The Art of Road Racing
winning insights for club racers

Thunderhill 5 mile course

In 2014 SCCA and NASA raced the Thunderhill 5 mile course that combines the east and west loops. As these were the first races ever on the west loop, everyone was puzzling out the line, which made it especially fun.


Start by studying this video of Mark Drennan’s smoking 3:39 qualifying lap. Note the RumbleStrip delta lap timer that shows you where Mark improves in his successive laps.

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Here is a turn by turn description of the qualifying line in a Spec Miata.

(Note, if you are interested in the 2 mile west loop, you can skip down to study T3W through T1W. This would be missing only T2W.)

T1

  • Approaching T1, make sure to keep the throttle down all the way to your braking point. We stay in 4th on the front straight in an SM, and you might find you hit the rev limiter briefly at the end, especially if you have the 1.8L engine because of its lower 7K rev limit. But don’t worry as this will not damage a Miata engine. Watch for traffic entering from the pit lane as you move right for a wide entry.

  • Set up fully right before the brake markers. Your right tires should be on the paint line. Brake moderately at the first marker. You will see three paint marks on the right side of the entry. The turn-in point is a little before the last one. This is a high speed turn, and good lap times depend on maintaining momentum here, so work to find the minimum braking and earliest turn-in needed.

  • Make a mid apex lightly touching your front tire to the T1 apex berm. The correct line will look early as you approach the berm, but you will touch mid apex.

  • Ideally you will be at full throttle before the apex. The car will be thrown wide and will arrive at the exit a little past the middle of the berm.

T2

  • As you approach T2, turn gently to aim the car tangent to the inside of the turn. Stay full throttle. Just a little before reaching the inside of the curve give a light brake and downshift to 3rd. At speed, the brake is very light.

  • Now hug the inside with robust, possibly modulating, throttle. Aim to put the left front tire almost in the dirt. When you see the exit berm in your left view, gently roll on full throttle. Your car should be thrown wide and reach the exit mid berm.

  • In the video I shift briefly into 4th before T3. Don’t worry about doing this until you find yourself bouncing off the rev limiter for an extended period. The transaction cost of upshifting and heel toe downshifting is barely worth it. Better to stay in 3rd and ride out the rev limiter.

T3

  • Aim to enter T3 just a little right of center. Err on the side of braking early as the turn is off camber, so if you brake too deep you will lose a lot of time and are likely to end up in the grass. Stay about a car width off the berm on your right at the beginning. As the berm runs out, aim to exit parallel to the end of the berm with your right front just scraping it. You should be applying robust, possibly full throttle, on this right hand sweeper. Counterintuitively, greater throttle helps the car turn here. This is because the off camber slope causes the rear end to slide out, so the rear tires aim a greater amount of thrust into the turn radius.

T4

  • Just as you reach the end of the T3 berm on the right, quickly turn the wheel left to aim the car at the T4 apex. The turn-in needs to be quick, almost abrupt, but watch that you balance the transition from right to left without the need for multiple corrections. There is no braking for T4, just a brief lift to allow the car to turn.

  • You should arrive mid-berm at the T4 apex. Rub your left tire on the berm there. Ideally you lifted very little for T4 and are hard on the throttle now. As you pass the apex, your car should be thrown wide onto the T4 exit berm. If you are not being forced to put a tire on the berm, you either apexed too late, or are not applying enough throttle through T4. Adjust accordingly to improve. Don’t worry if your right tire catches a bit of dirt as it runs off the T4 exit berm.

  • The temptation here is to beeline for T5 without using the T4 exit. Avoid this, unless you aspire to slower lap times.

T5

  • Don’t worry that you are out of position for T5. The uphill entry gives you plenty of traction to muscle the car into position. Line the car maybe 10 degrees off parallel vs the brake markers on entry into T5. You will need to brake before turn-in.

