ray08max

I was wondering who uses what type of gas? It says premium but I use premium but not 93, 91. Not every gas station carries 91 but I try to always go to the same gas station. But does anyone notice a different or know if it really does matter what kind of gas we use for our Maxima's?

Jatan

iTrader: (3)

Nissan recommends premium (91+) for performance but you can also put in regular or mid-grade if you want, it'll just decrease the performance

PrimedWick

89 Octane for me in all my Maximas (02,03,04,05,06 & 07). Never had a problem at all. My 06 could do 400mi (highway). Dunno if the 07 holds up -- all I do now is city driving.

JD05

Tried 87 for a while the car ran alright however there was less power which is no big deal for a daily driver went back to 91 and my mileage went up 3 miles to the gallon which pays for the extra .20 a gallon for premium I will stick to the 91 which is better for the car anyhow,the manufacture recommends premium fuel so why not use it when you spend over 30k for the car it breaks even money wise due to the increased MPG.

As for the comment which to use 91 or 93 it doesn't matter which ever is available in your location they are both considered premium fuel.

Negafen

I use the lowest octane i can get away with and not have knock. I'm not a big fan of high compression engines. Too hard to live with

rond310

i usually use 87 or 89 octane and no issues so far

SilverMax_04

Here in Colorado at 6K feet elevation, I burn only 85 octane regular gasoline in my 04 Max.

A general auto engineering rule says that for normally aspirated gasoline engines (that means there is no turbo-charger on the engine), you can subtract about 1 octane for every 1K feet increase in elevation. Using that general rule, 85 octane gasoline at 6K feet elevation should burn like 91 octane gasoline at sea level. I have no performance problems doing this and now have over 100 K miles on this Max.

I do notice some slight engine knocking using this gasoline octane with these specific conditions: the weather is hot (over 85 degrees), I let the engine RPMs fall below 2K and I am driving up hills. My solution to this is to shift to a lower gear to increase engine RPMs (and also cool the engine slightly).

When I drive east (or west) I will buy either 87 or 89 octane gasoline (depending on the cheapest price) and they work fine in my Max. In the states of Nebraska, Kansas and Iowa, the 89 octane gasoline with ethanol is cheaper than the 87 octane without ethanol -- because these states give a tax break to the ethanol-gasoline.

When my Max was much newer, I tried to see if there was any differnece in gasoline mileage burning regular versus premium. I did this test when I drove back east to SC and lower elevations. I could not find any difference in mileage between 87 octane regular and 91 octane premium when I was back east and doing this test.

Gasoline octane is a complex issue, with no easy answers as to what octane to burn in your vehicle. The simplest rule is to burn the lowest octane gasoline that runs your vehicle to your satisfaction. If I were racing my Max at sea level, I would only use 91 octane. But I don't race, and only rarely call for maximum performance from my VQ engine. So I burn regular gasoline.

If you want more detailed information on gasoline octane, look at my detailed posts on this earlier thread:
http://forums.maxima.org/fluids-lubr...hat-means.html

daveonli

http://www.toptiergas.com/retailers.html

I have been using Shell 91 in my 03 Maxima and she seems to run great,all the power i need

VQ'rInWLA

iTrader: (83)

91 at Mobil all the time. We dont get 93 out here in the West Coast. Otherwise, Id be running it.

SilverMax_04

It is my understanding that California limits the maximum octane for commercial grades of premium gasoline to 91 octane. As long as this is the law, you will never find 93 premium in California.

That law is also the likely reason that Nissan specifies 91 octane premium in the owner's manual -- although this manual also says that lower octane gasoline is acceptable if you are not looking to obtain maximum engine performance.

VQ'rInWLA

iTrader: (83)

Do you guys get 93 in CO?

SilverMax_04

You obviously did not see my earlier posting about the effect of altitude on an engine's need for octane. For all but Turbo-Charged engines, an increase in altitude results in a decrease in octane requirement for an engine. At 6 K feet an engine that needs 91 octane at sea level only needs about 85 octane gasoline -- all due to altitude.

But to answer your original question -- the maximum octane for premium gasoline here in Colorado is 91 octane. I have seen no gasoline station with a premium higher than 91. But at 6K feet elevation, 91 octane should perform like 97 octane gasoline at sea level -- so this should be sufficient for all but turbo-charged engines.

VQ'rInWLA

iTrader: (83)

Cant believe I missed that. Dont know how. Anyways that bit was very enlightening bro. I always thought it had something to do with the climate (between WC and EC) as opposed to elevation. It makes a lot of sense. Thinner air up there.

SilverMax_04

It all has to do with air pressure. Reduced pressure in an engine (except for the turbo-charged engine) reduces the engine's need for octane. For most engines the effect is about one octane reduction for each 1 K feet of elevation increase. For about 99% of gasoline engines, this effect ranges between 0.9 and 1.1 octane reduction (averaging 1.0 octane).

See the link at the bottom of my post #7 above for a more complete discussion of octane number.

Bobo

SilverMax:

Do you know if temperature affects engine performance dependent on octane used? I was under the impression that you can get by with lower octane fuel in colder weather. I am at sea level, but basically run the same octane year round. Locally we can get Chevron in 94 octane. To my knowledge it is the only station that has it. I mix 94 and 87 at a ratio of about 57/43 $-wise and come up with 91 octane at marginally above 89 octane cost.

