MPG affected by Octane?

[robmcole]

Has anyone else noticed a massive change in miles per gallon when you run different octanes?

89 octane = 17mpg93 octane = 13-14mpg

Any ideas here?

[elwesso]

Id say because the 89 octane is 87 with additives. The 87 is probably fresher..

How is the rest of the car, like knock sensors, timing, injectors, and so on.

How many times did you test this to come to your results?

[DAEDALUS]

Retarded timing? You sure your driving habits were the same?

[GreenQ45a]

Nice J30. How does the inside look?

[Q45tech]

Obviously 93 [89] [87] octane with ethanol will get much worse mpg than 93 [89] [87] octane with conventional non oxygenated hydrocarbons.

Plus you get to pay more for ethanolized fuel. A lose/lose situation that doesn't help air pollution on post 1995 vehicles and barely makes a 2% difference on 90-95 vehicles. It does help reduce pollution on pre 1990 cars.

[PoorManQ45]

Plus you get to pay more for ethanolized fuel.

I don't agree with this statement. Around here, 89 octane gas with 10% ethanol is the same price as 87 regular.

Everytime I use 89 or 93 with 10 ethanol, I seem to get better mileage. Now this was over a 1200 mile road trip. So none of the driving was exactly the same. But, I noticed that I was able to get about 50 miles extra miles out of each tank with the 10% ethanol gas. Now, I did all my testing based on the Gas gauge, so the measurements were not very precise. But I was able to notice an increase in mileage.

[robmcole]

Well I talked to a friend of mine tonight that is a tech for Volvo, and all he could come up with is if my compression was lower than average, it would run better on a lower octane.

Who knows. When I get some time, I might run it by the dealership one day and get them to do a diagnostic on it, just to see if any error codes come up (for piece of mind).

I only have 114k miles on it (83k when I got it 15 months ago) so I would not think it is losing compression already

Green45a: I will list some links to the inside of the J30. Thanks for the compliment.

http://www.alphadesigners.com/J30/J30_1 ... /J30_5.jpg

[DAEDALUS]

if my compression was lower than average, it would run better on a lower octane.

I don't aree with that. That would be true if you're at risk of pre-detonation--the part about lower compression. But dropping the compression on a stock engine shouldn't increase efficiency or power/stroke, octane aside.

[GreenQ45a]

That is a well kept J.

Very nice indeed.

The back seat pics look like product shots from a ad.

I like the rims to keeps it upscale yet sporty.

I see you avoided the front seats in the pics.Do they show the normal slight wear?

The last A**Hole who owned my 1994 Q45a had know love for the seats.Always had his wallet in his back pocket and it wasted the front seats.I will recover them but the dont look nice.

Just look @ Jedsa's pics. kinda like them.

I do have Sheepskin (fake ) seat covers.They do a good enough temp job.

I think you loose ALOT of the Q45's elegance with them

My first Q45

I was the SECOND owner of a 1993 Charcoal Q45.The seats were near untouched.All dealer maintained 72,000 miles. The guides were changed out (from plastic to metal) @ 60,000.Every TSB was accounted for and checked off Infiniti's mainfram database.You know "The Dream".

..... A moment of silence.......

RIP...

I will tell her story in another post.

Wasn't this about gas or MPG?? sorry

[Q45tech]

YOU AS A TAXPAYER get to pay a $1.00 per gallon SUBSIDY to the farmers who sell their corn [Payments to corn farmers totaled $34.5 billion between 1995 and 2002, making it far and away the most costly government subsidy to agriculture] and the distiller who converts the grain to alcohol, then there is a 54 cent federal subsidy to the blenders who mix the ethanol with gasoline.

Just because you don't pay at the pump don't asssume you don't pay.

There were no subsidies for MTBE production and now we are paying for the write off of MTBE production facilities so all in all the conversion to ethanol will cost you 30 cents per gallon.

