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PUMPELLY: Detroit Debrief

Spencer Pumpelly files his latest Sportscar365 column…

Photo: Austin Gager/Change Racing

Photo: Austin Gager/Change Racing

Detroit is always one of my favorite events of the year. I like street courses. I miss racing in places like Baltimore, Trois Rivieres, Long Beach, and Downtown Miami.

In the city center we have fans, both diehard and those who are indulging their curiosity, close enough to the race track to easily make the trip. The big crowds bring out lots of vendors and performers, giving the whole event a festival atmosphere.

Street courses are fun for drivers because they demand a little more precision. You can’t get away with any mistakes so confidence is the key. In the concrete canyons of a place like Belle Isle, a good, determined driver can get some extra time out of the car by being just a bit more daring, and that’s a good thing.

The bumps are also something the drivers and teams have to deal with. At first they are very annoying, but one you get the feel for where they are and how they affect the car, they become a lot of fun.

You can use them to your advantage the way a mogul skier does. It’s physical for sure but a welcome challenge in a world where sterile tracks are becoming the norm.

There is, however, one big draw back. Passing is damn near impossible. It’s hard to explain to an outside observer, or even an experienced driver who hasn’t raced a track like Belle Isle before. Four things work against passing a slower car.

First you have the tight corners. When two cars running nose to tail at high speed slow down, the time gap between them doesn’t change, but the physical distance between them does. If you slow down enough, that distance can become less than a car length.

If we were driving ghost cars like in the video game Gran Turismo, that wouldn’t be an issue, but in real life the following car must slow more than the leading car to avoid contact.

I call this the hourglass effect and it hurts any cars following closely behind another in a pack of two or more. With lots of first gear turns, Detroit is very “hourglassy.” Is that a word?

You also have the problem of aero understeer. With the new GT3 cars all running max downforce, the following car gets really tight in anything second gear or higher. It’s hard to get a run out of a corner like Turn 2 or 13 with a lot more push than the car ahead of you.

Even if you get a run, Belle Isle features mostly short straightaways. You find yourself in the next braking zone before you have the time to get in position to out brake another car. The short straight lead to short brake zone too.

The tight confines of the street course don’t help either. If you make a risky move on a typical road course you have some bail out options. You can put a wheel in the grass or shortcut an apex curb to avoid contact. Replace that grass with concrete walls and even the smartest move can become low percentage.

Finally, because there is not much passing, there is not much side by side racing. The result is a big buildup of dirt and marbles off line. Passing usually takes you off line at some point so at Detroit you just wait.

That’s not to say passing is impossible. Andy Lally made a last lap pass on Markus Palttala, but other than, that the order with an hour to go was the same as it was at the finish.

Knowing that passing would be hard our Change Racing team elected to run a reverse strategy. The plan was for me to qualify and start, hope for a yellow, and then let Corey Lewis finish the race.

The plan came really close to working. We got a yellow 14 min and 50 seconds after the green. Ten seconds later and we would have been able to pit for a driver change while the other cars were forced to stay on track as their Silver rated drivers hadn’t met minimum drive time.

But because the caution was within 15 minutes of the start, the yellow was a “Quick Yellow” and the pits stayed closed. We had to pit under green.

We ended up cycling through the pit sequence in 6th and that’s where we finished. Corey did a great job closing the race with all the pro guys out there. It was Change Racing’s best finish to date, but it goes to show how much the luck of where the cautions fall determine how these short races shake out.

Next up is the Sahlen’s Six Hours of The Glen where the strategy is much more conventional.

Spencer Pumpelly (@SpencerPumpelly) is one of America's leading GT racers, driving for Change Racing in the IMSA WeatherTech SportsCar Championship and Rennsport One in the Continental Tire SportsCar Challenge.

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