Gas Octane?

[scottrainey]

I have an '01 Pathy, and have dutifully been filling it up with either midgrade or premium fuel since I purchased it in August of 2010, mostly due to the sticker on the inside of the gas door that says something about best performance with premium fuel. My question is, am I wasting money? I mean, I drove a '90 Camry for the past ten years, and only put regular (87 octane) in it, and it ran fine, but my wife's car ('99 Odyssey) ran into some problems a couple years back (honestly don't remember the specifics - some sort of enginey-type thing - fuel injectors, maybe?) and the mechanic told us we needed to run midgrade (89 octane) or better in the van, which we've done ever since, and I've been scared to run anything lower than 89 octane in the Pathfinder. Now, I know the power plant in my Pathy is a more advanced and much more powerful one than in my old 2.0-liter four-cylinder Camry, but the question still stands: What octane of gas do you use? Does anyone have any conclusive evidence that one is better (or worse) in an appreciable sense than another? Does it really make a real difference, one way or the other?

2001 2WD Pathfinder
142K Miles
Average mileage = 16-17 mpg

[m0nkeyprince]

well, if your vehicle says you need at least a 91 octane rating fuel, stick with that. If you use 87, you might end up with knocking, which is your engine detonating prematurely. I think only high compression or high performance engines need that though, i doubt the 3.5 liter will really suffer from using 87. but you should probably take advice from the 3.5 owners, i always use 87 on my 3.3 :P

[Ron Burgundy]

I'm sure someone will chime in soon with some technical information soon but if I may touch on one thing...

My question is, am I wasting money?

On average Premium is $0.20 more than Regular Unleaded.

$0.20 x 20 Gallons = $4.00/FIll Up

Fill Up Once A Week for One Year: $4.00 x 52 Weeks = $208.00/Year
Fill Up Once Every 2 Weeks for One Year: $4.00 x 26 Weeks = $104.00/Year

Even if you are "wasting" your money - your not wasting much.

EDIT: For what it's worth, I fill with Premium every time. I feel like the engine runs smoother over unleaded, but unfortunately "feels" doesn't constitute conclusive evidence.

[KyooX4]

IIRC 3.5l pathy engine does use a bit higher compression, don't quote me though.

I know that when I run 87 I can definitely feel a detrimental difference. When I use 91-93 it feels smoother, 89 feels so-so. But again, what Ron said- 'feeling' isn't great conclusive evidence.

[740fizza]

As with any threads of this nature, it applies to just about any car which calls for premium fuel. The short answer is it will not hurt your car since the ECU detects the knocking and dials the engine back to prevent it from happeneing and damaging your motor. Now, if you DO run premium AND your car calls for it, then the engine will (slowly) detect it and advance the timing a bit. So the motor ends up making closer to the advertised power and fuel economy. As the above poster noted, the difference is minimal and is further diminished by the slightly decreased performance of running 87 vs. premium.

In other words, I just run Shell premium in both cars

[740fizza]

And to the OP: If I recall, the 2.5 V6 of that era Camry did call for premium but not the four banger. Had an 89 way back when but money was tighter so just ran 87 anyways.

[fueler]

my VG33 runs better on 87 octane than it does on 91. 91 is more resistant to detonation which is designed for high compression motors or forced induction motors. Our low compression & naturally aspirated engines run better on lower octanes.

[WPGQX4]

What about Mid grade at 89 octane? I'm running it now to see if there is any difference on fuel mileage. I hate winter fuel!

[Chuck Tribolet]

What does the owner's manual call for? Do it.

Chuck

[Buzzman]

We've all discussed this issue on here before, and there has never been a consensus as to what is right or best, at least as far as I've noticed. My suggestion is to run whatever you are comfortable with.
I switched from premium to regular gas after the first year I got my Pathfinder, and I've never gone back. Absolutely no problems.
As for the owner manual thing, don't believe everything you read...and here's why I say that: I have a 2003 Sentra Se-r with the 2.5 engine. The owners manual says to run premium. I also have an Altima, and it has the SAME 2.5 engine, and it says to run regular. Why? I asked a few guys at the dealership and here's what they had to say. One word: marketing.
The Altima is marketed as an econobox, family sedan, and therefore they say to use regular gas. This helps to make it easier to sell as an economical and cost effective vehicle. Mom and Pop love it.
The Se-r however is marketed as a "performance" car, so they say to use premium fuel, (as it's a premium vehicle.). It's all s*** as far as I'm concerned.

[Pathofinder]

In canada its almost .20 cents a LITER, so its quite a difference at about $15

Im surprised theres such a small difference over regular per GALLON to the USA

[740fizza]

We've all discussed this issue on here before, and there has never been a consensus as to what is right or best, at least as far as I've noticed. My suggestion is to run whatever you are comfortable with.
I switched from premium to regular gas after the first year I got my Pathfinder, and I've never gone back. Absolutely no problems.
As for the owner manual thing, don't believe everything you read...and here's why I say that: I have a 2003 Sentra Se-r with the 2.5 engine. The owners manual says to run premium. I also have an Altima, and it has the SAME 2.5 engine, and it says to run regular. Why? I asked a few guys at the dealership and here's what they had to say. One word: marketing.
The Altima is marketed as an econobox, family sedan, and therefore they say to use regular gas. This helps to make it easier to sell as an economical and cost effective vehicle. Mom and Pop love it.
The Se-r however is marketed as a "performance" car, so they say to use premium fuel, (as it's a premium vehicle.). It's all bullsh*t as far as I'm concerned.

Not sure I agree with that. Remember, this affects all makes, not just Nissan. Not to mention the Pathy isn't considered a luxury vehicle either but the manual still calls for premium. And also do the Altima and SE-R make the same advertised HP (I don't know)? But long story short, it won't hurt anything since the engine will compensate for it to prevent knocking/pinging. But if it calls for it and you do run premium, there is a marginal (perhaps not noticable difference) in MPG. I just run it because the diff at the pump is marginal.

[Pathofinder]

But you might have missed the part that higher octane is HARDER to ignite, so if it doesnt call for it...why hurt the wallet with an extra $15