Blanket statements that

(a) imply that mechanical devices have any capacity for human emotional reactions

(b) are brief comments interjected into a discussion that has developed way past that level, apparently without much real thought or from reading through the whole thread. Actually, I suspect it's a case of a newbie running the post count up for some reason (over the last 3 days, 30+ threads/49 posts), but at least he's going about it in a legitimate fashion.


N

 

Light, I think the certainty of your conclusions is unfounded. You have no data on the engine tuning of the Maxima beyond a single line the manual. From what I read of your posts, you rarely, if ever push the limits of the car. You can't account for the enormous variety of conditions people on this board encounter, or for production variations in the engines themselves. You don't know if the ECU is changing transmission profiles in response the higher octane.

And yet, you're supremely confident that anyone who feels a difference is deluding themselves. Well, you live in Atlanta. So do I. If you're running 89-octane or a blend, stop by and we'll trade cars for a bit. Perhaps you'll feel it yourself.

Norm, I'm surprised you even see those comments when you read these discussions. They're like snow on an old television.

 

alexdi - I am just going by my experiences and by magazine and technical articles I have read over the last sixty-some years.

I have been trying different octanes for millions of miles in dozens of vehicles since the late 1940s, and in Maximas continuously since 1984. I have run 93, 91 and 89 extensively in my '09, and occasionally do drive somewhat aggressively whenever I am in areas where there is little traffic.

With each change in octane, I make an attempt to judge exactly how the engine is running and the CVT is operating both before and after the octane change. The differences might be measureable with electronic devices, but I certainly have not been able to detect the diferences by careful observation.

Nissan tells us this Maxima is set up for 91 octane. I am currently running 89 octane. I would not be surprised if refined electronic gear might detect a difference between my car's performance with 89 and with 91, and such gear might also detect a difference between 91 and 93 in your car.

But if there is a clear and obvious difference easily observable by the driver in the behavior of your car between 91 and 93 octane, that would strongly suggest that either something is not right with your car or you have been getting some bad gas.

 

I'm sure that it's possible for an engine (maybe I'd better extend that to the entire powertrain and all of the associated electronics) with everything mechanical and electronic deviating slightly from "blueprint" - but still within tolerance - and crowded off in the direction of requiring higher octane to benefit from 93 octane under some operating conditions. Statistically, about 100 cars per year could be expected to fall outside 3 standard deviations on the high side . . .




Alexdi - Actually, they're kind of hard to miss, given that I start most weekday mornings off by looking at the notices of reply to topic that showed up in my e-mail overnight and clicking on the link. Even more so when they appear to either be perfectly aligned thoughts that I have already expressed, or completely opposite to them. Or when the reply is so short that I can read the whole thing twice before the thread window pops up.

Once I get involved, it's worth the risk of learning something new to read all of the replies as they are posted. Right this moment, I've got this and one other 7th Gen Maxima thread open (light is also in the other one, the one about the "HP war"). And three Mustang related threads on two different fora (one of which led me into a private discussion through still another forum that I haven't opened yet). I started replying here; haven't decided whether I'm going to add anything to any of the others yet. A slow morning, actually.


Norm

 

I'm getting ready to buy a 2009 Maxima and after reading the discussions regarding fuel choices I'm wondering if I should take this into account before I make my decision?

Specifically, I've noticed that fleet/rental cars are probably $2k less than comparable non-fleet/rental cars. Normally this would not be an issue because I've read that fleet/rental cars are usually well maintained. However, it seems to me that fleet car (and especially rental car) drivers might be inclined to purchase the least expensive fuel available rather than the recommended grade.

If this is in fact the case, is it possible that running non-premium fuel for an extended period in these cars could cause, at worst, engine damage, or at best, cause diminished performance?

 

you do not want a previous rental, no matter how much you save. People drive them extremely hard and sometimes off road (guilty! but I bought their insurance hahaha) Year ago I took a Plymouth Breeze up a dry creek bed, a place only true heavy duty off-road vehicles should be at. I didn't get stuck, but the car was not the same afterwards. I also jumped it in the desert while I was baja racing it, the road had a nice bulge in it and the weight came off the wheels. I doubt I caught air really, but it wasn't a smart idea what I did. Anyway, back to topic... avoid ex-rentals

 

Would you include fleet vehicles as "rentals". Specifically this one; http://www.autotrader.com/fyc/vdp.js...standard=false

 

Yes I was just in Houston and Avis has a ton of Maxima S models for full size rentals. It was great I connected my phone and it was as if I never left home.

