Ebook Extract: Pro vs. Pro

Posted in eBook

Video analysis shows how to gain a second through one of the best corners in the world

Daytona-carNigel Greensall on why a corner sometimes isn't a corner.

"You're driving a Porsche GT3 RSR at 168mph around the banking of Daytona International Speedway. You're approaching the chicane. When do you brake? How hard? On a recent test day with a two times Porsche Supercup Champion, I realised our techniques were very different and that it was possible to gain time in an unexpected way.

Daytona-circuitDaytona is famed for its 31 degree banked corners, enabling NASCARs to exceed 200mph. The bus stop, half way along the back straight on the 24-hour circuit configuration, is often overlooked by drivers who see it as a standard two-corner chicane. I thought I'd compare my technique with the other pro driver to see if I gained any time using a different approach.

After all, even the best drivers in the world compare their data with team mates in order to go quicker. For example, F1 driver Mark Webber famously used Sebastien Vettel's data in order to find 0.5 seconds in sector two at Abu Dhabi whilst he was fighting for the world championship.

For the most accurate comparison, the other driver and I drove the same 2011 Porsche GT3 RSR Grand Am Spec race car. Looking at the GPS and video data there was no difference in the lines we drove or our sector times around the circuit, except for the bus stop chicane. This seemingly insignificant section enabled me to gain 0.3 seconds. How? Let's take it from the approach.

As you can see from figure 1, we are both travelling at 168mph as we approach the bus stop. (My video is on the left, and my data is the red line).

The speed trace graph below the screenshots and the delta-t graph below that (showing difference in lap times as we progress around the circuit) shows almost identical performance until this point.

The Approach. As shown by the comparison video and data (I am on the left, with the red border), both of us have the same speed at the end of the banked straight.

However, I am closer to the wall, which opens up my entry into the left-hander.

Daytona-screen

The only difference now is in track position - I am edging the car closer to the wall. This opens up my entry to the left-hander and enables me to carry more speed.

Steering right towards a concrete wall at 168mph whilst looking to a left turn ahead takes some getting used to, but track position is the key to speed. You might think you are making full use of the entire width but it's important to look back at your video and data to see if you really are...

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