So since I've bought my Pathfinder a couple months ago, I've really been let down by the gas mileage. Locating any kind of specific info on what fuel I should use was surprisingly impossible, so I decided to run a little experiment and record my mileage first using regular 87 octane, then by running the "recommended" premium 93 octane (HOORAY CT). In the interest of keeping the figures represented here accurate, I would fill the tank when the gas light came on, only at Mobil or Shell, without topping off, approximately 18 gallons. Additionally, I made an effort to keep my driving consistent, 95% highway to work (cruise control at 62mph) and minimal city driving. Since I have bought the truck, I don't think she's seen 3k rpms. Now before anybody wants to jump down my throat, I realize there are many other variables that could have altered these numbers, especially with all the snow we got in the past few weeks, but I figured this process would give me at least ball park areas to make a more educated decision. Now bear in mind we still have that winter mix in the Northeast and I'd expect these figures to rise some in the summer.

Using the equation: miles traveled per tank / price to fill tank = miles traveled per dollar
Figures rounded to .100 where applicable

Regular Fuel 87 Octane; Current Price: $3.81
18 gallons * $3.81 = $68.58 Price to Fill

242.5 miles / $68.58 = 3.536 m/$
254.1 miles / $68.58 = 3.705 m/$
247.6 miles / $68.58 = 3.610 m/$
256.9 miles / $68.58 = 3.746 m/$
Average: 3.649 miles per dollar

242.5 miles / 18 gallons = 13.472 mpg
254.1 miles / 18 gallons = 14.117 mpg
247.6 miles / 18 gallons = 13.756 mpg
256.9 miles / 18 gallons = 14.272 mpg
Average: 13.904 miles per gallon


It is also worth noting that I waited a few tanks in between to allow the knock sensor to adjust to running the premium fuel. (Much thanks to Chuck Tribolet!)

Premium Fuel 93 Octane; Current Price: $4.11
18 gallons * $4.11 = $73.98 Price to Fill

262.4 miles / $73.98 = 3.547 m/$
261.6 miles / $73.98 = 3.536 m/$
256.3 miles / $73.98 = 3.464 m/$
260.7 miles / $73.98 = 3.524 m/$
261.2 miles / $73.98 = 3.531 m/$
Average: 3.520 miles per dollar

262.4 miles / 18 gallons = 14.578 mpg
261.6 miles / 18 gallons = 14.533 mpg
256.3 miles / 18 gallons = 14.239 mpg
260.7 miles / 18 gallons = 14.483 mpg
261.2 miles / 18 gallons = 14.511 mpg
Average: 14.469 miles per gallon

So taking a look at these numbers broken down, we can see that although you most certainly get worse fuel efficiency running regular fuel versus the premium, you in fact are spending less money to drive any given amount of miles (albeit the actual difference is minimal) on the regular octane. With that being said, my truck has 119,000 miles on it now, and I will continue to run the recommended premium fuel. This is because I find the actual amount of difference in miles per tank (about 9) and cost to fill (about $5) to be negligible. Also, and here's the key reason why recommended is no longer in quotation marks, when running the regular fuel that VQ felt like a tired old engine with 100k+ miles on it. However with that premium fuel, she feels light on her feet and peppy from a stop. Personally, after driving with both fuels back to back, the difference is incomparable.

This summer I'm planning to do a full tune-up as well as possibly a CAI to try to bump these numbers, but obviously I will strictly be running the premium fuel at that point. Thanks for reading! Hope it helps some who were unsure about what fuel to use like me.

Thanks for the writeup. I've noticed that the mileage difference between 87 and 91 is nearly negligible. However, I do agree with your assessment that you definitely feel a difference in how smooth the engine runs when filled with regular instead, even though in theory the difference should only be a few HP. I don't notice any difference using mid-grade 89 vs regular 87 though.

Just out of curiousity, have you noticed the engine to "smoothen up" after more fillups after running regular? Perhaps it just takes time for the knock sensor to adjust? I've never gone 5 or more tanks of straight regular so I can't comment on that.

