| bruno |
| Is there any reason , other than performance, that I should use high octane fuel? I've been running 87 octane almost all the time since new, 10K miles now, can this cause any engine damage? |
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| GMTURBO43 |
Some have reported knock when using 87. In general, there is about a 10 cent increase between grades i.e. 89 is $.10 more than 87 - 93 is $.10 more than 89. This is only about $2 per tank of gas. We get slightly better mileage using 93 than 87.
We have had knock using 87 - but it seemed to be only on one particular fill up - so it could have been bad gas. If I have a choice I go in the middle with 89. |
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| Snow MO |
I have run 87 with no negative effects...
I have noticed that I do get better mileage with the better fuels though, but that's to be expected. |
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| Stoker |
| I have been using midrange fuel (Shell Silver ) since I got my Mo and have been able to get pretty good mileage numbers. The only time I really notice a difference is when I am pulling my tent trailer. I find that using premimum fuel instead of midrange I get better fuel economy. |
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| SIM |
The MO's aerodynamics numbers must be pretty good because just adding the roof crossbars and a Thule bike rack (even with no bikes on it) has increased consumption. You can actually hear the wind drag on the highway and consumption was up close to half a liter per 100 km using 91 octane gas.
93 is not available anymore around here since a few years when Sunoco was bought by Ultramar. |
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| senza |
| 87 octane works fine for me...I can't say I notice any mileage difference between reg and prem...noticeable loss in acceleration at WOT with reg....cost difference here; premium 10 cents more per litre or (4.54 x .10) 45.4 cents/gal....approx. $8.00 CAN per tank... |
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| Eric L. |
Other than performance, no damage. You can use it without a problem.
If you are noticing knock on regular, your knock sensor is not working right. |
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| jimthor |
Eric, isnt some knock upon accel, when using 87 okay?
It goes away after a sec or two when first starting out . |
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| Eric L. |
quote:
Originally posted by jimthor
Eric, isnt some knock upon accel, when using 87 okay?
It goes away after a sec or two when first starting out .
In my experience the knock sensor is sensitive enough to detect the slightest knock, and retard timing almost immediately so the driver never notices the knock. If you can hear the knock, then something isn't working right. I have own two vehicles with Nissan VQ engines - they both recommend super, and I have run regular in both without ever noticing knock.
If it is really hot where you live, then I suppose its possible using 87 could cause more knocking than normal, even with the knock sensor. In that case I would try using midgrade when it is especially hot out. |
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| jimthor |
Eric You are correct. It was Very hot out when I noticed it.
It was only at the first couple thousand rpms. then It was gone.
I put 1 tank of super in per month |
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| rugiles |
| I am cheap when it comes to gas. I have run 87 most of the 23,000 miles on my MO. I get the same mileage with 87, 89 or 91. I recently switched back to 89 because the low range performance felt better and gas prices have fallen some and with my new job I get paid $0.375 per mile while driving for "business". ;) |
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| SugarRushMurano |
I have been using the 89 (medium) since i bought Mo with ocasionaly fill up of 93.
So far so good. no pinging.
I have never use 87 though....I just feel guilty putting 87 in ;\;) |
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| zebelkhan |
quote:
Originally posted by SugarRushMurano
I have never use 87 though....I just feel guilty putting 87 in ;\;)
Wow! That is exactly how I feel! - I just run 91 but to make up the extra cost I try to fill-up in stations that sell gas at warehouse prices (Costco - Safeway). I have had no pinging or knocking, even at 100+ outside temperatures.
I am trying to get myself to put in 87 on my next fill-up just to see if I will experience the pinging or knocking problem. |
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| ekaxel |
quote:
--------------------------------------------------------------------------------
Originally posted by SugarRushMurano
I have never use 87 though....I just feel guilty putting 87 in ;\
The oil companies love guys like you! Absolutely no insult or disrespect implied, but I had to say it! |
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| Eric L. |
| I use super because its the recommended octane for maximum performance. I purchased the Murano to drive it fun and fast, not like a Highlander. |
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| zebelkhan |
quote:
Originally posted by ekaxel
quote:
The oil companies love guys like you!
You may be right, but half of what we do with our MO comes from emotional side of things anyway. The reason I do not want to feed my MO anything less than the best in the market is no different than those who spend multiple days cleaning and shining the car just to stand at a distance and admire it. It just feels good! |
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| SugarRushMurano |
quote:
The oil companies love guys like you! Absolutely no insult or disrespect implied, but I had to say it!
