ok ok... sue me..

sharkman

 

I've been using regular for the past three tanks. Same mileage. (17 all city, 23 all highway, 19 or so in a 50-50 mix) Perhaps very slightly less power but I'm trying to decide if I'm imagining it or not.

 

This was actually tested time and again on the maxima forum years back. The average hp loss was between 7-10hp to the wheels. Coinidentally the QX56 has 10 more hp over the Titan and the only difference in the engines is one recommends 87 and the other 91. I myself have been tracking the differences in regular and premium in our 2k7 Nissan Quest. So far the Quest has been averaging between 1.5 and 2mpg better with premium. There is a noticeable difference in performance as well. So much so, my wife commented on it without the knowledge of me putting in premium. Overall it would still be slightly cheaper to use 87 in the quest, but I don't wish to find out what the long term effects will be.

 

Before I owned the G, I had an altima 3.5 and tested out this effect. There is definitely a power decrease. I also had exhaust, and when I turned on the car with regular gas you could hear a vague and weak start-up. I use 93 octane on the G because that is what we have here. Don't need to experiment with regular. At the end of the day here, you are only saving about 3 to 4 dollars a tank a week. While that may seem a lot, it is basically a meal at a Fast Food. So, I really don't see the need to put regular gas on the car.

 

Sure, times are tough, we're all looking to save money somewhere.

But, seriously? Save a $2 per fillup? If you go through a tank a week, that's only like $10/month.

There are waaaay easier ways to save money with a car. Like..... don't drive as much. Or, buy a used car. Or, keep your foot out of the gas.

But, for $10/month...... if you're that worried about $10..... you bought the wrooooong car.

 

I agree with this statement 100%

Saving 2 dollars per fill up on a 35k? Come on man...

 

some of these guys are driving all over trying to find premium when they could easily and safely use lower octane fuel for awhile or everyday.

i think there are a lot of misconceptions about how the knock sensor and timing advance work and the industry motivations to use premium fuel.

the ecu will normally try to set the timing advance as far ahead as possible to achieve max theoretical power while maintaining a margin of safety built into the ecu maps. this also happens to coincide with minimum nitrox emissions (NO and NO2). when the knock sensor senses pre-ignition or pinging due to the fuel igniting milliseconds before the spark, the ecu retards the timing to normalize the combustion front to coincide with the valves being fully closed and the compression stroke being completed. this effectively reduces the power out put of the engine somewhat (as previously posted) but also reduces the NOX emissions.

the spark retard on modern engines is completely electronic. it essentially switches over to a different map in the ecu. in fact some engines can even control this on a "per cylinder" basis meaning the spark advance is different at each cylinder. (not sure if the VQ can do this) there is nothing to "wear out". there is no harm in doing this all the time except that your emissions will slightly increase and your power slightly decrease. this is the motivation of the industry to recommend premium fuel. they are probably mandated by emissions law to do so plus the driver will experience a little more peppiness which is why so many are hesitant to move away from premium.

i agree that a couple of bucks per tank may not be worth it to most to use lower octane fuel, but you certainly don't have to drive around for an hour and a half to find premium at the risk of doing harm to you engine. you can run any grade you want as long as you understand the trade offs and the ecu can reduce the pinging by retarding the spark to compensate.

amp

 

It may be cheaper, but you will lose fuel economy with 87.

So why not play it safe, and give your car what it wants. You drive an Infiniti, not a Toyota.

 

Premium Gas (93 Octane), Synthetic Oil and always up on scheduled maintenance.

I always take the nothing but the best for my cars and they seem to last a very long time with minimal breakdowns, so I will stick with that approach. After a few years my car goes to the wife so I cannot play around.

Both performance and reliability are important. Even given the fact that I have an auto. LMAO.

 

I tried going from the recommended premium to 87 in our 06 MDX and although I didn't have any knocking, I did see an obvious decrease in MPG.
I haven't bothered trying it in the G.
I run strictly 93 now.

 

If $2.00 per fill up is going to break the bank then sell the G and buy a Prius. Just feed it what its wants and never worry about possible pinging.
These kind of threads are beyond stupid.

 

well From what i asked a bunch of people, while in wisconsin they said that it's okay to run 87 in winter, and there isn't going to be much of a difference because the air being sucked into the engine is so cold that it wouldn't knock and there isnt' enough heat/ pressure to cause it to detonate, however, in summer you would see a decrease in mpg and performance. Me, I figured that for like 10 bucks more a month i rather have an engine i know is going to last me outside the warranty period.

 

i had to do the same Shieet! had to put 87 at that texaco? gas station cause they only had 87 =[

felt hella notice decrease in the car for the whole trip back

 

I drive 3000 miles a month. At 21 mpg, which is what I average on reg or prem, that's 1714.3 gallons a year. So that's $0.30 times 1714.3, or $514 per year. I'd say that matters!

Lately I still burn premium, though. Just because I don't like the sound of the pinging and knocking. When the price hung around $4, I was dropping regular in. I typically ran regular when I would be taking long trips. Up and down traffic is when I hear the pinging and knocking. The up, or acceleration, of course. That's the opposite of what someone said above. If you're gonna skimp sometimes, when is it in fact better to do it? When you're going to be driving on the interstate and at constant speed for long periods of time or when you're gonna be in bumper-to-bumper traffic or driving around town? I'd think that on the open road with no varying demands and no taxing demands on the engine, regular would be just as good as the premium.