87 Octane

[atlanta3.5]

I know this has been discussed before, but, I filled up my 3.5 with 87 and YES there is a power difference. I dont think its just in my mind.

I know it states premium "for maximum peformance" but did not think it would be this noticable...

[dldjros69]

I use 87 on my 2.5. They told me at the stealership to use 87.

[AltiCoupeDriver]

I think only the 3.5 is recommended for premium fuel, if in fact that octane is premium.

[BatmansDreamCar03]

I use the highest at chevron (i think its 93) and i have a 2.5kind of expensive and i hear it burns faster but its worth it to keep my engine as clean as possible

i also use 91 sometimes if i am really low on money

[rjdmmfl1]

I use the highest at chevron (i think its 93) and i have a 2.5kind of expensive and i hear it burns faster but its worth it to keep my engine as clean as possible

i also use 91 sometimes if i am really low on money

that's interesting, I didn't think 93 octane existed in California... there's not a 93 octane gas station in San Diego!

[adidas2go]

Theres not 93 at Chevron in Cali. Im sure hes just mixed up on his numbers. 87, 89, 91 Now back home in VA I can get 93 all day

[wild willy]

I use the highest at chevron (i think its 93) and i have a 2.5kind of expensive and i hear it burns faster but its worth it to keep my engine as clean as possible

i also use 91 sometimes if i am really low on money

You are are very misguided young man and tossing 50 cent pieces out the window of your car for no reason what so ever........

[D-Roll]

I've used 93 once or twice, but been using 87 due to gas prices

[skiski329]

i was told 91 or higher. i use 93, you get what you pay for.

[cuzzbubba420]

Use nothing but 87 myself!

[heysteve]

i was told 91 or higher. i use 93, you get what you pay for.

quite unnecessary. your car is tuned for 91 and will receive 0 benefit from using 93 octane.

[Rmuth25]

Putting 91, or 93 in a 2.5 is just throwing away money. The only reason someone would EVER need to put that high octane in a 4 cylinder is if it has a turbo or supercharger on it and runs at a higher compression.

[dangeris]

I use the highest at chevron (i think its 93) and i have a 2.5kind of expensive and i hear it burns faster but its worth it to keep my engine as clean as possible

i also use 91 sometimes if i am really low on money

.Actually, The higher the octane, the more efficient your engine will be. 91 and above octane will burn faster and cleaner during detonation (When the piston is in it's highest point) unlike 87 which will burn slower and be wasted when the exhaust valve is opened. Using 91 and higher on a 4 banger IS a waste as the compression ratio does not warrant it UNLESS you have turbo or supercharged.

[tsigoloeg]

.Actually, The higher the octane, the more efficient your engine will be. 91 and above octane will burn faster and cleaner during detonation (When the piston is in it's highest point) unlike 87 which will burn slower and be wasted when the exhaust valve is opened. Using 91 and higher on a 4 banger IS a waste as the compression ratio does not warrant it UNLESS you have turbo or supercharged.

1) Octane burns slower and has a higher flashpoint than heptane. The "octane rating" posted on gas pumps is a reflection of the fuel's resistance to ignition based on a sliding scale of a mixture heptane:octane where 0 = 100% heptane/0% octane, and 100 = 0% heptane/100% octane . Note: it is possible to have higher than 100 octane rating (implying >100% octane) by using substances that have greater resistance to ignition than octane.

2) Efficiency of an engine is not dictated by the octane rating. Higher octane may produce "more power" because a) the computer will adjust (advance) the timing properly, and/or b) power will not be lost via pre-ignition ("pinging").

3) Using higher octane gasolines may benefit an engine because some manufacturers add higher concentrations of detergent additives than the minimum called for by the feds in their "premium" blends.

[stsxcrle]

I was using 87 until someone suggested using 91 or higher for better gas mileage. No better gas mileage but there IS a difference in performance. Temps have been about the same, just went to 93 octane.

[wild willy]

I was using 87 until someone suggested using 91 or higher for better gas mileage. No better gas mileage but there IS a difference in performance. Temps have been about the same, just went to 93 octane.

With the 2.5....You should notice no difference, Good chance it is in your head. Some cars tuned for regular actually lose performance with Premium

[squik]

Doesnt it take two tanks of gas for the car to adjust itself to a different octane? I know the VQ 350Z did.

