the basics of Honda F1 engines in 1987/88

Discussion in 'Lounge & Gossip' started by jimjams, Monday 3rd Aug, 2015.

  1. jimjams Guest

    I just found this Gasoline FAQ - Part 4 of 4Section - 10. Historical Legends
    IMO very interesting reading
    This section on the basics ofthe Honda F1 engines 1987/88

    There are many variables that will determine the power output of an engine.
    High on the list will be the ability of the fuel to burn evenly without
    . No matter how clever the engine, the engine power output limit is
    determined by the fuel it is designed to use, not the amount of oxygen
    stuffed into the cylinder and compressed. Modern engine designs and
    gasolines are intended to reduce the emission of undesirable exhaust
    pollutants, consequently engine performance is mainly constrained by the
    fuel available.

    My Honda Civic uses 91 RON fuel, but the Honda Formula 1 turbocharged 1.5
    litre engine was only permitted to operate on 102 Research Octane
    fuel, and
    had limits placed on the amount of fuel it could use during a race, the
    maximum boost of the turbochargers was specified, as was an additional
    40kg penalty weight. Standard 102 RON gasoline would be about 96 (R+M)/2 if
    sold as a pump gasoline. The normally-aspirated 3.0 litre engines could use
    unlimited amounts of 102RON fuel. The F1 race duration is 305 km or 2 hours,
    and it's perhaps worth remembering that Indy cars then ran at 7.3 psi boost.

    EngineStandardFormula 1Formula 1
    Size1.5 litre1.5 litre1.5litre
    Max Boost58 psi36.3 psi
    Max Fuel200 litres150 litres
    Fuel91 RON102 RON102 RON
    HP @ RPM92 @ 6000994 @ 12000610 @ 12500
    Torque (lb-ft @ rpm)89 @ 4500490 @ 9750280 @ 10000

    The details of the transition from Standard to Formula 1 (without
    considering engine materials etc) are:-

    1. Replace the exhaust system. HP and torque both climb to 100.
    2. Double the RPM while improving breathing, you now have 200hp
    but still only about 100lb-ft of torque.
    3. Boost it to 58psi - which equals four such engines, so you have
    1000hp and 500lb-ft of torque.

    Simple?, not with 102 RON fuel, the engine/fuel combination would knock
    the engine into pieces
    , so....

    4. Lower the compression ratio to 7.4:1, and the higher RPM is a
    big advantage - there is much less time for the end gases to
    ignite and cause detonation.
    5. Optimise engine design. 80 degree bank angles V for aerodynamic
    reasons, and go to six cylinders = V6
    6. Cool the air. The compression of 70F air at 14.7psi to 72.7psi
    raises its temperature to 377F. The turbos churn the air, and
    although they are about 75% efficient, the air is now at 479F.
    The huge intercoolers could reduce the air to 97F, but that
    was too low to properly vaporise the fuel.
    7. Bypass the intercoolers to maintain 104F.
    8. Change the air-fuel ratio to 23% richer than stoichiometric
    to reduce combustion temperature.
    9. Change to 84:16 toluene/heptane fuel - which complies with the
    102 RON requirement, but is harder to vaporise.
    10.Add sophisticated electronic timing and engine management controls
    to ensure reliable combustion with no detonation.

    You now have a six-cylinder, 1.5 litre, 1000hp Honda Civic.

    For subsequent years the restrictions were even more severe, 150 litres
    and 36.3 maximum boost, in a still vain attempt to give the 3 litre,
    normally-aspirated engines a chance. Obviously Honda took advantage
    of the reduced boost by increasing CR to 9.4:1, and only going to 15%
    rich air-fuel ratio. They then developed an economy mode that involved
    heating the liquid fuel to 180F to improve vaporisation, and increased
    the air temp to 158F, and leaned out the air-fuel ratio to just 2% rich.
    The engine output dropped to 610hp @ 12,500 (from 685hp @ 12,500 and
    about 312 lb-ft of torque @ 10,000 RPM), but 32% of the energy in
    the fuel was converted to mechanical work. The engine still had crisp
    throttle response, and still beat the normally aspirated engines that
    did not have the fuel limitation. So turbos were banned. No other
    F1 racing engine has ever come close to converting 32% of the fuel
    energy into work

