TheHaflinger.com

What grade of fuel does everyone use, I have always used 98. Is it worth the extra money using the top grade
for the Haflinger engine.

Dave

In Australia with a standard engine you only need to use 91 unleaded - I would not use E10. 98 is not a "top grade" fuel - it is the same fuel as the 91 but just has additives to increase its octane rating to 98. The higher octane fuel does not produce more power in itself but allows higher compression ratios to be used without the engine pinging, and higher engine tune - eg more ignition advance.

So if you have standard compression and standard tune there is no reason to use 98 except to to drain your wallet more quickly.

Garry

In the UK we have just gone to having E10 as our "standard" fuel with E5 as the "premium". So far the jury is out as to whether E10 is bad for classic cars or not. I personally think if you leave you car idle for long periods of time, like "mothball" it for winter then you could have issues with water in the E10 separating out and then you only "suck" water into the engine as fuel pick up is at the bottom of the tank and the water being heavier that petrol sinks to the bottom.
Luckily, the Haflinger has an easy to get to petrol tank drain, so you could just open that and let the majority of the water out and then the engine will run quite happily.
Octane rating for standard Haflingers is as Gary says still well above the absolute minimum the engine requires to actually run. Once the octane rating is above that required by the engine to run with out pinking increasing the octane rating with out altering the state of engine tuning i.e. changing ignition timing, most people will not notice any real change in how the engine runs other than the slight increase in mpg. I doubt that increase is value for the extra money you have to pay for the higher octane fuel.
I think the real reason to go for E5 over E10 will be down to the fact that there is more water in E10 to evaporate and condense on the top surface of the tank causing rust if your tank shows bare metal!

John

Thankfully we only have E10 here with a full range of "normal" fuels also available 91,95 and 98 Ron normal unleaded. E10 is sold as a cheaper alternative to 91 Unleaded but tests have shown that because of its lower calorific value is gives worse mpg and works out worse than 91 Ron on the basis of cost per distance covered.

For Dave - just be aware that BP do not sell 91Ron and their base fuel is E10 but still charge the same as 91Ron so I never buy BP fuels.

Thank you for the replys, I will lower the octane rating the next time I have to fill the
tank, and as Garry said keep the back pocket happy.

Dave

Dave if you are worrying about what petrol to use, you must now be very close to putting your Haflinger on the road with its very own number plates

So when will the big day be? Don't forget nothing happens without pics

Garry