Cool Fuel — Penske and the Art of Refuelling

Sunoco was approached by Roger Penske, in the fall of 1965, to sponsor his newly formed racing team. After the financial details were worked out, a representative from Sunoco’s Automotive Laboratory in Marcus Hook, PA, was loaned to the team. I was the first person to serve in this manner during the 1966–67 seasons. When I left the team, Jerry Kroninger assumed that responsibility and continued with it throughout the years of Sunoco’s Penske sponsorship.

The Sunoco representative on the team was to assure that the proper fuels and lubricants were at the track, that they were actually used in the car (for advertising documentation) and that they did not fail to perform as expected. The products were Sunoco 260 gasoline and Sunoco engine oil, gear lubricant and wheel bearing grease. This crewman was also expected to do all he could to recommend product improvements and whatever else he might do to help the team win within the SCCA rules. This was part of the team’s philosophy of the “Unfair Advantage”—read the rulebook carefully and if something isn’t specifically forbidden, see if you can take advantage of it. The famous acid-dipped “lightweight” 1967 Camaro was a product of this type of thinking.

Evolution of the Penske refuelling rig. Starting with a basic gas drum in 1968, the Penske team soon progressed to a higher-mounted container, with larger diameter fill hose for quicker pit stops. In its most advanced iteration, the refuelling rig stood 20-feet tall, and was jacketed with dry ice and acetone to condense the fuel and further speed up delivery. In this form, the Penske team was able to refill the Camaro’s 22-gallon fuel tank in as little as 3.3 seconds.

The Trans-Am series rules required fuel cells and limited the car’s fuel capacity to 22 gallons with the fuel at 72 F. For races such as Daytona and Sebring, the speed of refueling wasn’t very critical because driver, tire and brake pad changes usually determined the length of a pit stop. The refueling apparatus was required to be gravity fed. The Penske team’s first refueling rig was merely a 200-gallon, cylindrical tank laid horizontally on a 3.5 ft stand. Using a standard 3-inch hose and nozzle, such as used to fuel commercial jet aircraft, refueling the 22-gallon Sunoco Camaro tank took about 11 seconds. This arrangement was used for the first two races of the 1968 season, but it quickly became apparent that improvements could be made to reduce the refueling time. All of these rigs were designed, fabricated and tested at the Sunoco Research and Engineering shop. To be practical, the rigs needed to be able to be assembled by one person in less than an hour.

The second fueling rig developed for Penske was used for the remainder of the 1968 season and incorporated two new design features. First, the storage tank holding the fuel was placed on a 6-foot high stand, which was the maximum height allowed by the rules. This increased the pressure head and reduced the fueling time to 8.5 seconds. Second, a cooling jacket, filled with acetone and dry ice before the race, was built around the gasoline storage tank. By cooling the gasoline from its typical track-side temperature of 95 F to around 25 F, it would contract sufficiently so that the equivalent of 23 unchilled gallons could be added to the 22-gallon car tank. We enjoyed calling this advancement “Cool Fuel.” On at least two occasions in 1968, this technique saved an entire pit stop, enabling the Sunoco Camaro to win both races.

Mark Donohue brings the Penske Sunoco Camaro in for a pit stop at St. Jovite, in 1969. Note the enormous fill hose capable of dumping 22-gallons of fuel in under 5 seconds. As Penske crew member Preston notes, “We were fast…but not neat.”

Finally, a third refueling rig that was 20 feet high was built for the start of the 1969 Trans-Am season and met all of the existing SCCA rules. It was engineered for easy transport and quick assembly and incorporated many safety features. The increased gravitational pressure reduced our fueling time down to 5.5 seconds. However, the SCCA made a rule change that outlawed it after only one race. The new rule limited the total height to 12 feet.

Designing within the new rules, a fourth rig was built that flowed faster than any previous one. Although the overall height was 12 feet, by using special aircraft-industry parts, the diameter of the hose and nozzle was increased from 3 to 4 inches. This almost doubled the cross-sectional area and reduced the fueling time from the 66-gallon storage tank to a record 4.5 seconds! The racecar’s tank also had to be modified to provide adequate venting for the faster fill rate. With this new system, the acetone/dry-ice technique was continued.

Donohue and crew make a stunning 3.3 second stop during the 1969 Sears Point 200. Donohue went on to win by just 2.4 seconds, over 2nd place finisher Parnelli Jones whose pit stops typically lasted 14 seconds.

On August 3, 1969, at the St. Jovite 3-hour race, the crew twice filled the Camaro’s 22-gallon tank in about 5 seconds, helping secure a victory for Mark Donohue. Shown in the accompanying photos is a pit stop at the Sears Point 200 on August 14, 1969. This lightning-fast stop for fuel lasted only 3.3 seconds. A similar stop for Parnelli Jones in his Mustang took 14 seconds. At the finish, Donohue took the checkered flag in the Sunoco Camaro 2.4 seconds ahead of Jones’ Mustang and clinched the Trans-Am title for the Penske team’s Camaro for the second straight year.

Quite frankly, we were always surprised that the other teams did not take advantage of these techniques.