Altima question

[EZcheese17]

I was reading my owner's manual for my new '05 Altima and saw that the minimum octane rating for the engine is 87. Would it make much difference if I decided to use a higher octane ?

I have to 2.5 4cylinder

Thanks

[Juaquin]

I also have a 3rd gen, and although it's the 3.5L V6, putting higher octane in it does seem to make a difference. Maybe it's just psychological, but it really does seem to have more power, more response, and just overall a better feeling while driving it.

[Cold_Zero]

87 Octane is the minimum octane rating for the newer Altimas. Even though it’s the minimum rating, it doesn’t really mean that it’s the preferred or recommended octane rating. My wife and I always put 89 octane in as a minimum. I have put 94 Octane in the car before. To answer your question, I dont think that there is a noticeable difference between the use of these two octane ratings. I am sure that ECU may sense the higher octane in the gas and advance the timing to make a little bit more power, but our cars (stock) are limited in how much more power they can make over the normal factory ratings. You can try it for a bit and see for yourself.

BTW EZ, have you modified your Altima yet? How do you like your new car?

bud2002 (2.5S) Altima

[EZcheese17]

Thanks for the advice Zero, and nope i haven't modified the far yet. I haven't even made my first payment yet..lol. i am thinking about tinting the windows to start with. I love my car, it has the new Bose 6 CD changer stereo system in it w/ satelite radio, Sweet!!! I bought the SL, so it came w/ the leather seats also...very nice.

[jEzTeR]

The leather and Bose are two of the three things that I like about my Altima best also.

I use the higest octane gas that I can get on every fill up in my 3.5se. My wife will sometimes get the cheeper stuff and I can tell when she does.

[EZcheese15]

The way the ECU works is that it is optimized for whatever octane it says is "recommended". If it says it recommends 91 octane, then your best performance will be with 91 octane. A lower octane will make the ECU retard the timing and power will go down (slightly).

If it recommends 87 octane, then the ECU is optimized for 87 octane. It will not advance the timing to make use of the higher octane...instead it will burn it just as if it is 87. And because a higher octane burns at a higher temperature, the flame front will actually take longer to ignite, meaning the piston will be further away from TDC, which in turn will actually cause a slight LOSS in power (however, it is neglegable).

Anyway, the moral is, use whatever octane is recommended. Use lower octane if you are trying to save money. Never waste your money on higher octane than what is recommended.

[Juaquin]

If that's true, I wonder if having your ECU flashed (right now I think the only company that does it is Jet) will correct that.

[EZcheese15]

Correct what?

Also, Juaquin, if you could, please reduce your signature size. It is rather large. Perhaps resize those pics to 75% or even 50%.