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PostPosted: Mon Mar 05, 2012 1:04 pm 
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Location: meadview arizona
in this time of high gas prices has anyone noticed a variation in the economy of their daily driver,

my wife's chrysler 300m has a economy meter so i watch it with interest, if i buy my gas from safeway, or chevron, i get 25.6 on average, if i buy from my local grocery store or smiths, it drops to 23.5,

i checked how much i was putting in the tank and the quantity was about the same so it was not a case of short measure, but of a lack of energy contained in the fuel.

on a side note, i see that shell are advertising nitrogen enriched gas, now i don't know about you but nitrogen as a substance is innert, it has no fuel properties and is not a combustion promoter, it contains no oxigen, so how can this be an "additive", i would consider it a filler, and adding any substance as a filler will detract from the energy contained in the fuel by volume.

is the o2 sensor able to adjust the burn so that crap fuel will still seem o.k. in the engine.

this has nothing to do with octane, unless the octane rating of the fuel is so bad that they are adding stuff to it to slow down the burn rate and so increase the octane rating, a bit like chemical water injection, premixed into the fuel.

it doesn't ping but your milage suffers.

if you added the fuel and water together, on a car equiped with water injection, giving a total volune of liquide passing through the engine, would you end up with the same results as using cheap gas, a drop in milage?

has anyone measured the specific gravity of various makes of gas?

by the way, i posted some more pics of my build in my build log if anyone is interested, its almost complete now.

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oh to go down to the strip again where the blacktop meets the sky
all i ask is a small block and some fuel to make her fly
with slicks a smokin pushrods pokin next round i'll get a bye

she's up on song the shift was strong in the finals to boot
it's back to the pits and take it to bits and don't forget the shute
the final round was good and sound so come on give me the loot


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PostPosted: Mon Mar 05, 2012 1:26 pm 
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My biggest variation is my wife. When she drives she can drive down the mpg of 1,000 miles or more (I reset my mpg meter every 1-2,000 miles) by 1 mpg or more. It takes a lot to drive down 1,000 miles or more average.

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PostPosted: Mon Mar 05, 2012 1:50 pm 
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One fuel might contain more alcohol. Alcohol is a good fuel, but it requires a larger volume for the same calories. Wether the fuel is better or crappier is a different question then how much it costs or how much it takes. One could imagine that crappier is more likely though :)

Nitrogen is probably the most common "high energy" material. Think T.N.T or ammonium nitrate. It would only take a little nitro-glycerin in the gas to make a difference, but I would think it would cause knocking :rofl:. These materials don't require oxygen, like gunpowder. The energy is in the nitrogen bonds which are broken.

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PostPosted: Mon Mar 05, 2012 1:52 pm 
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What is the percentage of ethanol in each?

Ethanol doesn't get the same mileage as gasoline. Here in the USA, it's usage has been mandated and subsidized by the government (and from here, I get into a political statement, ending with noting that our hamburger will cost $5/pound by July 4), and most gasoline is a mixture of gasoline and ethanol. In the old days we called it "gasohol".

As I recall Indy car history, the Sachs/MacDonald crash in 1964 was horrible because, in part, there was an attempt to run the entire race on maybe 1 pit stop. This could be done with gasoline, but not methanol. In response to the accident, USAC banned gasoline at Indy, and teams stopped trying to run with only one stop. When Indy switched from methanol to ethanol, the cars got better mileage, and as I recall, the Indy people cut the size of the tanks. Still, ethanol doesn't get the mileage as gasoline.


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PostPosted: Mon Mar 05, 2012 2:04 pm 
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Location: meadview arizona
the pecentage of ethanol would be evident by measuring the specific gravity.

i do not see the connection with nitrogen and nitro parafins, nitro methane is an oxigent, i.e. gives of oxigen during combustion, if this were present in any fuel, it would speed up the burn.

_________________
drag racers lament

oh to go down to the strip again where the blacktop meets the sky
all i ask is a small block and some fuel to make her fly
with slicks a smokin pushrods pokin next round i'll get a bye

she's up on song the shift was strong in the finals to boot
it's back to the pits and take it to bits and don't forget the shute
the final round was good and sound so come on give me the loot


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PostPosted: Mon Mar 05, 2012 3:08 pm 
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The advantages of alcohol are in high boost turbo applications or very high NA compression ratios. Increasing engine power and efficiency. Energy per unit volume or weight is lower than gasoline and diesel. Diesel has an advantage in turbo applications of wanting to detonate!! It has a higher per unit volume energy than gasoline but about the same by weight. Natural gas has the best energy per unit weight of normal fuels other than Hydrogen(Hydrogen is not a good fuel for vehicles). Diesel is still the best per unit volume.

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PostPosted: Mon Mar 05, 2012 3:37 pm 
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bremms wrote:
Natural gas has the best energy per unit weight of normal fuels other than Hydrogen(Hydrogen is not a good fuel for vehicles).


And I have suddenly started to hear about manufacturers promoting LP versions of their vehicles. Hopefully we've convinced a new generation of the same problems that have always plagued electric cars, and can now move on to LP (which North America has in abundance).


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PostPosted: Mon Mar 05, 2012 5:59 pm 
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John, I'm not sure where you are located but the difference might be just 100% gas vs. 10 Ethanol. The MPG numbers you mention seem about right for this type of fuel difference, I can't buy 100% gasoline and haven't been able to for decades in the Chicago area. Some places still offer both so?????

