Q: Does ‘slow in – fast out’ always work?

Q: “Does ‘slow in – fast out’ always work? I hear the advice all the time, but I seem to do good going into corners really fast. My car control is really good, so that might be why. Is it because drivers with bad car control need to be slow in to be fast out of the corners?”

A: No. To both of your questions.

First, advice and tips and suggestions and instructions are guidelines, at best. There’s a reason that “slow in – fast out” has been given as advice to track drivers for decades. It works. No, not all the time, but more times than it doesn’t work.

Why is this advice given? Because by being slower on the entry to a corner you can get back on the throttle and begin accelerating earlier, and that – more often than not – leads to a faster straightaway speed, and ultimately a fast overall lap time. You can go too far with the “slow in – fast out” approach, though. One way of ensuring you get on the throttle early in a corner is to slow down to 5 MPH! If you were that slow, you could probably go back to full throttle the moment you turned into the corner!

It’s a trade-off, right? If you go into a corner too fast, you delay when you’re able to get back to full throttle. Go in too slow, and you can’t make up for the lack of speed, no matter how early you get on the throttle.

This has little to do with how good your car control skills are, and those of any other driver. Essentially, it’s a math and physics problem that you’re trying to figure out at speed, in the moment. Do I slow down a little more so I can get back to full throttle sooner, or do I carry more speed into the corner so I’m beginning to accelerate from a higher speed?

I see drivers all the time who either over-slow for corners, or carry too much speed in and are slow on the following straightway. It’s actually one of the most important trade-offs in performance driving, and it’s what makes the sport so challenging and fun.

If, currently, you’re good at carrying speed into corners, take a good look at your exit and straightaway speeds. Can you increase them by being just slightly slower on the entry to corners? That’s what you need to keep an open mind to, and constantly ask yourself. After all, it’s your overall lap time that’s more important than how much speed you carry into any individual corner.

8 Comments

  1. My observations working with students and developing drivers is learning the amount of entry speed into the corner is a later stage in their learning so the biggest tendency these drivers have is to over slow the car at the entry. Even with full throttle later in the turn they don’t get the full potential out of the car in the corner because they have over slowed the car at entry. Students and developing drivers build up a muscle memory using a cautious entry speed in the early learning and then have to relearn how to use the maximum grip and cornering capabilities from the turn in. So often the early “slow in fast out” taught them needs to be reframed as they explore the grip levels and capabilities of their cars. The section from the middle of the brake zone to the apex is the biggest difference between the casual driver and one who is interested in getting the most out of their car.

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  2. Indeed the key here is balancing the physics of car balance. First and foremost. sliding in the corner is not a fast technique. Slow in’s message is be just slow enough in so that you can apply substantial throttle prior to apex and be able to have full or near full throttle from apex to track out without sliding or lifting. If you take the example of a sports car with say 200 HP you have about 100 HP of stopping power and 200 Hp to regain your speed. Message brake for a very short time period, accelerate for the maximum time equals the best exit speed.

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    • One comment I’ll make is that there is NO rule about where you should be back to throttle – beginning to apply or at full throttle – in relationship to the apex. There are corners where you’re on the throttle just after turn-in and well before the apex; there are corners where you can’t be on the throttle at apex. I often have drivers ask me whether they should be on throttle at the apex (like there’s a magic formula that all corners are driven this way), and the answer is “no, not always – sometimes, but not always.”

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    • Oops. that was a bit of miss type on my comment. It was supposed to state that a sports car with 200 hp has around 1000 hp of stopping power, thus it takes much more time to regain the speed lost during braking.

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  3. I have always favored “balanced in, fast out.” “Balance” cuts right to the point. Balance can be defined by ideal and effective weight transfer, front vs rear slip angles, and line. To maximize Balance you can now work on perfecting each component individually and together, and ONLY when the car is properly balanced and the car sufficiently rotated can you apply throttle. You can’t do that with “slow”. What is “slow” and how do we know if it’s good or bad? Balance at all times!

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    • Great point and perspective, Art! You could even add “balance the speed – not too slow, not too fast.” Hmmm… there’s some kind of Goldilocks analogy there. 🙂

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  4. I think in terms of two extremes, with most corners in between those extremes.

    There are the corners where you want to focus on preserving momentum by floating a lot of speed into corner entry. At very high speeds, acceleration is less effective, so balance and momentum are the keys. T4 at Laguna and the Kink at Road America are examples. I usually don’t drive anything with enough HP to make up for over-slowing corners like that.

    Then there’s the rotate and go corners. The extreme is a tight corner on gravel. Be willing to throw the weight and traction around to get the damn car pointed in the right direction, then accelerate out.

    I wouldn’t take T8 and T11 at Laguna rally style, fully sideways, but I will favor crisp rotation over maximum possible entry speed.

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