Quote from: NAKID on October 05, 2008, 04:35:03 PM
Yeah, I think your fueling is off. There really is no reason, even with that make the beast with two backsed up commute, for your mileage ti be in the 20's....

lololol

the commute gives me 35mpg.
If i skipped the FDR/West Side highway portion of it, id break into the 27mpgs. Before my 6000mile service(minus valve adjustment), my bike was doing 22mpg with the above commute. Afterwords it shot up to 35mpg, but i can still creep into the 20's every so often if im doing all local traffic.

I just got my TPS reset and all that good stuff done less than 400miles ago....Still searching hte internet for a used PCIII to throw on my bike.

I can weigh in with
a) Excel help in regards to fuel economy. I have logged every fillup since I bought my S2R1k, which was new. The only riding it did before I got it was for the first fillup from the dealership (3km), after they put a splash and dash in to get it up the road.

b) MATLAB stuff... not so much, but I have had to use it a moderate amount in the past in my job.

c) Fuel economy stuff. Mine varies a fair bit, actually. It varies according to the seasons here in Australia, even with the O2 sensor unplugged.

d) Any medical thing... speak to someone who knows and hopefully cares. Might take a bit to find a decent doc in that regard though.

For fillups, I have run dry twice. Once on the road, where a 5L fillup from a jerry can and a 1km ride to a service station netted me a total fillup of about 12.8L; the second time I got 12.75L in and the bike coughed a bit, and stalled as I pulled up at a fuel pump. Yay for timing.


Click image for a bit bigger version.
x-axis distance (km), y-axis L per 100 km travelled. Think of it as somewhat the inverse of mpg; higher on the graph is worse economy.

The three biggest peaks correspond to winter '06 (~ 1000km), '07 (~7500km) and '08 (~14000km). Latest peak, almost up to the worst economy for winter '08, is the 20k km service (which I did at 15k km, 2ish years into owning the bike). Fuel tank was drained and probably not completely filled back up again, hence worse economy. How much temperature change do we get here? Coldest I have ridden each winter has been in the order of -8 to -5°C; warmest 42°C. Basic ideal gas laws give an indication that would involve a mixture change of about 8%.

It's fairly consistent in terms of how it changes season to season. Winter 06 to winter 07 yielded an increase in the worst economy of about 0.5L/100km. I think this is going to be due to the engine bedding in and thus having less drag. Winter 08 was colder than '06 and '07, although more humid, which would negate some of the better economy you'd get from the engine bedding in better between 07 and 08. Of course, the bedding in trend is going to taper off - I tend to model it using an exponential function with a low and negative power. A cruder version might be a smoothed curve matching the worst economy in each winter, and also something based on the summer economies.

As for fuel effects - I've mainly tried different fuel brands, but I see no difference in a Mobil 98 RON vs. 95 RON fuel, at all.  At least, not a statistically significant increase after you remove both the running-in and seasonal variations in fuel economy. Haven't really tried other brands - in Australia, Shell have replaced most of their 95 RON pumps with E10 fuels; BP likewise do not have 95 RON. I could try 92 RON, but, I am concious of the warning in the manual which, at least for Aus, specifies fuels of 95 RON and above. I don't want to get into an argument that 92 RON (equiv to the US 87, if my sources are correct) because... I just don't.

As for my creditials in this sort of data analysis? I play with numbers all day, this is just another time series to me. I think I have a plausible reason for why things vary.

Finally, I'm happy for someone to argue with me that I should get better economy in winter cause there's more total oxygen going into the engine and thus can make more power. First points to consder are, sure, I agree on the power, but I don't tap into max power that often on most of my rides. Also, if the fuelling becomes leaner, it'll make less power unless it squirts in more fuel, ergo, use at least some more fuel to maintain the same power levels.

that's just mad scientist stuff there. what a great fuel usage chart. i started keeping track of mine. then i got bored.