Iv been filling up 93 unleaded and it has been giving me great mpg around 21-23 and 320 miles per tank, but i used to fill up 93 octane and wouldnt get near 300 miles per tank would be on empty after 230 miles, does anybody else have any opinions on which gasoline is good for the maxima?

 

93 refers to the "RON" octane rating of the fuel or "Research Octane Number". 87, 89, 91, 93, etc are all octane ratings for the most common unleaded fuels, regardless of which station you're buying gasoline at. All fuels for quite some time have been "unleaded".

Also... asking for opinions on which fuel to use in this car has been debated constantly. Use the thing here called "search" in the forum....

 

you guys that drive your cars hard get terrible gas mileage. If I get under 500 miles to a tank, I feel bad.

 

You must drive and accelerate really slow, I have never been able to get any where near 500 miles in a Max or Z. Even when I drive normal and on highways its still 300 something miles.

 

The gas tank is 20 gallons...If you're only getting 300 miles per tank, you are getting 15 mpg.

 

 

indeed.

I don't even know where to start....with OP or with Doogie

 

go ahead and start. Tell me where my math is off, or tell me what I did so wrong.

 

Well your math is assuming that the tank was ran all the way to empty, Maximas usually have a few gallons or so left when the hand gets close to the E.

 

Very true, MONTE. The yellow 'fuel low' icon should come on with four or five gallons left in the tank.

Running the tank below the two gallon mark can result in damage to the fuel pump, which is inside the bottom of the tank, and must be immersed in gasoline in order to avoid overheating. Replacing the fuel pump means emptying and removing the tank.

If perchance the tank is run to empty, then there is the possibility of damage to the catalytic converter, which costs between $399 and $900, depending on who does the work.

We need to listen to MONTE. Those 'measuring' their fuel efficiency 'per tankful' are barking at the moon. 'Per tankful' tells us NOTHING about fuel efficiency. The longer we wait to refill the tank simply means that more gas will be required to fill the tank. No connection to fuel efficiency. The ONLY MEANINGFUL way to measure fuel efficiency is MILES PER GALLON.

 

Your car should be telling you to refill when there are still 4 or 5 gallons left in the tank. Please see what MONTE and I said in our posts just ahead of this one.

Assuming your car is in proper tune, gasoline octane is not related to fuel efficiency (MPG) as long as the octane is fairly close to the 91 the 7th gen Maxima fuel system is expecting. Despite urban rumors and 'but I know what I got' claims, octanes from 89 to 93 will give the same fuel efficiency in the 7th gen Maxima.

I have been reading this 'octane not directly connected to MPG' thing in auto engineering perodicals for decades, but still had to prove it to myself, which I have done with long-term studies on each of my last four generation Maximas.

And 'miles per tankful' has no connection to fuel efficiency. The more miles you run 'per tankful', the more gas will be required to refill the tank. Miles per gallon (miles per liter in metric countries) is the only standard measure of fuel efficiency.

If you wish to 'baby' your Maxima, then 91 or 93 octane gives those with little knowledge of fuel systems a 'feelgood' comfort factor. If you wish to pay less for fuel, then 89 octane (midgrade) works wonderfully well in this car.

But I would NEVER put 87 octane (regular) in this car. Some folks do, and sort of get away with it. But 87 octane definitely affects performance, often affects MPG, and, as reported here by some 7th gen owners, left the car almost undrivable.

Of course prices for the different octanes varies too much to even discuss here. In some places, the difference is like a nickel or dime per gallon. At my nearest stations, the difference is currently more - $3.19 for 87 octane, $3.59 for 89 octane, and $3.99 for 91 octane.

Such illogical price differentials have been the norm around where I live for decades, and that is why I researched the situation, and determined through careful measurement (18 months with premium followed by 18 months with midgrade with each Maxima I buy) that my fuel efficiency and performance did not change when I moved to midgrade.

But I guarantee you there will be subsequent posts right here in this thread that try to tie MPG to octane, and fuel efficiency to 'per tankful.' Urban rumors are now a way of life in the U.S. The 'Scientific Method' is becoming a faint memory from the distant past.

 

http://www.toptiergas.com/

 

Agreed 100% on all of this. When I fill up, the car usually takes around 16-17 gallons. Like Lightonthehill said, running the motor on fumes can cause serious damage to the fuel pump.

And got help you if you're running a 350 or 370Z on the track on anything less than 1/2 a tank. Those cars have fuel starvation issues bigtime on long sweeping corners.

 

So true. I fill up right before the low fuel light shows up.
Sucks for those who have to empty and remove the gas tank to get to the fuel pump.

 

OP wtf is unleaded or octane mean? all fuel is unleaded and has some octane rating. -___-

octane is the fuel's resistance to combustion at higher temps. by running 93 in a car with 91 does NOTHING. you would need to tune/advance timing in order to take advantage of a "slower" combusting fuel

but if you put 87 or 89 then the engine may knock or most likely it'll run super slow timing to reduce potential damage = more fuel usage and reduced power.

if you really wanna know what happens in the engine with various octane fuels then this dude in this video does an excellent job of explaining... how fuel burns in the cylinder is at the beginning and octane talk is at 4:45

 

Solid post, and good analysis. I agree with your scientific analysis, agree that 93 octane in a car that is intended to run on 91 gives no added benefit, and agree that, scientifically, what you said also applies to 89 and 87 octanes.

But -

Because miniscule adjustments are required to handle octanes very close to the intended 91, this car handles 89 and 93 octanes virtually the same as it does 91. Although 87 and 89 octane perform very differently in Maximas, 89, 91 and 93 perform essentially the same.

