Re: Octane question per Pathfinder

'nuther Bob · 2003-08-15T22:31:48+00:00

Actually, it's not quite that simple. No doubt the manual willsay "Use 91" but "89 is OK" like most Nissan manuals. But, there'smore to it. Stick with me until the bottom line. Here's how it works: When you accelerate, there's a chance for pre-ignition (knocking). The knock sensing mechanism is constantly checking for knock. If it detects it, it will retardthe timing (in a Nissan) and stop the knocking. So, within reason, _no_ gas will cause damaging knock or engine damage. Why do we care about octane ? Retarding the timing will reduceavailable power in the engine. You will have less power overall. If you are going up a hill, or pulling a trailer, or just enteringa highway, you may need to press harder on the accelerator. So, gas mileage will suffer. At the upper end, you will simply have less power. So, does it matter ? You will get slightly poorer mileage _depending_ on the exact driving conditions that week. If you aredoing a lot of mountain driving, or pulling heavy loads, or justlike a lot of power, you may find it somewhat diminished. Whetheror not it is more economical to use Premium or Regular is very arguable. Here's a sample calculation: 12,000 miles @ 20mpg = 600 gallons of gas used; at $1.59 for reggas you pay $954 for gas for the year. With Premium gas at $1.65, you pay $990 for the year. That's a whopping $36 a year morefor Premium. Whoopee. Even if Premium is $.20 more per gallon (and I doubt it) you still only pay an extra $120/year for Premium. And, we still haven't figured in any extra mileage due to using premium. If you get 22mpg using Premium instead of 20mpg because of the higheroctane, then you only use 545 gals of gas and the Premium costs youa total cost of $900 -actually $45 *less* than regular. If you geteven 1 mpg more with the Premium it costs the same as regular on a per year basis - and you get all power Nissan designed in.Bottom line: These number are speculative. Fill in your own. The factis that the difference in gas cost is going...

Aug 15, 2003 21 Replies

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Wes 22 years ago

IF THE HANDBOOK recommends using higher octane, you most likely will recognize 4-6 mpg improvement when using higher octane.

I can tell you that from personal experience on Pathfinders, Maxima's and my current Murano.

Wes

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John D. 22 years ago

Wes,

That's what I said: I told the guy to do what his OM stated...mine doesn't say that.

But I will repeat that using premuim for MOST cars makes NO difference re: mileage. These websites might be of interest to you if you haven't seen them already:

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The concensus?

Unless your car NEEDS premuinm (91 and above), don't buy it. If it says 87, then stay with that.

Of course, people can use whatever they want even if it doesn't really make any difference...it's their car and money at the pumps.

Regards,

John D.

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