Even after 2.4-liter V8 regulations took effect, the F1 engine development war continued unabated, reaching maximum engine speeds of 20,000rpm. In response, the FIA further tightened engine regulations in 2007. Maximum engine speed was limited to 19,000rpm, and the development of major engine parts was frozen. On the other hand, although the one-engine-per-two-races rule remained, Friday practice sessions were no longer included, somewhat relieving the harsh demands on engine reliability and durability. Pit crew speed and quality of work became critical, however, as the engines had to be swapped out after the Friday session.

Prior to the engine development freeze, the RA807E was slightly modified from the RA806E. Weight was reduced by another 100g to 95.1kg, just above the minimum weight. The center of gravity was also lowered by 4mm to 165.1mm. Bore x stroke was retained at 97 x 40.52mm, similar to the RA806E, but the compression ratio was increased to 13. With the maximum rpm limited, the main focus of development shifted from how much air and fuel could be injected to generate a larger explosion, to how effectively the engine could be used when running at 19,000rpm. Since the output advantage by engine speed could no longer be expected, the reduction of friction became important in the development of the RA807E.

Although development of the engine itself was frozen, there were no restrictions on the intake / exhaust systems and auxiliary equipment, and development in these areas continued. Specifically, induction boxes, exhaust pipes, and fuel systems were considered, but development focused on the air intake system as there were space limitations in improving the exhaust system, and the auxiliary equipment had little room for growth. Furthermore, lap time simulation technology was used to optimize the up-shift rpm, straight-end rpm control settings, and gear ratios to match each circuit, in order to use all of the car’s performance.

The 2007 season with the RA807E ended without reaching its potential, as the RA107 chassis developed and manufactured under the new Honda Racing organization had aerodynamic problems. In addition, the engine specifications and operation methods were pushed to the limit at 19,000rpm, which considerably reduced the margin of endurance and reliability, and resulted in several engine blowouts during the season. On the other hand, the RA807E powering Super Aguri was wildly successful. Honda supplied engines to Super Aguri again in 2007. In the Australian season-opener, Takuma Sato made it to Q3 and was the highest-placed Honda qualifier in tenth place. In Round 4, Spain, Sato finished eighth, earning a memorable first point for Super Aguri. In Round 6, Canadian, he once again proved the potential of the RA807E as he passed McLaren’s Fernando Alonso to finish in sixth place and send the Japanese fans into a frenzy.