After the initial poor performance of the Powermax, Phompsonby Automobile Racing started work on a successor to the Powermax. Basing the new model on the designs they saw at the Powermax’s races, they started building a new race car under the temporary title of the ‘Powermax II’. In half the development time of the Powermax, Phompsonby came out with a brand new and far better design under the name of ‘Green Arrow’.
The Green Arrow had a brand new engine with a massive 6 litre V12 engine called the Phompson Overclocker. This engine could make a total of 410.8 HP, 7 more than the Powermax, at 5,500 RPM and a total of 543.1 Nm of torque at 4,800 RPM. This engine, while not as large or quite as torquy as the Overdriver engine in the Powermax, was slightly more powerful and far lighter, greatly contributing towards the superiority of the Green Arrow. The engine still had direct acting OHC headers but it had a monstrous 6 carburettors, contributing to the power output of the smaller engine. To top it off, the engine was more fuel efficient at 6.5 miles to the gallon with the super leaded fuel!
It’s not like the car was slower than the Powermax either. Far from it, actually. The top speed was just 0.3 MPH slower at 129.7 MPH but it had a far better 0-62 at 8.9 seconds. It was still rear wheel drive with the 4 speed manual longitudinal gearbox and no differentials.
The driver was slightly more comfortable than the Powermax, with a better seating arrangement and an enclosed cockpit. There was less wind tugging at them and the driver could duck behind the windscreen to be more streamlined. The car was also safer in a crash than the Powermax due to the surrounding body around the driver. Learning from the Powermax, no spare wheels or any kind of extra weight was on the car, going completely for speed.
The ‘Green Arrow’ debuted at the end of 1925, appearing during the Powermax’s final race and racing alongside it to build up interest and show the world just how much better the ‘Green Arrow’ was over the Powermax. The ‘Green Arrow’ was lighter, faster, more streamlined, better handling and safer than the Powermax, making it a complete improvement over the previous. It showed in that race as it finished in front of the Powermax by several places.
The ‘Green Arrow’ was far more well received by the race crew, who praised the sleeker design, reduced weight and, most importantly, better handling over the beast that was the Powermax. The ‘Green Arrow’ raced all the way up to 1932 with far more success than the Powermax ever achieved. The ‘Green Arrow’ finished in the top half nearly every championship, winning 6 championships during its career, one in 1926, 1 in 1927, 2 in 1929, 1 in 1930 and one final victory in 1931. By the 1930s, the ‘Green Arrow’ was just not as good as the new competitors appearing on the scene. Only the skill of the driver was keeping it competitive, but Phompsonby had seen this time coming and had prepared a new model which once again debuted in the final race of the ‘Green Arrow’.