Wednesday, August 15, 2007
Thunderhill Driving Notes
Video of me on a lap around Thunderhill
NASA uses 5a and SCCA uses 5. SCCA slows down turns 1 and 8 by placing cones to divide the lane by 1/2. Use the same turn in points but slower. On 8, don't try to go outside after the cones as that'll usually cause you the miss the apex.
General note for any new track: Late apex everything to get a feel for the track. Slowly move back turn in point to find optimal point. Use all the track, even if you'll not going fast enough because eventually you'll and you want to burn the line into your mind.
Turn 1: Move quickly to right side of track after pit entrance. Brake on marker 3, DS on 2, and start turn in around 1. DS is optional but needs to be done at or before 5.
Turn 2: Tap brakes around 2. Turn in at 2/3 from inside. Not quite sure of the line yet, except to keep eye on apex and exit berm. Get on gas as early as possible and still hit apex. Needs more work.
Alternate path: Use a double apex. Start near the middle of the road, hit the 1st apex, drift to outside by 12'Oclock, turn in and gun it toward the 2nd apex. I think this will gave a much faster exist speed. I think I rode with an RX7 that did this and he had an incredible exit speed.
Turn 3: Entry turn one car width from right side. Stay inside the entire turn. Outside and middle of track has negative camber.
Alternative: Enter a wide. Done properly, this should allow more exit speed, but it's harder and there isn't much of a straight between 3 and 4.
Fun stuff to do: Try doing this turn in the middle and outside of the track. These are racing lines. However, once the car is on the outside, don't try coming toward the inside, you'll have to slow down too much to do this.
Turn 4: After exiting 3, use the short straight to let the car settle. Tap the brakes to load the front just before turn in. For 5a, exit is middle of berm. For 5, look ahead to entry of 5.
Turn 5a: May not be necessary to tap the brakes before the downhill, but its nerve racking not to. The downhill before turn 5 is probably the only place on the course where you may coast on a straight. Enter turn one car width from left. Turn in as car gets to the bottom and traction is regained. Stay inside as tight as possible with throttle steer. I think this is the funnest turn on the course.
Turn 5: Brake hard on uphill and slow the car way down. Whip car around to face the water tower and go full throttle while still on top of the hill. However the car settles at the bottom, leave it(don't change steering input) and use throttle steer exclusively. Near the beginning of the turn, the car will want to drift away from the inside. This is OK, just keep looking at the exit and the car will be in the right place for 6.
If you didn't brake hard enough or turn enough at the top of the hill in 5, then you'll still be turning on the downhill and won't be able to apply full throttle.
If the car is pointed too far right of the water tower, you may run off the road. The run off is pretty smooth, so it's probably safer to run off than correct and risk rolling sideways down the hill. I ran off and it didn't seem to cause any problems for my car. I was really surprise at the lack of any big bumps.
Turn 6: Tap brakes to settle the front, throw the car a the apex, and hit the throttle to plant the rear. If done right, you'll be applying a good amount of throttle through the turn and touch the middle of the exit berm. If you don't get close enough to the apex, you'll run wide and have to ease off the throttle to stay on the track.
Turn 7: Check tach. Depending on how you exited 6, you may not have enough RPMs left to make it through 7.
Turn 8: Tap brakes or briefly lift, thrown car at apex, full throttle and hold on. It may not be necessary to brake or lift. Consider the run pave off as part of the track. If cones are used to reduce the width of the track(SCCA), don't try to move to the right side after the cones. You'll miss the apex and/or unsettle your car whipping it right and left so quickly at such high speeds.
Turn 9: Brake at 3, throw car at apex at 1/1.5, and get on the gas hard. Leave about a car's width from outside at crest, the road will continue to turn such that you'll find yourself at the edge coming over the hill. At the bottom, concentrate on getting to right side of track with full throttle. It's not necessary to use the full left side of the track. Make sure the car is got pretty of straight for braking for 10.
Turn 10: Brake hard before 3, DS to 3rd at 2. Throw car at apex at 1. This is the highest banked turn on the track so it's considerable faster than 11.
Turn 11: This is a throw away turn. Brake hard and early, it's a very very slow turn. Exit in middle of the track to setup 12/13. Getting on the berm will help to whip the rear around and it won't unsettle your car as much as you think. the berm seem big, but you're very slow. Carefully getting on the gas here. Due to the low speed and tightness, even low horsepower cars spin out here. My Miata did and I've seem quite a few other do the same here.
Turns 12/13: An S turn combo. There should be a split second between 2 and 3 where the car is straight. Shift to 3 here. On 12, consider the runoff area as part of the track. It's pretty smooth.
Turn 14: Downhill after bridge, so allow an extra distance for braking, like an imaginary 4th marker. Turn in pass 1 and get on the inside berm at apex. The apex is about 15' pass corner and not visible at the start of the turn Turns 14 and 15 can be turned into a single large sweeper by using the bumppy run off area of the track. Don't venture more than a car's length or two into the run off area was what the instructors suggested. I didn't bother to found out why this is.
Turn 15: Don't hit the inside berm as that'll unsettle the car. Get on the throttle as much as possible coming out of 14 and stay on. It's OK to ride the outside berm. If you run of the track here, don't be in a hurry to get back on. This is the most likely place where you can crash into someone or the wall.
Recovery of getting 2 wheels off the track.
#1 Don't panic
#2 Don't jerk the wheel
#3 ease off throttle
#4 ease the car back on the track or let it run off.
