Yes, Cam. They also state "faster is better". With todays' anti-pollution hype, fuels will generally be designed to burn faster and cleaner, reckon you'll be hard put to find many slow-burning fuels on the market today. Perhaps that is the deciding factor between fuels like "ultimax" and the rest!
Upping the CR usually calls for higher octane fuel to prevent detonation. At the same time, ignition timing can often be retarded a few degrees to take full advantage of the fuel.
When setting up race engines on a dyno, where possible, I set the ignition for maximum power while running at WOT under full load. 98-octane pump petrol is used, if the customer then uses higher-octane fuel, I'm on the safe side. Final settings often have nothing to do with factory specs. Generally, the higher the CR and octane rating, the later the ignition setting, so, logically, the charge must be burning faster if I attain a higher output. Port flow, combustion chamber shape, A/F ratio, number of plugs and cylinder capacity strongly influence the behaviour of the burning charge, there are loads of variables to work through to keep you busy for a week or 2...
piet
Upping the CR usually calls for higher octane fuel to prevent detonation. At the same time, ignition timing can often be retarded a few degrees to take full advantage of the fuel.
When setting up race engines on a dyno, where possible, I set the ignition for maximum power while running at WOT under full load. 98-octane pump petrol is used, if the customer then uses higher-octane fuel, I'm on the safe side. Final settings often have nothing to do with factory specs. Generally, the higher the CR and octane rating, the later the ignition setting, so, logically, the charge must be burning faster if I attain a higher output. Port flow, combustion chamber shape, A/F ratio, number of plugs and cylinder capacity strongly influence the behaviour of the burning charge, there are loads of variables to work through to keep you busy for a week or 2...
piet