[LongBeachCoupe]

You guys havent ever seen 94 before? I mean... im on the "cheap stuff" wagon in my 2.5... ive seen 94 octane many times....FYI you guys know in cali you arent getting a full gallon right? evaporation is a killer!

[wild willy]

I would think one tank should be sufficient for the computer to recognize and adjust itself accordingly

[skiski329]

quite unnecessary. your car is tuned for 91 and will receive 0 benefit from using 93 octane.

unnecessary my a$$ i have the 3.5 I also dug this up in my owner manual this is on 9-4. "Octane rating tipsUsing unleaded gasoline with an octanerating lower than recommended can causepersistent, heavy “spark knock.” (“Sparkknock” is a metallic rapping noise.) If severe,this can lead to engine damage. If youdetect a persistent heavy spark knock evenwhen using gasoline of the stated octanerating, or if you hear steady spark knockwhile holding a steady speed on levelroads, have a NISSAN dealer correct thecondition. Failure to correct the conditionis misuse of the vehicle, for which NISSANis not responsible.Incorrect ignition timing may result in sparkknock, after-run and/or overheating, which maycause excessive fuel consumption or enginedamage. If any of the above symptoms are encountered,have your vehicle checked at aNISSAN dealer."
Modified by skiski329 at 6:20 PM 2/25/2008

[skiski329]

some thing eles i found page 9-3 in your owners manual " FUEL RECOMMENDATIONFor 2.5L engineUse unleaded regular gasoline with an octanerating of at least 87 AKI (Anti-Knock Index) number(Research octane number 91).For 3.5L engineNISSAN recommends the use of premium unleadedgasoline with an octane rating of at least91 AKI (Anti-Knock Index) number (Researchoctane number 96). If unleaded premium gasolineis not available, you may use unleaded regulargasoline with an octane rating of at least 87 AKInumber (Research octane number 91), but youmay notice a decrease in performance."

[wild willy]

). If unleaded premium gasolineis not available, you may use unleaded regulargasoline with an octane rating of at least 87 AKInumber (Research octane number 91), but youmay notice a decrease in performance."

In the 02 manual is says half of that with a twist.......If premium is not available, put only enough regular to get you to a gas station to fill with premium.

[stsxcrle]

hmm, back to 87 it is....

[niztec]

nothing but 91 in my 3.5

[BatmansDreamCar03]

yea i did get mixed up in the numbers it is 91but i dont use that anymore because i cant afford it, and thanks for your guys' input i am already switched to 89 (any problems with that ???)

and they do have higher than 93 in calidown here (fullerton) there is a 76 that sells 100 octane gasoline, its right next to the airport, and theres a shop or two down there that works with the F1 cars.

[Robs_altima]

I'm still just a little surprised that there are still car enthusiasts that believe that high octane equals better performance in a car tuned for 87 or that it even burns cleaner. Octane suppresses detonation. If I were to put 110 octane race gas in my car, I wouldn't benefit in the least unless I advanced the timing which would then result in more power. If you're afraid of bad gas pick up some midgrade. Even if you're not going to take advise from me or any other person on these forums you can always pick up an independent consumer spending mag or book, usually always has a myth on gasoline ect. If you want further detail, check out the SAE (society automotive engineers). Even though my education isn't specially in automotive, still had to be very familiar with SAE standards and ratings.

[mrregina]

Hello all,

I have been an automotive tech for over 15 years. The debate about which gas is better has long been discussed. Unfortunately by inexperienced people. The higher the octane level, the quicker and cleaner the burn in the combustion chamber. When you have a cleaner burn, there is less wasted fuel leaving via the exhaust valves and therefore better performance. The oxygen sensors will not read a higher level of wasted fuel as when using a lower octane rated gas and thus will not cause the engine control module to fluctuate or overcompansate for the wasted fuel by retarding the timing. The engine retards the timing to change the next firing interval in the cylinders which does cause performance loss. Here is a quick test if you can find a controlled environment to try it. Take 1 gallon of 87 octane and 1 gallon of 91 octane and nurn that fuel. You will see that the higher octane fuel burns faster, hotter and leaves almost no residue compared to the 87. However, using higher octane fuel does not save in mileage as that has to do with the way you drive your car. You must make sure that your air/fuel ratio is where it needs to be in order to get the best performance out of your engine. By the way, I just purchased an 07 Altima 3.5S and let me tell you, man is that car fast. Cannot wait to mod the **** out of it. I also get almost 27MPG in the city when I drive it nice.