Which would be the best race engine?
Discussion
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delta0 said:
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The 4 rotor 787b produced 900bhp. 700bhp was the endurance configuration to ensure reliability. This would need to be the case for the other engines as no way could you tune something like an F1 car and expect it to last very long."Back in the day", F1 engines were primarily V8 or V12 configuration, and began to move towards V10 by Renault as a compromise between power, efficiency/economy, and packaging.
The optimum configuration for any formula will be the engine that makes the most power with considerations for driveability, however in doing so can do it efficiently (space and weight for fuel), and can be optimised into the car most effectively (space required, and effect on the aero design for the car)
The F1 engines alluded to above were either 3000cc or 3500cc. A 6000cc normally aspirated cap might lead to a different direction all together, and the type of car and racing that it is intended for would need to be considered ........ A hugely complicated V16 could make huge power at mental RPM, however might need to be heavy and bulky, which wouldn't be ideal for a formula single seater. Whilst it might fit better into a proto-GT car, it could be thirsty and therefore heavy on it's brakes and tyres over a long distance.
If we were hypothetically creating a spec for a series to run with, the number and configuration of cylinders would be free, however limited to a reciprocating piston engine to keep things simple. The regs would cap capacity at 6000cc, rpm to 10k or maybe 12k, and there would be regulations governing the minimum weights and dimensions of components. This could be for a piston set for the engine, so that the multi-cylinder V12 or greater engines weren't regulated out. Add in a cap to the number of circular valves to 4 per cylinder, plus 2 cams per bank, and a limited dimension single air restrictor inlet, and there'd be a pretty level and cost controlled playing field.
...... basically all racing should be with a modernised and slightly increased dimension and capacity Ford DFV/DFR!!!
The optimum configuration for any formula will be the engine that makes the most power with considerations for driveability, however in doing so can do it efficiently (space and weight for fuel), and can be optimised into the car most effectively (space required, and effect on the aero design for the car)
The F1 engines alluded to above were either 3000cc or 3500cc. A 6000cc normally aspirated cap might lead to a different direction all together, and the type of car and racing that it is intended for would need to be considered ........ A hugely complicated V16 could make huge power at mental RPM, however might need to be heavy and bulky, which wouldn't be ideal for a formula single seater. Whilst it might fit better into a proto-GT car, it could be thirsty and therefore heavy on it's brakes and tyres over a long distance.
If we were hypothetically creating a spec for a series to run with, the number and configuration of cylinders would be free, however limited to a reciprocating piston engine to keep things simple. The regs would cap capacity at 6000cc, rpm to 10k or maybe 12k, and there would be regulations governing the minimum weights and dimensions of components. This could be for a piston set for the engine, so that the multi-cylinder V12 or greater engines weren't regulated out. Add in a cap to the number of circular valves to 4 per cylinder, plus 2 cams per bank, and a limited dimension single air restrictor inlet, and there'd be a pretty level and cost controlled playing field.
...... basically all racing should be with a modernised and slightly increased dimension and capacity Ford DFV/DFR!!!
RobDickinson said:
Ahonen I dont think you really understand what racing is about
I've only been a motorsport engineer for 20 years, so please forgive my lack of racing understanding. I've worked at LM several times and have followed the race for as long as I can remember - from the days when Simon Taylor would give his hourly reports by telephone after the hourly news on Radio 2.I may not understand what racing is about but I do understand that if you apply a weight penalty of 170kg (roughly a 20% increase in dry weight) to all the cars in one class they will be slowed down and their fuel usage will increase. If one car in that class somehow avoids that significant weight penalty then it is not a level playing field. For a Group C car we could possibly assume a weight effect of 0.15s per 10kg, per lap, being conservative. So there's 2.55 seconds a lap straight away. If we assume 0.2s, which is probably more realistic over that circuit then that rises to 3.4s of weight, per lap.That's quite a bit. I don't know the impact on fuel economy, but I'm sure it adds up over 24 hours. For a rough comparison an F1 team will assume between 0.3 and 0.4s/lap/10kg around a normal length 5.5km F1 track. Le Mans is obviously much more different because it is 60% longer yet has relatively few corners.
The Mazda beat the Jaguar by two laps. 3.4s/lap of weight over 24 hours, given the rough pace of the cars, is around 5 laps. Mercedes lost the 1991 Le Mans because the alternator bracket failed with three hours remaining. The alternator belt also drove the water pump, so the engine was cooked. At that point it was four laps in the lead and cruising, as it had been all race.
I appreciate that you don't care and it was all many years ago, but of all the races I've seen and been involved in over the years this is the only one that really bugs me.
But returning to the subject of racing engines, the problem with the rotary is the lack of engine braking. But from a weight and size perspective they are impressive.
mat205125 said:
"Back in the day", F1 engines were primarily V8 or V12 configuration, and began to move towards V10 by Renault as a compromise between power, efficiency/economy, and packaging.
...... basically all racing should be with a modernised and slightly increased dimension and capacity Ford DFV/DFR!!!
