Warning about 10% Ethanol mix on turbo cars
09-23-2009, 05:51 PM
#27
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Unfortunately in California we've had it for years.
be careful with that stuff Brettus
be careful with that stuff Brettus
.
09-25-2009, 10:06 AM
#34
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After touring a refinery about a year ago there were some interesting revelations.
Today's gasoline stock is colorless. Years ago when the sulfate content was a little higher it had a tinge of yellow. Mostly to get the color it has a dye added, or may just be part of the natural color of any additives.
Refineries create a gasoline stock and store it free of all additives. When a tanker truck pulls up to the pump is when the additives are mixed in because there are differences from state and local requirements, not to mention the same stock may go to a dozen different brands - each brand has their own solution of detergents added. How does this affect ethanol? Ethanol isn't added to the stock until the tanker truck begins to fill.
So 87 octane or 93 octane is the stock fuel octane. Adding 10% ethanol bumps the octane by at least 1-2 points. Not a big deal to some, but generally the 87 with ethanol is actually 89, and 93 is actually 94.
In closed loop the system will theoretically compensate. Having run various mixtures of E85/straight 93 in both a CX7 and an RX8 it does just that but it takes a while before the ECM seems to learn the fuel. While the CX7 is a piston engine it gobbled up fuel on the highway at 20% ethanol. I went from about 22 MPG to 19 MPG on the same consistent routes averging about 75 MPH, but virtually no difference in city driving, of 14-15 MPG. Throttle response was significantly improved after the turbo spooled (about 2000 RPM) but it seemed to have slightly more lag up to that point.
The RX8 (NA) had little change on highway MPG but dropped about 1 MPG on city. Improved throttle response slightly.
After about 10,000 miles on the RX8 after taking into account the cost differntials the E85/93 mix was about 5% less running 93 alone. Now that I've taken a different position I run straight 93 out of convenience.
Ethanol does absorb water however in a gasoline mixture the absorption rate is much slower. Unless you drive around with your gas cap off, you won't be exposing the ethanol to enough water vapor to make much of a difference, even if the car sits for a month at a time. Lighter fractions in the gasoline do a pretty good job of maintaining adequate positive pressure to prevent intake of fresh air.
As far as whether adding ethanol alters the amount of oil America imports, thats a debate that rages over political passion rather then fact so its pointless to discuss.
Today's gasoline stock is colorless. Years ago when the sulfate content was a little higher it had a tinge of yellow. Mostly to get the color it has a dye added, or may just be part of the natural color of any additives.
Refineries create a gasoline stock and store it free of all additives. When a tanker truck pulls up to the pump is when the additives are mixed in because there are differences from state and local requirements, not to mention the same stock may go to a dozen different brands - each brand has their own solution of detergents added. How does this affect ethanol? Ethanol isn't added to the stock until the tanker truck begins to fill.
So 87 octane or 93 octane is the stock fuel octane. Adding 10% ethanol bumps the octane by at least 1-2 points. Not a big deal to some, but generally the 87 with ethanol is actually 89, and 93 is actually 94.
In closed loop the system will theoretically compensate. Having run various mixtures of E85/straight 93 in both a CX7 and an RX8 it does just that but it takes a while before the ECM seems to learn the fuel. While the CX7 is a piston engine it gobbled up fuel on the highway at 20% ethanol. I went from about 22 MPG to 19 MPG on the same consistent routes averging about 75 MPH, but virtually no difference in city driving, of 14-15 MPG. Throttle response was significantly improved after the turbo spooled (about 2000 RPM) but it seemed to have slightly more lag up to that point.
The RX8 (NA) had little change on highway MPG but dropped about 1 MPG on city. Improved throttle response slightly.
After about 10,000 miles on the RX8 after taking into account the cost differntials the E85/93 mix was about 5% less running 93 alone. Now that I've taken a different position I run straight 93 out of convenience.
Ethanol does absorb water however in a gasoline mixture the absorption rate is much slower. Unless you drive around with your gas cap off, you won't be exposing the ethanol to enough water vapor to make much of a difference, even if the car sits for a month at a time. Lighter fractions in the gasoline do a pretty good job of maintaining adequate positive pressure to prevent intake of fresh air.
As far as whether adding ethanol alters the amount of oil America imports, thats a debate that rages over political passion rather then fact so its pointless to discuss.
09-28-2009, 09:01 AM
#35
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