Talk Morgan Forums Morgan Sports Cars Morgan Three Wheeler & Super 3 99 Octane Fuel (RON) - worth it?

A quick Google search for "octane and performance" brings up plenty of evidence that it is true, at least to an extent. If you want some heavy reading try downloading the PDF report here: Effect of Octane on Performance, Energy Consumption and Emissions of Two Euro 4 Passenger Cars

Quote: "The best agreement between performance and fuel octane number was found using an Octane Index [(1-K).RON + K.MON] with a K-value of minus 0.6 or even more negative.".

So now you know.

Basically true and at one time simply true. In these days of electronic engine management, knock sensors and such like you are likely to find that an engine will give more power and better mileage on higher octane fuel as the feedback loops will alter various parameters to give best running on the fuel being fed into the engine. Can make a big difference on turbocharged engines, generally less of a difference on naturally aspirated.
Did do some testing on bike engines on a dyno a long time ago and we found that the super unleaded of the day made for something like an improvement of 2% on power over normal unleaded but this was on highly tuned by car engine standard engines. Also found that one brand of octane booster made a similar difference on top of that 2%. Can't honestly remember which brand it was but it was based on toluene.

I did run super unleaded for several tanks full on my standard engine with just the bafflectomy. I did not notice any performance advantage & a very slight reduction in fuel consumption but not enough to offset the higher fuel cost. Now I use regular unleaded E5.

Easily get 40 mpg with Tesco Motillium 99 and it’s a sensible price.

My mechanic recommends putting in 100 octane fuel when I put the car away for the winter. He contends that's better than any of the gas treatments. It'll start right up in the spring. He puts that in any gas engines that he stores over the winter. I can get it at one local station here. The only problem is it's $ 7.00 a gallon !

That's a good price for 95 octane fuel over here!

Just a thought, has anyone tried Avgas LL 100 octane???

Where do you get it? Back 50+ years ago when ga was really gas and not something concocted by a corn farmer with a degree in chemistry 101 or 102 octane was available and I ran all my bikes on it as well as my sports cars.

Won't do the cats any good and will poison the Lambda sensors too.

Probably true. I was using it before computers existed.