Mreim769

I have always used premium gas. The gas station that I use offers 90/92/94. While I am sure the debate could be made that I should be using 94 since it is availablen to me I just don't see the need to go that high being I haven't gone over 10 psi worth of boost or driven a high performance car so I have always used 92 even back including my Audi.

Speaking of habits though, I was filling up my girlfriends Versa with gas, which is something I normally do when we take the rare drive around in her car, and of course without thinking I pressed the 92 and went on my merry way of filling her car up. Needless to say she was not very impressed that I filled her car with what should have been 87 (she uses a different station then me which carries the normal 87/89/91 grades). The price difference here between the two is about $0.15 per litre and when your car takes about 40 litres per fill it adds up but since I was paying she couldn't complain

OneWhtMax

nothing but 93

STARR

iTrader: (1)

Only ever used 93 in both my Maximas, always go with the highest grade the car can run on, people ask me why I run 93 and my simple reply is cause I bought the car

bk2k3max

Careful don't say that too loud, you may be accused of being too emotional.

STARR

iTrader: (1)

I have simply grown tired of dealing with people, over time I have been asked again and again what I put in my car and most sheep or people don't want to hear your answer they want you to agree with them

Im now 31 and my tolerance for the average idiot who knows nothing about cars is no longer what it was at 21

Norm Peterson

(it was loud enough to hear, but not loud enough to be worth repeating the last 20 or so posts over) . . .


Norm

IH8SPM

114 votes of which 93 have voted to use Premium or the highest grade available in there area. I have switched from using 87 to 89 in my car and my wife has also changed. I have gone through 3 tank fulls and I can notice a change in the cars performance. I can go up hill without the low muffler tones and cruising feels smoother especially when passing. I am going to try 93 this week to see how it goes since I am now driving the car daily. I want to point out that my performance is base on 700 miles of highway driving a week with about 100 of that being the local streets. I want to thank all who have and will continue to vote in this poll. I also want to point out that the car can run very well on the low grade stuff but if you have any desire to feel the cars outright power you will have to increase octane.

lightonthehill

Wow! Approaching this octane question from the OTHER side!

I know nothing about the science involved in going ultra high on the octane, but since this 7th gen Maxima which is set up for optimum performance at 91 octane seems to have absolutely no trouble adjusting to 93 octane, I would suspect it could adjust even further up the scale.

I would not be afraid to try 95 octane. It might even adjust to octanes higher than that without major problems. I will be interested is hearing what our resident scientists here have to say on this.

NiteCrawler

iTrader: (1)

There are various octane race fuels available. Why not just choose the highest octane and be done with it?

In short, higher octane usually costs more. Besides the increased octane, higher end fuels offer a performance improvement over the lower octane fuel due to better burning characteristics. Rockett Brand makes lower octane racing fuel to satisfy a wide range of engine parameters, and some racers do not have the desire to buy the higher priced gasoline. The fact is you may need a higher octane fuel than you think, because your engine may be detonating despite you not being able to hear the knock. You have to look for signs of detonation by carefully inspecting the spark plugs. If you think you might have detonation, try the next higher octane with out making any other changes. You can not "over octane" an engine regardless of what others might say.

If traditional pump-available 92/93 octane premium unleaded fuel isn't high enough octane, can I blend race gas with it? How do I know how much to blend?

First, remember that you should not blend leaded racing gasoline with normal pump gasoline for street use. You can blend unleaded gasoline with a high octane race unleaded fuel such as Rockett Brand 100. RocketBrand has blending charts that allow you to accurately blend to your desired octane number. You cannot accurately blend with traditional octane boosters. If your only goal is increased octane, blending pump gas with Rockett Brand 100 is an OK way to go. If you are trying to get the most performance out of your engine, use100 octane without mixing it with street gasoline. Our 100 octane burns more completely than street gasoline, thereby offering more power and less unburned hydrocarbons in the exhaust--in other words less tailpipe emissions.

Lead in the form of "Tetraethyl Lead", sometimes called TEL, is an anti-knock compound. When TEL is added to gasoline, it raises the octane number and therefore reduces the chance for detonation. If you have a race engine with very a high cylinder pressure (due to a high compression ratio, a high boost turbocharger, a supercharger, and/or a nitrous oxide system) you may need a leaded racing gasoline.

Pretty helpful info i think.....

76 Unleaded Racing Gasoline is a clean burning, street-legal racing fuel with a minimum-octane number (AKI) of 100, designed for high-performance and speciality vehicles. It is the highest octane street-legal racing fuel available. It contains a complete additive package approved by Environmental Protection Agency and California Air Resource Board that keeps carburetors, fuel injectors, and intake valves clean. 76 Unleaded Racing Gasoline can be blended with motor gasolines with no adverse effects. It blends linearly which means that if five gallons of the product are mixed with five gallons of 92-octane gasoline, the end result is 10 gallons of 96-octane gasoline.

