In Canada we can get 91, 92, and 94 octane gas. I realize the 2k1 Max requires (or highly suggested) 91. If I do use the 94 is there going to be any real difference in performance?

 

Your fuel filter will be a little cleaner running higher octane gas. Someone told me that airplane fuel will give you like 30 more horsepower, airplane fuel is like 120 octane.

 

How does NOS work? Is it just really high octane or something else all together? So i assume that the higher the octane the better performance?

 

What does a higher octane fuel do for your engine?

Well, it doesn't add horsepower. The higher the octane rating, the less likely your engine will ping. High octane gas is good for high compression engines. (Race gas is 115 octane, for example.)

The Maxima does not have a high compression engine, so it can't really make use of anything much beyond 94 octane. If you use gas with an octane rating of less than 91, the engine may ping. Not good.

 

It might have been true ten years ago, but nowadays all grades of gasoline have the same levels of detergents. So there is little sense in using high octane if you are doing it only for the detergents. The owners manual recommends 91 octane or higher. I don't think there will be an appreciable difference between 91 and 94 octane.

 

your best bet is to go with your manual on fuel recommendations. If it says 91+ octane required then use at least 91, but higher octane doesn't mean higher performance so you probably won't get any additional performance from anything higher than 91.

Same thing with my Accord V6. It says 86+ octane, so I just put 87 in it and it's good to go.

The common misconception is that higher octane means more performance, but this isn't so. The level of octane required in an engine is determined by the compression ratio. The higher compression, the higher the octane levels required in a fuel. Octane acts to slow down the burning of the fuel and prevents preignition (pinging, pre-detonation, knock, whatever you want to call it, etc...)

So because higher octane fuel is required on higher performance, higher compression engines, people tend to associate higher octane fuel with higher performance. And hence that explains your typical rice-boy Honduh owner putting 91 pump octane in their Civic DX

So always go with what the manual says. For the Maxima I think that's 91 octane. Any lower and you risk pinging which is very bad for the engine, and any higher is just more margin, and probably won't give you anymore performance.

 

NOS is not gas. (here comes the Chem lesson) NOS is Nitrous Oxide. Whent heated to a cetain degree it separates to a nominal number of Nitrogen atoms and a HUGE supply Oxygen atoms from the relatively small nitrous oxide molecule. This vapoization process also COOLS the air allowing the oxygen to become even more dense, and hopefully we all know more air=more gas=more horses. In this manner you can get upwards of more than 80hp from a single burst (just take it easy on the shots. You can easily blow yourself to kingdom come with a high shot rate if your engine isn't prepared for it)

 

I used to work at the airport.. every once and a while, somebody would put some 100 low lead in their car and burn the rings. you have to actually add some oil to the gas at the very least. even then, it doesnt over much.

 

You will need higher octane gas,if you have forced induction. For NA engines,just everybody else said-no gains.

Question-at higher alltituded (around 7000 feet)-do I still need to use 91 octane?
thanks

 

That air is much thinner up there than it is near sea-level where I am. My guess is that the thinner air would effectively decrease the compression ratio of the engine to the point where you might not need premium fuel anymore.

I'd run the tank almost bone dry until your next fillup, and then put in like a quarter tank of 87. If you notice pinging (pre-detonation) then you'll need to stick with premium and just go ahead and fillup the rest of the tank with premium. But if not then you might just be able to get away with regular fuel and save a couple of bucks.

The Maxima's engine is already "borderline" for needing premium fuel (only has a 10.0:1 compression ratio), so being at 7000 feet might clear you of any pinging problems that you would more than likely have at sea level.

I think the rule of thumb nowadays is that an engine with a compression ratio of over 10.0:1 will typically need premium, and below that regular fuel is fine. But if you're right at 10.0:1 then it could go either way. The Accord V6's J30A1 engine has a 9.4:1 compression ratio so we're good to go with 87 octane. Honda has also been playing with another version of this same engine with the compression bumped up to 10.0:1 with 200bhp, and supposedly they were able to tune it to still be able to run on 87 octane. The advantage is that it's cheaper (duh), but the disadvantage is that you get a little bit more torque on premium.

