I have an '01 SE Auto and my dealer says mid-grade is fine. Should
I buy premium? Thanks.

 

http://forums.maxima.org/showthread.php?threadid=86357

bargh? her-hee-her-haw-haw
bp

 

The ECU will adjust the timing to compensate for the octane of gasoline you use. I use nothing but Chevron Supreme with Techron in my 2K SE because performance is important to me. My wife, on the other hand, runs either Arco or Unocal 89 octane in her 2K GXE and has since the day she purchased her Maxima. Her car has over 40,000 miles on it now and I've only heard it detonate one time under WOT. A bottle of Chevron PRO-GARD in the gas tank fixed that.

 

There is a lot that determines what octane is optimal... and simply saying the highest is best is grossly over simplistic.

I frequently use regular and have never heard pinging or knock. Any adjustment the ECU makes due to feedback from the knock sensor has not resulted in noteably poorer gas mileage (and I've kept records). Performance may be affected, but I don't have 1/4 mile times to compare; I can not feel the difference by "seat of pants".

My suggestion is for you to burn any grade you want (there is no chance of damage if there is no knocking), keep records and run a linear regression and correlation analysis to determine if there is ANY sensitivity in mileage to octane. I did it... and there was none! There are so many other factors (load, temperature, how I felt, altitude, tire pressure, etc) that so grossly outweighed it any variablity due to octane was lost in the noise. I'd have to keep really good records (to support a much more complicated correlation analysis on multiple variables) and get a lot of data points to try and find how octane affects it. Either that or carefully control conditions, like a couple of long dyno runs.

Having said all that... there are a lot of people who swear up and down they see a gas mileage difference using premium, one that more than pays the $4 a tank difference. Don't know how they get there, but they do.

FWIW, I usually use mid-grade, just 'cause I am willing to. But I also use regular frequently, just cause I'd like a free snack.

And one other little tid bit: when selecting a race fuel for a given engine, you aim for the LOWEST octane fuel that will not result in knocking or pinging! Why? a lower octane fuel burns more readily, completely and quickly. The idea is to have the fuel release all it's energy at the correct point in the power cycle, even at high RPM's. Higher octane fuels, burning slower, will release (at least some of) it's energy at an un-optimal time.

BuddyWh

 

Great post, Buddy. Thanks.

I began running Chevron Supreme with Techron exclusively when I was experiencing detonation as a result of defective ignition coils. Nissan replaced my coils and the detonation problem went away. But I haven't been willing to go back to lower octane gasoline yet even though 89 octane works perfectly well in my wife's Maxima.

Old habits die hard.

 

Everyone seems to have reasons to rationalize their use of grades lower than 93 Octane. You be the judge, Nissan specifically suggests 93 Octane(super unleaded), premium fuel for your $30k car. I have read many posts of people cleaning their throttle bodies and getting lots of dirt out of them. Just cleaned my K&N filter and my throttle body today, throttle body was not very dirty at all. I wonder if the fact that I always run Super Unleaded has not helped clean that throttle body clean.

 

use whatever you please.. But if you choose not to follow the owners manual, you are on your own. literally.

"I've only heard it detonate one time under WOT"

hmmm, how many do you think it takes to cause damage? Have you ever seen what low octane will do to a car trying to large hill? I have. You get paperweights for pistons.

and Buddy, we dont have racing engines or ignitions systems.. but we do have high compression engines and THAT is what dictates our requirement.

To say "there is no chance of damage" is completely irresponsible. You dont know his elevation or driving habits.

jeffil, if I said "yeah, I know what the manual says but I can go 12K miles without a oil change" would you buy it because someone on the internet said it was ok? Sure under some situations and syn oils, you can, but that blanket statement would be grossly wrong. Or the dealer for that matter. He wont stand behind you if you werent running the what the manual said.

The manual states that the car will run on lower octane but that you should get high octane as soon as possible. Lots of people run regular and many never have trouble. For me, I call it insurance. I run lower octane in the PF as it only calls for mid.

Btw, my max runs like crap on low octane. I know this because my dealer filled it up for me a time or two and they used 89.

 

On the contrary, whenever I do use anything less than 93 octane I get pinging bigtime. So for the 2K2, 93 it is.

 

Hmmmm. Well by that definition, Tim, my engine should be fried as a result of the number of times it detonated with defective ignition coils. But it isn't. I had the dealer run a compression check when they changed the coils.

I know you're aware that detonation can occur for a variety of reasons, even with premium gasoline. And I suspect you'd admit that it takes more than occasional detonation to ruin an engine.

Still, your points are well taken. Certainly no one will go wrong running premium gasoline. That's all I ever use in my SE. But with all due respect, my wife's car runs great on 89 octane and has for over 40,000 miles.