[Q45tech]

YOU AS A TAXPAYER get to pay a $1.00 per gallon SUBSIDY to the farmers who sell their corn [Payments to corn farmers totaled $34.5 billion between 1995 and 2002, making it far and away the most costly government subsidy to agriculture] and the distiller who converts the grain to alcohol, then there is a 54 cent federal subsidy to the blenders who mix the ethanol with gasoline.

Just because you don't pay at the pump don't asssume you don't pay.

There were no subsidies for MTBE production and now we are paying for the write off of MTBE production facilities so all in all the conversion to ethanol will cost you 30 cents per gallon.

PLUS the 5% loss in mpg say another 10 cents..................~~40 cents....2 cents per mile driven.

[PoorManQ45]

YOU AS A TAXPAYER get to pay a $1.00 per gallon SUBSIDY to the farmers who sell their corn [Payments to corn farmers totaled $34.5 billion between 1995 and 2002, making it far and away the most costly government subsidy to agriculture] and the distiller who converts the grain to alcohol, then there is a 54 cent federal subsidy to the blenders who mix the ethanol with gasoline.

Just because you don't pay at the pump don't asssume you don't pay.

I'm only 17 and don't have a job. So I can safely say that I don't pay. . Oh ya, and my parents own enough farm animals so that we fall under the green belt. . So my parents don't pay for it either.

Anyway. I understand what you're saying about how even though we arn't paying for it at the pump, we are still paying for it with taxes.

Can you tell me what is the energy difference between 89 regular gas and 89 10%ethanol gas?

Doesn't it require ~50% more ethanol to acheive the same energy output as gas?

[Q45tech]

1 gallon of ethanol has 76-77,000 BTU1 gallon of conventional gasoline without MTBE 117-125,000 BTU

[GreenQ45a]

Q45Tech,

What brand of gas do you use?What is your Fuel System Maintenance Schedule?

[Q45tech]

Use QT brand generic gas as life would have it there as been one closest to my homes for the past 7 years [170,000 miles] . Use BG44k in the tank prior to my 90 day oil changes and change fuel filter every year. A rail flush every year for the past 5...........probably over kill.

The car may be fuel additive addicted.

Sure there has been some Chevron, Citgo, Exxon Mobil along the way but 90%+ has been QT. The car has never seen gasoline North of North Carolina/Tennessee or West of Mississippi except for a few tanks in Indiana.

We shall see what happens in Janurary when Georgia converts to Ethanolized Gasoline. Have 4 new injectors just in case.

We kinda hope ............. as Q business has fallen off as the cars are retired [junked]/wrecked.

[IvoryJ30t]

as far as the injectors go, i remember you saying something about adding a pint of isopropyl to a tank of gas.

the gas station i regular, was refurbished about 2 years ago. new pumps, tanks, and building.

we converted to ethanolized gasoline about a year ago around here.

considering the storage tanks are new, what effect would adding 16oz of 91% isopropyl to every other tankful have?

or did i misread one of your previous posts?

[Q45tech]

Pure 99% Isopropyl will absorb the extra water if phase seperation occurs between ethanol, water, and gasoline.In the past I didn't have to worry about Ethanol, just one more thing to abuse the injectors.

Need to get a 12 pack to be ready, the problem is especially severe in cold weather.

[IvoryJ30t]

would 91% be effective? or would it just exacerbate the situation?

i ask becuase 91% isopropyl is readily available.

[AlabamaDan]

Very interesting read. So I should be looking for conventional gasoline, i.e. no Ethanolized Gasoline?

What's the isopropyl for again? To remove water that accumulates in the tank?

BTW Dennis, did you got to MIT or something? Sometimes I just feel so inferior reading your posts. j/k

[elwesso]

Very interesting read. So I should be looking for conventional gasoline, i.e. no Ethanolized Gasoline?

What's the isopropyl for again? To remove water that accumulates in the tank?

BTW Dennis, did you got to MIT or something? Sometimes I just feel so inferior reading your posts. j/k

Good luck finding that...

The alchohol is for the water in the tank.....