NiteCrawler

iTrader: (1)

Oh i got some more facts fellas........


So what does this all mean to YOU in the real world ?

If you have a car designed to run on 87 octane, it can't take advantage of the benefit that higher octane fuel has to offer. So there is nothing to be gained in terms of power or mileage if you use premium fuel. The only effect would be a lighter wallet! In fact you might loose some power and mileage. Remember I mentioned at the beginning higher octane has less energy per unit ?

If you have a car designed to run on high (91/92/93) octane, then use high octane fuel. If you use low octane fuel, the engine will experience pre-detonation and as a safety measure the car will adjust to lower octane fuel i.e. it retards timing. Without going into too much technical detail, in simple English it just means you loose power and mileage. Not just that, you risk damage to your engine. Modern engines are quick to detect pre-detonation (even before you can hear it!) and retard timing but you still are putting your engine at a risk.

So just go with the manufacturer recommended fuel. Don't experiment. The only exception to this rule would be a really old engine that has a lot of miles on it. As carbon accumulates in the combustion chambers compression ratio rises. So a car that has a compression ratio of 9:1 when new could probably have a compression ratio of 11:1 after 75,000 miles. So now which octane do you use ? J Well first of all I would decarbonize the engine but if that's not an option, the engine could benefit from using higher octane fuel.
Another plus of "premium" fuel is that some (not all!) brands of premium fuel have better additives (than their regular fuel) to help keep your fuel system and injectors clean. That does help in the long run.

Worried about your spending for Premium fuel when cost of gas is so high ? Have you noticed no matter what the cost of gas is, the price DIFFERENCE between regular and premium fuel always stays the same ?

lightonthehill

I like this post. I pretty much think it says what we need to know.

I would only comment on two points. I have dropped to midgrade after 18 months in all my Maximas for 26 years, and have never had even a whisper of engine trouble, even though I have put over 200,000 miles on some of them. When accelerating up steep grades, I listen very closely for the first sign of predetonation. If I hear nothing in that situation, then I can feel safe during the 99 plus percent of my driving where I am not stressing the engine.

The other point I would mention is that the difference between regular and premium fuel may stay the same at any station, but that difference is much different in different areas of the country. Some folks have midgrade that is only a dime more than regular, and premium that is only 20 cents more than regular. But my stations range from 30 cents to 60 cents more for premium than for regular. During the gas shortage of two years ago, that difference reached 88 cents.

Nissan sets our cars for 91 octane. By dropping just to 89 octane, I save around three bucks a tankful. For the type of driving I do, that little edge 91 octane may give at wide open throttle is meaningless, because, in 26 years of owning nothing but Maximas, I have never been at wide open throttle. This car accelerates more than fast enough without going to WOT. I may drive fast, and I may love curvy mountain roads, but I am more into handling than all-out acceleration.

Sure, I can afford premium, but it would be wasted with my style of driving. Those of us who aspire to be comfortably wealthy in our old age accomplish that by watching every dime along the way.

smarty666

What I don't understand man, and I've had this since day 1 with my 2010 Max. I have had terrible knocking/pinging noises coming from my exhaust system BOTH when the car is running and not running (cooling off). I've taken it into my local Nissan stealer, have youtube clips of the noise and have gotten a whole host of answers. Some people tell me its absolutely normal, others tell me that they have it but not to the severity/intensity/consistency that I'm having it and NOT WHEN the car is running like I do. Even my local Nissan stealer admitted that a lot of Nissan's make this noise but that my car seems to be doing it to such an extreme severity/consistency/intensity that they are at a lost as to why its so bad.

I've run 93 Octane Shell Premium from day 1 on this car, had Nissan dino oil in the first 7500 miles and since then have had a full synthetic put in and the noise has not gotten any better. In fact, I think it has intensified if anything and I'm going on almost 12k miles now. I've even try two high grade fuel system cleaners in the car just for the hell of it and it did nothing to get rid of this knocking/pinging noise coming from the heat shield area. My stealer tells me there is nothing caught in the exhaust system but the noises are just so loud/constant to the point that when you have the windows down and your idling at a red light or stop sign per say, you can hear the knocking/pinging just sitting in the driver seat. It happens no matter what time of the year/temperature it is outside. I've had it just as loud in January like I have it now in July/August.

I'm just at a freakin lose with this stuff. I have a Infiniti and Acura that doesn't make any of these noises what so ever. I had a couple of crap Chevy/Buick sedans back in the 1990s that made a little of this noise, but only when the cars were cooling off after a long road trip or commute. Nothing like what I'm going through now and never when the engine was running.