 

Thanks,Stevepake. Great info
But you say I if i get pre-detonation,I will actually hear it? I don't think I've ever heard knock before. My older car required the use of datalogger to see if it was detonating.


The part with more torque-does it relate to Maxima engine,or the Honda one?

Thanks

 

Hmm...well you should be able to hear and/or feel it if it's pinging.

Ooops, my post was a bit confusing and out of context. Sorry

The advantage of being able to run on regular fuel (the Accord V6 engine) is that it's cheaper and will keep your operating expenses low, especially if you put a lot of miles on your car like me (30,000 miles/yr).

The disadvantage of running on or requiring premium fuel (the Maxima's engine) is that it's more expensive (higher operating costs) but the **advantage** is that premium fuel will give you a little more torque than regular fuel, as long as the ignition system is tuned and setup for premium in the first place.

 

Fuel for Thought...
http://ericgorr.com/twostktech/Fuel_Basics.htm

 

bah, just use at least 91 in your max.
My 92 HATES 87oct. The idle goes for ****s, and the car pings like an SOB. It even pings with 92, Ive had to back timing a bit due to pinging, and go with 94. Then again, i have crappy new Bosch Platinum plugs( I wasnt thinking when i bought them)

After i kill these plugs, i will be going back to the basic plug, NGK copper, and then the timing will be advanced once again, and this time i will add an FPR, and possibly a bigger fuel pump.
Cams would be nice, but nah.

Even my winterbeater got a taste of 92 once, the station ran out of the regular stuff, and had to sell the good stuff for the same price. The beater ran much smoother with that tankfull. After that, every third tank was premium.

Do the calculations, for just a couple of bucks more to a tank full, its more than worth it to fill with premium fuel.

Honda dont deserve any more than 86oct anyway. No matter what you feed them, they dont die.
My buddy ran his 88 Accord hatch for over a year on the same oil filter, and used go-kart oil!!

 

Datalogger? For which car did you need that?

 

Just to add to what Stevepak said, octane simply prevents pre-ignition of the gasoline. In a otto cycle engine, you want the gasoline-air mixture to be ignited by the spark plug.

What can happen, however, is that on the compression stroke the temperature can climb so high that the fuel-air mixture ignites spontaneously, resulting in knock or pinging. The higher the compresssion ratio (i.e.: the more you are compressing the mixture), the higher the temperature and the higher the chance of knock. Engine temperature and the temperature of the air entering the engine also plays a role. For example, it is feasible to run 89 during the winter and switch the 91 in the summer depending on where you live.

The reason that people associate performance with high-octane fuel is that most engines with a high specific horsepower (hp per litre) will usually have a fairly high compression ratio and thus require 91+ octane to avoid knock.

Going to a higher than recommended octane fuel than will not increase performance as you are only increasing the gasoline's resistance to pre-ignition. You are not going to a higher-energy version of the gasoline.

Thankfully, newer cars like the Maxima have knock-sensors which detect the first signs of pre-detonation and immediately retard the timing to avoid damage to the engine. As a result, you will not hear anything but you should notice a decrease in fuel economy and hp.

 

Just to put a nail in this coffin in case anyone doubts what has been spoken:

http://www.howstuffworks.com/question90.htm

 

does higher octane (87 vs 93) mean better mpg? In my car it does that.

 

Only if your car requires the higher octane gasoline.

 

However, in the latest issue of SCC they did a a dyno on the 350Z with 91 octane and with 100 octane, 100 octane ran a little better, 2-3 Hp and 3-4 lb-ft of torque. I can't remeber the exact numbers. Not huge gains, but gains. The compression ratio for the VQ35 for the Z car is 10.3:1. So higher octane does produce more power in some cases.