A Guide to Thunderhill West (Counter-Clockwise)

Northern California boasts some excellent tracks, but Thunderhill West is a favorite among the drivers of the momentum car. Compared to the grandeur of Laguna Seca, this almost seems like a glorified kart track at first glance, but the rate at which corners come at you, the way subtle camber changes and blind entries constantly challenge you and force you to occasionally improvise will keep you completely occupied.

Perhaps ‘kart track’ shouldn’t be regarded as an insult; go-karting’s busyness makes it exhilarating at 40 miles an hour. Double that for the average speed here and you get a level of mental stimulation that is hard to find elsewhere. 

Situate yourself by the pit walls and observe the lines taken by folks in the other run groups. The problem is you’ll miss Turn 1 on your way out, so getting up to speed with 9/10ths of a lap and then finding a new corner could be problematic. Its just one of the reasons you ought to tread carefully at first; an off at Thunderhill West often means tagging a hill or dropping into a ditch.

The first couple corners are visible from the pits.

Turn 1 is fast and exhilarating. Just as you’re getting a moment to breathe on the front straight, you’re confronted with a quick left-right. The curbing is very flat and should be used to straighten the trajectory as much as possible. Crucially, the important thing is to brake heavily before the second “right” in Turn 1. It’s quite easy to carry too much speed into this decreasing radius corner. This is because you approach it with a good head of speed, and you have to sacrifice the corner slightly. Also, bear in mind that the drivers leaving the pit exit may not always see you if you’re coming through quickly. 

Turn 2 is a 180 degree carousel that is on-camber at the beginning, flattens in the middle, and becomes slightly off-camber at the exit. It’s uphill at the start and downhill at the exit. The focus should be on attaining the greatest possible exit speed, which isn’t as easy as it might look; the middle of the corner lures the driver into pushing very hard, which can sometimes result in a pinched exit. Because of the shape and length of the corner, there is a period where the throttle application varies from lap to lap; but it usually takes some time before the throttle can be fully applied. Naturally, there are several line choices that will work here.  

A little snap at the exit may be a sign you’ve gotten on the throttle nice and early.

Turn 3 is a fast corner that needs to simplified to go quickly. It’s fast, and the amount of curbing can make it tricky to straightline this quick left-right flick. The curbing’s fairly flat, but as this is a fast corner, the curbing can upset the car.

Therefore, car’s platform ought to be fairly flat before tapping the curb. Some drivers like to keep it in a higher gear and roll more speed, making sure to get off the brakes by turn-in and apply some stabilizing throttle. Take a lot of the first curb, let the car settle, and make a subtle steering input to get the direction change done efficiently. 

Taking too much curb delays throttle application here.

Turn 4’s exit speed is crucial as it precedes one of the longest flat-out sections on the track. The entry is partially unsighted, and the mild amount of adverse camber post turn-in make this one tricky. The turn-in is late and relatively abrupt; make sure not to turn in too early lest you go sailing through the grass. Seek out a late apex and aim the car at the flag station on the hill.

“There is really only one correct line; it’s very easy to go too early or too late. The goal is to not touch either curb, and if your exit has you lined up with the T5 flag station, you probably did it right,” advises Joe McGuigan.

As you come over the hill and see the first part of the esses, remember to steer as smoothly as possible. There are a few direction changes necessary, but it’s a fairly straightforward section when it’s not complicated by traffic. The curbing is your friend here, and the exit should be sacrificed slightly to bring the car over to the right in anticipation for Turn 6. 

Turn 6 is long and the exit is blind. The braking zone is relatively short and strong, and the first half of the corner, because it tightens, is usually approached on partial throttle. Exiting on the edge of the track can sometimes startle you as the blind part of the shoulder appears. A dropped wheel can here sometimes results in a broken wheel.

The following hairpin represents a drastic change in pace. After all these long, quick corners that require little braking, this feels a little slow since it’s a slow, point-and-squirt hairpin. The change in pace takes a little recalibration to get the car stopped, which means it’s easy to blow the braking zone. If the brakes are trailed correctly, you’ll get the large rotation needed to get through Turn 7 cleanly. “If you are lining up your braking with the pole in the distance, you will likely take the correct arc. Be cautious of going over the exit curb as there’s a good 3-inch drop that can damage suspension,” Joe adds.

Turn 8 is fairly easy, even if there’s a blind hill in the middle of it. What’s important is to try and have the car balanced after the crest and as straight as possible in anticipation of the downhill braking zone. “Turn 8 is easy, but you don’t want to panic-lift there,” warns Joe. “Also, get comfortable modulating throttle if you need to back off slightly. Aim for the top of the T5 flag station and you’ll be good.”

Turn 9 is cambered around the apex, so you can roll a good deal of speed into what appears to be a slow corner. Track out and drive parallel to the edge of the road, headed towards the turn worker’s station, before braking—careful not to brake too much—and maximizing the radius for Turn 10. 

Keep your rolling speed up and take advantage of the camber.

“If you are straight line braking towards the T10 flag station, then you will likely have a good arc into the turn,” says Joe. Exiting Turn 10, running out towards the wall is usually smart, though there’s no need to overdo it. “While the exit is wide, going anymore than half the cars width over that white line is wasted time.”

Also, be careful when sharing the area with other cars. There’s a good deal of room at the exit, so make sure to not brake too much; the corner looks far tighter than it really is. For as important as carrying good speed in is, getting on the throttle early is even more crucial, since the front straight follows. 

The straighter the car and the earlier you are to throttle, the better shape you’ll be in for the upcoming straight.

And with all that memorized, you’ll have a blast—regardless of the car you drive. Though the straights at longer tracks in NorCal can make a Miata driver yawn, this technical track will challenge the Miata driver and the M3 driver equally. 

For a great example of how to attack this technical track, watch Tony Rodriguez’s stunner of a lap in his lively MR-S: