EFI in NASCAR Sprint Cup racing: A million miles without a failure

When Dale Earnhardt Jr. crossed the start/finish line to lead Lap 34 last Saturday at Charlotte Motor Speedway, there was no special fanfare beyond the standing ovation Earnhardt gets every time he leads a lap.

Race control didn't stop the action to give Earnhardt the NASCAR equivalent of a game ball. There was no announcement of a competitive milestone.

Yet when Earnhardt led Lap 34 in the Bank of America 500, he logged the one-millionth mile in NASCAR Sprint Cup Series competition since the transition from traditional carburetors to electronic fuel injection (EFI).

It should come as no surprise that the milestone was decidedly under the radar, given that the switch to EFI itself has been smooth, almost seamless and virtually invisible.

Yes, there were issues with fuel pickup, pump configurations, sensors and throttle linkages as teams adjusted to a new computer-based method of supplying fuel to the immensely powerful engines used in NASCAR Sprint Cup racing.

But not once in a million miles has the brain of the EFI system, the electronic control unit (ECU), failed, from the electronics supplied by McLaren to the computing power supplied by chip maker Freescale.

"The good news is, when it's a non-event, we tip our hat to it, because that means that it's done its job," NASCAR Vice President of Competition and Racing Development Robin Pemberton said of the successful transition to EFI. "A million racing miles is one thing, but it's probably almost equaled in test miles, and to my knowledge, we haven't had any failures."

With its frequency and length of races, NASCAR Sprint Cup racing arguably puts more stress on the engine and the EFI system than any other competitive series.

"We run the most races, our teams build the most vehicles, and we run the longest races," Pemberton said. "Granted, you can have Le Mans, the Rolex 24 Hour race, you can have a lot of those endurance races, but we run 400, 500, up to 600 miles every weekend on our mile- and mile-and-a-half tracks).

"Our short races are 250 miles, which is what other series run as their big races. With the full-bodied cars, with the minimal tires that we have, the brake heat and the (engine) heat that's generated, we put anything through its paces."

As a driver puts a car through its paces, the ECU records a wealth of data that can be downloaded and analyzed. In fact, the most visible difference between a carbureted system and EFI may well be the banks of laptop computers teams now set up in their garage stalls.

"I think the big benefit has really been for the teams, because they've been able to pinpoint times when there's been a failure (in the engine) and understand that," said Steve Nelson, director of marketing for Freescale. "And it's helped them when they go back and look at data to build engines that are more reliable.

"They can go right back to the event that happened. They can identify over-revs, missed shifts, all types of things. And there have been times when drivers have been able to help each other with their lift points getting into the corner and their RPM traces, things like that… Racing is always about data, being able to get more data out of the car."

You don't have to convince rookie driver Kyle Larson, who will move up to the NASCAR Sprint Cup Series full-time in 2014, taking the place of Juan Pablo Montoya in Earnhardt Ganassi Racing's No. 42 Chevrolet. In the meantime, however, Larson is learning from Montoya, and from future teammate Jamie McMurray, by studying their EFI data.

"They show me Juan's and Jamie's throttle and braking and all that," Larson said before his NASCAR Sprint Cup debut last Saturday at Charlotte. "It helps out quite a bit. I know (from a Charlotte test) I wasn't getting in the corner quite as hard as they were.

"You can tell different driving styles apart pretty well through that stuff, too. Like here (at Charlotte), Juan never really gets out of the throttle. I'm out of it for just a split second and back in it. That helps a lot. When I look at my data versus theirs, I can really tell what I need to do to get better."

Interestingly, the computer chips Freescale supplies for the EFI systems aren't custom-made for racing. You'll find the exact same thing in your street car.

"The little chips we put into those engine computers are the exact same ones we put into passenger cars," Nelson said. "We don't special-test them. They come right off the shelf. In our business, we ship things in very, very large volume, literally in the millions and billions. Something like racing is such a small market, there's no way financially we could ever do a custom version of a device.

"So, to take what is literally in the passenger cars in the parking lot -- the same parts that are in those engine computers -- McLaren buys the same ones. To do a million miles with zero failures with non-racing-specified parts is a really nice story for us."

By Reid Spencer - NASCAR Wire Service