  • T5 is a sharp left, kind of like a city intersection. There is a white paint mark on the right. That is your turn-in point. Make sure that you do not touch the apex berm on the left, as that will likely send you around backwards. Your goal is to get the car turned, and wheel straight over the crest, so that you can be full throttle there. The correct line will put your right front tire on the paint line almost touching the exit berm. It helps to practice driving slowly and putting your tires on the exit berm so you know where it is. The biggest mistake students make here is being shy of the exit and driving straight down the middle of the track.

  • You will want to be full throttle coming down the hill and around T5a, the right hand sweeper. The correct line in a Miata is to hug the inside. But to get that while maintaining full throttle, you need to quickly set your car into the turn. This is accomplished by quickly pointing the car at the dirt on the right just as you reach the end of the T5 exit berm. This requires quick assertive steering input, similar to the T4 entry. Don’t worry, the car won’t actually go into the dirt, as the full throttle will throw you wide.

T6

  • Hugging right will set you up perfectly for T6. Look for the paint mark on the right (it’s a little before the cone in this video.) You will need to lift, or very gently brush the brakes, to get the car to turn-in. The correct line will take you to a mid-berm apex and a mid-berm exit. The key here is to lift as little as possible. The sooner you can get full throttle, the more speed you will carry down the entire length of the back straight.

T7

  • It is not necessary to apex T7 in a Miata. You can drive full throttle anywhere on the track there. However, a tight apex will give you the shortest path on the back straight. So you should point the car right at the T7 apex immediately upon exiting T6.

T8

  • T8 is a 100mph no-brake 45 degree left.

  • After apexing T7, set up fully outside as you approach T8. At pace, there is no braking or lift for turn-in. But new drivers should work up to it.

  • There are no brake markers, but visibility is great, so measure your turn-in by looking through the apex to the exit. The entire road is needed, so you should make sure you don’t pinch the entry. Do not touch the apex berm on this one, as that will likely spin you around at almost 100MPH, which is very dangerous.

  • A good exit takes you into the wide runoff, straddling the white stripe paint there. There is room to go wider, but the rough pavement there is less favorable. As the exit pavement runs out, you will need to bring the car back left right away.

  • The technique here is to minimize scrubbing so as to maximize momentum. This requires a gentle hand on the wheel with minimum excess movement. Remember that the more weight you feel on the wheel the more speed you are scrubbing.

T9C (entering west loop)

  • T9C consists of a non-apex 90 degree right turn that takes you off the east loop pavement into a sharp left right complex that connects the east and west loops.

  • The run up from T8 to T9C is uphill. Gently move the car to the left side of the track and watch for the brake markers. Brake/downshift to 3rd as necessary to turn right at the last marker. Because of the turn is on the uphill, and further because the entry into T9C is also uphill, the speed adjustment needed is less than expected. It is easy to over-slow here.

  • Get back on the gas as you go uphill, then brake again for the left turn. I stay in 3rd, but you may want to downshift into 2nd here.

  • You should be full on the throttle as you pass the apex on the left, and you should stay on it as you immediately turn right to head down the hill. Use the full exit on the left to minimize scrub.

T3W

  • You will be full throttle downhill, eventually shifting into 4th. Note that there is a change in the road surface half way down the hill where T2W blends into the straight. The line down the left hand side of the track will launch your car there, so passing there feels precarious.

  • T3W is at the bottom of the hill and is a high speed 45 degree left. The apex is a flat triangle that you should completely drive over. As you will be going almost 100mph when you arrive at the braking zone, some speed adjustment is necessary, but no downshift, so you will stay in 4th. This is a fun turn.

T4W

  • The line out of T3W will send you into a berm on the right, that you will need to briefly follow to set up for T4W, which is a 3rd gear 90 degree left.

  • You will be charging into T4W in 4th gear, so you will need to slow and shift into 3rd. There are no markers, but you can use the left side constraint as a reference as you straight line it out of T3W. Brake and downshift as you pass that left side reference and head into the middle of the pavement.

  • T4W is visually confusing because the track boundaries there do not convey the line. In fact, the only constraints that matters here are the apex and exit. You will want to ignore the track boundaries otherwise, as you should not exceed them on the fast line. Your goal here is to take a wide entry, rounding out your arc to maintain momentum. The correct line will throw you to the exit berm on the right.

