Stay On Track: Down Force Debate

Andy BernsteinCorrespondent IMay 4, 2010

There's nothing questionable about the photo: it was the best shot I could get of the standardized tunnels on a Dallara IndyCar. This is Scott Dixon's car on the Tech Inspection pad at Homestead, 2009.

This is Mario Andretti in an interview with Gordon Kirby, 4/28/08:

"I don't think most of the people writing the rules understand what creates competition," Andretti said. "To stay flat on the throttle all the time like the IRL does, where do you go, where does the driver reach to be able to pass? You've got to have it so you're quick down the straightaway and have to slow-down and back-off for the corner. It's just a question of how much are you going to back off? That's what's going to make a difference and create some passing, which is so damn difficult right now in the IRL."

The story was the same this weekend at Kansas, and all the oval races of last year: in a car with a decent setup, a driver can lap with the throttle flat. All day long.

What has eroded over the years since Mario's last oval track victory at Phoenix in April, 1993...well, just about everything. To sum it up best in one word, what is missing are Variables.

In spite of his 1994 retirement, Andretti is not out of touch. He last drove a Dallara / Honda in 2003. Although uniform revisions have been made since, the cars we watched at Kansas are substantially unchanged. And nearly identical to each other.

You and I are not going to see the variety of chassis and engines that Mario last experienced in competition. All of the variables are gone: horsepower output, fuel consumption rate, tire compound, aerodynamic drag and downforce levels are all now...well, virtually level. An overtake assist of 9 HP does not constitute a solution.

And the most important variable of them all has thus been eroded: car control. Oval track racing has been reduced to what is largely an engineering exercise for the driver to actuate, foot to the floor.

There are two ways to answer the questions that Mario posed above. The most obvious, and the least likely, is to increase the power output. That won't cut it today: top speed is already governed for safety concerns with the mandated addition of drag to consume the extra horsepower.

So now we go back to Motegi 2009, and the quotes of current drivers re-printed in my previous article. Scroll down to begin with Scott Dixon:


To sum it up best in one word, what these comments point out are variables. Differences in setup for mechanical grip, tire wear, and most of all... car control.

The cars are flat on the straightaways at Twin Ring Motegi. Not through turns three and four, where on entry Dixon lifts early and Franchitti trail brakes. Each must assert their skills to maintain cornering speed and carry it onto the front straight.

Here is a brief look at the circuit, from the IndyCar qualifying highlights:


The 2009 rule book specifies a rear wing flap angle minimum of 15 degrees for Motegi with at least a 1 inch wicker. For comparison, the rear wing at Kansas and Kentucky is 12 degrees, same wicker minimum.

This means that you can add more downforce by increasing the flap angle or wicker if you choose...and of course balance the car with more adjustable front wing as well. Perhaps you could add enough downforce be able to go through three and four at Motegi flat. So what? You'll get waxed from all the added drag down the straightaways. 

The answer does not rely on firing up the bulldozers to reconfigure the other tracks on the IICS schedule. Reduced downforce levels will get the job done, so that negotiating turn three at Kansas requires the same choice of variables. Mainly, car control.

If you are with me so far, you're already "On It" with the arguments. "Too dangerous" might be the first one, if the expectation is to run an oval track without sufficient downforce to corner flat. Apparently Motegi is not considered as too dangerous, nor are a number of road course corners where lifting early or braking deep is required.

"Too fast" is the next argument, if the minimum wing specifications are reduced to the point where the big lift is necessary: less wing = less drag = higher straight-line speed. Too high.

That's why the tunnels are pictured above. Let the drivers request as much or as little wing as they need to best negotiate the turns. That immediately establishes a greater variety of straight-line and cornering speeds. But reducing the ground effect component of the total downforce, by decreasing the size of the tunnels, ends the prospects of flat out cornering.

There is a lot more to this picture, so please be patient with the rest of your arguments. All of the details are intended to reintroduce variables, and to do it with the existing Dallara/ Honda without significant modification. These are the same cars we will be watching for the balance of 2010, and 2011, and now perhaps 2012.

Is the argument that no changes are necessary? Better check with Mario on that one.

Link to other "Stay On Track" entries: 




The latest in the sports world, emailed daily.