1988
The car, with upgrades to suspension and aerodynamics, was dubbed the A10B and was more successful in 1988 when most teams had converted to running 3.5L naturally aspirated engines in preparation for turbocharged engines being banned from 1989. Arrows continued with the Megatron turbos and finished 5th in the 1988 Constructors' Championship and Eddie Cheever scored the A10's only podium finish with a 3rd placing at the 1988 Italian Grand Prix. Warwick also finished 4th in that race, only 0.582 seconds behind Cheever, in a great result for the team. Warwick finished 8th in the Drivers' Championship with 17 points while Cheever scored 6 points to finish 12th.
During 1988 Arrows were rated as a good chance to pick up points over the naturally aspirated cars due to having more power with the Megatron turbo, estimated to be around 640 bhp (477 kW; 649 PS) with the new 2.5 bar turbo limit (down in 1988 from 1987's 4.0 limit). The turbos were also restricted to just 150 litres of fuel per race in 1988, while the 'atmo' cars were allowed up to 250 litres per race. Unfortunately for the team, the FIA mandated pop-off valve had a habit of cutting in before the 2.5 limit, which restricted power and often left the cars with plenty of fuel to spare at the end of a race (the team had experienced exactly the same problem in 1987). Quite often the pop-off valve cut in at 2.3 bar or below in both qualifying and races (F1 engineers estimated that each 0.1 bar was worth approximately 20 bhp) leaving Warwick and Cheever with a hard time fighting off the atmos of Benetton, Williams and March, let alone challenging the other leading turbo teams: McLaren-Honda (who won 15 of the 16 races in 1988), Ferrari (who won the race that McLaren did not) and Lotus-Honda.
It took until just before the Italian Grand Prix for Heini Mader to get on top of the pop-off valve problem, which turned out to be the FIA unit being located too high above the engine, resulting in less power, a problem that Honda and Ferrari engineers had long since solved. By moving the pop-off valve closer to the engine, Mader had allowed Warwick and Cheever to exploit the raw power of the straight 4 turbo and to be much closer to the front than they had been all season. However, while the pop-off valve issue was finally fixed, the engine's other main problem that had remained since the 4-cylinder BMW had first appeared in F1 back in 1982, lack of throttle response from turbo lag followed by the power coming on like a light switch still remained, hampering the team in the final four races of the season, especially at the Spanish Grand Prix held at the tight Circuito de Jerez where the cars are constantly on and off the throttle over the course of a lap and good throttle response counts for more than outright top speed. Warwick could only qualify 17th while Cheever started on the back row of the grid in 25th.
In qualifying for the Italian Grand Prix, the A10B, with its Megatron engine finally exploiting the full 2.5 bar limit, was faster through the speed trap at 310 km/h (193 mph), than the McLaren-Hondas which managed 305 km/h (190 mph), though both Arrows and McLaren were slower on the straight than the Ferrari's. Despite this Cheever, who qualified the faster of the two drivers in 5th place (Warwick was 6th, only 0.155 slower), was still 1.686 seconds slower than pole man Ayrton Senna (McLaren).
During qualifying for the German Grand Prix at Hockenheim, Eddie Cheever, on a quick lap, had a close call at almost 200 mph (322 km/h) on the straight before the circuit's "Stadium" section. Cheever moved to his right to pass the Eurobrun of Oscar Larrauri, and found the Ferrari of Gerhard Berger attempting to pass them both, but Cheever had what was left of the road. Berger put two wheels on the grass which threw his car into a wild spin back across the track and directly between the Arrows and EuroBrun, just missing taking both cars and himself out in a high speed crash.
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