 

I don't inderstand all this fuzz about 93 vs. 87 gas. The main argument is that 93 gas is more then $3 per gallon and it's just too high... But you have to put a gas in anyway. In my calculation 93 gas costs appx $0.25-0.30 more than regular gas. On a full 20 gal tank it makes a difference of $5-6. Well, on those days I just don't buy coffee

 

I am a little **** about recordkeeping and I track my mileage by the tank and by the running average. To date I am averaging 24.69 mpg over the last 15000 miles. For the first 12 months of ownership I used 541 gallons of gas and with a maximum price differance of .30 cents/gallon I figure I have spent an extra $162 dollars for the premium fuel, or about .44 cents/day. I think my Max is worth it.

 

are u guys sure 87 octane is bad ? the dealers throw 87 octane in their cars all the time, when they fill up for u guess what they put in there ? 87 octane!

 

Several months ago, the gas station attendant accidentally filled my Max up with regular and I had all kinds of problems with that octane. It was rough idling like crazy, had problems accelerating, and sounded like it was going to konk out at certain points. As soon as premium was put back in the next tank it was back to normal.

I do not know how anyone is driving around with 87 octane in this car. Its designed for 91 and higher, that is what should be used. If you don't want to put in premium fuel people should have gotten an Altima instead.

 

and you know this . . . how?

(It's not quite as simple as 87 octane being either bad or good)


Norm

 

wow looks like the engineers on the maxima build the engine on low tolerances, because the engine should not make that much a difference with octane difference.

but even more reason for faster depreciation on this car, nobody wants to use 92 octane no more. it's all about 87 octane now and higher mpg.

 

The engine is designed to require 91 octane under some condition(s) that can be expected to occur during normal use. Neither Nissan nor anybody here can tell you if your specific driving includes such driving conditions, or that even if you know what they all are and actively avoid that sort of driving - that you might not find yourself driving there from time to time anyway.

No matter how closely you manage to hold tolerances on mechanical and electrical/electronic components, some cars will be closer to the edge than others.

A few may be past the edge and require more than 91 under unique operating conditions. Smarty's car may well be one of those cars that is more than 3 standard deviations away from the mean on the "high octane required" side. People whose cars are tolerant of mid-grade may have an engine whose tolerances ultimately make it less demanding.

Much of the time, in normal driving, the actual INSTANTANEOUS octane requirement is less than 91.

It's too complex of a problem to second-guess from the bleacher seats.


Edit (and out of simple curiosity), have you ever done any EFI fuel and ignition mapping?


Norm

 

What the hell do the Nissan engineers know about the car they designed (with requiring 91+)?!?! If (the proverbial) "you" feel it's best to use lesser octane, do so and enjoy the few pennies in your pocket.

After reading this thread for a while, I have just put two tank fulls in of 89 and I notice that the steering wheel has a slight vibration at idle. I have not noticed any performance change in my daily driving. When the tank gets real low, I'll return to the 91/92/93 (depending on whats available at the station)

 

Premium shell gas always the max gotta drink good!!

 

That may be what the mfrs and the various parties with their agendas and scare tactics are pushing, and what they want you to think.

I don't expect the demand for premium fuel to go away - it's what lets small engines with turbocharging or even just high efficiency normally aspirated engines be built. Don't for a moment think that the desire for performance is going to go away.


Norm

 

Those who claim only 20 or 30 cents difference between regular and premium are very lucky. My stations vary, but the last time I bothered to look, the prices were $2.59. $2.79 and $2.99 for 87, 89 and 93. That is FORTY cents between regular and premium. With an 18 gallon fillup, that is OVER SEVEN DOLLARS.

Despite the ridiculous price differential, I would not even consider putting regular fuel in my Maxima. I follow a process I have used for 26 years with my Maximas - I use premium the first 18 months, monitoring how the car is performing, MPG, etc. Then I drop to midgrade, and try to determine if I can detect any difference in performance or MPG. So far, with my particular Maximas (every car is slightly different), my style of driving, etc, I have never been able to detect any difference between midgrade and premium.

Again, I would strongly suggest not using regular in the 7th generation Maxima; 87 is just a little too far below the 91 octane level Nissan says the car is set up for. Although some 7th gens might be able to adjust all the way down to 87, I would suspect the car might not be operating quite as efficiently with that great an adjustment. But not being an engineer, I just decided it wasn't worth the monetary savings to risk finding out.

 

I accidentally put 87 octane in about 2 weeks ago. Something just did not feel "right", but I didn't have any knocking or anything like that. Besides that one case, I always use premium.

 

The gas station attendant filled your car? Wow. Here in the South we have to put gas in our own cars.

I agree, though. I knew from when I started shopping for a new car that if I bought the Maxima I would have to commit to putting premium in it.

