Okay, I'm new to this forum and I just bought my 2001 SE max about a month ago. I read the FAQ on the gas selection and I am not completely clear on the whole issue. Using a higher octane doesn't give you more power or better performance? M

y dealer did not tell me about using a high grade of gas, and so far I have used a tank of 87, 91, and 93...so hopefully using that 87 isn't going to hurt my new toy?!?!

So I take it 91 and up is the way to go and my car won't be too ****ed since I gave it a tank of 87 will it?

Thanks guys and I'm glad to have found this forum!!

 

you spent the $$ on your car spend the extra dollars on gas. (and buy from a quality name brand station) The higher octane is reccommended in the manual. Putting higher octane gas in a car than its not reccommended for will not help it. The higher octane gas helps prevent engine knocking. The lower octane gas will not burn as completly leaving deposits and possibly damage your engine. You might get away with switching between 87 and 91 but why chance it. A few tanks here and there of lower octane gas won't hurt it.

 

While we are on this subject. Can any one explain why most Hi test in Canada is 91 vs 92 or 93 in the US?

 

In colorado they did not have high octane gas because it was to expensive to oxgenate it at high altitudes. Not sure what altitude your at in canada. In colorade we only has 85 87 and 91. Maybe ask a few gas stations next few times you fillup.

 

Octane is ONLY a RATING of the gasonline's resistence to detonation.

 

Simply put, it is CANADA, eh?

 

congratulations on your new car. and welcome to the forum.

as for the gas, stick with the good stuff. i ran 87 during the break in period (force of habit) and i had knocking. switched to premium and voila! 2 tanks later, no more knocking. but i don't think an occasional tank of 87 is going to kill you.

 

..but you must take into account the compression ratio of the engine and its efficiency. Lower compression engines do not need higher octane. This is usually what the manufactures bases their octane recomendation on. Plus now they dump tons of additives (emmission reducers, detergents, etc) depending on what brand of gas you buy, just like motor oil.

 

I have never really noticed a difference when using 88 or 91 but I consistently use 91 now.

Some of you may not be aware of this but our Maximas have a lifetime fuel filter! It is in-tank and is supposed to last the life of the vehicle!

 

The higher octane, in and of itself, doesn't provide better performance. But the ECU, if it detects preignition, or knock, retards timimg which decreases performance. Higher octane gas has decreased tendency to knock, so no retarding is necessary. But that is in the FAQ....

I seem to recall that if driving at higher altitudes, above 4,000 feet, the manual suggests 89 or even 87 octane is adequate. I live at 4,000 feet and haven't noticed any change in performance or gas mileage from using 87 or 91. I use 89, just because. 87 if I can't get to a cheap station. 91 only at lower altitude on trips.

The only way knocking will damage the engine is if the knock is so bad the ECU can't compensate. You will definitely hear it, it's quite obvious. You will think something is terribly wrong when you step on the gas as to accelerate uphill or start from a stop. It may even sound, briefly, a little like a diesel. Which, of course, it just became. If left uncorrected, it can damage. But it takes some time and inattention for it to do so.

I don't know it, but I'd have to think that preignition so bad that it could damage the engine in a short period (say: 1000, maybe even 5,000 mi) would cause the ECU to set a code and light the trouble light. Could be wrong though.

Slight knocking is actually considered desireable by many automotive engineers. They claim it helps to keep the cylinder, piston, and valves clear of deposits. I don't imagine you could hear that level of knock, though.

Oh yeah, I also use Techron every 5,000 miles or so. Helps, really does. No snake oil here.

 

Don't know for sure... but I imagine it is the rating system used. The American pump "rating" is actually an everage of the two most common systems for measureing a fuels resistance to knock. The pump "rating" is called the AKI, or Anti Knock Index. The other two systems are the Motor Octane Number (MON) and Research Octane Number (RON). So AKI=(RON+MON)/2 for a given gasoline sample. The Canadian rating could be the higher of these two, RON, or it may be a third completely different one.

What is on the pump label? Does it say RON or Research Octane Number?

BuddyWh

 

where in Canada r u?

Sunoco sells 93 octane as does all the others that buy gas from Sunoco ... Pioneer ...

 

i only use moble and exxon 93 octane

 

I have doubts about lower octane causing engine problems. My brother has over 200,000 miles on his 1995 Maxima. He uses 87 octane.

I use 93. If 91 was available, I would use that. Also... in the driver's manual it states that it is okay to use 87 temporarily, if 91 is not available. I think it's more of performance thing than anything else.

 

In Toronto. Yeah I know Sunoco sells (I thought it was 94) higher test. The question was general regarding my observation that almost all US high test is 92 93 vs mostly 91 in Canada. It may be the number index is based differently.