Pure Gas milage vs. 10% Ethanol 88 or 91?

Ethanol is an octane booster. That's the one thing refiners like about it as other octane boosters are more expensive.

About a month ago I discovered that one pump at my local BP is ethanol free - mid grade "Silver" so 89 octane. I've been using it but haven't noticed any difference in any of my bikes. I think if you burn through it quickly it doesn't matter what you get. But in the non-riding months it's worth the money to not have any amount of ethanol sitting your fuel system.

Also I think when Europeans quote octane figures they are using a different scale. The highest I can buy in my area is 93.

 

True. Higher octane for higher compression to retard detonation.
Many motors will put out more hp on lower octane.

 

Those 95 and 98 test were before they started using ethanol as anything else than antifreeze additive. When I was a kid, they used to have 91 or 92 also, think that it had lead in it. That was banned as non ecologic in '92-'93 ish. Since then we've only had 95 and 98. And now just this ethanol stuff.. Some run E85 and say it works fine for them, cheap for the mpg, compared to the price of running normal gasoline here.

Ethanol as antifreeze is kind of funny, you have ice in the tank, then put "antifreeze" in it. Ice melts, but if any of that stuff is left in there, it will collect even more water to freeze.. :/

Riding on the storm

 

One engine that didn't like ethanol at all, went around 15% worse in mpg, when they switched from normal 95 to 95e10.

What I'm still wondering is how it got over 20% better mpg on the 98e5 compared to 95e10.

the difference shouldn't be that much, but it was. I religiously logged the average consumption at every fill-up. Maybe the renault 1.8 efi was just so poorly designed that it went haywire with 10% of "antifreeze" in it.

But since it's e10 in the 95, it's 98e5 for our hobby equipment..

Riding on the storm

 

Actually seems it WAS part of the Volvo modular family afterall.. (Always thought the S/V40 as a rebadged Mitsubishi Carisma with Renault driveline..)

"The B4184S is a 1.8 L (1,731 cc) straight-four. Bore is 83 mm (3.3 in) and stroke is 80.0 mm (3.1 in) with a compression ratio of 10.5:1. It is naturally aspirated with a power output of 115 PS (85 kW; 113 hp) at 5500 rpm with 165 N⋅m (122 lb⋅ft) of torque at 4100 rpm. It is equipped with Siemens Fenix 5.1 engine management."

So, lacking a smart enough ecu (to compensate for the added ethanol), maybe the high-ish compression ratio, made it run like crap on 95e10 and 98e5 picked up the slack?

Our 3rd and 4th gens have 11:1 compression ratio, so higher octane fuel should be okay.. I found out they have 95e5 and 98e5 in Sweden, so I'll have to run a few test runs next summer and see if anything conclusive happens...

Riding on the storm