Thursday, September 4, 2008

LTFT vs. Ethanol Content

Well, the E30 data wasn't at a 70 mph cruise, so there was a lot of crap in it. Not usable for the analysis I want to do.

I plotted long term fuel trim vs. ethanol content for the data that I have (Alcohol's two data files, and my Scangauge reading from my last tank), and lo and behold, not only is there a linear relationship, it is a very stron relationship (R^2 of 1!!!!!!)

Pretty frickin cool.

And now I have a nice equation that I can use to predict LTFT based on tank ethanol content.

1 comment:

Anonymous said...

Buzz- You are correct- there are only four valid frames in the E30 data (frames 1-4). The rest look like they are from Mars- LOL. The 4 frames were are 69-70 mpg and appear valid including the LTFT.
Soory to have sent it that way- one of those late at night deals.

BTW- those GM trouble codes you posted were excellent- more data than often found. Did you catch the comment in it below the +25 LTFT line? I did not quite get what it was saying about a +4 under certain conditions.