    In 1995 the FIA listed a detailed series of acceptable ranges for
    typical components in racing fuels for events such as F1 races, along
    with the introduction of detailed chromatographic "fingerprinting" of
    the hydrocarbon profile of the fuel. This was necessary to prevent
    novel formulations of fuels, such as produced by Honda for their turbos.
  2. Ichiban Founder Staff Team

    England CJ Leeds
  3. jimjams Guest

    glad it's not just me LOL

    With it only having ~40 views and no replies, I was beginning to think that pasting it all was a mistake, but I couldn't see any way to reduce it without also reducing its quality. One of the key points is that in those days, they were allowed to mix anything they wanted for the fuel, I presume that 84:16 toluene/heptane fuel gave a faster burn, while keeping it at the allowed 102 RON.

    btw I found section 10 after finding Section 7 , when searching for typical in-cylinder burn-rates. At one point in section 7, they say "a 12:1 CR gasoline engine at 1500 RPM would have a flame speed of about 16.5 m/s". Hence the burn-speed depends on CR amongst other things, and elsewhere they also imply that a leaner mixture burns more slowly.

    So with the speed of sound being about 300 m/s it's safe to say that, at under 10% of the speed of sound, in-cylinder burn speeds are very much sub-sonic. Also, burn-speed is not dependent on RON, so diesel is likely to burn at similar speeds. But being lower RON, small pockets in the diesel "charge" tend to detonate, which will be too fast, and therefore an incomplete burn. But injecting a higher RON into a diesel engine would be counter-productive, because a higher RON will resist self-ignition.
    - - - Updated - - -
    I forgot to add these two informative links

    In wikipedia, a table of F1 engine specs over the years of F1, it would take too long to type the table into a post
    Formula One engines - Wikipedia, the free encyclopedia

    From "F1 technical" , an article on the fuel
    Fuel -

    in particular it says
    Production begins for the purpose of obtaining as much power as possible from the engine without jeopardizing durability and with focus on fuel consumption. The first stage covers the use of a computer forecast model, in which a database is fed with more than a hundred raw materials to obtain experimental gasoline. In their search for the best mixture and the extra shot of power for those crucial split seconds, the engineers can mix and burn petrol virtually, without actually having to produce the fuel. Some of the teams have developed their computer technology so that the virtual petrol can even be tested in a virtual engine. This mathematical model was designed using the Formula 1 engine response to different kinds of fuel and all physicochemical properties of the raw materials.

    i.e. fuel companies also produce as fast a burn as possible, while keeping the RON close to the max available at the pumps
    Ichiban likes this.
  4. HondaHeritage Moderator Staff Team

    slim london
    i did read your thread athough it seems a little random,maybe I've missed something but what is the point of interest that most readers can understand and connect to??

    oh bye the way Hi im the sites grumpy old dinosaur :Wink:
    Zebster likes this.
  5. jimjams Guest

    Fair comment, it is somewhat esoteric LOL

    It works on several levels, one of which is that "the engine power output limit is determined by the fuel it is designed to use, not the amount of oxygen stuffed into the cylinder and compressed". In other words, it's all very well shoving a turbo onto an engine, but if the RON and/or burn-rate of the fuel is not changed, then as the article says "the engine/fuel combination will knock itself to pieces". In those days the FIA had little control over the fuels used to make a faster burn and some very aggressive mixtures were brewed that could be harmful to the engine, the mechanics, and even the drivers. The engines were not expected to last long, and there were no limits on the number of engines.

    Today the FIA limits the number of engines, and also state that ingredients used in the fuel-mix must be found in commercial fuels. AFAIK, each team can vary the mix, but it must be declared to the FIA, and the FIA can check at any time with chromatography and spectrometry machines.
    - - - Updated - - -
    edit: I suppose that these days, the fuel-mix and engine are modelled in a computer to see what power output they can get at certain compressor pressures, and the fuel usage for torque outputs (with the turbo ERS) over a race, and then they try to build a real engine to meet the performance. Maybe RON Dennis told fantastic stories to Fernando Alonso, which have yet to materialise.