Premium or Regualr?

[rex007can]

Rex. One question.

What do you consider high compression.

Normal engine. ~9:1
"Performance" engine at least 10:1
High performance engine 11+:1 (for cars)

Motorcycles, I guess from having to squeeze more poqer out of small displacement engines, usually use higher compression ratios than average cars, although most fat V-Twins will run what? About 9.5:1?


With gasoline, on average, 9:1 will work with 87 Octane, 10:1 should go up to 90-91 , and 11,12:1 should use 92 to 94 octane.
Above that would be race engine, which dont usually use regular fuel you can get at the pump.

That's also not counting Diesel which can get a much higher compression ratio.

there are also other factors such as combustion chamber shape and design, cooling, timing, valves etc that can influence the octane required vs compression ratio so it's not absolute.

Why do you ask?

[Chris Canning]

Never seen fuel over here as low as 94 and it's why I've always been told never to buy a US spec Power Commander because you we don't use that e'rrr paraffin and they are set up completely differently,blimey we even get two specs in diesel.

[brad1098]

I ask to see if your thoughts were on par with mine.

955 Tiger is 11.5:1 and I always run premium.

[rex007can]

I ask to see if your thoughts were on par with mine.

955 Tiger is 11.5:1 and I always run premium.

I always use premium too.
94 if I can get it (only one chain sells it)