide; if you get too far to the left before stabilizing the vehicle in a straight-ahead attitude you may come unstuck going over the burnout area of the drag strip and hit the end of the guard rail at driver’s left. One you’ve straightened it out, though, it’s just a matter of keeping your foot down and your eye on the mirror until you come into Turn 3 again. (Oh, and don’t forget to shift up occasionally.) Keep an eye out for merging traffic from the pit exit onto the track, beyond the starter’s stand coming into Turn 1.
