The difference between reg gas and prem is around 20 cent. I do 100% city driving and I was getting a little over 18mpg on reg gas. I just moved to a new city and do alot more driving now. I thought using the cheapest gas would save me money but it was actually costing me an extra 5/6 bucks a month. I put in prem last month and filled up today. I got 21.3 MPG would have been higher if I didn't have to use the heat. I think that's pretty wonderful for 100 percent city driving in a place like Denver.

From my calculations in order for it to be worth the extra for prem I would need to get 31 more miles to the tank, with todays fill up I got an extra 55.5 miles to the tank using prem. I had been wasting 5 bucks a month before. Not the mention the restored power. I have a good knock sensor, I replaced it with an ebay one last feb.

 

^^Have only used premium on 3rd (2007) & 4th gen (since first bought in 1997).

Definitely good advice.

 

This is a myth. Sorry. Unless Premium is required (not recommended) you get zero gain. Chances are, you were simply smoother on the gas when accelerating, kept your windows up when driving over 60mph and gas is denser the colder it gets. Makes sense you will get better mileage in the winter months.

 

Premium or don't fill up. I say it all the time.

 

i usually put in mid grade or premium. just depending on the mood im in for driving and spending the extra cents.

 

In my 95, it calls for prem. Since I had just moved to Denver I was trying to be cheap and run reg gas. I do only city driving and the same routes daily. I was getting 18 on avg for about 4 months and last month I put in prem and filled up today. My mpg was 21.3 with heater use. There is certainly something going on... my driving habits where unchanged.

 

Also you missed where I said 100 percent city driving.

 

Ignition timing isn't a myth

 

Good thing premium is required. Also that cold air thing is non-sense. The gas is stored underground and doesnt get cold until after you've pumped it in your gas tank, and even then it's negligible.

 

Tell that to my car, which this past summer was getting a pretty steady average of 26mpg on premium (vs 21mpg on other grades, approx half city/half hwy always).
Of course it does depend on where you get your fuel... the only station I've found near me that sells real 93 octane is Shell... other stations near me sell 89 in place of 93 and still market it as 93, shown by a drop down to 21mpg ... put Shell 93 in again and back to what I now consider normal.

 

This last batch came from Safeway I think. I put prem in again and this batch came from Costco. I will try and report back with numbers. They only sell up to 91 here in CO because of the Altitude.

 

You keep mentioning "running the heat" like it is detrimental to gas mileage. Why would this be so? I understand why the A/C cuts mileage due to the compressor drag. Heat is just water running through a heater core-- how would that affect mileage?

 

I'm just assuming that additional use of accessories would use more fuel. My lights dem a bit when I turn the heat on and my idle goes up around 100-200 rpms and then drops when I turn the heat off.

 

yah heater dont affect gas milege lol, don't know who started that one, alls its doing is blowing air through another like radiator and warming u up. only power it takes is the blower motor. and if that wasted gas then your saying you running head lights at night take more gas then driving during the day.


i dont know but you guys get great MPG i get 16 and 17 on good day with 93 octane and 15 with 87 octane. 235k miles auto with heavy rims.

 

With mileage that low seems like it's either your driving habits or some motor issues(old parts tune up cleaning needed etc)I have stock rims.

My idle still goes up when I turn the heat on so I don't know...

Pic of my car

 

well im running a cali spec ecu and its a fed car so cel is on for a 4th 02 sensor that the fed cars do not have so i think that automaticly ruins gas mileage lol. and yes i drive hard everywhere.

 

looks exactly like mine except without a drop and rims. all black 5 percent tint.

 

There was no change in my cars fuel economy when I switched from 87 to 91.

 

I knew I would get some static for what I wrote. It's a fact that unless Premium is required, it will not give you better gas mileage.

I will bet any single one of you that if we take a regular petrol engine out of a car, stick it into a dyno lab under constant pressure, humidity and temperature, and do two runs, one with 87 octane and one with 93, and empty a tank of gas with each, you will see no difference.

Largest decrease in gas mileage is caused by hard starts, on/off constant starts, driving over 60mph with the windows down, constantly using the ac, increasing weight in the car, higher rotational mass at the wheels, and so on...

But, you can listen to the experts if you wish: http://www.consumerenergycenter.org/...s_premium.html

http://www.cartalk.com/content/featu...ium/myths.html

http://www.consumerreports.org/cro/c...view/index.htm

 

You answered your own question. It's not the gas's reason for your higher mpg rating, but the fact that you drive more or longer per day so your engine has time to warm up. I used to work ~1/2mi from my work and got 16mpg on regular gas but when i started working farther away, ~8mi, my mpg rating went up to 22mpg on regular gas.

If your using premium your wasting your money imo

 

It's negligible, but runs upwards of an extra 8% per tank.

 

You are a tard. Read this
http://www.daytona-sensors.com/tech_tuning.html

Straight out of the FSM



This doesn't take into consideration dynamic compression, or the fact that aluminum heads dissipate heat faster and are less prone to detonation.