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PostPosted: Tue Mar 06, 2012 12:51 am 
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John,
The nitrogen bearing compounds that Shell is advertising are their equivalent (covered by many patents) to compete with the Chevron Techron (covered by many patents). Fuel system cleaner.
Ron


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PostPosted: Tue Mar 06, 2012 9:01 am 
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Quote:
The nitrogen bearing compounds that Shell is advertising


Ahhh!!! I was wondering what adding nitrogen would do since air is 78% Nitrogen. Air is is used 14.7 x more than fuel to start with. "What more could such a little bit more of Nitrogen do? And how do they keep the Nitrogen in the gasoline to start with?" I asked myself.

The nitrogen-"compound" is the magic. :BH:

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PostPosted: Sun Apr 08, 2012 3:46 pm 
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This is the easiest way to check.

http://www.youtube.com/watch?v=gsSQSuCiUjE

This became my #2 test for performance issues, after DTC's. Unfortunately where I'm at, the Tampa Bay area, is one of the highest in the country for fuel fraud. Ethanol is cheaper than gasoline. We also see contaminated fuel on a regular basis.

If you get fuel down here, don't be surprised if the ethanol content at a 10% pump is actually 12-18%. Much higher than that and you will have idle &/or cold start issues with sensitive cars.


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PostPosted: Sun Apr 08, 2012 9:47 pm 
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i have run engines on methanol and the consumption rate is between 200% and 220% of 91octane gasoline,

therefore it does relate that an increase in methanol/alcohol in the fuel will drop the milage.

so the big question is how do you know what you are putting in your tank.

methanol is mixable with water so if you add 10% methanol to the gas, then you could add 2% water without separation.

does this hold true?

and is it being done?

if the fuel remains within the bounds of the o2 sensor and the injector size and the self adjusting nature of the ECU, all you would notice is poor economy?

_________________
drag racers lament

oh to go down to the strip again where the blacktop meets the sky
all i ask is a small block and some fuel to make her fly
with slicks a smokin pushrods pokin next round i'll get a bye

she's up on song the shift was strong in the finals to boot
it's back to the pits and take it to bits and don't forget the shute
the final round was good and sound so come on give me the loot


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PostPosted: Sun Apr 08, 2012 10:42 pm 
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Location: Austin, TX
yes, all you would notice is the delta in the fuel economy between 100% gas and E10. The notice you see on the pump says that your gas, "may contain up to 10% ethanol". Depending on the fuel supplier's cost of ethanol they can blend up to 10% for E10. Your ECU willl do the adjustment. I have tried to find 100% regular unleaded in the Austin area, but most of what we have is gas that contains anywhere from 0-10% ethanol. I have not been able to find guaranteed 100% no ethanol.


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PostPosted: Sun Apr 08, 2012 10:43 pm 
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john hennessy wrote:
methanol is mixable with water so if you add 10% methanol to the gas, then you could add 2% water without separation.


Well, first, this is "Ethanol" not "Methanol". That extra carbon At-om (if I recall correctly) makes a helluva difference. For starters, ethanol is pretty much moonshine, won't burn your eyes and skin, doesn't melt pavement, etc etc. Methanol isn't missed one bit in the IndyCar garages. They now use E85 (prior to that it was E98).

Ethanol gets better mileage, but as I recall, not as much power, than methanol, and neither get near the mileage of gasoline. Back before 1964, some Indy cars ran gasoline, even though it produced less power, because they were trying to win the race on 1 pit stop (maybe less, if you believe the rumors). The 1964 Sachs/MacDonald crash prompted Indy to change the rules -- a 75 gallon tank limit and a mandatory 2 stops -- so that such gasoline wasn't used very much (last used in the turbine Lotuses in '68, and the use of gas instead of kerosine probably caused the bearing failures?).

Anyway, back to the subject at hand -- Pretty much everyone who has tried E85 will tell you that you'll get less mileage, to the point where costs will be a wash with gas. How much worse depends on the car's ECU I believe. Which goes to our suspicion that the original post's answer lies with finding out if someone is sneaking in extra ethanol....


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PostPosted: Thu Apr 19, 2012 10:42 pm 
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gregaustex wrote:
yes, all you would notice is the delta in the fuel economy between 100% gas and E10. The notice you see on the pump says that your gas, "may contain up to 10% ethanol". Depending on the fuel supplier's cost of ethanol they can blend up to 10% for E10. Your ECU will do the adjustment. I have tried to find 100% regular unleaded in the Austin area, but most of what we have is gas that contains anywhere from 0-10% ethanol. I have not been able to find guaranteed 100% no ethanol.


A few years back, when I lived in Iowa, 87 & 89 were E10, 91 was Ethanol free. The price was slightly higher (like $0.20, when gas was $2 or less), but you could see measurable fuel economy increases. The price difference paid for itself, but I don't have any of the data any more.

A separate incident with ethanol...I was working with a group on converting a carb'd engine to FI & E85. After getting the engine running on 91 we found it started and ran relatively well on E85 after replacing the injectors with some that were almost 2x the flow rate. I really think E85 could be done with a piggyback fuel computer and a new set of injectors.


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