regular vs premium

[jimboteque]

I have a 2007 Altima 3.5 SE CVT. Owners manual says premium, but gut feeling is that regular is fine. Thoughts? I figure it's more important to be putting quality gas in the car (staying away from places like Arco, Costco, etc) than it is to worry so much about octane. I also read on here somewhere that higher octane can actually decrease the power since it's tougher to ignite. What're everybody's thoughts on this?

[IBCoupe]

If I recall, you're not going to hurt your engine's lifespan by putting in lower octane gas, because the computer's going to adjust for it. But your engine isn't going to run the way it's meant to. We're talking about a $0.30 difference/gallon. That's about $5.00/fill-up.

Saving $5.00 might be worth it for you, but I typically opt for 93 (91 when it's available, because I think that's actually what we're tuned to)

[jimboteque]

Do you guys notice much of a performance difference between running 91+ octane vs regular? I'm thinking about letting what I have run down, then running a quarter tank of premium followed by a quarter tank of regular and seeing if I can tell a difference.

[atlM35]

Your engine will pull timing at the first knock detection and performance will be lost.
Higher octane reduces this.

[superbad]

i tried regular gas once just to see. i feel that the car runs better with premium and my mpgs are better with premium so it makes up for a little of the price difference

[boston824]

I run PLUS (89) in my 2.5S and get really great MPG. I ran 87 once and the MPG dropped dramatically.

[mattyfo0z]

I use 91 in mine, 93 if available. I figured if I tried to cheap out and save the 20cents or whatever it is would be worse in the long run, for the motor itself and my MPG in general.

[boston824]

http://www.nicoclub.com/archives/gasoli ... myths.html

I found this interesting article in the Tech Corner, discussing Octane.

[frankenberrie]

http://www.nicoclub.com/archives/gasoli ... myths.html

I found this interesting article in the Tech Corner, discussing Octane.

Nice find

[AltimaHeat]

Well, I am not Gas Octane Literate, but there are many other things to consider when you talk about octane and regular vs. premium.
For instance all gas have ethanol with reduces drastically the quality of the fuel, everywhere at the pumps have a sticker which states “Up to 10% ethanol” but is known that in some extreme cases the mixture had up to 20%, so this is not reliable.
The high octane fuel also has ethanol with the same ratio, but then your gas should be able to “Knock” better, so still you will receive some benefits.
Also there is the “season” mixture, which I read somewhere, All gas comes from the same refinery, but each brand add their own additives to improve octane, cleaning and everything.
On the other hand, and this is my personal observation, your car has been tuned to run a minimum of 87, but compensated to accept up to 93 without “special” tuning, if your car were unable to “knock” with 93, you would end up dripping non burned gas on the exhaust.
Last one, the Empiric learning, I have seen many “literate” guys over the internet explaining “the placebo” effect of premium gas, but I think there are many ways for you to define if a premium gas is giving you something extra for those few cents you pay on the gallon.
The only way to know for sure is try it by yourself, if you commute every day to the same place back and forth, is as easy as try one gas from the same station, just use regular for a month and premium for the next, if you see/feel improvement, it might be a placebo effect, but your Mileage increasing is on your dash, no placebo in there.

This is just my personal opinion.

[08AltimaMan]

would I notice any difference if I put 93 in my 2.5SL instead of 89?

[Blake@STILLEN]

To be clear, your car is not going to feel "faster" using say 91 compared to 89 or 87. Pinging is what you'll want to be aware of (detonating fuel inside the cylinder when it's not supposed to. This will increase pressure in the cylinder and can become harmful). I always put 91 in my car, not only because the owners manual tells me to, but because I want to avoid any possible damage to my motor (it's not a Nissan btw but that really doesn't matter).

Here is a list of top tier gas: http://www.toptiergas.com/retailers.html

You could get 91 at a non-top tier station and its quality can be much lower than a true top tier station.

Just something to consider

[06SE-R]

I know this thread is a bit old but I'll throw my 0.2 in anyways for future readers. My experience through out my nissan days started with the 240sx which is tuned for 91 octane my brother borrowed the car one day and put 87 in. big no no for sure with the 240sx loud knocking, power loss etc I have a 06 Se-R and my wife has a 05 2.5 I have NEVER put anything less than 91 octane in mine because the 3.5 is tuned for 91. As stated above if you put lower octane in the 3.5 the computer will adjust over time but IMHO I believe you will lose horsepower by using less than 91 in the 3.5 my thinking on it is this: It was tuned using 91 octane our cars (the 3.5) at the crank are rated at 260hp so by using a lesser octane it's not at it's full potential thus losing power. I could be wrong this is just my way of thinking. The 2.5s only require 87 octane I have goofed around with the 2.5 putting 91 and 93 octane in it and really didn't notice a difference. I'm sure someone on here has more in depth knowledge on this. the thread listed above has great information as well.

[Keyan]

I've wondered since the 2010 retune and now with the 2013 what happens if you put in higher octane. The premium fuel requirement is gone, manual says just regular 87, and the "for max performance use premium" is gone from the gas door. Did they really change the compression ratio that much, or did they just retune to get 270 on regular and if I drop in premium will it run closer to 290 like a max with premium? I haven't tried it yet.

[frankenberrie]

I do not care what the facts have proven.. For the past few months I been using Sunoco Ultra gas and I gotta tell you, you cannot even feel my engine is running when i'm idle.. its no longer rough, pickup/response is a hell of a lot better not to mention i have gained 2-3mpg.. and it only cost me about $5 xtra at the pump.

I also been using Seafoam engine cleaner every 10,000 miles.. (1/3 in gas, 1/3 in oil, 1/3 in man) - look on youtube for videos on how to use seafoam... well worth it.

[DLS]

So you don't know whether the Seafoam or the Sunoco gas is causing the improvement. Try one, then the other then none then the combo again. You might be surprised by the results.

BTW I use mid-grade octane in my 09 Altima. It gives just enough better fuel economy to cover the extra cost. So while I'm not really saving any money, I do have to stop less frequently for fillings, so the time saved is worth it.