RET127 Temp Digital

49 In terms of BoP, said Wiles, “We were adjusted a couple of times during the 2019 season due to slight power differences compared to the competition, but that was nothing major [in terms of impact on car performance]. The BoP for this year’s Daytona 24 Hours was set off of what we had last year. With that we went from a pair of 31.9 mm intake air restrictors to a pair of 32.2 mm.   “So not a large jump in bhp. It was definitely needed, maybe a little more than that was what was actually needed but we will take whatever we can get!” That 0.3 mm restrictor size increase is an increase in area of only 1.8%, and top-end power rose from 562 to 570 bhp. In terms of the advantages of the engine, Meesters remarked, “We have been working with this naturally aspirated platform for some years now, and that is one of our strengths. Also, having a naturally aspirated engine, our cylinder pressures are lower than those of our [turbo-supercharged] rivals, and I think that is a key to the game.” With the engine so well proven there was no testing specifically for the 2020 24 Hours – “only our regular engine validation for each build”, said Meesters, “nothing out of the ordinary”. As usual, factory-supported Cadillac DPi V.R prototypes – based on the Dallara P217 LM P2 car – were run by US-based operations Wayne Taylor Racing (#10),  Action Express (#31) and JDC Miller Motorsports (#5 and #85), JDC Miller Motorsports having taken over the running of the #5 from Action Express for 2020.  There were thus only four Cadillacs at the event this year. ECR had a fresh engine at the track for each of its four cars plus a spare for each, these being to the exact same specification as used elsewhere, and each car used the same engine for practice, qualifying and the race. The #31 was quickest in qualifying, fourth on the grid and 0.06% from pole. Alas, in the race a puncture dropped the car from contention. It then lost second gear, which eventually led to a 21-minute swap of gear cluster that left it seventh overall, 11 laps from the winner. Meanwhile, the #85 car had suffered a collision and it lost a total of eight laps to various issues, leaving it fifth overall. The sister #5 car ran strongly throughout the race, taking many turns in front, and despite incurring underfloor damage it finished third on the lead lap. It didn’t quite have the race pace of the #10, which lost time owing to a couple of penalties, a lights issue that required a change of rear bodywork, a precautionary change of brake discs and an electrical power-steering glitch, but nevertheless came through to win. MAZDA AER AT DAYTONA The Mazda DPi powerplant is badged as the Mazda MZ 2.0T, and is a 2.0 litre I4 turbo both designed as a pure race engine and developed for this application by AER. Known internally by AER as P91/P91B, the engine was first raced in DPi in 2017 and was updated for 2018 and 2019, as described in the respective Prototype Engine Reports. The 2019 version was the first known as the B spec. The brace of P91Bs raced in the 2019 Daytona 24 Hours did not see the finish. Current AER technical director Michael Wilson was brought in soon afterwards, initially on a consultancy basis. He said, “After the 2019 Daytona 24 Hours race there was a huge push on the reliability front, on quality control and on build process. We looked at what was being done, how was it being done and if everyone was working to a defined process.  “That real focus is what substantially changed [on the engine front] between the 2019 and 2020 Daytona races. The base engine had potential, it was making sufficient power. Most of the scope of the work I got involved in was quality control and reliability. It began at the AER factory and then I started escorting them to various events. My involvement grew more intense while ramping up to the 2020 Daytona 24 Hours, with extensive dyno and in-car testing.”  In terms of any specification change to the 91B between the two CADILLAC ECR AT DAYTONA ECR Cadillac DPI-V.R V8 5.5 litre, 16-valve, pushrod V8 n/a GM director of racing: Mark Kent Cadillac Racing programme manager: Laura Wontrop Klauser ECR Engines president: Richie Gilmore ECR Engines director of engineering: Matthew Wiles ECR Engines sportscar programme manager: Scott Meesters ECR Engines lead engine assembler: Joe London ECR Engines lead electronics engineer: Judd Glenn Track support leader: Scott Meesters Track support #5: Ian Magor Track support  #10: Lucas Lafond Track support #31: Joe London Track support #85: Benjamin Michael 10 Cadillac DPi (Xtrac/Michelin) 1st – 833L 1st DPi 5 Cadillac DPi (Xtrac/Michelin) 3rd – 833L 3rd DPi 85 Cadillac DPi (Xtrac/Michelin) 5th – 825L 5th DPi 31 Cadillac DPi (Xtrac/Michelin) 7th – 822L 7th DPi AER prepared a 2.0 litre I4 turbo for the Mazda DPi cars (Photo: Anne Proffit) t