 

it is a state law in NJ. I guess people don't know how to fill their own gas tanks .... ....

though I do love paying their prices

 

Noo Joisie and Oregon are the only two states where an attendant is required to operate the gas pump.

I never saw the need for requiring an attendant until the few times I had to fill up in Atlanta at night. At those times, I would have loved an attendant. Only a desperate person or a fool gets out of their car in Atlanta at night. Even a baby in an infantseat in plain view doesn't stop these evil doers. A life in Atlanta at night has a value of less than five cents.

I never take my Maxima into Atlanta at night; draws far too much 'attention.' We use one of our work trucks for such dangerous activities.

 

87 and she runs great...

 

Just be sure and be aware that Nissan specifies in the owner's manual that if the only fuel you can find at the moment is regular, then buy just enough to get you to where you CAN buy appropriate fuel, and to be sure and do NO quick accelleration or aggressive driving until you have proper fuel in your car.

 

i have an 02 max but since those say to use 91 octane also i hope my opinion counts. I use premium and when I was coming hope from maxus09, somewhere in new jersey I went to a full service station. I told them to put premium and they put regular in. the next day my engine started ticking...put premium in and it was fine. I only go to mid grade if premium goes to $4 per gallon and never regular. in my opinion $4 is rediculous idk... has happened i think 2 winters ago.

 

You do realize that if the price differential between premium and mid-grade holds constant (whether that's $0.10 or $0.30) - when the prices themselves go up, the difference between them computed on an actual-use cost per mile basis shrinks . . . making it actually a tiny bit easier to justify using the better grade.

You do have to get past any psychological "barriers" such as seeing a 4 to the left of the decimal point.


Norm

 

Today I noticed prices at a pump. Good news - it was only 21 cent difference between 87 and 93. Bad news - 87 cost $2.80. That's what the mixed feeling is!

 

I use premium and will always use it. Will cost approx $300 more per year than regular. It's worth the higher quality fuel.

 

I never thought of that.

 

premium all the way. however, i'm sure that regular won't necessarily hurt the engine, the ecu is smart enough to adjust timing to prevent knock however OPTIMAL performance will be reduced

 

Is the ECU smart enough?
Probably.

Will it always react fast enough?
That's where the greater concern lies, since the knock sensor has to "hear" knock that is already occurring before it can tell the ECU that it has to do something about it. Some of the effects of "knock" are fatigue related, and this is a cumulative thing (kind of like bending a paper clip back and forth until it breaks, except that engine problems resulting from knock aren't likely to happen nearly that fast in a stock motor).


Norm

 

true indeed

 

Norm knows of what he speaks. I would strongly advise against putting regular fuel in this 7th gen Maxima, even if I was only going to drive it on a level road one mile to Sunday School at 35 MPH once each week.

For drivers who may wish to drive this car as it was meant to be driven, I would say using regular fuel would be penny wise and pound foolish.

 

Apparently all these 87 octane people didn't read my posts where several months back an attendant accidentally put regular in and I had troubles with the car the entire time that tank of regular was in. The engine struggled and I was worried it was going to crap out it sounded and idled so bad. Don't put regular in this car period!

 

87 octane in an engine with a 10.3:1 Compression ratio is just asking for detonation. Typically once you cross the 10:1 threshold, 91 or 93 is recommended. Smarty- you know what's up.

To be honest, I can't believe this thread has gone on for so long. Nissan recommends 91 octane. I'd heed their warning. I only use Shell and Texaco (both top-tier fuels) 93 octane, however I will run 89 here and there to see if there's much of a difference. To be honest, besides the idle feeling just a smidge rougher, I could barely notice any difference in MPG's, power, etc.

To end my senseless jargon above, just use what Nissan recommends. They engineered the snot out of this engine, I think they know what it should drink.

 

Does anybody know what a brand new out of the box VQ35 costs these days?

 

Guess it would depend on the year. Would think at least 7-9 grand for one. I know an LS3 turnkey crate engine will run you about $7,500. Now given thats an OHV, 2-valve per cylinder pushrod V8, but you get the point.

All I know is that I hope none of us ever have to find out the hard way!

 

I use 89 all the time on my 2010. It runs great!

 

I actually thought it would be a bit more then an LS3 just for the amount of VQ35's people buy straight from the factory.


But anywhos, the point I was trying to make was......$7 more for a premium fill-up or $7000 more for a brand new engine?

Detonation can destroy engines period. Will it get destroyed that first time? No. Second time? Not Likely. But after frequent usage the amount of stress and fatigue and even damage goes up and up and up. Why do that to a brand new car just to save a few bucks?