TE=SilverMax_04;7886395]It all has to do with air pressure. Reduced pressure in an engine (except for the turbo-charged engine) reduces the engine's need for octane. For most engines the effect is about one octane reduction for each 1 K feet of elevation increase. For about 99% of gasoline engines, this effect ranges between 0.9 and 1.1 octane reduction (averaging 1.0 octane).

See the link at the bottom of my post #7 above for a more complete discussion of octane number.[/QUOTE]

SilverMax_04

Seems that nobody wants to follow a link to another set of postings on this topic. So I will copy the part of my post #4 on that different thread that answers bobo's question above:

What Determines an Engine's Octane Requirement:
By using high octane gasoline, we are attempting to prevent engine knock. Engine knock is the premature and spontaneous ignition of gasoline. In effect the fuel EXPLODES rather than BURNS, and this results in incomplete combustion, a loss of power and (over time) engine damage. When this happens, you hear an audible "knock" or "ping", sometimes referred to as detonation. Detonation may vary from a faint noise on light acceleration to a constant, deep hammering noise while driving at speed.

Octane requirements are dictated by the following three engine operating factors:
- Cylinder Pressure,
- Spark Advance, and
- Engine Temperature.

Also, engine deposits can affect all of these factors, and produce engine knock where it otherwise would not exist.

Modern engines (like the VQ35) do a good job of controlling the spark advance and to some extent engine temperature. Cylinder pressure is less well controlled and is more dependent on the environment (the engine’s compression ratio, the altitude where you’re operating and the throttle position). But things get real exciting when you go to maximum power output at WOT (Wide Open Throttle). That's when bad things can happen fast. That is typically one of two times when you need maximum gasoline octane to prevent engine knock. The other is lugging your engine when engine temperatures are high.

Anything you do to increase any or all of these three factors will increase your engine’s octane requirement. So, if you put a turbo-charger on you car, you will increase cylinder pressure. If you’re driving a loaded car up a steep grade at high speeds, you will increase the engine’s temperature (but also slowly decrease the cylinder pressure due to ever higher elevation).

Because many OEMs (Original Equipment Manufacturers) are conservative, their stated octane requirement for their vehicles are frequently based on a series of very strenuous tests on the engine dynamometer that are in all likelihood never seen in the real world. In effect they have you driving at WOT (maximum power) for several hours at a time. The last I checked, all Highway Patrols kind of frown on that.

All of this being true, it is also possibly true that the current VQ35 engine (with a 10.3 to 1 compression ratio and advanced engine controls) is operating on the edge of what can be safely done burning regular gasoline. And this even though the owners’ manual says it can be operated on 87 octane regular gasoline – although they recommend premium. The 3.5L VQ engine in the Maxima is among the most advanced in engine technology today (see Wards Automotive 10 Best Engines for more details). The Honda Accord V-6 advertises use of 87 octane regular, but it only has a 10.0 to 1 compression ratio. Because of this, perhaps the VQ is not so close to the edge with 87 octane gasolines. If you do run 87 octane, I recommend that you work to keep these factors above as low as possible (but there's not much you can do about spark advance).

{This post - copied above - then goes on to discuss what the 2004 Maxima Owners Manual says about Octane requirements. It then lists 3 common misconseptions about Octane and Octane Blending.}

cags

i was told by my tech guy that i am not using the right gas in my car. Here in the bahamas we only have 87 octane so he recommend that i use octane boost. Is this safe for my car?

SilverMax_04

That depends on what it contains. The quickest and cheapest way to boost octane is by usine lead additive (Tetra-ethly Lead). But that will ruin the Cat Converter very quickly - which is very expensive to replace. Some racing additives for boosting octane contain lead, so be careful.

If the octane boost is based on Toluene or Xylene -- it will be fine.

But before you go spending money to boost the octane, you need to answer one question. Are you having knocking problems with your vehicle?

If not, you will be just fine continuing to burn 87 octane regular gasoline. I suspect that your tech wants to sell you this octane boost product. For my 04 Maxima, 87 octane works fine for me when I go to South Carolina ever summer (which is very similar to Bermuda in climate and altitude - just feet above sea level). You probably only need an Octane Boost if you are racing your vehicle.

SilverMax_04

Bobo, I answered you first question -- but did not pick up on your in-your-gas-tank octane-blending scheme until just now.

The ratios you quote will in fact get you 91 octane - provided that gasoline octane blending is linear - which it is NOT. So it turns out that the only way to be completely certain of the octane is to test it after blending. It turns out that octane is not a linear phenomonon. But it also turns out that it blends fairly close to linear, so you are probably close to 91 octane with your blend.

In most gas stations the 89 octane mid-grade gasoline is in fact blended into the tanker truck by blending premium and regular (the only two grades most terminals now store) using the assumption that this blending is linear. So you are probably close enough with your blending.

You have also found the trick that most gas station owners don't want you to know - you can tank blend a mid-grade gasoline yourself a what is likely to be a cheaper cost per gallon than the gas stations sells this product for at the pump. Or alternatively, you can get a higher octane mixture than the pump mid-grade at the same price per gallon as the lower octane pump mid-grade.

Bobo

I figured out the blending thing about a year ago. As stated, I blend the equivalent of about 91 octane at marginally more than 89 at the pump. I can blend my own 89 at Chevron at just over $2 less (3.5 cents/litre) than buying 60 litres of 89 at the pump. It appears to me that the gas stations would be delighted if everyone bought 89 octane at the pump.