Thunderhill Raceway Park

5250 Highway 162
Willows, CA 95988
P: (530)934-5588

Originally Posted Here:

Turn 1 - Turn 1 at Thunderhill is a total entry speed corner.  If your series allows it we definitely want to cross over the pit exit line on our right before braking as this opens up the radius of the corner and allows the race car driver to roll in more entry speed at corner entry.

There are no great markers for braking or turn ins on this race track so drivers who heavily rely on markers may tend to struggle more, but it’s a great place to practice on relying less on markers! For Turn 1 we want a heavy initial brake, but we will quickly want to get off of peak brake pressure so that we can roll in great entry speed while still trail braking down to the apex or close to it. If the driver is picking up initial throttle before the apex point, which comes about 1 car length after the start of the apex curb, then they have likely over slowed. 

Here is a great free article on what is trail braking & how to trail brake

On corner exit, we can use absolutely every bit of the road. We want to open up our hands as early as possible to maximize that entry speed and still get a good exit.

Turn 2 - A great objective to have for Turn 2 at Thunderhill is to try and reduce the amount of time spent on maintenance throttle. It is pretty much impossible to wait to pick up initial throttle until the point we start to unwind the wheel, but let’s aim to do that. We can accomplish that by focusing on a light initial brake into the corner and rolling speed into the corner.

We want our turn in to come before the road drops downhill, but it is a light turn to get the car pointed towards our first apex. This is not a traditional “double apex” corner, but I find thinking about the corner in those terms helps them from over slowing. My goal is to have enough entry speed to hit that first apex point and have the car drift about half a car width wide of the inside of the corner during the middle section of this corner.

I do want to get back to where my front left tire is close to the grass as I am starting to feed the initial throttle back in. Again here it is critical to have our eyes looking up and open our hands as early as possible.

This is not a corner that will have much trail braking happening.

Turn 3 - Turn 3 is one of those corners that you never feel like you perfected, I almost always feel like I’ve over slowed it. It is blind on entry and the apex is quite far around the corner. I only want to apex when I get to the apex curb, which comes quite late in the corner. If you are apexing the grass or anywhere before that curb it is likely you have over slowed, turned too early or actually turned in too aggressively.

We need to turn in before the road drops downhill, but we don’t want that turn in to get us to the inside of the corner too quickly. This is a fantastic place for race car drivers to work on turning in slower and more progressively. If done right we will apex that apex curb and only feel in initial throttle at that point.

Turn 4 - Our main objective in Turn 4 is just to get set up for turn 5 (the bypass).  It should be a quick lift in most cars, and on exit, we don’t want the car to end up more to the right than mid-road.  We want our race car all the way back to the left side of the road before turn in for Turn 5.

Turn 5 - Turn 5 is almost all feel and experience. It is truly blind and one of the most intimidating corners initially on any race track in the world.  The most important thing for Turn 5 is to start our turn in before the crest of the hill. There is a lot of grip once the car lands on the other side of the hill and there is a lot of room after the crest, but not before.

So, we will typically have a very light brake or even a short lift and turn in before the crest of the hill.  Once we land on the other side of the hill we want to be about mid road and try to apex the last bit of the corner. After that last apex we want to let our car drift about mid-road, but no further so we can set up for Turn 6.

Turn 6 - The most critical thing on Turn 6 is maximizing our corner exit. But, it is not a traditional corner leading onto a straight as it is still quite quick and cambered.  So, over slowing can become an easy trap to fall into.

We also want a decently early turn in here to take advantage of the camber. In most cars, we want to apex about 1 car length past the start of the apex curb and that is also where we want our initial throttle application to happen. If we are earlier than that with our throttle we can induce a lot of understeer mid-corner, which will delay the point that we can get back to full throttle.

It is crucial here to have our eyes far ahead of us and start opening our hands as soon as we can on exit.

The Chicane - With the uphill braking zone and turn in we can roll quite a lot speed in here and brake late and hard. It is easy for that late hard brake zone to make us over slow, so think about the brakes here similar to Turn 1, a hard initial stab but start reducing that brake pressure quickly.

Similar to most uphill corners we want an early turn in here. Because this chicane really opens up on exit that early turn in allows us to roll great entry speed, while still executing on a great exit.  We want to apex about midway through the first apex curb and be aggressive to throttle at that point as well. Use all the road to our right after the first apex as the second apex should be flat out in most cars.

Turn 10 - With the downhill starting aggressively at corner entry here we will need an early turn in to get pointed while we still have the grip. Most of our braking needs to be done before that turn in and downhill section, so it will be a very light trail brake down into this corner.

Our apex comes right in the middle of the apex curb and that is also where we want to pick up initial throttle. Use absolutely all the road on exit here.

Turn 11 - The most important part of master Turn 11 is by focusing on corner exit here.  If you are driving in a series that let’s you run all the car over the exit curb on exit then we can still get a strong exit with an early-ish turn in and good apex speed. If you can’t use that exit curb on exit, then we need to have a later turn in and apex.

If we can use that exit curb then we want to apex right about the middle of the apex curb and just kiss it with our front left tire. Again focusing on opening our hands as early as possible to maximize our drive off the corner onto this next straight.

Turns 14 & 15 - We want a strong trail brake into Turn 14 to maximize our entry speed and get the correct car angle to get a great run and exit out of Turn 15. Our apex in Turn 14 will be a somewhat long one that we hold for 2 car lengths or so.

To find the right apex I always look for where the rubber starts on the apex curb. The road has a little camber down by the apex, so we want a somewhat earlier turn in to take advantage of that camber.  It is critical to trail brake down to this apex and only pick up the throttle when we are ready to open our hands on exit.  

Out of Turn 14, we want to use as much road as we can until it starts to unsettle the car.  The road to the left of the curb can upset some cars, so experiment here with how much road you can use before that happens. Depending on your car, most cars will have a small lift at turn in for Turn 15. We want to be full throttle by the apex point here, so try and manipulate your throttle lift to happen right as you turn in.  Our apex should be the middle of the apex curb. We do want a slightly early turn in here so that we can flow great entry speed!