See the end of the video to view my recovery.
NASA uses 5a and SCCA uses 5. SCCA slows down turns 1 and 8 by placing cones to divide the lane by 1/2. Use the same turn in points but slower. On 8, don't try to go outside after the cones as that'll usually cause you the miss the apex.
General note for any new track: Late apex everything to get a feel for the track. Slowly move back turn in point to find optimal point. Use all the track, even if you'll not going fast enough because eventually you'll and you want to burn the line into your mind.
Turn 1: Move quickly to right side of track after pit entrance. Brake on marker 3, DS on 2, and start turn in around 1. DS is optional but needs to be done at or before 5.
Turn 2: Tap brakes around 2. Turn in at 2/3 from inside. Not quite sure of the line yet, except to keep eye on apex and exit berm. Get on gas as early as possible and still hit apex. Needs more work.
Alternate path: Use a double apex. Start near the middle of the road, hit the 1st apex, drift to outside by 12'Oclock, turn in and gun it toward the 2nd apex. I think this will gave a much faster exist speed. I think I rode with an RX7 that did this and he had an incredible exit speed.
Turn 3: Entry turn one car width from right side. Stay inside the entire turn. Outside and middle of track has negative camber.
Alternative: Enter a wide. Done properly, this should allow more exit speed, but it's harder and there isn't much of a straight between 3 and 4.
Fun stuff to do: Try doing this turn in the middle and outside of the track. These are racing lines. However, once the car is on the outside, don't try coming toward the inside, you'll have to slow down too much to do this.
Turn 4: After exiting 3, use the short straight to let the car settle. Tap the brakes to load the front just before turn in. For 5a, exit is middle of berm. For 5, look ahead to entry of 5.
Turn 5a: May not be necessary to tap the brakes before the downhill, but its nerve racking not to. The downhill before turn 5 is probably the only place on the course where you may coast on a straight. Enter turn one car width from left. Turn in as car gets to the bottom and traction is regained. Stay inside as tight as possible with throttle steer. I think this is the funnest turn on the course.
Turn 5: Brake hard on uphill and slow the car way down. Whip car around to face the water tower and go full throttle while still on top of the hill. However the car settles at the bottom, leave it(don't change steering input) and use throttle steer exclusively. Near the beginning of the turn, the car will want to drift away from the inside. This is OK, just keep looking at the exit and the car will be in the right place for 6.
If you didn't brake hard enough or turn enough at the top of the hill in 5, then you'll still be turning on the downhill and won't be able to apply full throttle.
If the car is pointed too far right of the water tower, you may run off the road. The run off is pretty smooth, so it's probably safer to run off than correct and risk rolling sideways down the hill. I ran off and it didn't seem to cause any problems for my car. I was really surprise at the lack of any big bumps.
Turn 6: Tap brakes to settle the front, throw the car a the apex, and hit the throttle to plant the rear. If done right, you'll be applying a good amount of throttle through the turn and touch the middle of the exit berm. If you don't get close enough to the apex, you'll run wide and have to ease off the throttle to stay on the track.
Turn 7: Check tach. Depending on how you exited 6, you may not have enough RPMs left to make it through 7.
Turn 8: Tap brakes or briefly lift, thrown car at apex, full throttle and hold on. It may not be necessary to brake or lift. Consider the run pave off as part of the track. If cones are used to reduce the width of the track(SCCA), don't try to move to the right side after the cones. You'll miss the apex and/or unsettle your car whipping it right and left so quickly at such high speeds.
Turn 9: Brake at 3, throw car at apex at 1/1.5, and get on the gas hard. Leave about a car's width from outside at crest, the road will continue to turn such that you'll find yourself at the edge coming over the hill. At the bottom, concentrate on getting to right side of track with full throttle. It's not necessary to use the full left side of the track. Make sure the car is got pretty of straight for braking for 10.
Turn 10: Brake hard before 3, DS to 3rd at 2. Throw car at apex at 1. This is the highest banked turn on the track so it's considerable faster than 11.
Turn 11: This is a throw away turn. Brake hard and early, it's a very very slow turn. Exit in middle of the track to setup 12/13. Getting on the berm will help to whip the rear around and it won't unsettle your car as much as you think. the berm seem big, but you're very slow. Carefully getting on the gas here. Due to the low speed and tightness, even low horsepower cars spin out here. My Miata did and I've seem quite a few other do the same here.
Turns 12/13: An S turn combo. There should be a split second between 2 and 3 where the car is straight. Shift to 3 here. On 12, consider the runoff area as part of the track. It's pretty smooth.
Turn 14: Downhill after bridge, so allow an extra distance for braking, like an imaginary 4th marker. Turn in pass 1 and get on the inside berm at apex. The apex is about 15' pass corner and not visible at the start of the turn Turns 14 and 15 can be turned into a single large sweeper by using the bumppy run off area of the track. Don't venture more than a car's length or two into the run off area was what the instructors suggested. I didn't bother to found out why this is.
Turn 15: Don't hit the inside berm as that'll unsettle the car. Get on the throttle as much as possible coming out of 14 and stay on. It's OK to ride the outside berm. If you run of the track here, don't be in a hurry to get back on. This is the most likely place where you can crash into someone or the wall.
Recovery of getting 2 wheels off the track.
#1 Don't panic
#2 Don't jerk the wheel
#3 ease off throttle
#4 ease the car back on the track or let it run off.
See the end of the video to view my recovery.
# posted by Mack @ 11:21 AM 
