...never had any problems or odd engine noises.
My '99 ran well.
I never looked at the manual and never knew 93 was supposed to be used.

Now after negotiating my lease buyout residual to a cost I'm happy with I will now with to synthetic oil and after reading some posts here going to use 93 octane to play it safe.
Gas mileage wasn't too good with 87 octane.
I hope it rises with 93 Amoco.

 

You should be fine with 91 at the minimum.

I know higher octane is a leaner and cleaner fuel that will eliminate 'pinging' and knocking which can prevent engine damage over time and yield slightly more efficient/higher performance, but can it actually increase fuel mileage??

 

Premium fuel will yeild better gas milage, but for the amount extra you pay over regular you are still losing more $$$.

I have experimented and gone from regular to premium, and I found somethin' interesting. With premium my car seems to revv better and respond better.

 

Yes it does improve fuel economy. We've proven this on my buddies I30. He claimed to be using to much gas recently, did the 60K tune up bla bla bla.. Still he claimed to only get slightly over 300 miles on a tank of gas. (Mostly highway)

Finally I asked him what grade of fuel he was using. He had switched to Regular a few months back to save a few bucks. I told him get some premium in there. So we calculated the mileage after a few tanks of gas (1+3/pie squared) and we did come up with savings.

Bottom line, use premimum in our cars, there designed to run on it.

 

I am aware of several Maxima's, 4th and 3rd gen who all thought they had problems. After taking the cars to several delearships, they finally changed to 92/3 octane gas the problem was instantly solved. Personally, my car gets an attitude when I go cheap. But she is ever so nice to me when I treat her right.

 

In NJ it's 87,89,92,93,or 94 octane.
Never seen 91 so 93 will be the one.

 

nice...but mechanically, does anybody know how does it make your engine get better mileage?

 

I was just reading on a website that high octane doesn't give you more mileage. I know it give the gas a higher ignition rate so you don't waste fuel. I need to read all of this octane info again.

 

I agree with you.. i've read in Road & Track, Click and Clack etc...about higher octane gasses, and they do not help in gas mileage. Performance wise and in regards to pre-detonation, it will help substantially over time.

 

For optimum output, the car was designed for 91 or better. If you use 87, the computer retards the ignition timing to help prevent detonation. In normal conditions, to produce the same amount of power, you would need a larger throttle opening. This is neglible just cruising around and accelerating gently, so no real MPG difference is apparent, there are just too many different variables. However, the harder you accelerate and the more you demand higher power settings from your engine, the greater the MPG difference will be. Does this help clear things up or confuse them more??

 

next tank is going to be premium, will report any findings

 

I have never noticed any mileage difference between regular and super. As for performance, I suppose if I were racing and needed that extra .1 second for the quarter mile then premium would help there.

In the end, your Maxima will suffer no harm at all using regular unleaded. If you use super, you will get that extra little bit of power, but I would doubt that you would notice it. The choice is up to you. Regular is not "bad" for the engine, but it runs optimally using super.

 

What about an 89 octance compromise?

 

I was getting some crappy gas milage, so I did a few things

I checked the air pressure in my tires, and it needed it.
And I cleaned my Air filter.

And I've noticed much better mileage without any driving style changes.


So now I check the air pressure about every two weeks, and I make sure to check it when the tires are cold, cause when the air is hot the pressure is much higher then.

 

kind of confuses things, I think...so you're saying that the ignition is retarded, but the injectors still dump the same anount of fuel regardless of the grade? If that is the case, then mpg would remain the same, but performace would see a difference. Right? probaly wrong...

 

I always use 87 and 91, back and forth. Haven't been able to tell ANY difference yet. Seems my MPG is always close to 22, 60% hiway 40% city.

 

any tips on getting better gas mileage??? what gas pressure for your tire, because i know that matters alot. thanks!

 

1) Make sure to do the 60k tuneup - spark plugs, oil change, fuel filter, etc.

2) Check your air pressure when the tires are cold. Cold is when the car hasn't been driven for 4+hours and you don't drive over a mile. So check your pressure before you leave, then go to the gas station and put the proper air pressure in the tires with an accurate guage.
I use 32/33 in the front and 30/31 in the back.

3) Make sure your air filter is clean, or replace it if it's disposable.

4) Remove any excess crap that's laying around in your car. Extra weight hinders gas mileage.

5) In warm weather, it's more efficient to use air condition then leaving the windows down (at least with highway driving).

