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03 July 2017

2017 REFUEL EV Race Sees New Track Records

 

Last week at 9th annual REFUEL all-electric time trials at California’s Mazda Raceway, Billy Kwan grabbed first place in his category driving a 2017 Chevrolet Bolt EV.

In the process, he set a new track record at 1:56.619, actually beating every Tesla entry from last year’s race, but not this time.

The Monterey track, formerly known as Laguna Seca, is 2.2 miles long and features 11 turns including number 8, known as the Corkscrew, which plunges at up to an 18-percent grade between curves.

As for Teslas that were faster, Cameron Rogers took first place in the higher-powered “Production GT” car category this year with his 2016 Tesla Model S90D which lapped at 1:52.425.

This year also saw a new REFUEL record time of 1:50.146 for a production-class motorcycle by Trevor Doniak riding a Zero SR.

Kwan’s Premier-trim Bolt EV was unmodified except for Toyo Proxes R888 215/45 racing tires which he mounted on the original factory 17 inch wheels.

A video of him was posted by Tesla P85 driver Jack Brown’s dash camera:

In an interview, he said he drove with traction control disabled but in had to glide through turns to avoid losing grip and spinning his tires during acceleration.

“I could not get the power down in the mid-corner,” he said. “All I can do is to roll on the go pedal, minimize my steering input and carry as much momentum into the corner as possible without getting into an oversteer.”

Drivers say a track like this generally requires a lot of full acceleration and hard braking and not much in between. It didn’t help that Kwan had hardly broken in the friction brakes on his relatively new car.

During the two practice sessions earlier in the day he had engaged the Bolt’s “L” shifter position that enables stronger regenerative braking, but for the actual timed race at the end of the day he forgot and left the car in its default drive mode.

In spite of having to make last-minute adjustments to his braking strategy Kwan managed to surpass his best practice lap time 1:58 earlier in the day.

The Bolt EV hit its maximum governed speed of about 92 mph at least twice during the lap including the final all-out run through the finish line.

He topped-off the charge on his pack above 95 percent before the time trial lap which may have helped with acceleration since lithium-ion batteries can discharge at their maximum power at higher charge levels.

Better grip from the sticky Toyo tires helped over the stock low rolling resistance rubber.

Kwan has been racing since his mid-20’s starting with a modified Honda Civic gas car but shifted to focusing on his career and gave up racing for 15 years. He works now for the Nokia division that sells computer network routers.

A few years ago he got back into racing. He and his wife now drive laps occasionally at Sears Point in Sonoma Raceway formerly known as Sears Point.

Kwan previously competed in 2013 with a RAV4 EV at 2:07 and improved his time to 2:07 in both 2014 and 2015. The RAV4 is over 400-pounds heavier than the Bolt and its big cabin is a problem because safety rules require the front windows to be down which Kwan compared to “running with a parachute — it was very hard to get any straight line speed.”

He credits his long-time racing coaches and sponsors Vicman Ng and Ken Myers with sharing racing skills. He gained hands-on mechanical experience on many weekends in Ng’s auto garage preparing his car for upcoming races.

Like some other electric cars, Kwan said his Bolt EV went into a reduced power mode after two or three laps of hard racing during practice runs presumably due to a buildup of heat in key components like the inverter, motor, or battery pack. He saw no evidence of thermal limiting during the official race lap itself, however.

Kwan said he misjudged some of the turns and thinks he can get his time down further with more racing experience with his new Bolt. “I am still adjusting to the car”, he said.

Cameron Rogers.

Cameron Rogers works in marketing at Apple but his five years of racing experience helped him take first place this year among the Tesla cars that compete in the Production GT category.

Before he bought his 2016 Model S 85D has was racing a Mazda Miata and a Mazda RX-7. He placed first in the Global Time Attack race at the Buttonwillow Raceway last year in the RWD RX-7 but in Sunday’s REFUEL race he had the advantage of all four wheels pushing against the pavement even though they were stock Michelin tires from the factory.

Unlike Billy Kwan in his Bolt EV, Rogers drove his car with traction control enabled because it cannot be disabled on the S85D at high speeds. However, he said he was very impressed with how Tesla has implemented it and noted that EV motors are inherently capable of reacting quicker to traction changes than a conventional gasoline drivetrain.

In another difference from Kwan, Rogers started the time trial lap with the battery pack less than 25-percent charged since he had Supercharged in the morning and had not had a chance to recharge during the day at one of the 50-amp outlets available to racers.

Each hard driving lap of 2.23 miles on the track ate up close to 25 miles of normal rated range or about 10-times more energy than ordinary highway driving. Rogers doesn’t think the low battery level hurt his acceleration although he questioned if it might limit a P85D with more powerful motors.

During the last stretch of the race he noticed an on-screen warning that his power was being reduced due to thermal limits.

Rogers remarked at the Bolt EV’s quick performance.

“It was very fast,” he said. “I was very impressed.”

He described the Mazda Raceway as a “power track” that has only two turns typically entered below 60 mph.

The best ever time in the Production or Production GT class at the REFUEL races was set in 2013 by Joe Nuxoll in his Tesla Roadster with a time of 1:48.935 seconds. Vehicle suspension engineer Aaron Bailey managed 1:48.917 in a Model S in a special category for cars driven by Tesla employees in the 2013 race.

Other categories of vehicles in the race include prototypes, gasoline vehicles converted to electric cars, and ground-hugging electric racing karts.

Production gas cars can still score better times than the best cars at REFUEL as seen in these race results at the track earlier in June.

The REFUEL event is among the very few all-electric races established so far around the world. It is open to professional drivers but many of the competitors are amateurs driving their own personal cars.

Car race results

Motorcycle race results

Full results for all years.

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