Nobb,
Happy to do it as long as it helps people. As far as the engine "smoothening up," I recorded the mileage for the in between tanks and it definately took about 4-5 tanks before the engine ran noticeably smoother and the mpg leveled out.

For the record, Premium is indeed 93 octane here in CT

I get higher mileage with premium than regular. However, most stations here in Alberta (at least the big ones, Shell, Esso, and Petro-Canada) state that their 87 octane gas has up to 10% ethanol content. Their 91 octane gas has no ethanol. With typical driving habits, that alone is going to make the biggest difference in fuel economy.

I did the math on scrap paper a while back this winter, with a small sample size (maybe 3 tanks, and not taking into account the time needed for the Pathy to "adapt" to the new gas) and concluded that the premium gas was negligible in cost per km (it was about a $0.02/km difference). I wouldn't doubt that, given a larger sample size, a "change in fuel adaptation period", and taking the weather into account (there were weeks when it was -30°C, which kills fuel economy, and weeks where it was -5°C), the premium would be much better on a cost per km/mi rating.

I also seem to remember that in general with my '03, the advantage in cost savings for premium over regular seemed to be *larger* in the winter than in the summer. Whether that has to do with the winter blend or the extreme winter temperatures in Edmonton, I don't know.

Densetsu,
Good points. I could be wrong, but I believe all gas in the U.S. is now 10% ethanol regardless of grade, which certainly makes for worse mileage. As for the obnoxious weather conditions in Alberta, I'm sorry and thankful it doesn't get that bad in CT, I can't stand it as it is! Either way, I don't think anything likes moving in -30°C, let alone a big hunk of metal.

In terms of specific winter and summer blends, my knowledge pretty much stops at "there are different oxygenates." However, the refineries do have to shut down for the switch, and the summer blend is a bit more expensive to produce, which accounts for the increase in price. At least that's what "they" tell us

Who knows? It just seemed to me the way the truck ran vs. the cost difference was negligible enough to the point where it was no contest. She purrs with that 93.

Stay Warm!!!

This is interesting. Not too long ago I was at a Shell gas station here in PA. There was a tanker truck filling up the stations tanks. Just for sh#ts and giggles, I asked the driver how much of a pain in the butt it is to fill the different fuel grade tanks. He said he doesn't check. He just fills 'em all with the same thing.

Now. Either this guy could care less about his job, or it is common practice.

Anyway. Thanks for the write up.

Pathfound49,
Possibly he was just yankin on your chain a little bit.

All I know is I'll never fill up at the Shell in Wind Gap, PA if I'm ever makin my way through.

Their is a cute one that works the register there.

Are you the one who also posted in www.thenissanpath.com?

Very informative

So in short... Premium is better and the cost would break even?

AZhitman wrote:http://www.nicoclub.com/archives/gasoli ... myths.html

but for Pathfinders its rated for Premium.... and i havebeen recently putting in regular, Last fill was my third tank of Regular and i feel that its really slow to pick up and all.

Pathfound49,
Maybe I'll have to check in for a soda then!

PathPro2002,
Indeed that is me on thenissanpath.com I also posted this in that dead forum Try to get as much info out to the wanting masses as I can.

Innovazn,
In short, it is actually slightly more expensive to run the premium fuel, but not by much. You hit the nail on the nose. With the lack in pick up and torque on the highway, the regular fuel is clearly inferior to me. It feels like two different engines.

AZhitman,
I personally only agree with about half that article. I have had numerous performance cars dynoed, and always get maximum horsepower and torque levels with the premium fuel. I think my numbers speak for themselves.

On a personal note, still a newbie to forums and havn't quite figured out the quote feature yet Sorry!
Should have also noted my Pathy is 2001 LE 3.5.