Can you or anyone else think of what I could do? The only suggestion I've gotten for the hell of it, is to try Nissan Ester Oil at the next oil change and see if that by chance makes a difference b/c some were telling me that people with the VQ 3.7L V6 had some knocking/pinging noises and once they put the Ester oil in, the noises reduced a lot or went away completely. Other's have told me it has nothing to do with the oil at all but at this point, I'm out of options at this point.

asand1

iTrader: (1)

Dont flame me cause I already know, but I run 87 ethanol blend with a KS resistor. Theres slight knock if I croud it, but I drive pretty easily.

sonomamax

I have always used at least the midgrade, but found out that some midgrades are better than others, for a penny or two more with shell mid grade vs hess midgrade for a couple of pennys less, can change the mpg by 2-5 mpg.

sonomamax

smarty666. If i had that car i know exactly what i would be doing with it, Parking it in the service lane of the dealer and telling him to call me when it is fixed,

lightonthehill

smarty - I'm not sure why your car makes such noise, but the fact it can make this noise when your engine is not even running tells me that gas and oil have nothing to do with it. This is a manifold/exhaust system problem, and your dealer's service department should be able to use a simple tool automotive folks have use for years to pin down the PRECISE location of the noise, which should be enough to enable them to either fix it, or at least make it like most other Maximas.

You shouldn't have to drive a car that looks like a Ferrari but sounds like a Yugo.

lilconfused

i get about 26-27 on long freeway drive, id say around 19 -21 in city/town, and the car says i average 22-23 mpg

i try to only run premium, i live in cali so octane 91

CT Maxima

The exhaust noise you hear when the car cools down is thermal contraction of very hot parts rubbing on each other. Perfectly normal. But the noise has an erratic metronome and is not like ping which follows cylinder ignition. A car that pings can made to ping worst by going uphill at full throttle. It sounds like rhythmic firecrackers going off.

If your noise during operation is similar to cooling exhaust, I suspect a loose part in your exhaust system. Exterior parts, such as heat shields are notorious for these sounds.

Ester oil is a red herring. Except if you own a Nissan dealership, then it is a profit center.

Norm Peterson

I wonder if any of the exhaust tubing is double-wall, in which case you might never be able see the cause.


Norm

Tali43

I run on 91

jecurtis

Premium all the time. I started off that way on my old maixma (2004 SE) as well but when gas was up to $4/ gallon in Seattle, i started short cuttin' it, to save a few bucks, and put in midgrade or regular unleaded. after about a year of doing it, my engine started making a "clickity" sound...very obnoxious. i asked the dealership about it and they said right off the bat, "you haven't been using premium gas. start that and the noise will go away." Took about a month (2 or 3 fill ups) and sure enough, it started going away. i've learned my lesson and my 2010 will only get premium...no more shortcuts like that, just to save a few bucks.

lightonthehill

Midgrade would not have caused your engine to make a 'clickety' sound (I have dropped to midgrade after 18 months in every one of my Maximas since 1984 with no change in performance or MPG for me). But regular will definitely cause some of these Maxima engines (especially 7th gen ones) trouble. In my opinion, using regular in a 7th gen Maxima engine should be considered auto abuse.

IH8SPM

Is this the sound that you are referring to? It's normal and not only on Maxima's I heard this on another car the other day but honestly cant remember the make.

http://www.youtube.com/watch?v=0O1brN0Ur50

My wife's car does it more than mine and she makes small local trips and I drive longer distances and I don't here it much.

lightonthehill

This is the manifold/exhaust system cooling down, and can be heard on many vehicles. As you say, it is not unusual.

Interestingly, with each Maxima I have owned, this sound is usually very loud the first few months, but gradually quiets down. After a year or two, I seldom hear that sound unless I drive the car hard, especially in hot weather.

Flip2cho

I had a friend ask me yesterday what type of fuel I run in my max and I told him 93. He said that he could already tell by looking at my exhaust pipes because the exhaust dust was more whitish compaired to the normal dark black sut. If you can see a difference on the outside I can imagine it makes a huge difference on the inside.

smarty666

Yeah, that is my youtube clips I made of the noise and I can't understand for the life of me understand how you guys think that kind of noise is normal. Neither my Infiniti nor my Acura make this noise when cooling off. That tells me, its an inferior design feature that Nissan vehicles have that don't allow enough room for expansion in the manifold and heat shield area.

The only time I've ever heard this noise is back in the 90s on a couple of my Chevy and Buick products when cooling off but never to that loud extent. If we are using 93 octane Shell gas and full sythentic oil, there is no reason the car should make that amount of knocking/pinging.

