View Single Post
beepbeep beepbeep is online now
Registered User
 
beepbeep's Avatar
 
Join Date: Jun 2001
Location: Sweden
Posts: 5,560
Quote:
Originally Posted by turboteener View Post
But E85 is close to 6.00$ US a gal to make. You can't buy it in many areas all over the country and most 930s get bad enough mileage as is. Actually the number is about 27% more E85 than regular gasoline, but you can make some huge power out of it.

Unfortunately E85 is a myth that keeps being perpetuated by the media. It is more expensive to produce than Gasoline and we don't have the land to actually supply it consistently.

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,
__________________
Thank you for your time,
Old 03-10-2008, 09:58 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #36 (permalink)