I have used premium for the first 18 months in each of the last four Maxima generations, then used midgrade the rest of the time I owned each car. In NO case did my overall long-term MPG change when I changed to 89 octane, in NO case (even in hard acceleration going uphill) was there ever even a HINT of a knock with 89 octane, and in NO case did I ever detect any change in performance with 89 octane.

The very few times I tried 87 octane, there was knocking, hesitation in acceleration, a drop in MPG and a detectable reduction in overall performance. I strongly urge folks to avoid 87 octane in the Maxima.

I agree that your analysis is true, and can be proven by something as simple as repeated and very carefully controlled elapsed time runs using 89 octane and 91 octane. I would expect the 91 octane would probably show very slightly better elapsed times, because no fuel system adjustment is necessary.

But, for any type of normal driving, in over 15 years of carefully measuring with my Maximas, I have found absolutely no difference in performance between 89, 91 and 93 octanes, and have never had even a whisper of engine trouble, even up to 206K miles using only dino oil.

So, considering the ridiculous current difference between octanes at my local stations ($3.19, $3.59 and $3.99), I have no hesitation in using midgrade, with the caveat that, when using midgrade, I stick to major brands. My three primary brands are BP, Chevron and Shell.

 

Great information in this thread. I have always used 93 in my cars that say "premium fuel". Mostly because there is only 87, 89, 93 at the stations by my house. I calcualted price difference and I would only save about $77 per year. So I just figure why not run the 93.

 

Your right not enough savings to make me not use 93!!!

 

^^ really... 77 a YEAR is enough to not use it? wow.

 

Depends on where you live. The three stations nearest me are charging $3,19, $3.59 and $3.99 for 87, 89 and 91. Stations in this area have used 87 octane as their advertised 'loss leader' for years, and make much of their profit on higher octanes.

Because of this type of gasoline gouging, if I used ONLY THREE 17 gallon fillups each month, my difference between using 89 octane and 91 octane would be almost -

$250.00. (TWO HUNDRED FIFTY DOLLARS) PER YEAR.

I have the money to burn, and do not hesitate at paying $700 for the premium 30K mile maintenance program on my car. But, for my style of driving, the 89 octane does exactly what the 91 octane does. I would rather put that extra money to far more worthy causes such as either the Salvation Army or the colleges I attended or the Disabled American
Veterans organization.

I guess we each make the decisions that are right for us.

 

Also interesting is that premium can (or seems to be) from 91-93 octane with 89 as the mid grade depending where you live region wise.
I'll often run a mix of 89 and 92 on occasional half tank fill-ups.

 

This is what I do as well and have for years, just alternate between the 89 and 93 at half or slightly above half fill ups.

 

I used 93 for the first 3 years, but dropped down to 91 last few months, no problems as far as I can tell. wouldn't go with 87 though! If it says premium, probably need to stay on the higher end to be safe.

 

My area, Central Ohio, there's typically only $0.09 - $0.11 difference between each octane. $0.80 difference between 87 and 91 seems criminal.

 

Agreed. In Utah right now: 87 is $3.45, 89 is $3.55, and 91 is $3.65.

I didn't even realize there was such a big difference between steps elsewhere--I thought $0.10 between grades was standard. I guess I'm lucky!

 

10 cents between grades WAS pretty much standard in most places I have lived until around the time the price of gas began fluctuating like a yo-yo. it has only been in the last few years that the difference in price between octanes has gotten ridiculous around where I live. Stations put out a BIG sign showing the artificially low price of regular, but make up for that low price by gouging those buying higher octanes or diesel.

What really annoys me is that I can go less than twenty-five miles in almost any direction and find clearly lower differences in the price between grades. In some cases, the differences are HALF what they are near me.

If I were less fortunate in my financial situation, I would probably find the nearest station with reasonable differences in price between octanes and bypass my local stations, even though they are operated by local folks that I know.

If my car REQUIRED 91 octane, I would do just that. But 91 octane is only RECOMMENDED, while 93 and 89 octanes work very well in this car. 87 octane is STRONGLY DISCOURAGED BY NISSAN, and I will not be putting 87 in my Maxima.

 

Along these lines, I use an app on my phone called GasBuddy (many of you probably do as well). Allows me to quickly see the gas stations near my current location, and see their prices for Regular, Midgrade, Premium & Diesel. Might be a useful app for those in areas where the price differences between grades are great.

Hope I'm not breaking any rules here, my apologies if I am.

 

thanks for the post compliment lol, i try

well 89 isn't that bad. my friend has a g35 and he fills 89... he used to fill 87 and like you said, he got a lil bit of knock and in general it was kinda laggy. i'm thinking it can take 89 because the stock fuel maps are pretty rich. you won't notice a difference in mpg cause the car is mostly used under light throttle around town, the more load you put on the engine the easier knock can occur. knock sensor will protect it and retard the timing + more fuel. but again, thats under certain loads

WOOOOW your gas is CHEAP! your premium is $1.05/L!!!!!! here we pay $1.23+/L for 87 octane and add 6 or 7 cents for the next octane so i usually end up paying 1.40/L for premium, so like $85/tank. funny thing is Petro Canada has 94 octane and its only 3 cents more than 91

i'm tuned so i can't run anything lower than 91 :/

 

3 cents between grades that are three octanes apart! That is wild! It is strange that the differences in prices between grades varies so weirdly in different areas.

Sorry your gas is so expensive. At least we neither one have to pay what they are charging for gas in Europe. It would cost way over $100 bucks to fill up our Maximas there.

I haven't mentioned another aspect that I feel might enter into the equation - If I were pulling a trailer or lived in a mountainous area or in any other way put my car in extreme conditions, I would probably stay with the 91 octane I have always used during the first 18 months of ownership of all my Maximas.