I guess even more valuable , in historic perspective terms , to reflect on engines that have been successful in Grand Prix racing ,and since modern F1 began post war, we have seen straight 4 and 6 engines ,V6s 8s 10s and 12s and Flat 12s all enjoying repeated success. And myriad more which didn't win often ,or sometimes at all .......... basically all racing should be with a modernised and slightly increased dimension and capacity Ford DFV/DFR!!!
I'd go for your updated DFV as long as I can have similar updates of Flat 12 Ferrari and V12 Matra
Ahonen said:
I've only been a motorsport engineer for 20 years, so please forgive my lack of racing understanding. I've worked at LM several times and have followed the race for as long as I can remember - from the days when Simon Taylor would give his hourly reports by telephone after the hourly news on Radio 2.
I may not understand what racing is about but I do understand that if you apply a weight penalty of 170kg (roughly a 20% increase in dry weight) to all the cars in one class they will be slowed down and their fuel usage will increase. If one car in that class somehow avoids that significant weight penalty then it is not a level playing field. For a Group C car we could possibly assume a weight effect of 0.15s per 10kg, per lap, being conservative. So there's 2.55 seconds a lap straight away. If we assume 0.2s, which is probably more realistic over that circuit then that rises to 3.4s of weight, per lap.That's quite a bit. I don't know the impact on fuel economy, but I'm sure it adds up over 24 hours. For a rough comparison an F1 team will assume between 0.3 and 0.4s/lap/10kg around a normal length 5.5km F1 track. Le Mans is obviously much more different because it is 60% longer yet has relatively few corners.
The Mazda beat the Jaguar by two laps. 3.4s/lap of weight over 24 hours, given the rough pace of the cars, is around 5 laps. Mercedes lost the 1991 Le Mans because the alternator bracket failed with three hours remaining. The alternator belt also drove the water pump, so the engine was cooked. At that point it was four laps in the lead and cruising, as it had been all race.
I appreciate that you don't care and it was all many years ago, but of all the races I've seen and been involved in over the years this is the only one that really bugs me.
But returning to the subject of racing engines, the problem with the rotary is the lack of engine braking. But from a weight and size perspective they are impressive.
As mentioned already the weight penalty only applied to the cars that hadn’t changed to the new 3.5l engines. In fact they were banned from even starting in the top 10. If Mazda had entered a 35b then it would have been unbelievably quick. Instead they were allowed to enter a 26b in the Group C2 class (equivalent of LMP2) and managed to win the entire race. The only second class car to have ever done this. Although Jackie Chan Racing came close last year.I may not understand what racing is about but I do understand that if you apply a weight penalty of 170kg (roughly a 20% increase in dry weight) to all the cars in one class they will be slowed down and their fuel usage will increase. If one car in that class somehow avoids that significant weight penalty then it is not a level playing field. For a Group C car we could possibly assume a weight effect of 0.15s per 10kg, per lap, being conservative. So there's 2.55 seconds a lap straight away. If we assume 0.2s, which is probably more realistic over that circuit then that rises to 3.4s of weight, per lap.That's quite a bit. I don't know the impact on fuel economy, but I'm sure it adds up over 24 hours. For a rough comparison an F1 team will assume between 0.3 and 0.4s/lap/10kg around a normal length 5.5km F1 track. Le Mans is obviously much more different because it is 60% longer yet has relatively few corners.
The Mazda beat the Jaguar by two laps. 3.4s/lap of weight over 24 hours, given the rough pace of the cars, is around 5 laps. Mercedes lost the 1991 Le Mans because the alternator bracket failed with three hours remaining. The alternator belt also drove the water pump, so the engine was cooked. At that point it was four laps in the lead and cruising, as it had been all race.
I appreciate that you don't care and it was all many years ago, but of all the races I've seen and been involved in over the years this is the only one that really bugs me.
But returning to the subject of racing engines, the problem with the rotary is the lack of engine braking. But from a weight and size perspective they are impressive.
Edited by delta0 on Saturday 29th September 15:52
delta0 said:
As mentioned already the weight penalty only applied to the cars that hadn’t changed to the new 3.5l engines. In fact they were banned from even starting in the top 10. If Mazda had entered a 35b then it would have been unbelievably quick. Instead they were allowed to enter a 26b in the Group C2 class (equivalent of LMP2) and managed to win the entire race. The only second class car to have ever done this. Although Jackie Chan Racing came close last year.
Mazdas were previously entered in the IMSA GTP category from '86 to '90 - which was basically their own class as there were never any other entrants in that class. The smaller Mazdas were in C2/Junior before '86. In 1991 they were in Category 2, which was the same class as the Mercedes C11s, 962s and the rest of the older C1 cars - it was the grandfathered class for the old top class cars after it became clear the new cars were going to be a disaster. Category 2 was very different to the old Group C2 class. The Category 1 cars were the new 3.5s built to completely different technical regs. The Mazda had the same fuel allowance as the C11s, 962s and XJR-12s, but was 170kg lighter.
The Qualifying situation was farcical, because a Mercedes C11 set the fastest time but was only allowed to start 11th on the grid because it was an older generation car. The beaurocracy was all fabulously French...
I was trying to look into the history of Mazda 35B engine but I can't find much info. What was it used in? I don't recall it in sportscar racing so I guess it must have been successful somewhere else.
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