Premium is recommended for best performance but with these higher gas prices I wouldn't mind going to a lower grade if it wouldn't hurt. What are your guys using and is your gas mileage worse or better when changing octane?

 

I ran some 91 octane ethenol on the trip back from Iowa. I hated it...I got 27 mpg on the highway at 75mph average. I refueled midway and switched to 93 octane (no ethenol) and got 30 mpg the rest of the way back. I think ethenol is a killer of gas mileage...

 

Oh no!!!!!!! Not another octane thread. In Cali, the best we have here normally is 91 octane, but some places carry 100 octane fuel. I prefer to run 91 with a splash of 100 octane, meaning about 4 gallons of 100. I have a reflashed ECU and other mods.

 

93 octane.

 

Me too. Im in the 93 crowd.

 

there are some threads already but i cant search..maybe someone who can will post the links

 

i use 91 only... i have never got over 24 on the highway ... curious how u get 30

 

big dave: u ran a 14.53 stock ? do u have slips or any other info ... i would love to see that... the fasteset i have seen so far was a 14.7

 

Yes, I ran those times with nothing done. If you look in the drag racing section you'll see the thread I started on my runs at the track.

 

I guess I'm wondering if using 89 octane is ok as long as I'm not doing any "spirited" driving. I tried some in my '97 and the economy got better, but performance was noticeably worse.

 

93 always, tough habit to break

 

The sticker on the inside of the fuel door explicitly states "For maximum performance use premium fuel" and who am I not to listen to the sticker on the fuel door. 93 only

 

What is the compression of the Max's motor? I'm trying to figure out how toyota is able to make more horsepower and get better economy with their motor on regular fuel. I would hate to think that with premium fuel, the camry and avalon would make even more power than the nissan motor. At least the new altima is more powerful, but it still does demand premium gas and is still not as efficient as toyota.

 

But you need to read the owners manual on which gasoline to use. There is says to use premium for maximum performance, but that it's OK to burn regular -- if you don't want Maximum Performance.

You need to go the the Fluids and Lubes section of this site for more discussion about gasoline octane. I'm surprised this thread has not been moved there by the administrators.

Octane is a funny subject. So many people think they know about it when if fact they don't. And there are a lot of old-wives tales about octane floating around in peoples minds. Althought I worked for an oil company for 35 years before I retired, I'm still learning about octane and how tricky its accurate measurement can be.

For a more complete run-down on octane go to my post on that subject:
http://forums.maxima.org/showthread.php?t=396716
Start with post #1 to see what areas you are most interested in learning about.
SilverMax

 

Beginning in about 2003, Nissan increased the compression ratio of the VQ3.5 from 10.0 to 1 up to 10.3 to 1. The recommendation on premium gasoine for maximum performance did not change with this increase in compression ratio.

Honda has a 10.0 to 1 compression ratio in their V-6 engines and recommends regular gasoline. Nissan has a 10.3 to 1 compression ratio in their V-6 engines and recommends premium gasoline for maximum performance -- but says that regular gasoline will perform adequately. I think the difference in these statements is mainly in the image each company wants to project. Honda has a car for the masses with regular and Nissan has a premium car that needs premium gasoline to provide optimum performance.

 

I just noticed that I did not answer the question raised in this thread.

Here in the mountains of Colorado, I burn 85 octane regular. At 6 K feet elevation, 85 octane gasoline performs in most non-turbo charged engines like 91 octane gasoline performs at sea level. See the link in my first message on this thread to see why this is the case.

When I drive away from the mountains, I burn the cheapest gasoline available (with at least 87 octane). So in Iowa and parts of Nebraska, I am burning 89 octane with ethanol.

It has been reported that the VQ engine was designed to provide maximum performance when burning 91 octane gasoline. So, unless you have made modifications to your engine, that is all of the octane you need. The 100 Research Octane racing fuel discussed in one of the posts above is not the same as 93 (R+M)/2 octane gasoline that you get at the gas station. 100 Research octane is about 95 (R+M)/2 octane -- the measurements posted on gas station pumps. So by putting about 5 gallons of 95 octane racing fuel into about 15 gallons of 91 octane gas station gasoline, you will get about 92 octane on average. That is a fairly expensive price to only get one octane boost on average.

