Wednesday, January 21, 2009

Tank #30

I filled up at Meijer last night.

I got 4.008 gallons of E85 at $1.80 a gallon.

I got 10.512 gallons of 87 at $1.90 a gallon.

My new tank is 26.37% ethanol and 91.57 octane.

The last tank finished at 21.5 mpg at 25 mph average speed. The awful weather is reflected in that awful mileage!


Joeypete said...

Hey Buzz...just curious, how do you get such exact measurements of your octane levels?

buzzcut said...

Yeah, it's a false precision. Just doing the math, that's all.

87 Octane is... 87 octane. E70 is 100 octane. E83 is 105 octane. I just interpolate for the intermediate grades.

Since I don't know exactly what the ethanol content of the E85 that I buy is, this is not all that accurate. If anything, I'm probably a little low.

Same goes for the etahnol content, BTW. I just calculate it, and it is a little inaccurate.

What I really need to do is get an ethanol sensor from an old Ford Taurus and hack a microcontroller to read it. Then I'd know exactly what I'm running.

Sadly, when they come up on eBay, those sensors are really expensive.

Joeypete said...

Oh ok cool! I was just wondering because I've just been guessing on mine.

buzzcut said...

I've got a spreadsheet that I use to keep track of everything, so that I don't need to do the math every time I fill up.