CUP: Circuit Breaker Issues A Concern For Martin, Stewart

Sprint Cup

CUP: Circuit Breaker Issues A Concern For Martin, Stewart

Last Sunday's race at Phoenix was the first for a non-restricted engine, and the race had its share of engine issues...

Bob Pockrass | http://www.scenedaily.com | Posted March 07, 2012 Charlotte, NC

While some Toyota and Chevrolet drivers had issues with circuit breakers at Phoenix International Raceway, it might seem as if the Ford camp might breathe a sigh of relief that its teams didn’t suffer from similar gremlins associated with NASCAR’s new fuel injection systems.

But that’s not the case for one simple reason: It’s too early in the fuel injection rollout for anyone to feel totally confident in the system.

The 312-lap race was the first for a non-restricted engine, and the race had its share of engine issues – from the circuit breakers flipping off for Tony Stewart and Mark Martin to the valve-train issue of Marcos Ambrose and an apparent broken valve or valve spring for Jeff Burton.

Martin’s relay box with the circuit breakers showed broken parts that indicated a vibration must have caused the circuit breaker to flip, said Toyota Racing Development President Lee White in a phone interview Tuesday. He said the breakers are set to flip at 5 amps of electrical current and they are drawing under 100 milliamps.

TRD provides engines to Michael Waltrip Racing and Joe Gibbs Racing.

“Our feeling at this point is that it is probably endemic to how the individual teams mount it, so it’s vibration related,” White said. “We are not even close to the overload electrically. We are miles away from that. … In our particular case, all of our issues were with the Waltrip side.

“We had zero issues with the JGR side. In doing some investigation, there are some subtle differences in how they mount the box.”

Hendrick Motorsports declined to comment on its investigation into the circuit breaker issues of Stewart and Kurt Busch, who had a problem in practice. Both teams utilize Hendrick engines.

The aluminum relay boxes – which provide power to the fuel pumps, injectors and the electronic control unit – contain two circuit breakers. The circuit breakers and relay boxes are not part of the NASCAR-mandated pieces that teams must buy from specific vendors, but most buy them from McLaren because it’s easier since McLaren makes the electronic control unit.

Engine builders have worried about durability throughout the process of moving to EFI because a Sprint Cup engine and car endure a tremendous amount of punishment during the course of a race.

Roush Yates Engines CEO Doug Yates said the circuit breakers work similar to those in one’s house, as a safety feature to prevent a fire as a result of overloading.

“I’m concerned because the other guys are seeing things, and now that we’re getting some races on this, there’s a lot to learn,” Yates said. “It’s a little bit of a surprise [with the circuit breakers]. What was high on our radar screen [were] sensor issues and sensor failures.”

White said IndyCar and sports-car carbon-composite chassis dampens vibration, something that doesn’t occur in a NASCAR stock car. He said he believes this will be a quick fix for the teams, but the overall fuel-injection learning curve as far as durability will continue through May.

“Everyone is tip-toeing through this maze early in the season because no one has put this type of system in this environment,” White said. “Once you start looking at the probably hundred feet of wire to support this thing when you include the fuel bumps and hundreds of plug-in connectors and sensors and all the feedback that has to support it and make it do what it does, … until you actually race, it’s very difficult to test and simulate race conditions with the pit stops and the side-by-side [racing] and the heat and everything. “

In other words, teams are testing on race days. That’s not a comfortable feeling for crew chiefs, even for someone such as Joe Gibbs Racing’s Darian Grubb, who won the race at Phoenix with driver Denny Hamlin.

“I'm going to knock on some wood somewhere,” he quipped after the victory. “It is a new system. You're always going to have the doubt in the back of your mind because it's not something you're comfortable with.”

Tony Stewart's car is pushed down pit road during Sunday's race at Phoenix International Raceway. (Photo: Getty Images)

Crew chiefs rely on their engine departments to handle situations such as this.

“I really don’t understand the total why it’s there,” said Stewart crew chief Steve Addington right after the race. “I’m sitting here talking to the engine guys, and it’s something that we’ve all just got to put our heads together and figure it out before Vegas.”

The Phoenix race, relatively short at 312 miles, also saw drivers have non-EFI related engine issues.

The Ambrose engine failure was a product of high RPM and high temperatures that damaged the valve train, Yates said.

Yates could diagnose the issue easier because the team is getting more information on RPM and temperatures from the electronic data it gets from the fuel-injection units. Before, teams only knew the temperature of oil and water from a driver reporting back to the crew chief what was on his dashboard gauge. Now engine builders know, through data compiled by the system and downloaded after the race, the temperatures throughout the entire event.

“That’s been interesting to see the differences between car to car and team to team,” Yates said. “When you look at the average data for the entire race, there’s pretty big differences car to car and that’s going to help us with our engines and engine strategy going forward.

“It’s really neat to have the data. It’s a little bit overwhelming because how do you process all the information?”

Stewart’s team should be able to diagnose exactly when the circuit breaker flipped off. He didn’t know he had the problem until he shut the engine off while trying to save gas, and then the engine wouldn’t refire.

With the data, organizations will now know exactly when and how each driver flips the engine on and off to save fuel. Some drivers, such as Stewart and Roush Fenway’s Carl Edwards, seem to be among the best at it.

Now their secrets will be available to their engine departments (or in Stewart’s case, Hendrick engine department).

“Their fuel saving strategy or how they cut the car off or the method they use are all somewhat different,” Yates said. “Now you can see what they’re doing because the data tells exactly what’s going on.”

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