Ethanol Fuels

[customboss]

Absolutely spot on Grumpy Bear!

 

I would submit that cleanliness of combustion and not forming deposits on high heat areas, secondly not forming deposits on vented areas on non combustion zones is more critical than octane rating.  If you can stop, restrict, or remove deposit formation in your IC engine you can run lower octane fuels for a time with very little possibility of detonation.  ECM controlled, VVT, Cam Phased engines that are well tuned, driven normally, and maintaned with above average lubricants and fuels can optimize even lower octane fuels.  Getting cleaning, clean burn, and lower deposits formations with ethanol of any source is a plus. 

[Grumpy Bear]

3 hours ago, customboss said:

Absolutely spot on Grumpy Bear!

 

I would submit that cleanliness of combustion and not forming deposits on high heat areas, secondly not forming deposits on vented areas on non combustion zones is more critical than octane rating.  If you can stop, restrict, or remove deposit formation in your IC engine you can run lower octane fuels for a time with very little possibility of detonation.  ECM controlled, VVT, Cam Phased engines that are well tuned, driven normally, and maintaned with above average lubricants and fuels can optimize even lower octane fuels.  Getting cleaning, clean burn, and lower deposits formations with ethanol of any source is a plus. 

 

The sentence in bold above alone makes sense but the context surrounding it makes it unclear. Are you saying oil side deposits or combustion chamber deposits can effect octane requirements? 

[customboss]

2 hours ago, Grumpy Bear said:

 

The sentence in bold above alone makes sense but the context surrounding it makes it unclear. Are you saying oil side deposits or combustion chamber deposits can effect octane requirements? 

Both in the worst scenarios but primarily any deposit that holds heat at uneven or not at more evenly distributed design temps in combustion chamber and associated rolling stock, valves , etc.   Just a small carbon or varnish deposit can affect detonation affectations.  Why LSPI "resistant" engine oils were introduced which means we took out your calcium and added magnesium, with a bit of a solvent enhancing additive. LOL 

[Grumpy Bear]

4 hours ago, customboss said:

Both in the worst scenarios but primarily any deposit that holds heat at uneven or not at more evenly distributed design temps in combustion chamber and associated rolling stock, valves , etc.   Just a small carbon or varnish deposit can affect detonation affectations.  Why LSPI "resistant" engine oils were introduced which means we took out your calcium and added magnesium, with a bit of a solvent enhancing additive. LOL 

 

Clarification is always good. Combustion chamber deposits increase static ratios that call for more detonation resistance. Old story. Remember, I love 40/50's big Brit singles.  

 

Oil side....yea....much harder sell. Not that deposits can't have an effect. I've seen some seriously slugged up motors that were thermally insulated like a blanket but it takes a bit more than a film to have this effect. 

[Grumpy Bear]

Know those little stickers on the pump that says 70% minimum alcohol content? Yea...not true. Just hit a station that tested 65%. Still legal for the grade but not for the advert. If you use this stuff for the octane, test. Same station also had the only E20 pump I've seen this side of the Mississippi. To far away for a regular visit but it was nice to be in my range.  

[Grumpy Bear]

Have now logged about 3K miles on the Terrain with 15 to 20% Ethanol. 28.7 mpg and as with the pickup it has eliminated the KR with little sacrifice in mileage. Only issue is blending consistently with an E-85 that is inconsistent from station to station without test each station in real time. Much easier at stations with any other ethanol over 20% which are always within 1% of the pump sticker. The one station I have found to date that has E-20 cost more than I can blend to. 

 

But the Terrain likes this blend it seems. No loss in mileage I can calculate with I attribute to it ability now to run without KR.  

[customboss]

Similar results with L3B trail boss using Maverik E15 which can be as low as 86 avg octane here at 7500' . Suspect when its 87 octane the MPG bumps up. Still testing and its slow because I am not driving as much as last month.  Tail pipe cleanliness is literally perfect, no soot or very very low soot.  I mix Kroger 91 octane or a mix of Cenex 85 and 91 with the Mavrik E15 to try to get optmized octane and the Cenex additives to help keep clean.  