Hehehe :rolleyes:
In a way, I am a citizen of an OPEC country.
So a portion of the money do goes back, the more ppl like me the better. But i agree with what u said ekaxel, it is more emotion than logic that are involved in this issue. ;) |
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| hfelknor |
There have been only two tanks of econo gas in my Murano.
I always fill up with 93 octane. There is no 91 here in Florida.
However a couple of weeks ago I evacuated to northern Florida to get away from Ivan the terrible.
Because Frances had gone through the area where I went, just a few days before, things hadn't gotten back to normal.
All they had was 87 octane.
With trepidation, I did the deed.
We stayed there for several days running around looking at the area, so I did it again. AFAIK they still don't have premium gas up there.
NO Pinging/knocking.
Homer
No acceleration either! VERY noticeable. :1: |
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| ekaxel |
| I drove from Portland to Vancouver BC yesterday, 70-75 mph, averaged 20.5 MPG on 87 regular. If I use premium, mileage may go up about 2 mpg. |
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| seaofdunes |
| i use 87 because i believe that is what the owners manual of my 03 SL AWD says to use. Going up will add more performance, and more gas mileage however, i believe it is all in your head. The price difference between two of the octane levels is so different per gallon compared to the gain in gas mileage. I prefer to save the $2-3 every fill-up and spend it on her oil changes (better synthetic oil). But hey thats just me. And I think the acceleration is all in your head. Yeah, it gives better performance, but so does a K&N air filter. The difference is barely noticable on a dyno, let alone while driving. |
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| Eric L. |
| I think it depends how hard you drive the car. Some people drive very gentle and never take it past 3000 rpm. In that case, there would probably be no noticeable difference in acceleration. For the lead foots among us, I can definitely state that the car feels a lot more peppy on super. |
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| nycmurano |
| Maybe I use 93 because it's a habit after driving around my fully modded Eclipse for years, where 93 barely sufficed. As for performance, I agree that there is a noticeable difference between octanes when you're heavy on the foot. Now if only there was a kit to drop a 20g turbo in my MO like I have in my eclipse. :2: |
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| ekaxel |
| Return from Vancouver, 75mph 22.0 mpg. on 87. |
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| SIM |
What the manual says is this:
Use unleaded regular gasoline with an octane ratin of at least 87 AKI number (Research octane number 91).
And if you look inside the fuel door, you will also see:
Premium fuel is recommended for maximum performance
So, what I understand from this is that you can use 87 octane gas as you can use regular mineral oil and it will make it go. But you should use 91 or better as you should use synthetic oil if you want better results from this powerplant.
Am I getting this right? |
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| ekaxel |
| Better results does not necessarily = maximum performance. Under normal driving coinditions (mine at least) you would be hard pressed to tell the difference. In town driving, where the average MO gets 16-18mpg, premium fuel won't make any noticeable difference. On the highway my experience has been about 10% more mileage on premium. Since the difference in $2.20/gal premium is about 10%, I guess it makes some sense to use premium for highway driving to get the advantage of the extra detergent and lower sulfur content (in some brands). |
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| mgthe3 |
hmmmmmmmmm
no one has stepped into the relatively high compression ratio area....
"Many vehicle owners believe that higher octane fuels are better for their vehicles since they are labeled "PREMIUM." The logic is that since it is a premium fuel it must be better. In reality, the premium label originates from the higher cost to refine and the resultant higher retail cost. Some refiners label their high octane fuels "SUPER." Some owners think that these fuels will make their vehicles more powerful. Only engines with high compression ratios can deliver all the potential energy from higher octane fuels! Always consult the manufacturer's octane recommendation to determine the proper octane requirements for any given vehicle. Generally, engines with compression ratios of 9.3 : 1 or less will safely operate with unleaded 87 octane fuel. Engines with higher compression ratios usually require higher octane fuels."
That was from an internal combustion engine training course.
When I found out that the VQ35 is at 10.3 to 1 compression ratio, it raised my eye brows. Typical engines I have been used to owning all had 8.5 to 1 ratios--that's the typical ratio for all american V8's.
In the late 60's you could get a factory stout 10.3 to 1 engine but you were forewarned that you MUST run high octane fuel to keep from having detonation---"pinging".
on to the VQ35....
