Getting conflicting reports on this. Please post a link to your source as well. Thanks
LS1NOVA
Can someone tell me the true octane rating of E85?
Well I have around 14to1 bbc and all I can say is get someone who knows how to build one for you and run it.E70 is 105 octane e85 is around 110 but has all the cooling factors. Don't be afraid just run it.
.
I've seen a couple of places claiming 107 but they also say it runs much cooler
and is much more detonation resistant then 107 octane gasoline??
.
I've seen a couple of places claiming 107 but they also say it runs much cooler
and is much more detonation resistant then 107 octane gasoline??
.
Ethanol AND methanol can NOT be properly rate by regular
"octane rating methods"
If you look up how gasoline is rated for octane you will understand.
The scientists have a special one cylinder engine , that just does this one job.
It is a lengthy process run under strict observation.
It is a very complex process, and I am not going to explain it.
Also, ethanol (and methanol) has a very high latent heat evaporation rate,
this means as the ethanol is made into tiny droplets ,
the methanol basically sucks the heat out of the air.
This drops the intake temp like a prom dress.
This process helps prevent detonation, therefore you can use
more timing, compression, etc to build more cylinder
pressure, hence more horsepower (actually more torque).
It is kinda involved, but that should give you an idea.
If anybody tells you that E-85 has an "X" octane rating,
they do not know what they are talking about or
are trying to blow smoke up your ass.
Gasoline can be "octane rated", all other fuels are a GUESS/ESTIMATE!
Your Pal, Gary
"octane rating methods"
If you look up how gasoline is rated for octane you will understand.
The scientists have a special one cylinder engine , that just does this one job.
It is a lengthy process run under strict observation.
It is a very complex process, and I am not going to explain it.
Also, ethanol (and methanol) has a very high latent heat evaporation rate,
this means as the ethanol is made into tiny droplets ,
the methanol basically sucks the heat out of the air.
This drops the intake temp like a prom dress.
This process helps prevent detonation, therefore you can use
more timing, compression, etc to build more cylinder
pressure, hence more horsepower (actually more torque).
It is kinda involved, but that should give you an idea.
If anybody tells you that E-85 has an "X" octane rating,
they do not know what they are talking about or
are trying to blow smoke up your ass.
Gasoline can be "octane rated", all other fuels are a GUESS/ESTIMATE!
Your Pal, Gary
Investigation of Knock Limited Compression Ratio of Ethanol Gasoline Blends
http://delphi.com/pdf/techpapers/2010-01-0619.pdf
This SAE paper reports the octane rating of ethanol/gasoline blends is essentially constant with blend ratios between E-50 and E-85.
The stoichiometric A/F ratio of E-50 is 11.57/1 and E-85 is 9.61/1, so the AFR must be corrected for ethanol variations by jetting or pulse width adjustments.
This stuff is easier to read if you start with the “Abstract” at the beginning, then scroll down through the paper to the “Discussion” and “Conclusions” and then go back and cherry pick the things you find interesting.
More to study.....
CALCULATION-85S OF KNOCK SUPPRESSION IN HIGHLY TURBOCHARGED GASOLINE/ETHANOL ENGINES USING DIRECT ETHANOL INJECTION
http://web.mit.edu/mitei/lfee/programs/archive/publications/2006-01-rp.pdf
L. Bromberg*
D.R. Cohn**
J.B. Heywood***
Massachusetts Institute of Technology
Cambridge MA 02139
February 23,2006
*Plasma Science and Fusion Center (PSFC)
**Laboratory for Energy and the Environment and PSFC
*** Sloan Automotive Laboratory and Department of Mechanical Engineering
http://delphi.com/pdf/techpapers/2010-01-0619.pdf
This SAE paper reports the octane rating of ethanol/gasoline blends is essentially constant with blend ratios between E-50 and E-85.
The stoichiometric A/F ratio of E-50 is 11.57/1 and E-85 is 9.61/1, so the AFR must be corrected for ethanol variations by jetting or pulse width adjustments.
This stuff is easier to read if you start with the “Abstract” at the beginning, then scroll down through the paper to the “Discussion” and “Conclusions” and then go back and cherry pick the things you find interesting.
More to study.....
CALCULATION-85S OF KNOCK SUPPRESSION IN HIGHLY TURBOCHARGED GASOLINE/ETHANOL ENGINES USING DIRECT ETHANOL INJECTION
http://web.mit.edu/mitei/lfee/programs/archive/publications/2006-01-rp.pdf
L. Bromberg*
D.R. Cohn**
J.B. Heywood***
Massachusetts Institute of Technology
Cambridge MA 02139
February 23,2006
*Plasma Science and Fusion Center (PSFC)
**Laboratory for Energy and the Environment and PSFC
*** Sloan Automotive Laboratory and Department of Mechanical Engineering
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