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A.Wayne A.Wayne is offline
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Join Date: Aug 2007
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Quote:
Originally Posted by beepbeep View Post
Hmm....I'm quite sure it takes roughly 40% more volumetric flow to get same lambda as gasoline. My WBO2 measurments also show this to be true.

Gasoline:
44 Energy content [MJ/kg]
735 Density [kg/m3]
305 Vapor energy [kJ/kg]

Ethanol
27 Energy content [MJ/kg]
785 Density [kg/m3]
840 Vapor energy [kJ/kg]

1L gasoline contains 735 [kg/m3] * 44 [MJ/kg] = 32340 MJ/m3 = 32.3 MJ/L
1L ethanol contains 785 [kg/m3] * 27 [MJ/kg] = 21195 MJ/m3 = 21.2 MJ/L

With other words, you need 52% more volume to obtain same amount of energy from pure ethanol ( 32.3/21.2 = 1.52 )

E85 usually contains 85% ethanol, 12.5% gasoline and 2.1% MTBE, so volumetric flow to obtain lambda 1.0 is usually around 1.4 of gasoline instead of 1.5 which would be the case with 100% ethanol.

So number is not 26% more but roughly 40% more.

I won't delve into enviromental merits of E85 as they are somewhat dubious. But as high-performance fuel for tuned turbocharged engines, it's quite handy. Fortunately, it's available at almost every pump overhere and cost's less per litre than gasoline. MJ per MJ, it costs roughly the same...

Regards,
Agree on the e85 comments and yes it is closer to 40% + to match gasoline.
The water met setup is easier here than finding and modifying a stock fuel system to accommodate e85....

Regarding the damaged engine , i would dis-agree that it was just a backfire that caused that damage , it looks like excessive EGT's , coupled with an engine misfired midbore ( lean condition) the resulting Cylinder pressures lifted and torched the cylinder head .
Old 03-10-2008, 02:17 PM
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