 

Sunoco Power Plus 94+ octane or Shell V-Power 91 (when Sunoco not available).

I find the car just MISSIONS on the 94 stuff.

In winter I use 89 all the time and the performace is sufficient. Not that I do any spirited driving in winter, I mean you can only push 17"SL rims and tires so far on ICE tee hee hee

Kamski

 

I use VP Racing Streetblaze fuel. http://www.vpracingfuels.com/vp_01_fuels.html

Here is an exerpt of the description from the above website, regarding the 100 octane I splash the tank with:

All VP fuels are available in 5- (19 liter), 15- (56 liter), 30- (113 liter) and 54-gallon (204 liter) pails and drums except where noted.


Oxygenated with ethanol, this CARB-legal fuel is specifically engineered for high-performance street cars including sport compacts, muscle cars, street rods and more. It's environmentally friendly and street legal throughout the U.S. In applications with anything from 4- to 12-cyclinders or engines equipped with a turbocharger, supercharger or nitrous oxide system (NOS), StreetBlaze 100 will generate optimum power and performance. In turbocharged or supercharged applications, it allows an increase in boost without fear of detonation. NOS users can also leverage their higher octane ratings to step up to a more powerful nitrous oxide system. Dyno tests with a turbocharged application proved StreetBlaze100 generates up to 14% more horsepower compared to premium grade 91 octane unleaded gasoline. Designed for use in cast-iron head engines with CRs up to 13:1 and aluminum head engines up to 14:1. Works well on the latest generation of electronically-controlled turbo engines. Contains no metal compounds and won't harm catalytic converters or oxygen sensors.

• Color: Orange
• Oxygenated: Yes
• Motor Octane: 96
• R+M/2: 100
• Specific Gravity: .746 at 60° F

 

Gas is indeed an SOB these days. I actually read a CNN post on gas prices. Some spokes dude stated that prices will remain until 2009. It might fluctuate a few cents here and there. But losing a whole dollar wont be until 2009 for of our Gas companies. Plus the "war" is not helping it at all.

But anyhow.... When I am broke and get the 89octane or 87. I usually buy a bottle of octane booster. That usually saves me about 5-7 bucks. But hey... Thats a free pack of smokes!! lolololol

 

93 all day long!!!

 

I only run the best...in the end, it's a good investment for a small upgrade, money wise...Every service tech i have asked told me to only use the highest grade. Not that I do everything they recommend, but this one i do.

 

If the Motor Octane is 96, then the (R+M)/2 octane would be about 100. For many years Union Oil sold a 100 Research Octane racing fuel in CA, that I assumed this was a continuation of that product. Obviously it is more than that. But they don't tell you how much ethanol is blended into this product. For most gasoline engines it should not be more than 10% ethanol. This is obviously a good product to run in turbo-engines. Doubt if it's needed in a non-modded VQ -- and something less than premium gasoline will work just fine for them.

So 4 gallons of 100 octane (I believe this is what you said you were putting in your tank) plus 16 gallons of 91 octane will get you just short of 93 octane for the full tank of blended gasoline.

But, like I said before -- if you have not modded your VQ engine, you don't need more than 91 octane for Nissan designed maximum performance.

On the post by Kam from Canada: Based on information I've received from reliable sources, Sunoco no longer offers 94 octane blended gasoline in the USA -- government regulations caused them to give up the tanks that they were using for this unique product to the multiple environmental grades of gasoline different levels of government now require to meet the many environmental regulations. Can't speak about what they do in Canada.

Based on the many posts on this thread, there are still many Max owners out there saying -- give my girl only the best -- without considering whether their driving style is such that it is not calling for maximum performance from their VQ engine. This would allow them to use something less than premium gasoline and still get adequate performance. Then again, there may well be that many members on this site who call for WOT at every stop light. If so, their poor gas mileage will show the results of this practice.

 

i always use 93

 

Yeppers, 94+ still avail here.

There is a gas station right beside a highway ramp I allways take to work and back. I can tell you 100% difference bettween 91 and 94 on that on ramp.