 

The use of any specific octane fuel is NOT REQUIRED by the owners manual. You do not "go it alone", you do not put your warranty in jeapordy when you burn low(er) octane fuel; only use of leaded fuel would leave you unprotected. Even if you brought in your car with three pistons burnt through your case is valid: the anti-knock system and/or ECU was defective. The only possible reason for denying would be you continued to operate for extended periods under an obviously defective condition, which would be true.

I'll say it again, and there is nothing irresponsible about it: if there is no pinging or knocking, there is no chance of damage. <(see the period?) Driving habits and elevation are fully wrapped in that statement. There are no other properties unique to high(er) octane fuel that can prevent or deter any kind of damage. To suggest otherwise is itself irresponsible, grossly misinformed or both.

And yes, I have seen what too-low-octane fuel does to a car. I helped tear apart a friends Vega when it started blowing oil (unrelated, all Vegas blew oil within 60k) that had a stuck advance plate; it pinged and knocked like mad for over 30,000 miles. Shiny piston tops, small pits and blobs but nothing burnt through. I think I know what knocking can do... and not do. It takes 10's of thousands of very hard, almost abusive, miles with a lot of extremely hard knocking, bad enough to be unmistakeably heard, to do damage serious enough to be detected without a tear-down. Although, you will be able to read it on spark plugs (a lost art, reading spark plugs).

And I know what it sounds like, both severe knock and light pinging. People today seem to have absolutely no idea as the anti-knock systems in modern cars do such an effective job. People who've never driven '70s American cars would probably freak when they actually hear it... there will be no "I think I heard it once at WOT". HAH... if your engine is prone, you will hear it as you start to accelerate and steadily increase, "rolling" as it were, and then it can actually drop off at WOT. It is unmistakeable, and a clear indicator service is demanded. If you hear it at WOT, at all actually, then you have a defective anti-knock sensor ECU, or both. Using the maximum octane available does NOT fix it, it masks a defect that should be fixed. Drive your car, broken, if you want but I would have mine fixed while still under warranty. My 2k1 is not broken... it has never pinged, even with the 84 octane I once fed it this past summer.

And finally, racing engines and ours are not so very different in this regard and those differences are mostly in our favor: our engines are timed such they are much more tolerant and they are equipped with knock sensors. Which should work.

Use the octane you want and be happy, but I stand by my answer and consider it highly responsible. The questioner should be left more informed on the topic than when he asked it, not mis-informed with the same old half-truths, old wives tales and FUD that have pervaded this topic in the past.

BuddyWh

 

You have a defect, you should not have pinging. Your anti-knock sensor could be defective. Take it in, pinging, with 89 or 91 and have them fix it.

BuddyWh

 

on half truth.. thank you. I was lost without your years of antidotal evidence on the effects of using lower octane than specified.

I still dont prescribe to the "works fine for me" method of car care.

 

The manual, under recommended specifications for fuel, reads:

"Unleaded gasoline with an octane rating of at least 91 AKI (RON96)"

It goes on to read:

"Use unleaded premium gasoline with an octane rating of at least 91 AKI (Anti-Knock Index) number (Research octane number 96)

If unleaded premium gasoline is not available, unleaded regular gasoline with an octane rating of at least 87 AKI (Research octane number 91) can be used.

However, for maximum vehicle performance, the use of unleaded premium gasoline is recommended."

It later goes on to state that you shouldn't use gasoline with an octane rating below 87 or it will cause "persistent, heavy spark knock.... this can lead to engine damage."

I guess it matters how you want to read this information. I read it that you're allowed to use below 91 octane, but it seems the manual suggests that should be the exception and not the rule; and that it really isn't recommended for normal usage. You probably won't get your warranty voided for doing it. For me, however, I have a $30k car I'm not going to risk it or reduce the performance on to save $2-3 at the pump. I bought the car knowing it called for premium unleaded... cost of ownership.

 

"hmmm, how many do you think it takes to cause damage? Have you ever seen what low octane will do to a car trying to large hill? I have. You get paperweights for pistons."

Your question demanded an anecdotal answer, what else would you expect?

Thank you for posting the manual extract... the very first line says it... "Fuel Reccomendation", in fact the whole section is dominated by that word: first and last. And the cautionary note makes it clear that "fuel specified" refers to unleaded fuel.

Observation: if you don't like the "works fine for me" method, you are in pretty sad shape as that, essentialy, is all there is. Sad truth is that maintenance reccomendations are based on experiences "worked fine... lets make it....".

And then, generaly, we follow a much shorter oil change interval than the manual reccomends. Somehow I feel confident you do NOT adhere to the manual reccomendations here; if so, that alone belies your statement.

BuddyWh

 

To sum it all up, after reading people defending their use of 84 octane, opinions indeed are like a$##holes. Everybody has one, most of us would be better off without viewing others. Bottom line feed your car whatever gasoline grade you want. Bought my car with 15k, dealer had obviously used low-grade level gas when they fulled it up. First two weeks i got 19-20mpg, even on long trips. I have used nothing but 93grade since I've owned the car. I have consistently gotten 23mpg city, 26-28mpg highway, you do the math.