What is more disturbing is, the Max makes those noises while the engine is running. I've never had a car make those noises when the engine is running and its gotten so loud you hear the knocking/pinging at a stop or waiting to make a turn with the windows down. If your trying to tell me thats normal for a 38k dollar vehicle to make then its not as refined as I thought it was. Very disappointing and unrefined sounding to say the least.

smarty666

Problem for me light is, I'm not duplicating your experience. The noise has not gotten any better, and in fact, seems to be worse at times. It doesn't seem to matter either whether its real cold or real warm out and it makes the same level/intensity/severity.

Flip2cho

My car used to do this. Now that I have the Y-pipe I never hear it anymore. It def helped that out!

smarty666

thanks for the tip flip!

lightonthehill

If your noise has not gotten better, something is not right in your exhaust area. Also, I have NEVER been able to hear this noise above normal background noise while driving, even with the windows down. Your car is absolutely not behaving normally, no matter what the dealer says.

I suspect that if you start replacing parts in your exhaust system with aftermarket parts, this noise will either disappear or become much softer. But you shouldn't have to go that route. I feel a really competent service tech should be able to narrow your noise to one part of the exhaust, and replace that part under warranty.

If you are into detective work, there is a tool available (someone here will know where you can buy it) that enables you to put on earphones, and hold an attached wand against individual parts and be able to hear the noise that create. You could narrow down the source of the noise to one part. Any dealer service department that does not have this tool is very poorly equipped to serve their customers.

beerman1378

I dont mean to be out of line here but this is an uneducated statement. 100% sure? A new G37s is NOT going to need its motor replaced because of low octane fuel! Octane is the amount of fuel that can be compressed before ignition. Higher compression engines call for higher octane gas(but dont require it...only recommended), but the "newer" engines 1995+ or so can handle a lower octane and still run efficiently. Using a lower octane gas with a high performance engine will cause knock. Knock can damage the longevity of an engine. But in this case, cars 1995+ have such an advanced ignition system, compression strokes, etc...that they will run on lower octane gas. We're talking about a 290HP V6. The bad knock that can damage engines over periods of time seem to happen to the muscle cars of old....or the 83 Plymouth Reliant! lol

Norm Peterson

Ummm . . . no.

"Octane" as used in this sense is a measure. Not a real "thing". It's a rating based in part on the knock resistance of the hydrocarbon of the same name (C8H18). What you buy at the pump is not exactly the same stuff that the scale is based on, as there are at least 24 different ways that you can assemble 8 carbon and 18 hydrogen atoms in a molecule, all with slightly different properties (google 'octane wiki', or see 'isomers' and 'stereoisomers'). The other end of the "octane scale" is defined with zero being heptane (C7H16, - normal heptane to be more precise), which has truly crappy knock "resistance" (if you dare call it that).

In addition to compression ratio, things like spark advance, spark plug location, intake port and combustion chamber design (and the associated air/fuel mixture motions inside), head material, and the load that you're demanding that the engine cope with - also affect the octane requirement.


Norm

alexdi

Not to bring this thread back from the ether, but I wanted to post a quick note of my own experiences. Until recently, I used a 50/50 blend of 89 and 93 at the pump. Max RPM was 6200 RPM and the car generally felt lethargic at part-throttle, though still capable of quick acceleration with the pedal floored. Wheelspin off the line was minimal. I moved to 89 for a tank and didn't notice a difference.

Then I tried 93 octane alone. Mid-range response is significantly improved, and the car and more inclined to rev with less throttle. The engine doesn't lug as often. Max RPM is now 6600 RPM, right on the limiter. On a road with occasional damp patches, wheelspin was present and annoying for much of 0-70 run, with VDC cutting in for most of it.

I'm not convinced the extra RPM makes the car faster, but I wouldn't give up the mid-range response. 93 all the way.

kmonn001

Premium. I have always used 93 on all my cars.

one less digit

dont insult your car with regular or mid

Norm Peterson

<sigh>


N

lightonthehill

<sigh for me too, Norm>

k757

iTrader: (1)

no worries fellas, there are people who comprehend your knowledgeable posts

alexdi

What are you sighing about?

lightonthehill

Lots of things, but primarily the conviction of so many drivers here over the past decade or more that the car performs much better with 93 octane than with the 91 octane for which Nissan has set the car up.

If the Maxima is properly tuned to OEM specs, it may be theoretically possible that carefully timed wide open throttle tests alternating between 93 and 91 octane in the same Maxima might produce a fraction of a tenth of a second difference in zero to 60 times, but not a difference a driver would be able to detect without sophisticated timing devices. Certainly no difference that would be noticable in any normal driving situation.

Any operational evidence to the contrary probably results from either the psychological impression of the driver that the extra money paid for higher octane is worth it, or there was some bad gas involved in some way.

But urban myths never die; they just continue to propogate on internet boards.