|
|
#1 | |
|
Rear Admiral Lower Half
![]() ![]() Join Date: Apr 2005
Posts: 2,245
|
Gas Too Pricey? Make Your Own
Quote:
Last edited by kgsilvas : 05-01-2006 at 09:32 AM. |
|
|
|
|
|
|
#2 |
|
Vice Admiral
![]() ![]() ![]() ![]() |
You can mix gasoline and ethanol? I thought your car had to be configured a certain way to take ethanol....
|
|
|
|
|
|
#3 |
|
Chief of Naval Operations
![]() ![]() Join Date: May 2000
Location: LEVITTOWN< PA> USA
Posts: 13,621
|
AS far as I know, it is presently being added to ALL gasoline at a 10% level. BTW, you get lower MPG with it. It has a lower BTU content per gallon than gasoline.
__________________
“Socialism is a philosophy of failure, the creed of ignorance, and the gospel of envy, its inherent virtue is the equal sharing of misery.” (Winston Churchill) |
|
|
|
|
|
#4 |
|
Fleet Admiral
![]() ![]() ![]() ![]() ![]() ![]() |
![]() Most cars can take 10% ethanol with no problem - 20% and you may be shortening the life of your engine. GM makes some new cars that can take up to 85% ethanol, but like Johnny says, you get about a 10-20% drop in fuel economy. |
|
|
|
|
|
#5 |
|
Vice Admiral
![]() ![]() ![]() ![]() |
So with a drop in fuel economy...does the savings even equal out to anything?
I'm not great with numbers...the article says it'll take gas prices from $3 to $2.40 in a way. But if you are getting less MPG, doesn't that mean you have to fill up a little more? |
|
|
|
|
|
#6 |
|
Vice Admiral
![]() ![]() ![]() ![]() |
The price at 2.40 was with a 15% ethanol mixture. Running at 80% would probably drop the price to below 1.00.
Does ethanol burn cleaner than gas? If it's going to save the environment it's probably worth it. BTW...where's the link?
__________________
"I know the pieces fit, cause I watched them fall away." "Cold silence has A tendancy to Atrophy any Sense of compassion." MJK |
|
|
|
|
|
#7 | |
|
Rear Admiral Lower Half
![]() ![]() Join Date: Jul 2001
Location: Colorado
Posts: 2,743
|
Quote:
http://www.popularmechanics.com/scie...tml?page=1&c=y Specifically, this chart: http://media.popularmechanics.com/do...uture-e852.pdf |
|
|
|
|
|
|
#8 |
|
Fleet Admiral
![]() ![]() ![]() ![]() ![]() ![]() |
That's based on buying it at the pump for $2.41/gal, tho - if you're brewing your own, it should be quite a bit cheaper than that.
However, I don't know if I trust myself to make my own highly combustable fuel. Don't stills explode on a fairly regular basis? |
|
|
|
|
|
#9 |
|
aka the keg killer
![]() ![]() Join Date: Dec 2002
Location: Ala-effin'-bama!
Posts: 2,738
|
Anything over 10% can cause problems with rubber/plastic parts in automotive fuel systems. Not every car, and not every time, but it can happen. Some metal fuel rails, lines and fuel tanks ('80s and earlier vehicles, primarily) have a zinc (or similar) inner anticorrosive coating that can be displaced by large amounts of alcohol as well.
Thunder Road nonwithstanding, I am here to tell you that Tennessee has nothing on Franklin County, VA and Wilkes County, NC with regards to the production of whiskey. Junior Johnson is a native of Wilkes County. Dawson County, GA was another old-school moonshining hotbed.
__________________
"The price of progress is trouble." (C. F. "Boss" Kettering) "50% of the American public has below-average intelligence. 70% of the American public now has regular access to the Internet. Do the math." (unknown) Last edited by mechmike0034 : 05-01-2006 at 12:45 PM. |
|
|
|
|
|
#10 | |
|
Admiral
![]() ![]() ![]() ![]() ![]() Join Date: Nov 2001
Location: East coast
Posts: 7,116
|
Quote:
I don't understand how they computed the E85 usage. They state in the text that E85 provides ~15% less fuel mileage than gasoline. If that is the case then based on the numbers they provided - if the gasoline powered engine gets 34 mpg then it should get ~29 mpg with E85 not 17 mpg which is what they state. Also if M85 gets ~35% less fuel efficiency than gasoline then the M85 chart should show ~22 mpg not 14 mpg. In the chart in Cubsfan's link the PM people are comparing apples and oranges. They should be comparing a gasoline powered taurus to the E85 and M85 taurauses. They should be comparing the gasoline powered golf to the golf tdi. I really do not like they way they slanted, purposefully or not, this chart against ethanol and methanol. Last edited by guiseppewv : 05-01-2006 at 12:49 PM. |
|
|
|
|
|
|
#11 | |
|
Admiral
![]() ![]() ![]() ![]() ![]() Join Date: Nov 2001
Location: East coast
Posts: 7,116
|
thing I did like about the article is this:
Quote:
This is one of the ways diesel fuel vehicles are so efficient. For those that do not know - diesel vehicles compress the fuel/air mixture until it combusts so the compression ratio is high. Question for any automotive experts (i.e. MechMike) - why can't a high compression engine be produced that will run on E85 but can have the compression ratio reduced to run on 93 octane? |
|
|
|
|
|
|
#12 | |
|
Rear Admiral Lower Half
![]() ![]() Join Date: Jul 2001
Location: Colorado
Posts: 2,743
|
Here's how they picked the cars:
Quote:
|
|
|
|
|
|
|
#13 | |
|
aka the keg killer
![]() ![]() Join Date: Dec 2002
Location: Ala-effin'-bama!
