Honda RA260E engine

Developed in 1980 for Formula Two racing. The designer was Nobuhiko Kawamoto. The goal was to surpass BMW's in-line 4-cylinder engine, the M12/7, which was a regular win in the same category at the time. The cylinder block is an 80 degrees V6 made of cast iron.

Based on this engine, the turbocharged Formula 1 engine, dubbed the RA163E, was developed with the stroke reduced from 52.3mm to 39.2mm.

The RA260E of the F2 engine is a number of minor changes such as 2 of F2 and 6 of V6, and the single-digit value of the 1980s is reflected in the engine model name. As an example, in 1981, the fuel injection manufacturer was changed to RA261E.

• Engine type: Water-cooled V-type 6-cylinder DOHC 24-valve naturally-aspirated
• Bank angle: 80°
• Total displacement: 1,996.3 cc (121.82 cu in)
• Bore x Stroke: 90 mm (3.5 in) x 52.3 mm (2.06 in)
• Compression ratio: Not disclosed
• Maximum output: > 310 hp @ 10,500 rpm
• Weight: 125 kg (276 lb)

Kawamoto personally started drawing racing engines for F2 in 1977 in order to inherit the engine technology that Honda had cultivated since the first F1 entry. At the end of the year, when Honda got OK, he started designing with a few young people.

At that time, the in-line 4-cylinder BMW M12 / 7 was overwhelmingly strong in F2, so the goal was to overcome this, and unlike the conventional Honda engine for F1, which had been difficult, the number of revolutions was increased. The design was made with the goal of producing horsepower. The conventional Honda engine has the concept of squeezing horsepower at high rpm, and since it was at a high limit, it is severe in all aspects such as price, work accuracy, materials, and sacrifices serviceability and usability. rice field. Therefore, it was intended to have a margin for the number of revolutions (maximum number of revolutions was suppressed to 12000 rpm) so that the conventional drawbacks would not occur, maintenance was easy, and it was easy for each team of the supply destination to handle.

While BMW prioritized medium to high-speed torque with a long stroke of in-line 4-cylinder, Honda repeatedly examined the number of cylinders with 4, 6, and 8 cylinders, but 6 cylinders because 8 cylinders are too many. If there are 6 cylinders in series, the total length of the engine will be long, so I chose a V-type 6-cylinder engine that arranges 3 cylinders in a V-type.

It is said that the pent-roof combustion chamber was developed by Keith Duckworth of Cosworth with the FVA of the 1600cc F2 engine, but before the FVA, Honda had already adopted it in its racing engine and raced. He participated in the race and achieved good results. However, this engine was not commercially available as a Honda-only engine, so even if it achieved good results in the race, its contents were not disclosed to the outside of Honda.

On the other hand, since FVA was marketed to participants in F2 races, it was possible to obtain FVA and copy its combustion chamber shape, gear train, etc. and reflect it in its own racing engine. In particular, FVA uses the cylinder block of mass-produced cars, so it is highly versatile in design and easy to copy and use, and became the basis of the basic design of racing engines after FVA.

FVA's pent-roof combustion chamber uses a gear train with four intake and exhaust valves installed to make the valve pinch angle narrower than 40 degrees, and a large number of small-diameter gears when using a gear drive to drive the valves. The pattern was the basis of the racing engine at the time.

Kawamoto avoids the shackles of mass production, determines the bore x stroke and combustion chamber shape, outputs even in the low rotation range, and as an engine that can increase the rotation to 12000 rpm with a margin, the valve pinch angle is better than Duckworth. The combustion efficiency has been improved by setting the angle between the valves.

For the valve drive, a rocker arm was placed to secure a lift larger than the cam lift. Furthermore, the valve was driven by a gear drive, but the combination of three gears suppressed the occurrence of timing deviation.

Since 1979, F2 has introduced the wing car that was already popular in F1. Kawamoto chose Ralt, which had been associated with Honda in the past, as the chassis to be mounted on Honda, consulted with the designer Ron Toorak in 1979, and considered installing the Honda V6 engine on the Ralt RT2 chassis that was competing in the same year. As a wing car compatible, we received orders from Ralt to "mount the engine with a rigid mount " and "mount the exhaust pipe as high as possible and cut down the engine width as much as possible".

In particular, Honda changed the bank angle of the V6 engine to 80 degrees and at the same time changed the design of the mount part for rigid mounting in order to narrow the engine width, which was an essential condition for mounting on a wing car.

For fuel supply, Lucas ' mechanical fuel injection was adopted.

In 1980, the Honda engine was installed in the Ralt RH6 and started participating in the European F2 Championship in the middle of the season. Geoff Lees and Nigel Mansell were appointed as drivers.[3]

Honda entered the F2 series by improving the engine every season until the final year of F2 and supplying it to a small number of teams instead of supplying it to many teams like BMW. The development goal was to commercialize the engine to teams that wanted it , but it could not be commercialized because the Fédération Internationale de l'Automobile (FIA) did not tell F2 that the series would continue to be held in the future.