 

Hey... I never intended to use 84, the station had swapped location of the regular and mid-grade handles (their trick backfired that time). When I noticed, it was too late so I made a note to observe performance.

I have done the math... based on a lot more than just one tank of gas. I wanted to make an intelligent decision based on logic and reason, not emotion; that is all I suggest anyone do. Use a variety of fuels without fear, keep records, and do the math. You don't have to accept anyone's opinion, including the manual's, like it is dogma; but you need to be armed with a little knowledge.

As for me... and I imagine quite a few others also on a budget... I kind of like putting that $4 back in my pocket at fill-up. After all every sixth fill-up is free!

BuddyWh

 

Octane is a numerical value assigned to fuel that represents it's anti-knock property. The higher the Ocatane value, the slower the fuel burns. Engines with high compression ratios, such as the Maxima, require slower burning fuel to compensate for the higher compression ratio. The ECU can retard the timing to compensate for a lower Octane fuel. This is more of a "work-around" than a permanent solution. The knock sensor plays a critical role in this process as it tells the ECU knocking is occuring which in turn the timing is retarded. The important fact to remeber here is the the ECU retards the timing AFTER the knock(ing) is detected. The use of low Octane fuel all the time means this is occuring all the time. The ECU will adjust itself but there will be times when it doesn't. This is why the owner's manual specifical states the use of 91 Octane or higher.

 

Jason96GLE - your right on, you should have kept going with it! Years ago, I used to build some high compression V-8's to drop in some american muscle and can tell you for a fact, timing is everything. I've put a D-port 427 big block on a dyno and turned the distributor by hand while watching the needle. A few degrees of advancement could translate in 50+ horsepower gains, but you had to be careful with detonation and running a big enough radiator. We didn't have knock sensors to take care of the timing and we had to rely on our ears instead. How many of you remember advancing the timing til she pings, then back er off a couple of degrees? Or what about those spring & weight kits to recalibrate the advance curves - better yet, vacuum/mechanical or full mechanical advance when running a heavy cam? The point is our max's have a high compression motor and an ECU that will take full advantage of it, technology is great!

I've read some of the previous posts about lower octane igniting faster and should be used when racing. The faster igniting is right, but the timing is so retarded to keep it from hammering itself to death that it won't have as much power. If you use the higher octane in the max, the ECU block learns are happy as a lark and she'll sing like there's no tomorrow. With the higher octane, there are also less BTU's in a gallon of gas, but with the advanced timing, it becomes about a wash in fuel efficiency. The max's ECU learns what you are feeding it based on throttle position/knock sensor readings and anticipates a timing curve it will use when you press down on the pedal. If you use different grades of fuel, it confuses it for awhile until it re-learns and is why it sometimes knocks. If you are using low grade fuel and switch to high grade, you probably won't notice the power increase initially since it gradually adjusts the timing curve to use. If you live in a cold climate area, your likely to encounter oxygenated fuels (read crap)in the lower octane ratings and is why some swear the premium gets better mileage. Your very lucky for owning a car that can actually take advantage of premium fuel, most domestic cars can't and it's just a waste of money. You will have to be the judge for yourself what to use, but I would try to be consistent with whatever you choose. Peace

 

isn't it 91 octane?

 

Ive had the car for 2 weeks. I wil use Premium till the price of gas hits 2.00 a gallon here in Calif. Then it will be 87 Octane !

 

I dont understand.... Buy a $30K car and be a cheap ***** to save a couple dollars every fill up. I know I drive my car hard so I exclusively run Sunoco ultra 94. Never had any problems... Not to mention a slight mileage increase using the good stuff. Although I will say my 92 Pontiac Grand Prix with 145K miles wont run right unless I use 87... Anything higher than that and it stalls out and idles rough.. But, thats not the case with the Max.... So ultra it is, all the time in the Maxima......

 

if you want to run your Max hard, like 90% of us do, use the premium. If you want to go get groceries, like Buddy's wife, use regular.

 

I was waiting for someone to post this

 

Good for you...

 

What can I say.... there a a lot of people with a lot more money than brains.

Enjoy the company.

 

And I thought my ECU was the only thing retarding itself. sorry, couldnt resist.

man, premium fuel and synthetic oil? I must be crazy! I'm lighting cigars with $100 bills. I got Oprah getting mail. Trump does my laundry. Snipers on the helipad to keep an eye on my lawyers...

yawn...

I think the point here is that just about everybody has their own justification for running what they do. Most are not spending more mindlessly. I dont enjoy spending more. But I dont like the car loaping or hesitating/pinging either.

