E85 or 100 octane

[wasinger3000]

Just after that line it state's "pure ethanol has a 113 octane rating." So it's 113 then they add race gas to increase the octane even more.

[FoMoCoSHO]

So on this fill up i actually added a little more E-85 that 93.

New blend...
E43
99 octane

FRP still a tick over 2500, but I haven't driven much on this tank. I suspect I will see higher #'s

LTFT is over 25 during certain cruising RPM's no CEL or DTC's yet.

I am seriously considering reversing my fill up scenario and adding the corn first then driving to Shell just to see what happens.

Worst case is car freaks out on my short drive to Shell.

Best case is nothing happens and I cruise right by...

Leaving plenty of room to add 93 will be key if I decide to move forward with this little experiment...

[wasinger3000]

I put e85 in before 91 and drove for a little. I got a CEL , bank rich. Nothing with drivable ty happened so I wouldn't worry.

I just talked to my e98 supplier. The cost is 2.25 a gallon. It's so incredibly cheap I want to bury a fuel tank in my yard.

[FoMoCoSHO]

I put e85 in before 91 and drove for a little. I got a CEL , bank rich. Nothing with drivable ty happened so I wouldn't worry.

I just talked to my e98 supplier. The cost is 2.25 a gallon. It's so incredibly cheap I want to bury a fuel tank in my yard.

Interesting you got a rich code. 1st time at 40 trims went crazy high but ended up well under 25. But that is a lean condition.  I would have suspected a bank lean code due to trims over 25.

[wasinger3000]

I put e85 in before 91 and drove for a little. I got a CEL , bank rich. Nothing with drivable ty happened so I wouldn't worry.

I just talked to my e98 supplier. The cost is 2.25 a gallon. It's so incredibly cheap I want to bury a fuel tank in my yard.

Interesting you got a rich code. 1st time at 40 trims went crazy high but ended up well under 25. But that is a lean condition.  I would have suspected a bank lean code due to trims over 25.

I'll have to do it again and see what happens. It was the very first time putting e85 in but the tank was almost empty. Maybe 2 gallons of 91 in.

[FoMoCoSHO]

How did your fuel trims behave?

[wasinger3000]

I wasn't watching trims when I first started e85. All I was worried about was the a/f at the time. Last night my LTFT was in thr 14's.

[wasinger3000]

ok.. ive been doing some thinking. I really wish there was a way to test octane so i could know for sure whats what.  Has anyone run a 40% mix tuned yet? or is it a certain thing that 30% is limit.

So far everything i do could be wrong if the octane rating of different percents of ethanol is off. Most calculations ive seen say anything at 50% and up to 85% are 105 octane. Which means using 65% ethanol would yield a higher octane rating with a lower overall % concentration of ethanol than using 85%. Which would allow us to have a higher octane and still have enough fuel pressure vs using 85% to achieve the same octane.

Now after that, i've found that 98% is found to have 113 octane. Which would allow for a higher octane rating and still a lower concentration of ethanol which would allow for higher octane and more fuel pressure.

Here are some of the mixes i've calculated.
E85 (Gals) 9.00 @ 65%, 105 octane.
Gas (Gals) 10.00 @ 0%, 91 octane.
96.7 octane
30.8% ethanol (or E31)
-----------------------
E85 (Gals) 9.00 @ 85% 105 octane.
Gas (Gals) 10.00 @ 0% 91 octane.
96.7 octane
40.3% ethanol (or E40)
---------------------------
E85 (Gals) 8.00 @ 85%, 105 octane.
Gas (Gals) 11.00 @ 0%, 91 octane.
96.1 octane
35.8% ethanol
------------------
E98 (Gals) 7.00 @ 98%, 113 octane.
Gas (Gals) 12.00 @ 0%, 91 octane.
99.1 octane
36.1% ethanol

[Larrylu]

What kind of numbers would you expect to get if you only added a couple of gallons of E85 to a fill up on E10 / 93 octane?

[wasinger3000]

I don't have access to any 93. Also I went with 91 at 0% because it's a top tier station that has the separate hoses for the different grades which ensures that you are getting 91 the entire time. Where as the stations that use a single hose for 3 grades requires you to use up to 5 gallons before you get the selected grade. So I would be getting 5 gallons of 87 in the car which would bring down my overall octane rating.

But the use of say 93 at 5% would make 97.4 octane @ 34%.

[FoMoCoSHO]

What kind of numbers would you expect to get if you only added a couple of gallons of E85 to a fill up on E10 / 93 octane?

I'm at 8 gallons and 43%.

So you have 1.9 to start plus 2 more which should put you around 20ish percent.

[wasinger3000]

I'm going to ask torrie to make me a 100 octane tune once I get my e98. Should be interesting.

[Larrylu]

What kind of numbers would you expect to get if you only added a couple of gallons of E85 to a fill up on E10 / 93 octane?

I'm at 8 gallons and 43%.

So you have 1.9 to start plus 2 more which should put you around 20ish percent.

20 ish %   Gotcha!  Sounds real interesting.  What would be a good guesstimate for the octane equivalent of that mix?

[kinder]

There are several portable octane testing instruments available out there. last I heard they were about $7-1000.

Just saying that if you are gonna play the mixing fuel game with your car maybe it is a worthy investment?

http://www.shatox.com/index.html

http://www.zeltex.com/portable/zx-101c.html

[FoMoCoSHO]

There are several portable octane testing instruments available out there. last I heard they were about $7-1000.

Just saying that if you are gonna play the mixing fuel game with your car maybe it is a worthy investment?

http://www.shatox.com/index.html

http://www.zeltex.com/portable/zx-101c.html

There is more than one way to skin a cat.

Dicking around testing fuel while I'm filling up just sounds like a terrible way to keep my car from smelling like fuel. I am guaranteed to spill fuel on myself.

Anyhoo, it occurred to me tonight that the car might help us figure this out, if you know your average and/or WOT LTFT's on straight 93 and a blend....

Comparing average LTFT's on straight 93 as a baseline to now at approx e-43 (calculated with Torque, msds sheets, receipts and a the online E-85 calculator), I know my car is enriching at an average of 14% on both banks. By average I mean the trim #'s I see most of the time after the ECU adjusts to a new blend.

100 percent E-85 requires around 30% more fuel so working backwards this puts my blend at 46.6% . So 3.3 % higher than my figures. I feel this is a reasonable margin of error since I haven't always been 100% accurate losing a receipt from time to time soooo some of my existing percentages may have been a little off when doing the calculations.

I'd like to recalculate this with WOT Trims but would require me to run the corn out as somehow I never noted my WOT trims on 93(derp). Since my tuner will be arriving soon, I probably need to do that anyway, so i can get to whatever baseline Mr. Torrie suggests.

Of course, I could be completely wrong in my thinking.