 

 

[Grumpy Bear]

Counting Cost

 

 

A snippet of a spread sheet I use to calculate the cost of blended fuel and guess what? Unless you run your tank empty every time it's always blended fuel. Save that very first tank. It also helps a great deal in keeping track of tank ethanol content when you are not measuring directly from the tank. Or running 'What If's" to find what blend gives a desired for result.

 

Example: Your very first 10 gallon tank cost $5.00 per gallon and you got 20 mpg. So 5 gallon cost $25 and you drove 100 miles sot the cost per mile was $25 / 100 = 25 cpm. 

 

Your second tank is an 8 gallon fill at $4.80. Cost was $38.40 for the fill But you still have 2 gallons of $5 fuel in that tank. It's cost $10 so this tank holds a blend of cost making that tanks value $48.40 or $4.84 a gallon not the $4.80 you shelled out.  If it repeated the 20 mpg number that was 360 miles. Miles you drove on a higher priced fuel but replaced with a lower priced fuel. the cost is a blend not the replacement value. 

 

Same situation when blending alcohol content. Your tank isn't what you put in it but what that fuel blended with the remainder is. 

 

I get it, no one what's this much trouble to track fuel cost BUT if you don't track alcohol percentage like this you will make some mistakes in you conclusions on MPG vs Eth%. 

 

Food for though. YMMV

 

[customboss]

Can a new scanner read the fuel density in the tank from new GM ECM's?

 

Mine is old so I can't.

 

That  would be an accurate way to correlate % of ETOH to gasoline and would show actual mix in our tanks for those so inclined. 

 

 

[Grumpy Bear]

2 hours ago, customboss said:

Can a new scanner read the fuel density in the tank from new GM ECM's?

 

Mine is old so I can't.

 

That  would be an accurate way to correlate % of ETOH to gasoline and would show actual mix in our tanks for those so inclined. 

 

 

 

Density? Hum....mine reads % alcohol from the ethanol sensor Flex Fuel vehicles use. Exactly what it reads I'm not privy to. 

[customboss]

3 minutes ago, Grumpy Bear said:

 

Density? Hum....mine reads % alcohol from the ethanol sensor Flex Fuel vehicles use. Exactly what it reads I'm not privy to. 

If I am not mistaken  fuel density reading is exactly how  it gets % alcohol on the ECM. I THINK our L3B engines have a hidden ethanol fuel map too. I know my 2014 Chevy E3500 6.0L V8 dually Freedom Elite Motor Coach had a second fuel MAP but I could pull that up.  On my 2022 LTD I cannot see it with my ancient scanner. 

[Grumpy Bear]

 

[Grumpy Bear]

[customboss]

This 2012 paper is confirmed by technology 10 years later. Good read. 

 

https://advancedbiofuelsusa.info/wp-content/uploads/2012/08/New-Ethanol-Engine-Tech-Revised-Aug-2012-Formatted.pdf

[Grumpy Bear]

3 hours ago, customboss said:

This 2012 paper is confirmed by technology 10 years later. Good read. 

 

https://advancedbiofuelsusa.info/wp-content/uploads/2012/08/New-Ethanol-Engine-Tech-Revised-Aug-2012-Formatted.pdf

 

He mentions 17:1 as the 'ideal' ratio. Mathematically correct but not practical in any world at any time. Valve shrouding starts being a real issue around 14:1 and even if it were not. The cycle efficiency between 14 and 17 is so small as to be insignificant. Enter the forced inductions contribution to increasing "dynamic' ratio...the one that really matters. 

 

The post best contribution was in showing that without huge cost and complexity getting both fuels to live in one motor at perform thermally the same is impossible BUT the ECOTEC and ECOBOOST make a compromise possible. Delayed IVO closing and timing maps let the 4.3 run 11:1 on 87 at a somewhat reduced efficiency from what is possible and yet quite a bit better than not using it. By the time you get to E-30 in this motor these methods wane from prefect and once again straddle it without perfecting either. 

 

His cost analysis is spot on the money but again with limited information about the blends effect on same. All or nothing is confusing to the reader. Then again that is the point of such things. Bias builders.

 

I was a bit disappointed that cleanliness was not addressed nor was air quality. 

 

All in all a good read with the proper filters in play. 

Edited July 18, 2022 by Grumpy Bear