Technically speaking, on surpassing 100 mpg (US)
During my September 2005 100 MPG Challenge, where I travelled from Victoria to St Johns and Labrador, I was able to achieve better than 100 mpg (imperial) on five different occasions.
I knew I would be coming back to Saskatchewan this spring/summer to try and beat my previous fuel economy record of 113 mpg (imperial).
I wanted to run on biodiesel, and achieve 100 mpg (US), which is 120 mpg (imperial). That would require a 6% improvement. My gut feeling was that I could do it given the same road/weather conditions, with less cargo, and a few more PSI in the tires.
With all this in mind, I ran my tank down to 1.0 L remaining Tuesday morning as I drove to Birch Hills, SK, just outside of Prince Albert. When I arrived there, I stored my luggage in a friend’s shed, put 20 litres of soy based biodiesel in the tank, and topped up with petroleum diesel at the local Coop. The PSI in the tires had already been set to 43 (cold) in the morning.
I set out for Yorkton, but by the time Wadena came on the horizon, I knew the run was failing. And sure enough, 215 kms on 6.747 litres was way short of the goal. I turned around and headed back to Birch Hills - trying again, this time without using cruise control… but once again, I was way short - 199.3 kms on 6.370 litres. The winds were not in my favour.
With my luggage reloaded, I went back to Wadena again. Attempt # 3 was yet another failure - 204.4 kms on 6.674 litres. I began to wonder if the 40-80% biodiesel blend was contributing to the low mileage. Surely I could get a better number than 88.3 mpg (imperial)? (618.7 kms on 19.791 L = 3.2 L/100km)
I decided to wait in Wadena and see which way the wind was blowing. A call to ‘Walter from Wadena’ revealed the answer - and by Wednesday morning, I knew I had to get to Yorkton, refill, and head north-west again in order to have any chance. Luggage again was placed in the car. I then had a leisurely morning, taking in breakfast and some gab with Walter… I insisted that he take my car around town, while I tracked down a back issue from the Wadena Times that my car was on the cover of last summer.
By the time I arrived in Yorkton, it was 4 pm. A stop had been made in Foam Lake, which was well worth the time - but more on that later. I filled at the Fas Gas and was approached by a fellow biodiesel enthusiast who had seen my car downtown, and followed me. We exchanged cards, I reset the GPS trip meter, and then hit the road. After the only light was passed, I engaged the cruise control - 83 kmh on the smart’s speedo -which is actually 80.5 kmh as per the GPS.
The drive along Hwy # 9 and # 5 was nearly flawless, save for one stop at a section that was being repaved. The elevation gain was very slight over the entire distance, but flat. Passing through some very beautiful areas - I knew stopping was not an option. I could literally see the wind blowing the trees and fields in my direction of travel, and at times I felt like I was being carried. As I passed through Invermay, I had the ECM Records cd ‘Freigeweht’ by Rainer Bruninghaus playing…
I made it to the Wadena Coop by 6:30, and topped up, more precisely than ever before. I actually paid for fuel twice, as I added 0.273 litres 5 minutes after the first 3.104 litres.
In the end, the car used a mere 3.377 litres to go 151.13 kms.
That’s 126 mpg (imperial), or 105 mpg (US).
Regarding the biodiesel.
I was supplied with 40 litres of a soy based biodiesel by Cascadia Biofuels in Delta, BC for this specific tour.
For my run between Yorkton and Wadena, the residual biodiesel was 19.6%, making it essentially B20 - a common bleand that can be purchased in select retail locations, including Delta, BC, close to where I work. Biodiesel provides excellent lubricity for the fuel system and engine, although there are some indicators that the ‘energy content’ is lower than that of petroleum diesel. None-the-less, there are many studies indicating that using even 5% biodiesel provides overall advantages.
You can learn more about biodiesel at the following sites:
Regarding the car.
My car is a 2005 smart fortwo cdi coupe. It has a 799 cc 3 cylinder turbo-diesel engine with common rail injection, and a six-speed sequential transmission controlled by an electronic clutch that can be engaged by shifting with paddles on the steering wheel.
My car has had no engine or computer modifications done to it. I do have an after-market cruise control system, which is designed specifically for this car, and functions similarly to the OEM cruise control available in Europe. I also have a front spoiler, made by Brabus (and a common upgrade), which ‘may’ provide some aerodynamic assistance to an otherwise aerodynamically challenged car.
I ran stock size tires for this tour: 145mm in the front and 175 mm in the rear.
I typically keep the windows closed, and do not use air conditioning during record fuel economy attempts.
Recommended tire pressure for the car is 28 PSI. I chose to run 43 PSI this time, which is 1 PSI lower than the maximum pressure listed on the tire.
Although suspension modifications for this car are available, which make it lower (thus increasing aerodynamics), I have elected not to have any done. Other than cruise control, and the front spoiler, this car is stock in all aspects that would have any effect on performance or fuel economy.