The manual states that you CAN run on no less than 91 octane BUT you should run 96 octane. I haven't seen 96 octane in many years. I remember when Sunoco used to have 103 (I think) octane. All of us hot rodders at that time used ONLY Sunoco premium for our 10 to 1 and above compression motors. But this is today and I haven't seen any Sunoco pumps in Atlanta.
During the mid 70's compression ratios dropped drastically to 7.5 to 1 so we could use cheap gas due to the shortages and meteoric rise in prices of gas.
With all that said....
Cam timing and crankshaft stroke have a lot to do with how our modern engines deal with compression ratios. As the VQ35 has it's 10.3 to 1 ratio, it wants higher octane--period. So it isn't vain to put the good stuff in her, it is just the right thing to do. YES, our VQ's can retard timing to deal with low octane....but I have a problem with ANY detonation at all going on in my engine. Detonation is like hitting your piston with a hammer instead of the powerful push of a correctly firing cylinder. Also, since this explosion has no qualms about which way it displaces it's forces, it is also hammering your heads distributing the stress on your head bolts as well. I won't go into detail of how detonated cyclinder charges are incompletely burning the fuel and then that crap residue having to find it's way either across your rings or coating the head and the backsides of your exhaust valves. Detonation is unacceptable in my book.
Octane use is a pay me now or pay me later thing like the correct oil to use. Most of us here won't see 10 years on our Mo's I suspect, so the oil thing won't matter. But, the effects of detonation in your engine will rear its ugly head much sooner.
:cool: |
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| zebelkhan |
| Great writeup. Thanks for the good info. We have been hearing the same thing from many other members but this one convinced me to stay with 91 octane for my MO. |
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| Eric L. |
I'm not sure what manual you have been reading, but only the 350Z requires 91 octane of higher. The Murano's owners manual, which can be downloaded either here or at FA, states that premium fuel (91+) is recommended but regular fuel (87) is acceptable as well. Since this recommendation for the VQ has been the standard since 1994 with the first 3.0L V6 in the Maxima, I have never seen any reported engine trouble, damage, or drivability problems from using super, after being a member of Maxima.org for over 7 years.
The 3.5L V6 in the Murano has a knock sensor which can compensate for lower octane fuels. 87 is not the optimal fuel for the engine, but its not going to cause it to self destruct either. Using 91+ will allow the ECU to optimize timing and run the engine at maximum efficiency. Its like water and gatorade - they are almost the same thing, but gatorade gives the athelete a very slight edge in extreme conditions. |
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| ekaxel |
Eric L.
Thanks for the reasonble debunking of the "sky is falling" detonation rant.
I will continue to use 87, with an occasional tank of 91 (particularly on long trips). |
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| mgthe3 |
The manual, which I have here by my side, which is from my 04 SL, not downloaded, says it is "anti knock index" 87, not 87 octane which is not even the same. 91 AKI is 96 OCTANE--the number we use on the pump in the USA.
The sky is not falling, facts are facts, and those are pure internal combustion engine engineering facts about what OCTANE should be used with what compression ratios.
You can use 87, I ain't uh stoppin ya. But, you must read the manual a little closer next time, they do post the OCTANE number as well.
You can take a horse to the water, but you can't make him drink.
:rolleyes: |
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| Eric L. |
The octane rating at the pump is the average value of Research and Motor octane ratings - this is the anti knock octane rating posted at the pump. It even says so at every gas pump I have ever seen in the US: (R+M)/2
As far as anti knock index goes - 87 is regular, and super ranges from 91-93 (sometimes 94). Most people would call this octane rating for a gasoline. We can argue symantecs, but I think all would agree when one talks about octane, they are talking about the rating at the pump.
The research octane rating has no bearing on consumer choice, since its not something we can verify at the pump. |
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| mgthe3 |
| Here is the manual. |
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| mgthe3 |
Here is what you should have read. I dont' know what they use at your pumps, but mine are research octane numbers--not AKI.
So there!
hehe |
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| Eric L. |
Do they really post research octane numbers on gas pumps at Atlanta? So does that mean AKI is not posted, but RON is posted?
I have never seen this, but then I've never been to Atlanta. |
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| ekaxel |
I do not believe the definitions/terminology in the manual are the accepted standard.