#1 our cars DO require it (high compression).

#2 High compression + low octane = detonation. Detonation = retarded timing = lower fuel economy.

Do you really think NISSAN would tell us to buy expensive gas if wouldn't benefit us. That wouldn't make sense from a marketing standpoint. Expensive gas or low MPG isn't exactly a selling point.

With that said, I am running the resistor mod and regular fuel with no noticeable detonation, unless I crowd it on a hot day. The fuel itself won't make any difference in MPG, the ECU will.

 

they sell racing fuel down here in the small town i live in. better mileage with that?

 

Mature.

All I can suggest to you is to check the manual. (in case you need help, page 10-2) The manual "recommends" 91 octane. It does not mandate 91 octane.

And a Maxima does nt have a high compression engine. I find that actually amusing. And no, our engines will not pre-detonate using 87 octane. And if you think Nissan is 'recommending' anything for your benefit, then you really are ignorant to the ways of the world.

 

my gauges say use unleaded only, and gas cap says premium fuel for Maximum performance. either is good just more power with premium.

 

i guess im lucky, i can get 100 octane up the street if i want or 93 a little further down. 100 octane is 4.35 a gallon, i tried it once and boy maxy ran like her a$$ was on fire.

 

91 over here in cali is about 4.09

 

93 octane is 3.29 gallon here!!!

 

LOl, the drop is because the shocks are bad. I had them replaced and the core support done so the car sits higher now. I had 5 percent all around but I was having trouble seeing out the front windows so I had to get 15 in the front. The rims are the stock nissan, I just painted them black some some spray paint.

 

I think you mis understood what I said. In Boston I drove about 100 miles a month.

Here in Denver I drove about 500 a month and have been doing so for 5 months now. I start using the cheap 87 gas because I was driving more and having to buy gas more often. I figured something was wrong with me only getting 18 in the city despite having all my maintenance done.

I filled up with prem last month and got 21 mpg this time. My route/routine here in Denver haven't changed.

 

I also noticed an increase in performance. As someone stated above the engine was designed to use prem gas althou it can use reg gas as well. My driving habits have not changed but my switch from reg to prem gas yielded a 3 mpg increase from 18 to 21.

 

4 years of mpg spreadsheets from nearly all fillups. Premium gives me better mpg, and more bang for buck. I dunno why. Basically, it's cheaper to use Premium over regular in my case. But then again, my car was a mutant that ran 15.1 stock at 100k.

Same with my Toyota v6 Camry. Premium makes a huge difference. But not with my Volvo i4. CostCo gas kills my mpg, no matter which grade. Same with Chevron. I avoid those 2 whenever I can.

Dr J

 

When it comes to both of my maximas premium has given me better performance and gas mileage. It doesnt hold true with all the cars I have owned buy with the maxima I will always use premium

 

I use regular, been using it for years. 218k and still runs smooth, who cares if you use premium. big deal.

 

Octane readings determine the fuel's ability to resist detonation, higher the number, the more resistant, they don't determine the fuels performance qualities. If your engine isn't knocking then you don't need to run higher octane. 10.0:1 is not a high compression engine.

 

who cares some use premium some dont. after 1 million threads no conclusive answer!

./thread

 

In what? The world of Honda Owners????

I never put anything less than 91 in my 4th gen, and never will.

I have had MULTIPLE trials of 93 vs regular in my stock (pretty much) 5th gen.

Results came out to be what I expected now (but couldn't explain why back then).

Regular vs. Premium on Highway mileage, not a damn difference... The big difference was...

Mixed and city driving.

My route to school every day was a mixed route in and out of traffic of 21.5 miles.

On premium I could easily get 400+ before the light would come on, but on regular I would never see a mile over 350 before the car showed signs of fuel starvation (light came on around 330s)

I also noticed how gutless the car felt below 3k, on premium I could shift before 2.5k and keep up with traffic, on regular I had to go to 3k just so I wouldn't get left behind with traffic.

I took these findings and never went back to regular ever again with a high compression motor with coil packs (a vehicle with the ability to advance or retard timing).

 

The inside of a combustion chamber doesn't know, or care, if it's a Honda, or a Nissan. The fact that you notice a difference in mileage in stop start city driving doesn't mean anything exactly because you are stopping, and starting all the time, which uses more fuel, but whether you drive the exact same route every day, you do not drive identically every day. It isn't the fuel, it's the driving. Theoretically lower octane fuel should be MORE economical since it detonates more completely than higher octane which resist detonation better. I used premium when I got my Max because the knock sensor was bad, and I am running the resistor in it's place, but when gas hit 4+ a gallon I switched to 87, and noticed zero difference in performance, and mileage.

 

Man, this is a touchy subject.. 87 detonates quuicker than 91, and since we have high compression, we need it to detonate a little later to get the correct ignition timing, which means better performance and gas milage. Simple as that.

 

agreed, I used to run my 4th gen with regular when I first got it, it ran like crap... knock sensor codes.. crappy acceleration.... started filling up with the V-power and everything went back to normal.....