The car began shakedown testing on 20 July 2006 on the runway at RAF Wittering with the lower-power 600bhp version of the JCB444 engine, the team slowly ramping up the speed to prove the chassis and engines.
On 22 August 2006, after being re-fitted with 750bhp 'LSR' versions of the JCB444 engines,[REF] the JCB Dieselmax car broke the official FIA diesel engine land speed record, attaining a speed of 328.767 mph (529 km/h).