Thunderhill Raceway was built by the SCCA as a learning track. It has a wide variety of turns, and tons of runoff area. It's a great place to learn car control and, due to the summer heat, how temperature affects track conditions.
NOTE: it's a good idea to follow along with a track map and in-car video opened in another window. Links for both are above.
Since this turn is at the end of a very long straight, some heavy braking is usually required, but keep the car in 4th gear. As you approach the Start/Finish, glance to the exit of the turn to ensure that it is clear. There is a flag station there that is sometimes occupied. If you're comfortable with it, stay on the throttle until after the Start/Finish line. Get your braking done prior to turn-in at or before the "1" marker, and charge for a nice and late apex. You should be able to get back on the power shortly after turn-in due to the slight incline throughout the turn.
Set up for this turn just to the right of track center. You will need to do some braking and downshift to 3rd gear. The track runs slightly downhill here, so keep that in mind when choosing a braking point. Glance at the exit of the turn prior to turning in. As you proceed through the turn, practice looking to the turn exit every second or two to maintain a reference for where you are in the turn in relation to the exit and the apex. This is a great turn to get a feel for how the car reacts to throttle inputs in a steady turn. As soon as you know that you can achieve your desired apex, start feeding in power and unwind the wheel as appropriate. You should be at full power at or shortly after the apex, tracking out neatly to the exit.
You will need to brake heavily as you approach the little hill before Turn 3. Just over the rise awaits an off-camber monster that I'm sure has made more than one heart skip a beat. Crest the hill near the just to the left of center of the track, and try to reel in the exit/apex (they are at the same point) at track-right. Work up your speed entering this turn slowly to avoid a suprise spin. The track gets a little bumpy toward the exit, so expect a bit of bouncing or porpoising here.
Turn 4 is a fun little bend that is a welcome relief from the madness of Turn 3. Begin turning in immediately after the exit of Turn 3, and aim for the last third of the apex berm. It's a good time to look up the hill toward the flag station at the top of Turn 5. Track all the way out to the exit berm to maximize speed through this turn.
The Turn 5 Cyclone is Thunderhill's signature turn. After exiting 4, charge up the hill. Start braking heavily at or slightly after the "3" marker. Begin turning in at the "2" marker, and slowly dial in more steering input prior to hitting the apex berm on the left. Straighten out the steering and get back on the power just after the apex berm, and drive down the hill, with your exit point just at the end of the berm on the right. You can be on the gas all the way down the hill up to the braking zone for Turn 6, just adjust steering input to maintain the balance of keeping a tight line and putting the power down.
You will likely need to get a moderate amount of braking done before 6, but likely less braking than you may originally think. Since Turn 6 preceeds one of the fastest sections of the track, exit speed is critical here. Turn in, and ease back on the throttle, apexing about 75% of the way down the apex berm. You should be at full throttle prior to the apex. Unwind the wheel a bit as you pass the apex to track out to the exit berm on the right.
As you are learning the track, Turn 7 may not seem like it is worthy of being called a Turn at all, but as you pick up speed you will see the necessity of it, so make it a real turn with a real apex. Aim for a late apex a few carlengths prior to the access road, and track out all the way to the right to set up for Turn 8. You will need to shift from 3rd to 4th gear here.
If you are comfortable doing so, stay on the power all the way through Turn 7, and approaching Turn 8. Depending on the car, there will likely be some very light braking necessary just prior to turning in. This is more to shift weight to the front tires than to scrub speed. Turn in about halfway down the concrete strip on the right side of the track, aiming for an apex about midway through the apex berm. Feed in the power smoothly, being at full throttle just prior to the apex. Don't be afraid to put two wheels in the runoff area on the corner exit -- that's what it's there for! Speeds here are very very high, and it's quite a thrill every time!
Turn 9 is the most misunderstood turn on the track. It's quite unique in its layout, and generally fools many a student (and instructor) into following the wrong line. As you are climbing the hill from Turn 8, stay on the power until the braking zone. Brake, downshift to 3rd gear, then turn in between the "2" and "1" markers, setting up a fairly early apex on the left-side berm. Get right back on the gas after turn-in, since the uphill helps to hold the rear end. Track out to the right, with your exit point flush with the berm on the right side of the track just beyond the crest of the hill. As you crest the hill, the steering wheel should be straight ahead. Don't worry -- there is tons of track on the other side.
Accelerating all the way down the hill from Turn 9, allow the car to drift left as it wants as you descend the hill. You'll likely need to shift into 4th gear at some point. As you approach the Turn 10 braking zone, get the car back to the right edge of the track. Brake heavily, downshift to 3rd, and turn in just before the painted marks on the right edge of the track. This turn is nicely banked, so it's suprising how fast it can be taken. Get all the way up on the apex berm (this is the only place on the track you should do this), and shoot for the last third of the exit berm.
Turn 11 is significantly slower than Turn 10. It's flat, so you don't have the banking to pull you through the turn. Most cars will benefit from downshifting to 2nd gear entering the turn. Turn in, aiming for a very late apex at the end of the berm on the left, then set up the car to go through the little esses of Turns 12 and 13.
Accelerating out of Turn 11, try to straighten out these two turns as much as possible. There is ample space in turn 12 to put your two right tires inside of the black and white striped berm. Accelerate hard here, but be mindful of spinning, since you are accelerating through 2nd gear. Turn back to the left to drive over the black and white paint at the apex of 13, and track all the way out to the right to complete the sequence. Accelerating down the long-ish straight here, you will likely get into 4th gear. Stay on the power just past the bridge if you are comfortable doing so. Don't worry about moving the car to the left edge of the track immediately, since the track will mostly come to you on that side if you drive a line from the exit of Turn 13 to the braking zone of Turn 14.
Turn 14 is at the end of a long straight, so heavy braking is absolutely necessary here. The car should be all the way to the left just as you approach the braking markers. Since this is a tight turn, aim for a late apex. Turn in a couple of carlengths after the "1" marker, and try to hit your apex toward the end of the thick part of the berm. Get on the power, and drift out, putting two wheels into the exit paint. Staying on the power, pause for a beat with the front wheels straight ahead, then turn in to Turn 15. Use a normal apex, and unwind the wheel a bit after apexing to drift out to the exit berm. This leads to the front straight, where your lap is complete!