RET127 Temp Digital

52 GIBSON TECHNOLOGY AT LE MANS The design and development of Gibson Technology’s naturally aspirated 4.5 litre GL458 V8 was described in RET 111 (June/July 2018) through to its debut in the 2018 Spa WEC event. Its subsequent deployment at Le Mans 2018 was covered in that year’s 24-Hour Prototype Engine Report ( RET 112, August 2018). As described in last year’s 24-Hour Prototype Engine Report ( RET 120, August 2019) since Le Mans 2018 its maximum permitted fuel flow rate had been increased from 108 to 115 kg/h, and that led to the introduction of a ‘B’ version of the engine first raced at Spa in May 2019, with mechanical and software changes to exploit the higher power potential. We have now learned that the B spec included a reworking of the cylinder head casting to accommodate internal changes including different port geometry, different valve spacing and slightly larger valves. Clearly, such modifications are consistent with the higher fuel flow, permitting additional output. The B spec has been standard equipment for this 2019-20 WEC season, and there has been no further development of it since it was introduced, aside from what Gibson Technology operations director John Manchester described as very subtle changes. He added that there are some further changes in the pipeline for 2021 that also apply to the LM P2 engine and which are aimed at enhancing durability.   LE MANS 2020 Le Mans 2020 was the penultimate round of the 2019-20 World Endurance Championship, which began with a four-hour race at Silverstone on September 1, 2019, and was due to conclude at Bahrain with an eight-hour race on November 14 this year. All the other races aside from Le Mans had been six hours, aside from a 2019 event at Bahrain, also running for eight hours. The original plan had been to start the 2020-21 season after Le Mans in June, but the coronavirus pandemic put paid to that – hence Le Mans moving to September and the 2019-20 season extending through to November 2020, to be followed by a calendar year 2021 season. The pandemic also put paid to the traditional Le Mans Test Day, as it did to the traditional city centre scrutineering on the Sunday/Monday before the race. That was replaced by scrutineering at the circuit on Wednesday, September 16. Track action began on the Thursday, when there were three hours of free practice from 10 am, another three from 2 pm and a final four from 8 pm. Between free practices two and three there was a 45-minute qualifying session starting at 5.15 pm. The quickest six in each of the four (LMP and GT) categories then went forward to a 30-minute ‘Hyperpole’ starting at 11.30 am on Friday the 18th, during which the pit lane entry was kept closed. Before that there had been a final free practice, for an hour from 10 am. Warm-up was for 15 minutes on Saturday the 19th, beginning at 10.30 am, with the race starting at 2.30 pm. The mandatory E20 fuel was again supplied by Total. The LM P1 powertrain regulations were fundamentally unchanged aside from the imposition of various measures under the so-called Equivalence of Technology. Thus, Le Mans 2020 was contested by LM P1 hybrid (LM P1HY) factory Prototypes (Toyota being the only representative) and LM P1 non-hybrid (LM P1NH) privateer Prototypes (all three Gibson-powered). For Toyota, the maximum release of the energy recovery system was set at 300 kW and no more than 8 MJ per lap of Le Mans, as in 2019. Also as in 2019, the maximum amount of petrol energy that can be expended over a lap was 124.9 MJ for Toyota and unlimited for the Gibson engines. Again as in 2019, the maximum instantaneous petrol flow was 80 kg/h for Toyota and 115 kg/h for the Gibson engines. Maximum petrol per stint was 35.1 kg for Toyota, as in 2019, and 55.4 kg for the Gibson cars versus 50.8 kg in 2019. This adjustment was to allow the Gibsons to run as many laps (in theory) as the Toyotas between refuelling stops. At the same time, the Toyotas had to carry an extra 7 kg thanks to a new minimum weight of 895 kg. For the 2019-20 season there was no limit on privateer engine use, whereas the Toyota Hybrid is limited to seven power units. Since all the engines have to be homologated (including data on aspects of performance) there is no scope for the privateers to exploit qualifying engines. Night time at Le Mans 2020 (Courtesy of the ACO) Gibson Technology supplied a naturally aspirated 4.5 litre V8 for the Rebellion LM P1s (Courtesy of Gibson Technology) One of the Oreca-produced Rebellions – this #1 car came second overall (Courtesy of the ACO)