Posted on the pump here in the Pacific NW are 87/89/91. |
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| mgthe3 |
Eric you just stated "every gas pump I have ever seen in the US: (R+M)/2" that is NOT AKI it is the research octane number.
Look at the picture--Nissan even says it. |
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| mgthe3 |
"The Anti-knock Index is calculated by (RON+MON)/2. RON is a measurement of how gasoline will resist knocking (i.e. premature ignition) under "non-stress" conditions (e.g. cruising, low load); MON is indication of how gasoline will resist knocking (i.e. premature ignition) under "stress" conditions (e.g. acceleration, high load, high temperatures).
(Ron+Mon)/2 is sometimes referred to as "pump octane," because it the minimum value for a gasoline that is displayed on retail dispensers (e.g. 87 for E-Regular and 94 for E-Ultra94)."
But, I will still use 93.
:) |
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| Eric L. |
quote:
Originally posted by mgthe3
"The Anti-knock Index is calculated by (RON+MON)/2. RON is a measurement of how gasoline will resist knocking (i.e. premature ignition) under "non-stress" conditions (e.g. cruising, low load); MON is indication of how gasoline will resist knocking (i.e. premature ignition) under "stress" conditions (e.g. acceleration, high load, high temperatures).
(Ron+Mon)/2 is sometimes referred to as "pump octane," because it the minimum value for a gasoline that is displayed on retail dispensers (e.g. 87 for E-Regular and 94 for E-Ultra94)."
But, I will still use 93.
:)
Ahhh its ok. ;)
Glad its settled now! |
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| ekaxel |
What are octane ratings?
Octane ratings measure a gasoline’s ability to resist engine knock, a rattling or pinging sound that results from premature ignition of the compressed fuel-air mixture in one or more cylinders. Most gas stations offer three octane grades: regular (usually 87 octane), mid-grade (usually 89 octane) and premium (usually 92 or 93).The ratings must be posted on bright yellow stickers on each gasoline pump.
How is octane rating determined?
Gasoline is subjected to two testing methods to establish its octane rating: one, called the motor method, runs the gasoline in an engine under load; and a second, the research method, runs the gasoline in a free running engine. The research method gives slightly higher ratings, and the octane number displayed on the pumps is an average of the two methods. |
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| mgthe3 |
beatcha with my "stand corrected" post....
but
Compression is compression and I refuse to have a retarded cat, a retarded dog, and, most definetly, a retarded ignition on my Mo for the savings at the pump. If I can afford a vehicle at this price, I can afford the gas for it. |
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| KGBhoy |
quote:
Originally posted by rugiles
I am cheap when it comes to gas. I have run 87 most of the 23,000 miles on my MO. I get the same mileage with 87, 89 or 91. I recently switched back to 89 because the low range performance felt better and gas prices have fallen some and with my new job I get paid $0.375 per mile while driving for "business". ;)
Seriously, how much would you save on a full tank of gas by putting in 87 instead of 91? $2? Not worth it, put 91 in and enjoy the ride! |
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| mgthe3 |
didn't see your reply of "it's ok".... we be cool. :)
I didn't mean to "Rant" on my compression diatribe, I was just trying to explain why I will use the highest octane available for the mere fact of detonation.
I have rebuilt engines.
I have seen the damage done by detonation.
I do know that the VQ retards ignition when it encounters detonation.
But I bought this thing to drive the HELL out of, and that I do. I don't want it to retard my ignition so it can't give me everything it has to offer. I betcha there are scores of folks here in Atlanta that have said, "Daaaayum, those things MOVE!" just because I zipped on by.
My apology is offered to those I might have offended.
I'll go back to the corner now.
;) |
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| zebelkhan |
quote:
Originally posted by mgthe3
beatcha with my "stand corrected" post....
but
Compression is compression and I refuse to have a retarded cat, a retarded dog, and, most definetly, a retarded ignition on my Mo for the savings at the pump. If I can afford a vehicle at this price, I can afford the gas for it.
Actually, on freeway driving, especially if you are towing, most have found out that on the average they will get about 10% better gas mileage if they use premium gas. In california, @ $2.25 for regular and $2.45 for premium, that is about 24 cents a gallon savings, more than enough to pay for the difference in gas price. So you actually save money by using premium. In city driving though, it is cheaper to use regular. |
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| HwnMurano |
I've been occassionally alternating between regular and premium.