Also any one in the car with me can tell the difference, its usually the big smile on my face showing 94 is floating around in the tank.

Kamski

 

I've been running 87 octane, averaging 21 combined city and highway, and cruising at 70 get 28-29 mpg. tommyturbo2

 

I've been filling up the tank and driving off

 

The Canadian governments (federal and provincial) have not done like those in the USA and started mandating different formulations for gasoline in different jurisdictions. So Sunoco in Canada can differentiate itself from other oil companies by offering a unique product -- in this case 94 octane gasoline. A few years ago 94 was also available from Sunoco in the NE USA -- close to their refineries there. But new regulations required them to either build expensive new tanks or take the 94 tanks for use by the mandated different formulations. They chose to not build new tanks.

Those who like their 94 octane can thank the environmentalists for its demise. The same thing happened to BP's Crystal Clear Ultimate gasoline -- gone due to environmental requirements for those tanks.

 

The ~$.20 price diffrence between regular and premium comes out to a $4 savings at the pump (if filled from EMPTY). Now please tell me how filling up with 87 and buying a bottle of octane booster saves you $5-$7

 

And it will be $4 /tank different regardless of price per gallon.

 

While many gas stations have a 20 cents per gallon differential between regular a premium grades, that difference is much higher at the wholesale price level -- and so is likely to eventually end up in the retail market place. Already a number of stations have more than a 20 cents difference per gallon.

When one oil company needs to buy premium from another (or swap regular for premium) they freequently are now paying a differential of about 30 cents per gallon over the regular cost. I expect that by next year, the differential will go up above 20 cents at most locations. This cheap differential can not last given the costs at the wholesale level.

 

i didn't know anyone that read the forums regularly ever did below 91 - i use 93 100% of the time

 

Some of us read the owners manual where there is a detailed discussion of gasolines that will work in your Max. I burn 85 octane regular here in Colorado. Works fine -- and at 6 K feet elevation works like 91 octane works at sea level in most non-turbo vehicles -- including those with a VQ engine.

 

87 octane since my baby was 4 months old, and she still runs like a top. Save your money unless you are a street racer.

 

I use 93 octane always! 87 octane is for my wife's honda element!

 

have any of you guys noticed any pinging when using anything less than 93?

My '97 hates 89 octane so I wouldn't even dream of using 87. The loss of power is incredible.

 

The only time I get any light pinging here at 6 K feet elevation burning 85 octane regular is when the outside temp goes above about 80 degrees, I'm climbing the hill to my house, and the RPMs fall below about 2 K RPM. I simply down shift, the RPMs go up and the light pinging goes away.

 

Thanks for the quick reply. I don't think I could deal with any pinging and the would be enough reason for me to increase my octane. You said that 85 octane in that altitude is like 91 at sea level. Could you explain that. I really don't understand.

 

Higher octane doesn't make your car faster if you don't need it, in fact it will make your car slower because of it's resistance to ignite.

Only raising timing will give you more power in relation to octane, if you can raise your timing then you add octane to prevent detonation. Find the least amount of octane that doesn't make your engine detonate and you have the fastest gas for your vehicle.

 

Light pinging is OK so long as it does not continue for any length of time. Read the owners manual on the topic.

Rather than repeat what I have already written on altitude and octane, go to this thread and read my post #6:

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

It would also be good to read post #4 to see the 3 factors that affect an engine's requirement for octane.

 

This is quite close. Higher octane has a greater resistance to burning, so it could make a car that does not need it slower -- but this would be a very marginal difference that would be hard to measure.

While raising your timing could increase the engine's power, it is not the only way. A turbo-charger will increase the pressure in the engine (and push more air into the engine). With a turbo, most engines need the highest octane available to prevent knocking.

Even when I was in Mechanical Engineering Engine Lab back in the 60's -- the word was (and remains): Find the gasoline that gives you very light ping on hard acceleration and that is the best fuel for that engine. Anything with a lower octane will reduce preformance (and could damage the engine) and anything higher will not give you better performance (and could marginally reduce performance) -- and also is a waste of money and resources.