 

http://www.caranddriver.com/xp/Caran...e_gasoline.xml

Bottom line, no, you don't NEED premium gas . . .unless your car knocks without it, but if performance is important to you, by all means, use it.

I ran premium (only 91 octane) the first month I had my car, my last tank I tried 89 and seat of the pants says no diff. No knock, either. I'm not concerned with losing that possible .3 in the 1/4 mile like some of the cars in the test did. I do enjoy WOT romps every now and then, but I'm not into racing, street or otherwise, so 89 is good enough for me.

 

Your exactly right! Like the manual says... for "maximum performance"... I never said you should NOT use premium... IF i ever raced my car... very VERY doubtful... I'd use premium too.

Just feel free to experiment.

BuddyWh

 

Don't get so discouraged Buddy. We are Maxima fanatics we will not scrimp on the small things. If your wifes using 15 gallons a week, and saves three bucks, it adds up to about $150 a year. That kind of savings does not justify going against the owners manual and possibly losing performance. People on the org invest thousands of dollars into thier rides, we don't run groceries, not to be rude. Keep on posting dude, you obviously know your ****.

 

What about the purity of it and leaving deposits inside your engine... Not neccessarily felt by a performance loss, not to mention the seat of the pant you would not feel really unless its more than 5 HP. Also modifications on you motor would possibly neccesitate the premium gas. I know that most chips/ECU reprogammings require it... 15 gallons of gas @ .10 cents more = $1.50 per fill up. Thats a cup of coffee or if your a smoker 1/3 a pack of butts.

I am not bucking heads with you just cant really rationalize in my head why you would not use premium. Oh-well. Enjoy your Maxima either way... I will...

DIFFERENT FOLKS DIFFERENT STROKES

STEVE

 

regardless, everybody seems to be able to run their engines far past the rest of the car (like trannys and such) to like 200K+. So the point is probably moot.

Buddy is right..it's not *required*, just recommended. Nissan service has just scared me into following the letter of the manual. I want them to have as few excuses as possible :/

 

As far as I am concerned you are taking your chances by using Regular or anthing below 91. It's up to you what you use, but don't blame Nissan when you have probelms. No I am not saying your engine will blow up.

It's more then just octane ratings, do the research rather then go by anecdotal evidence from a car nut who still lives in the 60s,70s or 80s, cars now are much different.

Knock sensors that retard timing are a safety feature not a workaround for you to use cheap gas. Want to see a difference, go to the Dyno with some regular gas and get your numbers, then fill up woth Sunoco Gold 94 and you will see the difference. Having said that it doesn't mean that the high the better so dont waste your money on 110 race gas.

If you want to run cheap gas buy a a Civic.

Here are some links...

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

http://theserviceadvisor.com/octane.htm

http://chemistry.about.com/library/w...abyb100401.htm

http://www.ftc.gov/bcp/conline/pubs/autos/octane.htm

 

Except, most refineries only produce and stock one grade auto fuel, varying by time of year. Our local refinery distributes to all the local gas stations, the only difference is a branded additive package put in the tank trucks. Also, the package varies only in the amount of anti-knock, so you get the same benefit of detergents in regular.

Far more than I was aware, they don't get the package ratios correct. So you can not be assured that you are getting what is labeled on the pump. Although, from what I have read it most common that pumping regular actually gets "premium". I'd guess it's because additives are so cheap it makes the distributor's job easier.

If you are truely interested in maximizing performance, buy racing fuel of a known octane rating. Even if not, at least put in your own detergent package periodically to know your engine is clean.

BuddyWh

 

Thought I was "maximizing performance when I bought a Maxima......

 

Here is an even better link. But it might make for a little difficult reading...

www.faqs.org/faqs/autos/gasoline-faq/part1/

And probably more technical than most are willing to wade through, but by all means not as technical as it can get.

Your URL's, like most of the opinions expressed here including my own, are too simplistic on the subject.

BuddyWh

 

Knock sensors aren't just a safety device, they are an integral part of the engine and emission control system. The ECU constantly monitors it and makes adjusts accordingly. If you doubt, disable it if you want and see how it performs, even with 93 octane.

Why should I? What are you, some kind of Maxima Owner Purity cop or something?

 

I hear ya

 

Interesting write up, but 95% of it is irrelevent to this thread. The question is if one should use the recommended Octane rating and the answer is simple, use what the manufactrer recommends which is 91.

I paid good money for my 255hp (claimed) in my Maxima and if it means using premium gas to get it then I will do so.

What's the point of having a colour TV if your signal is only black or white, or HDTV and using a coaxial cable for the signal? it will work but you are not getting what you paid for.

 

Exactly how I feel buddy... Super it is....

 

Paragraph 1: Yes it does make adjustments, like retarding time so you don't blow your engine, umm can you say saftey device.

Paragraph 2: uh?

Well like I've said each to their own....