Does using 93 octane advance the timing further, or does it top out when using 91 octane? I wonder this because if you run anything higher than 87 in a vehicle rated for 87, the timing won't advance and may even slow down, and I wonder whether the same applies to using higher than 91 octane in our VQ35DE.

Matt4949 wrote:Densetsu,
Good points. I could be wrong, but I believe all gas in the U.S. is now 10% ethanol regardless of grade, which certainly makes for worse mileage.

Not all, but most, is E10.

AZhitman wrote:http://www.nicoclub.com/archives/gasoli ... myths.html

That's a good article, with one exception: it ignores knock sensors. Our VG35s have a knock sensor, and they aren't
new: my '87 Corvette has one. A "premium gas" engine with a knock sensor will dial back the advance if you put
regular gas in it. It won't hurt the engine, you'll just have less power, and less MPG. The consensus seems to be that
the additional 4.9 % cost of premium (this afternoon's prices, at a Standard station I happend to drive by half an hour ago (regular 4.09, premium 4.29)) comes back in better gas mileage.

Gas mileage data is VERY VERY VERY noisy. Air temp, humidity, atmospheric pressure, where you drove, how you drove,
vehicle load, traffic conditions, ..., have a BIG effect on gas mileage.

The original poster had a very small sample size of very noisy data. That small sample is not "THE ANSWER".

BTW, I'm in Northern California, home of the highest gas prices in the lower 48. That Standard station is a usually a couple
of cents a gallon higher than the other stations in town (none are close), and town (Morgan Hill) is usually about three cents
a gallon higher than most of Silicon Valley. But over the weekend, I bought 4.24 at University Chevron in Marina, and saw 4.49 at the Shell station by Home Depot in Monterey. And the weekend before, somebody over on CorvetteForum.com posted
a picture of a Standard or Chevron station in Death Valley that wanted 5.something for premium. Dunno if it's still
there, but there used to be Shell station in Carmel Highlands that was a buck a gallon higher than Silicon Valley
(full serve only).

Moral: It pays to shop around and keep your eyes open. My experience is that the stations that are a couple of cents a gallon
cheaper today, will be a couple of cents a gallon cheaper most of the time. I've got a friend that I visit a couple of
times a year, and right where I get off I880, there's a Shell station that's aways a nickel cheaper than ANYWHERE else.

Here in N FL, its now $3.50 for reg vs 3.80 for premium. So about $6.00 more per tank. wrks out to about 32 more miles per tank which premium needs to have better than reg. didnt feel that was achievable that time i tested it...

Thank you all for the input!

Just wanted to point out that I agree my numbers were never expected to be 100% accurate. However, I felt with how I drove, and the relative stable conditions I drove in, would make my numbers work in a scientific manner. Any sample size can be used to give a general idea of the whole picture. That's why it's called a sample.

I got my answer...Premium all the way!

Matt4949 wrote: I got my answer...Premium all the way!

Well, that answer may work for you, but for me, I got my answer too....regular all the way.
Over the years, I've tried premium, half and half, and regular, and switched back and forth between them all. Tried going back to premium again last week, and all it did was empty my pockets a little faster.
Sorry to tell you this but I didn't see or feel any noticeable difference in performance or mileage. Never have.
When it costs almost 9 bucks more to fill with premium as compared to regular, then it's a no brainer for me.
Truck runs great on plain old regular, so I'll stick with that. No more experiments for me.

It takes a tank or two for the computer to adapt to higher octane. It will adapt to lower octane quickly because the
knock sensor will complain.

How do you come up with nine dollars? Here in California, the standard difference between regular and premium is
twenty cents. Assuming you let the truck get really empty, 20 gallons, four dollars. I don't let it get that empty.

Must be Canadian. The difference between regular and premium is around 13 cents per litre (that's 50 cents / gallon), so with a 60L fillup it's just under $8 more.

I have had my 2003 since spring 2004, and tried premium several time with no noticeable difference in performance or economy. $0.30 difference here and gas is around $3.40 for reg. Even tried resetting the ECU by removing power for several hours. ( yes i know it doesn't take that long, just being sure.)
Note the later PF have different throttle maps with faster pick up.

