4 gal E85, 5.6 gal E10, 2.5 gal E10

Final Report



I've finished with as much E85 and ethanol testing as I am going to do for now:

1) E85 - runs in both the NHW11 and ZVW30 but will raise a harmless, "check engine" light, P0171 code. Clear the code and keep on driving. No adverse impact on hill climb other than it takes longer.

2) Cold-start fuel trim - the initial fuel trim when the car is started is for straight gas. So in freezing weather with the engine coolant is 3C or lower, the engine in both cars will 'stall out.' Clear the codes and restart until enough latent heat is in the cylinders to keep the engine running.

3) Ethanol is not priced per energy content - it has about 75% of the energy of straight gas and I could see this even without a formal mph vs MPG test. This was evident in my commuting MPG, ~35MPG vs normal 50MPG with with these temperatures. If E10 gas were priced $4/gal, E85 should be pump-priced at $3/gal. Right now, E10 is ~$3.60/gal and E85 ~$3.40/gal. and would have to be $2.70/gal. to make economic sense.

4) E55 - based upon measured long-term fuel trim, it looks like E55 is about as high as we can go and avoid the "check engine" light. So if one could mix 50/50 of E10 and E85, it would work. But until the E85 is priced at 75% of E10, it makes no economic sense.

I understand my injectors may be much cleaner. I have not inspected the fuel line filters but there is no evidence of clogging at this time.

Bob Wilson

 

You might want to test that hypothesis with recording the long-term fuel trim using TechStream or AutoEnginuity. My experience and observations have been that during the start, we can actually see the initial long-term trim and how the engine ECU has to rapidly re-trim to a value consistent with E85. That with the start retry seems to work.

Sad to say, we are rapidly approaching a time when North Alabama won't have low temperatures to capture the data. I did see it with Graham Miniscanner this afternoon but then I was expecting it.

Bob Wilson

 

I would take that bet.

E50 works without a code but not tested in very cold weather, well below freezing. E10 in winter blends that often contain butane works. I really won't get concerned until E25 and Toyota could flash code in their current production cars. Legacy car might need a hack above E25.

Bob Wilson