T5W

  • Coming out of T4W, you should be full throttle through T5W which are esses consisting of a right, left, and right again. Set up wide for the entry. You will need to shift into 4th after the first right. Straight line it as much as possible.

T6W

  • T6W is a sweeping left with a long berm. T5W points you right at that berm, and you will slow and downshift into 3rd as you approach it.

T7W

  • The track between T6W and T7W has a two bends. Straight line it through those bends to T7W. You will need to shift to 4th.

  • T7W is a 2nd gear 170 degree left hand hairpin. The inside boundary is practically triangular, and so misleading. Don’t pay attention to it. The constraint you should be thinking about is the late apex and exit.

  • On the fast line, you are not going to be able to get parallel to the right hand side of the track at turn-in. Rather, you will be pointed at an angle off-track while braking and downshifting from 4th to 2nd. But then you will turn for a wide entry just before running out of road. Your goal is to round out the arc as much as possible to maintain momentum. If your speed adjustment, vector, and timing are just right, you should be able to get full on the gas before the apex and not run off the exit berm.

T8W

  • T8W is a 3rd gear 45 degree blind right with a crest. Coming out of T7W, you should be full on the throttle and have shifted into 3rd before T8W. The crest should not unsettle a Spec Miata, so stay full throttle there.

T9W

  • T9W is a 130 degree 2nd gear right. You will need to brake and downshift.

T10W

  • T10W is a 120 degree 2nd gear left. If you upshifted into 3rd coming out of T9W, you will need to downshift back to 2nd as you brake.

  • Like T7W, you will not be parallel to the right side of the track during braking and downshift. The only constraint that matters is the late apex.

  • In order to achieve the largest arc here, we drive well into the runoff on the exit, a whole car width past the line.

T1W

  • T1W is at the end of the straight and consists of a left hand apex followed by a 3rd gear right hand sweeper delineated by three apexes.

  • The entry off the main straight is a 30 degree turn at full throttle, threading a straight line between the gate formed by the left apex and first right apex.

  • Braking and downshift to 3rd is in a straight line as you pass the gate. Ideally you are tight to the next two apexes at full throttle, to get a nice shot into the connector back to the east loop.

T10C (exiting west loop)

  • The connector is a blind crest followed by a 90 degree turn onto the east loop heading into T10. Coming out of T1W, set up on the left hand side of the connector. You will stay in 3rd here.

  • You should brake just as you go over the crest. This is important to keep the front end planted. It is also important because the turn-in is right away. Any delay, and you will have blown your apex and gone deep. This is an easy mistake here.

  • You will stay in 3rd gear all the way to T10.

T10 (5 mile course)

  • T10 is deceptive because the preferred line is earlier and faster than expected since the apex is banked, so you need to turn early to stay on the banked pavement. Study the video to see how much the road drops off as you approach the apex.

  • If you are accustomed to the long (3 mile) course, it is easy to over slow for T10 on the 5 mile course. Recognize that you have just come out of a 90 degree turn rather than down the hill, so your speed will be closer to 70 than 100mph. Only a small speed adjustment is needed here, if any at all. This is a great place for left foot braking.

T11

  • T11 is a 90 degree left with similar dimensions to a street intersection. Set up fully right on the run down from T10.

  • 3rd gear is good here for an SM at pace, but 2nd works as well and is more forgiving. 3rd gear is favorable only if you can keep up your min speed. Watch the video for min-speeds, which appears around 53mp for Phillip. Braking is moderate here as you downshift and turn-in.

  • It’s really easy to pinch this one off. So take care to wait until the turn-in point, and then very deliberately turn the wheel.

  • T11 feels like autocross. Make the apex and get on the gas as soon as possible. As this is the beginning of the long run down the back straight, getting on the gas early is critical. Your exit will be determined by the constraints placed in T12.

