Mixing E30 in an E10/E85 world

Given 1 gallon of E85, how many gallons of E10 are needed to make E30? Once we know this ratio, it will hold for any quantity.

(1*(.85e + .15g)) + (n*(.10e + .90g)) = (1+n)*(.30e + .70g) ## adding 1 gallon of E85, "n" gallons of E10, to make E30
.85e + .15g + .10en + .90gn = (1+n)*.30e + (1+n)*.70g
.85e + .15g + .10en + .90gn = .30e + .30en + .70g + .70gn
.85e + .15g - .30e -.70g = -.10en + .30en -.90gn + .70gn
(.85 - .30)e + (.15 - .70)g = (-.10en + .30en) + (.70gn - .90gn)
(.55)e + (-.55)g = (.20)en + (-.20)gn
(.55)e + (-.55)g = ((.20e) + (-.20)g)) *n
((.55)e + (-.55)g) / ((.20e) + (-.20)g) = n
.55 * (e-g) / .20* (e-g) = n ## the "(e-g)" term confirms nothing was lost in the earlier algerbra
.55 / .20 = n
2.75 = n

Ok, so with this approach:

	Column 1
0	E85 E10 E30
1	0.25 0.69 0.938
2	0.5 1.38 1.875
3	1.0 2.75 3.750
4	1.5 4.13 5.625
5	2.0 5.50 7.500
6	2.5 6.88 9.375
7	3.0 8.25 11.250

Now if the local Jet station will let me pre-pay for exact amounts, it should be fairly straight forward. Estimate the amount to fuel to add, right column, and pre-pay the amounts of E85 and E10 needed.

There is a credible report that E30 can lead to engine tuning to achieve equivalent power levels as straight gas. This is something I plan to test with our Atkinson engines but first I need to way to mix it in my tank.

Bob Wilson

 

Hi Richard,

I appreciate your concerns but the paper is very interesting. Whether or Atkinson engine and "tune" to make use of E30 is the unknown. It may not work.

For those interested in the paper: "2007-EERC-11-02" should Google it up.

I was also able to find paper in opposition to E30. Their chief complaint is the exhaust temperature at higher power setting might rise and do harm to the catalytic converter. Certainly it makes sense to put in an exhaust temperature probe and measure the effect. Now there is a fairly simple mitigation, cooled exhaust gas injection.

Experimentation is not for everyone and needs to be done with 'eyes wide open.' But informed experimentation is how we eventually master these systems. It is so nice to "know" what works and doesn't work.

Bob Wilson

 

Try Google for the title:

"OPTIMAL ETHANOL BLEND-LEVEL INVESTIGATION"

But like I said, folks need to go into any testing with their eyes 'wide open.' So far, the strongest objection is a 25-30C increase in exhaust temperatures at wide-open throttle. This definitely needs to be part of any testing.

First test:

• 5.542 E10 - $11.97, $2.159/gallon
• 2.037 E85 - $4.40, $2.159/gallon

I filled on "flash" so there was probably a couple of gallons still in the tank of E10. But so far, nothing remarkable to report. It'll take some hill-climb data before I'll have any results to share.

Bob Wilson