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Some Say NASCAR Monitoring System Is Darn Good

| Senior Writer, RacinToday.com Thursday, July 30 2009
The actual stops during pit stops are the easy part these days. It's getting in and out of the pits that is the problem.  (Photo by Chris Graythen/Getty Images)

The actual stops during pit stops are the easy part these days. It's getting in and out of the pits that is the problem. (Photo by Chris Graythen/Getty Images)

By Jonathan Ingram | Senior Writer

Despite the pit road speed limit fiasco of Earnhardt Ganassi Racing and driver Juan Pablo Montoya at Indianapolis, it’s likely somebody will be caught speeding in the pit lane during Sunday’s Sprint Cup race at Pocono by running too fast between the nine timing loops.

Is it a fair system?

“It’s a pretty foolproof system,” said Travis Geisler, the Penske Racing crew chief for Sam Hornish Jr., one of those caught prior to Montoya at Indy. “It’s an outstanding system except when it’s your turn to get bonked.”

Unlike other racing series where computer-driven engine management systems allow a driver to push a button to control speed, in NASCAR it’s up to the driver to maintain the proper RPM. “It’s not a technology thing, it’s a sporting thing,” said Iain Watt of Richard Petty Motorsports.

As the director of peformance engineering at RPM, Watt provides teams with the pit road “map” for events. He predicted drivers will get caught on the 1,820-foot pit road at Pocono. “Typically there’s a lot of pit stops under green in the latter stages of the race,” he said. Under the pressure of a green flag stop late in an event, that’s when drivers are most likely to make a mistake pushing the envelope.

One of two things happened with Montoya to get the penalty at Indy, said Watt. “Either he didn’t hit the RPM or the team miscalculated its pit road speed limit.” Without speedometers in the car, a team determines an RPM that matches NASCAR’s mandated pit road speed using a calculation of the gear ratio and tire circumference.

Montoya had previously entered and exited the pits on lap 92 without incident. He had no reported change in tire pressures on a Target Chevy already dominating the race, which might otherwise have skewed the team’s calculations for its pit road RPM. Crew Chief Brian Pattie has not commented on precisely what went wrong in post-race comments, other than to say the team took the car apart after Indy to look for any problems.

The most likely scenario: Montoya came into the pits a little too fast, tried to dip below the scheduled RPM to account for the mistake and didn’t get slow enough by the first timing loop from the yellow line marking the pit lane entrance. At Indy, the limit was 55 mph with the usual five mph margin for error. Anything over 59.9 mph drew a penalty. Montoya’s entrance into the pits was slightly over that.

“Getting somebody for 0.2 mph over the limit looks pretty bad,” said Geisler of the case of Montoya. “But they’ve already given you five miles an hour.”

Penske Racing, like other teams, has one person assigned to create a pit road map prior to events, including the location of the timing loops and any changes to the pit road set-up from the previous events. It’s up to the crew chiefs and engineers for each driver to calculate the RPM for the pit road speed limit.

“At Indy, we used 57 mph,” said Geisler. “That’s what we’re comfortable with. The most important thing is not how much time you can gain on the pit road, but the in lap and the out lap. With two mph on the pit road, you can’t gain nearly as much time as you can by decelerating by 150 mph from 200 quickly.”

The other side of that coin is getting up to speed more efficiently leaving the pits.

According to Watt, who reviews all NASCAR timing data after each race, there are some drivers who consistently gain time with their in laps and out laps on pit stops made under green.

All drivers are under some pressure from crew chiefs to post good in and out laps. “That’s when I’d like have a driver be good than on the pit road,” said Geisler.

The most common method of getting good in laps and out laps?

Coming into the pits across the yellow line a little hot, then dropping the RPM below the team’s calculated pit road limit before the first timing loop. It’s the average speed that counts.

For the out lap, if a driver is below the RPM for the speed limit at the next-to-last timing loop, he’s free to accelerate over the limit before he hits the yellow line at the pit exit, which is the final loop. He carries more momentum out of the pits without messing up his average speed.

Like many teams, including Earnhardt Ganassi, the Penske team uses the equivalent of shifting lights for the tachometer to indicate if the driver is at the right RPM. Green lights followed by orange lights for getting close to the maximum and red lights for over it.

“We give the driver a high and a low (RPM) number with the high number at exactly what five miles an hour over is,” said Geisler. “There’s green, yellow and then red lights that warn the driver when you get in that window.”

At Indy, Montoya said he was within the green lights on his dash when he was called for speeding by NASCAR. Generally, it’s up to the driver, the tachometer and a seat-of-the pants feel for avoiding a penalty. “I’m surprised how accurate our drivers  are in being able to calculate their speeds,” said Watt.

Another wrinkle is the location of pit boxes. If a team pits just over a timing loop, the driver is free to accelerate to the maximum to the next loop after his car has been stationary in the pit box without increasing his average speed for the time spent between the two loops.

NASCAR has a method for drivers to check their RPM settings. During one of the pace laps prior to the start, the pace car turns off its lights, signaling that it’s circulating at the pit road speed limit – 55 mph in the case of Indy.

In the case of Hornish, the driver left the pits at maximum speed after more than 30 laps in the garage for repairs following a meeting with the wall in Turn 4. “Sam just completely forgot about the pit road speed limit,” said Geisler. “At that point, it didn’t make much difference.”

– Jonathan Ingram can be reached at jingram@racintoday.com.

| Senior Writer, RacinToday.com Thursday, July 30 2009
One Comment

One Comment »

  • John R. says:

    Well written article! It clearly explains NASCAR’s part of proving info before the race, the teams process and responsibility for calculating the RPM for their car set-up, the technology in the car to alert drivers when too high, and NASCAR’s use of pace car to allow drivers to verify their pit row speed limit rpm calculations. It also discussed team strategies.

    If our fellow writers and fans would read this article they would understand that there was likely an rpm miscalculation by Montoyas team or car equipment error. He was over the speed limit by 9%!

    Again, very informative article.