Posts: 2,738
|
Quote:
A couple of things to consider- Take a Taurus for example. The E85 engine isn't mechanically different internally than the gas engine. There are some fuel system (injectors, fuel rails and fuel supply system) and computer changes to allow for flex-fuel operation, but since by definition a "flex-fuel" engine can run on anything from 100% unleaded gasoline to an 85/15 mix of ethanol to unleaded gasoline the engine has to be designed for gasoline. There isn't yet enough E85 usage nor availablility for automakers to justify designing/building "E85 only" engines. There have been experiments with "variable compression ratio" engines, but there's nothing (that I am aware of) in production. Mechanical compression ratio is only one variable. Actual internal cylinder/combustion chamber pressure is also determined by intake airflow and camshaft profile/lift/duration. The other "catch"? Racers and engineers have known for years that increasing compression (or effective cylinder pressure) makes for more efficient combustion in a gasoline engine. More efficient combustion equals better mileage and more power. The downside is that increases in combustion chamber pressure and temperature also dramatically increase NOx (Oxides of Nitrogen) emissions. NOx is the pollutant most responsible for smog courtesy of its photochemical (reacts with sunlight) properties. In short, there's no such thing as a free lunch. I hope that at least partially answers your question. |
|
|
|
|
|
|
#14 | ||
|
Admiral
![]() ![]() ![]() ![]() ![]() Join Date: Nov 2001
Location: East coast
Posts: 7,116
|
Quote:
I realize that but, for example, a civic hx is comparable in size and weight to a cavalier - I would not use these cars to compare fuel efficiency of 2 different fuels. Seems like common sense to me. If one car (car Y) gets 34 mpg on gas and the gasoline version of car X gets ~25 mpg then why would I compare the E85 version of car X to Y????? Wouldn't it be more real world to compare the gas version of car X to the E85 version of car X? Quote:
It does, thank you!!!! I already understood the first part of your post - where the taurus gasoline version is not mechanically different than the flex fuel taurus. The part that was of most interest was the explanation of the variable compression engine. Also, I was going to ask about street racers increasing combustion chamber pressure after I read the first half of your post but you answered that in the last paragraph. Thanks for the education!!!! Last edited by guiseppewv : 05-01-2006 at 02:27 PM. Reason: Automerged Doublepost |
||
|
|
|
|
|
#15 |
|
aka the keg killer
![]() ![]() Join Date: Dec 2002
Location: Ala-effin'-bama!
Posts: 2,738
|
More on Variable Compression and some other information
Good articles: http://www.autoworld.com/news/saab/s...ompression.asp
http://www.channel4.com/4car/feature...ndscc-508.html Last edited by mechmike0034 : 05-01-2006 at 04:06 PM. |
|
|
|
|
|
#16 |
|
Admiral
![]() ![]() ![]() ![]() ![]() Join Date: Nov 2001
Location: East coast
Posts: 7,116
|
I read your articles yesterday and they were very informative. Thanks!!!! For those of you who have any interest in cars you should read these articles because this new tech is pretty amazing and has the potential to improve fuel economy considerably. These articles have to be 2 of the best articles I have found in the automotive forum.
A couple of thoughts/questions: Why can't the timing on E85 vehicles be advanced so they can take somewhat advantage of the high octane of the E85? Currently, on most cars, computers control the timing of the engine, so why can't the computer advance the timing when it senses high octane E85 so you can get more hp, tq, and fuel efficency? You aren't going to see as much of a gain in hp, tq, and ecomony as when you can adjust the compression of the engine but you should see a significant boost. Just curious. ![]() |
|
|
|
|
|
#17 | |
|
aka the keg killer
![]() ![]() Join Date: Dec 2002
Location: Ala-effin'-bama!
Posts: 2,738
|
Quote:
It already is. Modern engine control computers are fast enough to constantly adjust ignition timing "on the fly" based upon rapidly changing inputs (engine speed, engine load/mass airflow, engine coolant temperature, transmission gear selection, vehicle speed, etc.) Most E85 vehicles have a "flex-fuel" sensor as an input to the engine control computer. This is one of the things the engine control computer looks at when adjusting both the spark and fuel curves. Optimizing timing will certainly help performance, but I suspect you are looking for a bigger gain than actually exists in the real world. "Significant" can have different meanings to engineers and vehicle owners/end users. Remember also that automakers take a general stance that any gains in performance and/or efficiency cannot occur if they have a detrimental effect on durability, emissions compliance, or cost-per-unit/profitability. Many masters have to be served, be they laws and regulations or corporate business practices. |
|
|
|
|
|
|
#18 |
|
Admiral
![]() ![]() ![]() ![]() ![]() Join Date: Nov 2001
Location: East coast
Posts: 7,116
|
Always good info, mechmike. To me, a significant change is a 10+% increase in hp, tq, and/or fuel efficiency. If you can close the gap on the fuel efficiency (compared to running gas) of the engine when using E85 then it becomes a more viable option. If you can increase hp and tq then you could shrink the size of the engine and maintain the same hp and tq that the larger, non E85, engine had then you can increase effciency even more without sacrficing performance.
Just thinking out loud. ![]() |
|
|
|