Reviving old thread - where is it suggested that the Pathfinder use 93 octane gas? I don't see that in the user's manual.

Thanks,

Micallen wrote: ↑

Tue May 15, 2018 8:31 am

Reviving old thread - where is it suggested that the Pathfinder use 93 octane gas? I don't see that in the user's manual.

Thanks,

You are correct. The Owner's Manual does state you should use a minimum of 91 octane, not 93 octane, don't know where the OP got 93 from.

p. 9-5
http://www.vadennissanservicecontracts. ... finder.pdf

mac,probably the OP hears " needs Premium" , OK, they go down corner gas station - in their locale 93 is at the pumps , they may have forgot/ never looked at manual .

04pathse wrote: ↑

Tue May 15, 2018 10:10 am

Micallen wrote: ↑

Tue May 15, 2018 8:31 am

Reviving old thread - where is it suggested that the Pathfinder use 93 octane gas? I don't see that in the user's manual.

Thanks,

You are correct. The Owner's Manual does state you should use a minimum of 91 octane, not 93 octane, don't know where the OP got 93 from.

p. 9-5
http://www.vadennissanservicecontracts. ... finder.pdf

Thank you. I couldn't even find the 91 octane in the manual... getting old.

I hadn't really seen this thread when I was digging around the forums couple of months ago. FWIW, I found no real difference between running 87, 89 and 93 in terms of mpg. 93 did make the QX a little sprightly off a stop, but the 87 octane doesn't make her feel like a significantly slower.

Driving style and weather seem to have adverse effects on gas mileage irrespective of the octane rating. I plan to continue running regular 87 in my car....

Micallen wrote: ↑

Tue May 15, 2018 10:27 am

04pathse wrote: ↑

Tue May 15, 2018 10:10 am

You are correct. The Owner's Manual does state you should use a minimum of 91 octane, not 93 octane, don't know where the OP got 93 from.

p. 9-5
http://www.vadennissanservicecontracts. ... finder.pdf

Thank you. I couldn't even find the 91 octane in the manual... getting old.

The requirement is 87 AKI octane (type stated in US and Canada), which is equal to 91 RON. Both of these numbers are given in the 2001 QX4 manual, in section 10 TECHNICAL AND CONSUMER INFORMATION.

Here in California my choices are 87-89-91, so 91 is premium. Regardless, being aware of the knock sensor on my '03, QX4, I typically run mid grade, 89. It being a vacation vehicle, which often includes high altitudes, the octane and needs there, tend to be even lower. I'm normally much more on the technical side, a numbers and stats guy, but in this case I'm just going to say mid grade. I've used all 3, haven't really noticed much if any difference, but limited trials. One but however... 240HP seems way overrated. Possibly it would be closer with premium and not seem as much overrated. My butt dyno compared to other cars says ~220, which curiously is similar to online time/weight HP guesses.

Rambled a bit OT I suppose, sorry, but it's possible premium enables the trucks to come closer to rated HP. If premium is even a wash, price wise, to me it's a steal, more power, same fuel cost per mile? Easy call. But I'm skeptical.

Different way to calculate octane -- the 3.5 as fitted in the later R50's was designed for regular fuel. The R50 was never known for good miles especially on the highway at high speeds. Bought one new -- ethanol was not widespread. !5mpg at most. I had two Jeep GC limited V8's prior to getting my 1st R50 so MPG is relative -- the later GC (98) was not built as well as the first(94) -- so it was a Pathfinder or 4Runner as replacements. The Pathfinder LE's were expensive vehicles .. with a reputation of being very durable. I bought the durability -- the 4 Runner was a bit more truck like and the family did not like. The Pathfinders running gear while outdated by others offerings w/ 5speeds and AWD -- gave me enough of what I wanted.

The 4 speed transmission is the major problem w/ MPG ... second is the old school design of the 4wd.