T12 & T13

  • T12 and 13 make up an S turn. The track is delineated here, but there is a huge runoff space on the right, and the clubs typically let you use it to greatest advantage.

  • The exact path here is determined by the constraints that the club will there. Sometimes barrels, sometimes sticks, sometimes tires, and placed in varying locations. Muscle the car through there whichever way works, as long as you don’t hit those constraints.

T14

  • T14 is a sharp 120 degree turn that connects to T15. There is a little straight pavement between the two, but the car does not fully settle out there, so the two turns are connected.

  • T14 turn is critically important because it is the beginning of your run down the main straight. The sooner you can get on the gas, with the greatest minimum speed, the better the beginning of your run.

  • T14 is a 3rd gear turn during qualifying, with 2nd gear useful in traffic. This is the hardest braking spot on the track as you are going from ~100mph to ~50. Brake at the first marker and turn a little past the 3rd. If it feels early, that’s probably the right line. Actually there are three paint marks there that you can use for reference. Turn-in is between the first and second mark. Phillip looks like he turns just after the first mark.

  • The most important trick in T14 is how you cheat the apex. Since the turn is greater than 90 degrees, every bit you can reduce that apex constraint makes a big difference in how tight the car needs to turn. Study the video and note that the apex berm is flat. That means you can drive right over it without problem.

  • The right way to take that apex is to straddle that apex berm, with your right tire almost in the dirt for just an instant. Because the car is leaned over, the tire doesn’t actually drop into the ditch there. Try practicing this, going further over, until you can’t. Better not to have traffic behind you in case you spin.

  • You should get back to the throttle near the apex. It will feel like you are not done and still pointed to go off track. That’s about right. Your job is to muscle the car around so it doesn’t hit the barrels, and straighten it out so you can make T15.

T15

  • Typically the barrels are positioned so that you can straddle the stripped paint on the runoff between T14 and T15, and that’s exactly what you want to do. There is a triangle of solid paint at the end of the stripes. That’s the turn-in for T15, which you should be able to accomplish without lifting.

  • It is critical to make the apex on this one, so scraping your right tire on the apex berm is a helpful reminder that you are on course. Surprisingly running over that berm a bit does not disturb the SM much. Let the car out to exit with your left tires on the berm.

WARNING: T15 exit berm

  • Watch out if you are off line and the car is on a trajectory to drop a wheel. The danger here is that when you drop a wheel, the car will pivot around the front tires and pirouette across track into the pit wall. It is counter intuitive that this happens, but it is a fact of physics, and a regular occurrence in T15.

  • To help avoid disaster, ensure that the front tires are not turned when you drop off the berm. So straighten the wheel and neutralize the throttle just before dropping the wheel. Don’t pull the trigger to early: take this action only when the left front tire has climbed the berm and it is clear you are going off. No sooner, unless you enjoy unnecessarily playing in the dirt.

  • Once you have wheels in the dirt, wait until you are past the end of the exit berm to gently bring the car back onto the pavement. Waiting is critical as the exit berm can catch your rear tire, and you again risk looping into the wall.

Main straight

  • You are almost done! Wait until you are just short of hitting the rev limiter to shift into 4th. This is the best shift point for a Miata. Don’t worry about hitting the rev limiter by mistake, as this does not hurt a Miata. Actually, a good way to learn your up-shift points is to purposely brush up to the rev limiter. Note that over-rev on the downshift is not so forgiving and is a good way to bend valves or worse.

  • You will be spending ~15 seconds on the front straight. Relax a bit, stretch your fingers, check your gauges, wave at your friends on the pit wall. If there is a car ahead, stay dead center behind them to benefit from their draft. Remember the S/F line is 200 feet past the flag stand, so don’t let up until you are past it.

That’s it! You have completed a lap of the Thunderhill 5 mile course course at pace. For your added amusement: this is what it’s like to race the 5 mile course. Beware the dangers of clipping the T9C apex curb… Enjoy! -Juan



Hope you find this guide useful. If you have any feedback, please write us in the comments section at the bottom of the page.