Kind of strange to assume that I didn't research. I am actually the guy that compiled this quick reference list for the 1st gen recently:

2003-2004 6MT and 5AT SEDANS: 87, with 91 recommended for better performance
2005-2006 6MT SEDANS: 91
2005-2006 5AT SEDANS: 87 with 91 recommended for better performance
2003-2006 Coupe (all): 91

While you're correct about your 'recommended' versus 'required' statement in Infiniti's case it seems, it is kind of an assumption that all manufacturers follow this 'reccomended' vs. 'required' wording. Perhaps I'm wrong, and there is some regulation governing this. But i doubt it. And furthermore, ridiculous to dispute over it. I'm just happy to see someone actually do some research to back up a statement though in one of these threads, that sir, is refreshing, thank you
That Edmunds list is pretty cool, I like Edmunds, they put together good stuff. Too bad they don't have anything prior to '08.

In the list above, and in your quote out of the owners manual for the 05 it's pretty clear that they don't "tolerate" it persay, yes, you can run lower octane in the models/years that call for 91, but YOU SHOULDN'T unless absolutely necessary, black and white, right there in the manual. But it's model/year/transmission specific for the 1st gen, which is why I made a quick reference list.
the Compression ratio of all of the 1st gens is the same, also, not sure where that plays in maybe I'm missing something there too.

 

No reason to go back and forth, it's only a couple of dollars. If spending extra 2 bucks going to break the bank then skip on that bottle of soda you want to get or the piece of candy and get premium. It's better for your health and your car.

 

It's the same with your oil, however the difference in oil pricing is a lot more noticeable. This isn't a single cam non-VTEC Civic man.

 

This question is asked so often that it should be under FAQ. Do people not have any idea how to search or are they just too lazy? If you can't search this topic or scroll down on Today's Posts one or two pages then you shouldn't have access to the forum.

 

OK For all you pimple faced punks still living with Mom and Dad, the '05-'06 MT models are the revup motors and they have different cams than the motors in the AT models. I refer you to page 181 of the '06 sedan Engine Maintanace manual. Not only is the timing, duration and lobe centers, diferent but the revup cams have more lift.

 

I'm stunned, you're 100% correct. Nissan actually changed the cam from the MT/AT models on the rev-up (05-06)
From another silly thread comes some good info thanks dude

 

Haven't tried it in the G, but in my Nissan Frontier 4.0 V6, it got me exactly 1/2 mpg better. Same with gas without ethanol. Not worth the price.

 

Yeah no ethanol is where its at!!

 

the truth is rather simple about fuel and modern cars.

It should not be surrounded by such a vast amount of myths

All you need to do is simply google what octane number is and you will find out all about it.

Our modern cars equipped with fuel monitoring sensors and sophisticated computers that determine the octane number of the fuel you put in and monitor it's amount delivered to the cylinders in order to avoid pre mature detonation or knocking. As the result of this, using lower octane fuel will either result in better or worse mpg numbers depending on the area you live in, your altitude, air temperature and number of other factors. But using 87 octane fuel in place of 91 in NO WAY WILL DAMAGE your engine.
In case you do hear a knocking noise while accelerating, switch to 91 immediately because your fuel delivery system is clearly unable to compensate and you will damage your engine.

So to sum it up. Usually the use of lower octane fuel in cars that are set up to be ran on higher octane fuel will result in more fuel consumption. That is simply because of the way your engines computers are programmed and nothing else. Having said that, there are cases where people get better gas millage using lower octane fuel than their engines designed for due to their geographical location and climate.

 

By the way

Let's apply a bit of math to this entire debate.

Average miles driven per year are 15k miles
Average premium fuel price for 2011 let's say was $4.00 per gallon
Average regular fuel price for 2011 let's say was $3.50 per gallon
Average mpg achieved by our G35s during those 15k miles let's say 18 to be fair.

Math:
Using premium fuel you would have used 833 gallons @ $4.00 per gallon that would be $3332 dollars total spent a year
Using regular fuel you would have (assuming you got same mpg) used 833 gallons @$3.50 per gallon that would be $2915.50

Difference in savings per year is $416.50

So you save $400 a year.
You own a car on average for 5 years. That accumulates in $2082.50 in fuel savings.
So in 5 years you don't save enough to get you a new engine in case yours goes belly up for using a non recommended fuel in it.
Does it worth the risk?
Is 2k in 5 years really the money you cannot live without?

I suggest for those that struggling with bill at the fuel pump find another ways to save money and not dig your self and your car a grave from which you will need much more money to get out.
Look into your other spending habits that could easily be reduced or eliminated without any risk at all.

 

Problem for me is, I have to drive forty five miles to get to non-ethanol gas...

 

You've probably seen this, but in case not, or for anyone else, this is a pretty solid site to find Corn-free gas:
http://pure-gas.org/

 

These are very conservative numbers as well.....cost savings per year goes way down if you use a $0.20 difference in price between regular and premium and only drive 12k miles a year instead of 15....even if you keep the 18 MPG (I get like 16). Ends up closer to $130 a year.