Blending E85 with 91 octane to create E21 (93 octane)

[kpriv]

I know there are some older e-blending threads, but figured I'd start a new one to solicit any advice as I start testing out some blends to bump up california 91 octane to 93 octane. Been doing a fair amount of research and here are my initial conclusions (any input correcting misinformation is greatly appreciated);

- True E85 is 105 octane (though need to test each batch you pull as regional / seasonal variances can result in what is labeled as e85 at the pump being anywhere from e55 to e85)
- Blending with 91 octane (E10 from the pump) you need to get to ~E21 to bump up your octane 2 points to 93. I created a little spreadsheet to calculate how much e10 to mix with whatever e% you are pulling from the pump to create an e21 mix. Very simple, but happy to share it if helpful.

Questions for the group:
1) Anyone have any strong opinions on why e21 could be a bad idea for our cars? Obviously, you need more fuel above certain e levels, but from what I could find thus far on the google machine it doesn't appear that e21 results in any fuel delivery challenges
2) I am going to run a bunch of logs to see if I have any issues running this on the 93 tune file. I would really appreciate any thoughts on the best parameters I should be checking to test whether I'm creating risk of either short term or long term issues. Figure it is some mix of timing, lambda, long/short term fuel trim, requested/actual fuel pressure, etc...

In the long run, not sure it'll be worth the hassle factor but it's been an interesting research project so far. If I decide to keep this up, I will most likely install the zeitronix ethanol content analyzer so I have real time readings (thanks mickey for the recommendation).

Thanks in advance for any insights / recommendations.

Kyle

[Chris Morales]

Not a California person, but I did some experimenting with E85 blends and found that my tuned S8 running 650+hp would not tolerate a blend much above E25. It would however run well at full bore in the E20-E25 level. An S6 or S7 presumably has the same fuel system but less power without a turbo swap, so I would think you guys should be fine running an E21 blend. The blending part is a hassle, though.

[cobrario]

I know there are some older e-blending threads, but figured I'd start a new one to solicit any advice as I start testing out some blends to bump up california 91 octane to 93 octane. Been doing a fair amount of research and here are my initial conclusions (any input correcting misinformation is greatly appreciated);

- True E85 is 105 octane (though need to test each batch you pull as regional / seasonal variances can result in what is labeled as e85 at the pump being anywhere from e55 to e85)
- Blending with 91 octane (E10 from the pump) you need to get to ~E21 to bump up your octane 2 points to 93. I created a little spreadsheet to calculate how much e10 to mix with whatever e% you are pulling from the pump to create an e21 mix. Very simple, but happy to share it if helpful.

Questions for the group:
1) Anyone have any strong opinions on why e21 could be a bad idea for our cars? Obviously, you need more fuel above certain e levels, but from what I could find thus far on the google machine it doesn't appear that e21 results in any fuel delivery challenges
2) I am going to run a bunch of logs to see if I have any issues running this on the 93 tune file. I would really appreciate any thoughts on the best parameters I should be checking to test whether I'm creating risk of either short term or long term issues. Figure it is some mix of timing, lambda, long/short term fuel trim, requested/actual fuel pressure, etc...

In the long run, not sure it'll be worth the hassle factor but it's been an interesting research project so far. If I decide to keep this up, I will most likely install the zeitronix ethanol content analyzer so I have real time readings (thanks mickey for the recommendation).

Thanks in advance for any insights / recommendations.

Kyle

I have E20 in my car now - runs great on the 93 file but of course we have 93 in VA, only thing I'd suggest you not assume your pump is 10%, I bought 2 extra fuel jugs so I could get the E values as correct as possible, 1 of which I filled with 93 Pump the other with Pump E- turned out my E85 was E70 and the 93 was less than E5- prob not a huge difference but if you plan to do this regularly I'd do as Mick suggested with the Z E Analyzer. I'll be logging mine over the weekend to see how it all seems to work on a few 3rd and maybe 4th gear pulls. Good Luck !

[kpriv]

Excellent, thanks gents. Interesting point about the regular pump gas not being e10 for you. I wouldn't have thought to test that but will certainly do so. I only have the quasi-scientific water in a vial test, but I was pleasantly surprised to see the e85 from the pump appeared to be pretty good hooch. I am just pulling 2-2.5 gal into three separate mini gas cans. Then I add from there in the correct ratio when I fill up with 91.

http://i.imgur.com/iYYGWKY.jpg (https://imgur.com/iYYGWKY)

[DGVR6]

VAG Converted their line up after 2014 to safely handle e15, what’s a few more points ;).

I run e25 when I feel like getting 15mpg. You’d be safe at e20.. enjoy the boost in power it offers

I believe shell gas is true e10, atleast from what I heard.

As Chris said, RS guys need to be careful running high blends because of high boost.

[kpriv]

VAG Converted their line up after 2014 to safely handle e15, what’s a few more points ;).


That's kind of how I thought about it. The oem's have their vehicles ready to run something >e10.

I am a shell loyalist. Going to test a batch and see if it's 10% e...



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[nefkntym]

sudded for more updates and info

[kpriv]

Did some logging yesterday. Haven't had a chance to download and make sense of it yet, but I'll post it up as soon as I do.

Dumb question alert: is there a target profile for lambda and things like fuel trim? Or do I need to log my baseline with pump e10 91 octane and just compare to that?

[DGVR6]

yes .. do a few pulls on with 91, you want WOT afr targets.. part throttle won’t matter much.

So let’s say apr targets 11.8:1 with 91, youll see 0.80 on ur lambda WOT.. it’s best to get that, and compare next to each other..
You generally don’t want to see lambda higher than normal when you’re WOT.

Give it some time to adapt, I like to take things slowly.

[Chris Morales]

I haven't logged my lambda in a while but I seem to recall it running in the .8 range at WOT on 93 octane. Definitely log your baseline at WOT to know what's right for your car, but I would expect something in that range both before and after. If your lambda is creeping up from the baseline, you have gone too far. The computer should be adding the required additional fuel to hit the same target lambda.

[kpriv]

excellent. much appreciated

[kpriv]

Here are a few quick WOT logs from over the weekend. Need to gather better data points over a more extended run and baseline info from regular pump 91 octane. The second one is pretty clean, however I'm mostly curious to see if those lean 'blips' are not present with pump e10 (ie, do they represent fuel flowing through that was more highly concentrated ethanol), or if that is pretty normal to see every once in a while and as long as the general baseline is in that 0.8 - 0.9 range you're good to go.

http://i.imgur.com/vd0Za3V.jpg (https://imgur.com/vd0Za3V)

http://i.imgur.com/OApqEeu.jpg (https://imgur.com/OApqEeu)

http://i.imgur.com/lPlQytD.jpg (https://imgur.com/lPlQytD)

[kpriv]

One more on this front. Did another 4th gear pull on the 93 file the other day and logs look clean. Lambda in the 0.80 - 0.85 range, no misfires and no pulled timing. Pretty happy with the experiment thus far...

http://i.imgur.com/eI5UbT2.jpg (https://imgur.com/eI5UbT2)

[Ze_Nardo6]

Good stuff Kyle! I have my Zeitronix ECA kit all wired up except for the flex fuel sensor that needs to be spliced into the fuel line.

This part scares me. Any ideas as to the best place to splice in the sensor? The fuel lines coming off the HPFPs are quite small, may be a tight fit