Last year, I wrote a couple of columns about gasoline, one explaining that octane prevents engine knock; the other that ethanol is used primarily to replace lead as an octane booster. However, ethanol also reduces gasoline’s energy content by about three per cent, which affects engine performance.

I recently drove to Florida, and I brought my 1986 Honda CH80 scooter along to ride locally. Arriving in Florida, I noticed some gas stations advertising ethanol-free gasoline. I then got the idea to run a little experiment. Part of taking my scooter out of winter storage for the trip included filling the tank with fresh fuel, in this case 87 octane gasoline that contained up to 10 percent ethanol (the pump doesn’t specify the actual amount). 

I had run errands on this scooter all summer, so I had a very good idea about how it performed. Its 79 cc four-stroke single isn’t very powerful, so I basically ride it flat out all the time — I know exactly how fast it can go. For my experiment, I would use up the ethanol blend, then refuel with ethanol-free gas to see if I’d notice a difference in performance. 

Back home, the little Honda tops out at 70 km/h on level ground and reaches 75 km/h often enough with me tucked in that I can consider this to be its absolute top speed. The engine has a 9.3:1 compression ratio so it doesn’t require premium fuel, and it has never pinged or knocked. I have tried premium in the past, but other than costing more, the scooter went no faster. 

In Florida, I saw the exact same top speeds on the fuel with which I had filled up back home. The 45-mph (72 km/h) speed limit on nearby boulevards meant I just about kept up with traffic. After running the scooter to empty, I refuelled with ethanol-free fuel. The ethanol-free fuel I saw at two different stations was available with either an 88 or 89 octane rating; I filled up with the former so it would better match my Canadian fuel, though as I’d seen before, higher octane made no difference on my scooter. 

After letting the ethanol-free fuel run its way through the fuel system, I began my flat-out testing. On the same roads, I immediately saw 75 km/h while sitting bolt upright. It then crept to 80 km/h, the fastest I’ve ever gone on the CH80, and it stayed there. Huh. I tucked in, and the speedo needle crept to 85 km/h, and did so many times during my stay in Florida. That’s a 13 per cent increase in absolute top speed. Note that my non-scientific experiment relied entirely on the accuracy of the speedometer, so while the actual speeds might be different, the increase in those speeds is indisputable.

Another thing I noticed is that the scooter started up much better and ran better when cold. The CH80 has a carburetor that utilizes an automatic choke. Back home and during the first part of my testing in Florida, it took several stabs of the starter before it fired up when cold and needed a bit of throttle for a couple of minutes to avoid stalling. On ethanol-free fuel, it fired up from cold on the first attempt and settled into an idle immediately. This was probably due to the richer fuel mixture provided by the absence of ethanol. 

Ethanol-blended fuel is naturally oxygenated (ethanol contains oxygen; pure gasoline does not), and it will subsequently lean out the fuel mixture. Therefore, a vehicle runs richer on ethanol-free fuel, which accounts partially for the improved performance. 

My experiment did not end there. Another drawback of ethanol-blended fuel is increased fuel consumption (about three per cent). For this test I used my 2008 Mazda B4000 pickup. I always record my fuel consumption and cost on long trips; it took 12 fill ups, or 664 litres to make the 5,376-km-round trip. I averaged 12.4 L/100 km. Two consecutive fill ups on my return were with ethanol-free fuel, since I could not find any north of Florida. The worst consumption I saw per fill up over the trip was 13.4L/100 km; the best was 11L — it was on ethanol-free fuel. The second best was 11.2L, also on e-free fuel. 

Ethanol-free fuel costs about a dollar more per US gallon than regular fuel, which meant about $15 US more per fill up. While the reduced fuel consumption adds about 70 km more per tank, that didn’t justify the added cost. In 2022, the Canadian government mandated at least 10 per cent ethanol in all gasoline. Given the choice, however, I would use ethanol-free fuel exclusively in my two wheelers.