The gas cap on my 07 says premium fuel recommended. Should I be using 91 octane? What happens if I put 87 or 89 in? I'd like to avoid using 91 if it's not necessary because prices are sky high right now around here ($3.15 gal). What octane gas you guys use?

 

There is a huge thread on this in the General discussion forum too.

I use 91 octane just cause. This is the "best way to get the most performance". You can use 89 octane, and you will get better gas mileage doing that. You may get some knocking every once in a while, but nothing to really worry about.

 

This has been an ongoing topic since the board began.

You can use any octane. 91 gives a slight edge in accelleration, 87 may give a very slight edge in fuel economy, and 89 is a good 'middle ground'; slightly better fuel mileage than 91, slightly better accelleration than 87. 89 is the best compromise for my style of driving.

I have friends who have used 87 octane in their Maximas for years with no knocking, so that may not be an issue for you.

The only aspect of this discussion that I do feel very strongly about: DO NOT constantly change octane. The onboard computer has to recalibrate and adjust the fuel and ignition systems every time it detects a change in octane, and this change process is not instantaneous, hence things will be out of kilter for awhile after every octane change.

Some folks change octane for winter and for summer, and that should be fine. But I feel strongly that changing octanes frequently is not a good thing to do.

 

OOOOOOHHH NOOOOOOOOOO, not another octane thread!!!!!!!!!!!!! My opinion is that if its recommended, then use 91. I have a reflashed ECU, so I like to splash some 100 octane in it to raise the octane a few points. I also turn off traction control becuase the traction control retards timing, and we can't be havin that!

 

http://forums.maxima.org/showthread.php?t=390733

 

two thumbs up on previos comment...LOL!!!!!!!!! but if it wasnt for us sometimes missing it what would be the fun

 

Depends on how you drive and what you want out of the car. 87 can save you gas if you don't mash the pedal, 91 can save you gas if you mash the pedal.

 

[QUOTE=chernmax]

really fun pic

 

 

C'MON NOW.. use 91, the only difference in price between 91 and 89 is about 10-12 cents, so in a fill up of about 14 gallons thats like $1.50 on avg. is that really saving up anything?

91 Octane FTW.

 

Just a slight correction. There is no sensor in the car that measures the octane rating of the gas in your car, but what happens is that the ECM will detect engine knocking when a lower rated fuel is put in and make an appropriate adjustment.

Then when you put in a higher rated fuel, the ECM will not immediately change engine operation for the higher octane fuel. Instead it will adjust the timing and mixture over a long period of time for the recommended rated fuel until as long it detects no problems.

 

I second that.

 

Some of us who've been here a while seem to be tired of this topic, but there are always new members who have questions, so they need to be patient.

"light" gave you some good answers -- this is the first I remember getting his always good advice on the topic of Octane -- and the first I've heard him say that he burns 89. I particularly agree with his point about not continually changing the octane in your tank. Pick a grade and stick with it.

Well here at 6 K feet elevation, I burn 85 octane. Check your owners manual on this topic and you will see that this is OK "at elevation." The recommendations in this manual are what you should follow: 91 or higher for the best performance (read acceleration) and 87 octane is acceptable, but your acceleration may suffer a little. Not stated, but implied, 89 is a compromise.

If you really want to know something about OCTANE, check out my many posts on this older thread on this site:

http://forums.maxima.org/showthread.php?t=396716

 

SilverMax that the link to that thread is gold! it should be formulated into a sticky. It answers many questions people keep asking over and over. Mods where art thou ?

 

Thanks Andrei.

I've thought that for some time, but this thread still languishes off of the single screen on the Fluids and Lubes section. I put in a link on threads like this because its easier than trying to repeat all of the details on that ignored octane thread.

As you can see, octane is a complex subject -- and there are so many misunderstandings about it, both on this site and among the general public.

 

I use 93 on the road and 120 at the track

 

If you went to this site:

http://forums.maxima.org/showthread.php?t=396716

You would find out that the 120 Research Octane racing fuel you are buying is not directly comparable to the 93 Octane premium you use on the streets. This is another myth about Octane -- there are different measures and they don't directly compare without knowing what the differences are.

I also suspect that your Max will not see any additional improvement in performance for octanes above about 95 Octane (or 100 Research Octane Racing Fuel). Only if you have modded the engine (like adding a turbo-charger) would any octane above 93 show any actual improvement. So I suspect you are wasting your good money paying extremely high prices for 120 Research Octane Racing Fuel.

There are also reports that it takes the VQ's fuel system between 200 and 400 miles of driving to completely compensate for a major change in the fuel being burned -- doubt if you run racing fuel for that length of time before you race with it.

 

I wouldn't use anything less than what the mfg. recommends unless you like your knock sensor working overtime. Are the few dollars you save per tank worth potentially harming your motor and reducing it's performance?

Around here in VA premium is 93 oct, and I use nothing other than Shell V-Power with great results.