 

Nope, what I was trying to say is with the timing retarded it will take more fuel to generate the same of power. For example, if it 20hp for the car to cruise at 70 mph, with premium fuel the engine might burn 6 gallons per hour, but to generate the same 20hp on 87 octane, it would need to burn 6.5 gallons per hour, since the engine can't extract the same amount of energy from the lower octane. Also, if the engine was capable of generating 190 hp on 91 or higher octane, that same engine would be able to generate only 185 hp on 87. My point the harder you drive the car, the lower MPG you will get on 87. Also, someone who drives on the highway at a steady 70 mph with no traffic will get drastically different results than someone who also drives on the highway, but is constantly accelerating and decellerating a little to deal with traffic. Please note that the numbers used above are for illustration purposes only, I have no idea of the actual HP difference between the two octanes or the road horsepower required. And for the record, during track season, I use 93 or higher, but now with my winter tires and me taking real easy, I use 87. On my last tank, I got 28 mpg just cruising, I don't believe 87 will hurt the car, it will just not be able to perform to it's full potential.

 

nuff said...sounds logical to me! dang...I hate being wrong!

 

I'll tell ya this much, I noticed 30 more miles per tank when I put the Bosch +4's in my car. I don't know whether it had to do with doing the tuneup or switching from the NGK's all together. I really hope it was the tuneup because I am going back to the standard plugs next Spring.

 

Don't forget to change the fuel filter every year too....

 

You don't need to change the fuel filter every year. That would be like changing your oil every 1500 miles. It's not bad to do, but also not really necessary. Nissan has no recommended interval for servicing the fuel filter, but I would say every 30k is a good bet.

 

changin your fuel filter often cant hurt cause you never know whats in the gas your getting......but for the people that say they get better gas mileage with higher octane i cant see that being true cause the higher the octane the quicker the fuel burns so you should get worse gas mileage but the performance will be better!

 

who kow...but I'll get a real answer on that soon...

anyhow, GoodYear sent out an article that did a study on tire pressures and the correlation to gas mileage. It stated that a 10% drop in tires pressure (4 - 5 psi) can reduce your gas mileage on the average of about 10%.

 

I'd buy that. With all the insane temp variations MA has been having I've been checking my pressures 2-3 times per week. I hate spending money when I don't have to

 

If they are using aftermarket, its a good idea to do it every 15000 though. I am close to the 15000 mark but I think I'll wait tell next spring to do it along with other things.

 

If you do your own maintenance, than that's a good idea. The parts are cheap. But for people who service their cars at the dealer, if you change your fuel filter over there, they will rape your wallet for $50 for this $15 part. It always irks me when people pay for unnecessary services from the dealer, which always overcharges its customers. They should at least go to an independent shop and get those services done for half the price. If you do your own maintenance, well it's cheap and the labor is free, so whatever you want to do is fine.

 

$50 for a filter???? Well, I should be guessing that anyone coming to this site should be looking to do their own work anyway.

Save that money people.

 

87 might not hurt your car if you drive like a old granny, but if you consistently push your car, i think that the premium would be helpful. wouldnt you also get better gas mileage if your pushing it with premium? i get a little over 20 MPG, not sure what yall get but i drive it real hard... i think thats pretty good. btw, my mom has a 98 and she gets around 20 with 87.

 

You'd definitly get better gas mileage as wells as performance with premium. Right now, with snow tires on and a highway commute to work, I AM driving like a granny. As soon as the weather improves and track season starts again, it backs to 93 for me.

 

I hate the idea of dragging this subject out any more, but the bottom line is just to use premium fuel. Using a higher octane will give you better gas milage in a Maxima, and paying a little extra at the pump will save you more money in the long run.

Most cars will want to use the lowest octane without causing any pinging or knocking. The Maxima, however, advances and retards the timing automatically so using the highest octane is recommended.

 

o.k. here's the scoop that may have been covered over the course of the last 3 pages, but may not have been concluded.
The octane rating only has to do with the point of detonation, not the cleanness of the gas. Our engines like most high performance engines have a high compression ratio and require higher octane so the gas won't all detonate until under high rpm stress, when it is needed. Lower octane would all detonate earlier (i.e. not make it to the higher rpms) when needed and therefore not make as good use of the high rpm power. The pinging you get from using a lower octane gas is a result of premature detonation. Which is why switching to a higher octance prevents this. Hope this helps!!

 

actually come to think of it, I need to correct myself. Obviously if the engine is pinging at idle then the high compression engine needs a higher octane throughout the whole rpm range, not just up top. This should explain why switching to a higher octane should yield better gas efficiency, because it is not being wasted as much by not detonating at much...ha!

 

I agree, with one exception, the engine does not REQUIRE high octane fuel. It is recommended in order to develop the high performance it was designed for. Running 87 will not hurt it, there is a knock sensor to retard the timing before harmful detonation occurs. If there wasn't a knock sensor, it would need 91+ (for the reasons you stated) and running 87 or even 89 would be harmful as well as stupid.

 

ok, cool. I know that since high octane is recommended, then it is recommended for a reason, and what I stated was to explain why it is recommended, not whether it is required or not. Thanks.