Here's question for you tech savvy "Mo mechanic types". A friend of mine who knows a little about engines told me that I should just stick to premium, because the regular fuel does not burn cleanly and tends to clog up the fuel injectors if you use regular for a long time. He said that it would be very expensive to replace the fuel injectors if they get really bad. Any truth to this? |
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| ekaxel |
| I don't accept that. Since the almost universal use of fuel injection, all fuels are required to contain enough cleaners for this not to happen. |
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| SIM |
| Fuel formulation varies from company to company and from gas types as well. It is well known and admitted by all gas companies that there are more and better cleaning agents in premium gas than regular. The formulation is a secret for all of them. Again, no gas will destroy your engine and no mineral oil either. I guess that it simply is a matter of how long you intend to keep your MO. 3-4 year or less? Go with the cheap stuff and leave the potential problems to the next buyer. More than 4 year? Well, IMHO, Syntec and Premium gas are wise investments. |
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| jimthor |
I seem to recall from a Post here or somewhere else. That Premium Fuel use is not all its cracked up to be.
For instance. A fella that buys a Porsche in Italy. I bet they are told Premium fuel use is best. However, I also bet that in most parts of Italy. one would be hard pressed to find 91 or above octane fuel.
I only Italy as an example. Insert Sweden,Russia whatever.
The engines are made to accept the lower fuel. Thay have to be. Not every part of the World has Premium fuel.
Jim |
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| Eric L. |
quote:
Originally posted by jimthor
I seem to recall from a Post here or somewhere else. That Premium Fuel use is not all its cracked up to be.
For instance. A fella that buys a Porsche in Italy. I bet they are told Premium fuel use is best. However, I also bet that in most parts of Italy. one would be hard pressed to find 91 or above octane fuel.
I only Italy as an example. Insert Sweden,Russia whatever.
The engines are made to accept the lower fuel. Thay have to be. Not every part of the World has Premium fuel.
Jim
The Murano's 3.5L V6 engine will run on regular fuel just fine (i.e. no damage to engine) but it is tuned to produce more power on premium fuel (91+ octane rating). Use whichever you want, and if you cannot feel the difference using regular vs. super, then use regular. |
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| jimthor |
Found this
"I personally use regular even though my owner's manual says you'll get better performance with premium," says Lewis Gibbs, consulting engineer and 45-year veteran at Chevron oil company. He's chairman of Technical Committee 7 on Fuels, part of the Society of Automotive Engineers (SAE) Fuels & Lubricants Council. Gibbs knows gas.
"My wife runs midgrade (89 octane) in her car, and it's a turbocharged engine" meant for 91-octane premium, he says. |
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| jimthor |
All Porsche engines are designed for premium, too, but it's not available everywhere. "Our cars must be able to drive all over the world, and so we are able to run on regular," says Jakob Neusser, director of powertrain development at Porsche's research and development center in Weissach, Germany. "You don't have to feel that a mechanical problem or anything else will happen" using regular gas, even in the highest-performance, regular-production Porsches.
Premium, in fact, sometimes is worse fuel than regular. It resists knock because it's harder to ignite than lower-octane fuels. As a result, some engines won't start as quickly or run as smoothly on premium, notes Gibbs, the SAE fuel expert
There, New I saw this so,mewhere |
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| jimthor |
I would stop driving rather than use a lower grade of gasoline," says Andrew Martschenko of Boston, who drives a 2003 Nissan Maxima. Nissan says premium is "recommended" for that engine — automaker code for regular is OK, but you'll only get the advertised power on premium.
All the above was from usatoday oct 2003
And the debate rages on |
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| Eric L. |
I think I'd trust what the engineers say over what consumers think.
Fact is - yes you can run regular without any damage to the engine (there won't be) - you just won't be getting MAXIMUM performance. What's the difference? 1%, 2%, 5%? Who knows....but the fact is that you can run either depending on how much you want to spend. I wouldn't knock either side of topic - no pun intended. :D |
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| tofferr |
In my Mo, I see about a 1 percent improvement using premium (19.8 mpg to 20.0 mpg). As in most places premium costs me about 10 percent more.
I do still get premium from time to time for the detergents. |
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| SIM |
| Premium here is less than 3% more than regular so it would be a waste of money to go for regular. Economy and fun... Way to go! |
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