2001 Pathfinder Fuel Question

[husky570]

Reading through the owners manual says should use 91 octane or higher for the 3.5 in my 01 pathfinder, didnt realize this, have ran a tank of 87 octane through it already with no noticeable problems or spark knock---is it absolutely vital and necessary to run premium through these things?, what is the risk if I do not ?

[SaKaNa]

I asked myself the same thing the other day, and used that "SEARCH" button in the top right and found several topics covering it.

[Terrano]

Good reply, Sakana

[husky570]

Good reply, Sakana

 

 

Did a search, looks like its not too big a deal to just run regular unleaded through the motor, havent heard any real signs of spark knock even pulling steep grades or passing.

[muttmobile]

i've ran both, i *think* i can maybe feel a bit more ooomph with the good stuff, but i don't think it'll hurt anything to run the cheap stuff.

[XPLORx4]

The engine prefers to run on 91, but will also operate at reduced performance and potentially reduced fuel economy, with 87. Considering that it costs over $50 to fill up the Pathy these days, an extra $3-4 per tank for 91 isn't really that much extra.

 

The 20-cent-per-gallon savings (roughly 6% savings at $3.00/gallon) of using 87 may potentially be negated by lower fuel economy. If you get 17mpg (~$0.176/mile) with 87, but get 19mpg (~$0.168/mile) with 91, you'd actually save 4% per mile in fuel costs by using 91 instead of 87.

 

You should perform some experiments to determine your average mpg with a few tanks of 87, and also with a few tanks if 91. (Averaging over several tanks will reduce fluctuations caused by different driving patterns between different tanks of gas.)

[navygz19]

^^ He's right...I've been using 91 for about 6 months now, and notice a decent increase in MPG. Yes, it ran fine on 87, yes it was cheaper, but by no means was it as efficient as running 91. I average a consistent 17.5 MPG 50/50 split b/w city and highway; I was lucky to see 15 back then.

Edited June 22, 2007 by navygz19

[Trainman]

^^ He's right...I've been using 91 for about 6 months now, and notice a decent increase in MPG. Yes, it ran fine on 87, yes it was cheaper, but by no means was it as efficient as running 91. I average a consistent 17.5 MPG 50/50 split b/w city and highway; I was lucky to see 15 back then.

 

Hmm, I may have to try again.

 

I did a fairly long test last year (a couple of months, several thousand kms) and saw no difference.

 

Maybe our cheap Canadian gas is just that much better than US (sort of like our beer )

[mws]

Modern cars have knock sensors that sense knocking and retard timing (and other performance robbing adjustments) to accomodate bad gas and minimize damage - so you should not hear it. But you will see mpg reduction - sometimes.

 

Knock happens far more often when cylinder pressures and temperatures are higher - like when accelerating, or when climbing grades (anything above about 1/4 throttle). So if you are just droning down a highway at reasonable speeds, it will run equally well with either - and return about the same mpg.

 

However, when climbing grades or driving around in town, the low octane will result in more knocking and the timing (and performance) will be affected far more often and you will see a noticeable difference.

 

Other factors:

Air temp (hot temps mean higher engine and combustion temps and more knocking/less mpg)

What the octane really is (name brand gasolines tend to be more consistent and higher than off brands)

 

My behavior in my 2000 Maxima to minimize cost (same basic engine, also recommends 91):

Around town in winter: 89

Around town in summer: 91

On a long road trip in winter and NOT in the mountains: 87

Long road trip in summer on the flats: 89

Long road trip in summer while crossing Sierras or Siskiyous: 91