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Premium Fuel

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tornadog said:
When did I ever say anything about being cheap. I just asked if its ok to go with 93 since 91 is not an option here. If I wanted to be cheap I would have bought a Kia or a Ford...lol
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It only says 91 because that is the lowest octane premium fuel can have, and is commonly found in some states instead of 93. 93ish is the more agreed upon for 'premium fuel'. There will be absolutely no harm to your car to run either of those fuels, those mixing it are just being stupid, especially since no way in hell are they going to get the mixture right so god only knows what they are running. The car will run best on 93, and might even give you less than the rated power on 91 simply due to the engine having to compensate for pre-detonation.


If you have to you can run the car on 87 octane, nearly had to do that once during a gas shortage. Just know that you'll lose power and it's best to not flog it with that octane, and put in some premium fuel as soon as possible to raise the octane level.


Cars with turbos or highly tuned naturally aspired respond best to high octane fuels. Those who buy these vehicles generally do so for the power anyway, so it's ridiculous that they would cheap out on the fuel. However something like a civic isn't going to noticeably benefit from premium fuels.
 
i dont know what the disparity in pricing is in other states, but there is a minimum of a 30 cent difference between 87 and 91 here. 30 cents more at 24 gallons, 1.5 average fill ups a week adds up. all that said, i run 87 in my truck because it doesnt require (or take advantage of) higher octane.

i used to have a car that required 91, and when i bought it i knew it. i didnt bitch at all about it, i knew going in i was going to have that cost.

as for the OP, go ahead and use 93 like people are saying. the 91 in the manual is the minimum, not the only octane rating you can use.
 
do 93. I have an Altima SER and it doesn't REQUIRE 91+ but it recommends it for "best performance", I've never ran 87/89 but people who have just say they had a little loss of power, some noise, and worse MPG. So it all evens out in the end.
 
tornadog said:
When did I ever say anything about being cheap. I just asked if its ok to go with 93 since 91 is not an option here. If I wanted to be cheap I would have bought a Kia or a Ford...lol
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That was directed at another poster who runs 87 even though he says his car requires 91.
 
If the car calls for 91, and it isn't available, go with 93. Or, as someone else mentioned, do half a tank of 89 and half a tank of 93 if you really want to be nitpicky 😛

If your car calls for 87 there is almost never a reason to put in anything higher unless it has the tables for it. My previous car called for 87, but the station was out so I got 89. It seemed to run fine, but I lost 2mpg that tank. OK, one time isn't enough to judge anything. But the next time that happened and I ran 89 again, I again lost 2mpg.

I laugh at the guys with their riced honda civics with stock engines who put in premium fuel as if their CAI and fart exhaust somehow makes the engine require higher octane fuel all of a sudden 😀
 
SparkyJJO said:
If the car calls for 91, and it isn't available, go with 93. Or, as someone else mentioned, do half a tank of 89 and half a tank of 93 if you really want to be nitpicky 😛

If your car calls for 87 there is almost never a reason to put in anything higher unless it has the tables for it. My previous car called for 87, but the station was out so I got 89. It seemed to run fine, but I lost 2mpg that tank. OK, one time isn't enough to judge anything. But the next time that happened and I ran 89 again, I again lost 2mpg.

I laugh at the guys with their riced honda civics with stock engines who put in premium fuel as if their CAI and fart exhaust somehow makes the engine require higher octane fuel all of a sudden 😀
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Funny enough, the Civic Si requires premium. It needs it to hit in the 'high 120's' for torque. :biggrin:
 
89 would be fine in a factory stock N/A car that "requires 91". Just don't go flooring it with the AC on the middle of summer uphill with 6 people and a trunk full of illegals in the car.

Manuf. tunes are extra safe and always have margin of error for bad gas and worst case load and environmental scenarios in all regions the car is sold in. 2 points of octane aren't going to change a thing on a stock tune.

87 is pushing it though. That stuff is half piss, unfiltered even.

If you are supercharged or turbocharged, and/or have a modified tune, you better use what the tuner or manuf. tells you to use because your margin of safety for worst case or unpredictable scenarios (eg bad gas) is much smaller.

In either case, just use 93. If you can afford a car that requires premium fuel, you can afford the extra $1 it costs per $40 fill up.

I once got half a tank full of 87 on my boosted Cobra. Even though I hit 91 I saw halfway through that it was on 87 for some reason. Longest week of my life.
 
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SparkyJJO said:
I laugh at the guys with their riced honda civics with stock engines who put in premium fuel as if their CAI and fart exhaust somehow makes the engine require higher octane fuel all of a sudden 😀
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ExarKun333 said:
Funny enough, the Civic Si requires premium. It needs it to hit in the 'high 120's' for torque. :biggrin:
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a lot of the honda owners that actually are making little speed demons (relatively speaking) are increasing the compression in their engines to the point of needing to run special mix and higher octane. i almost went with a mini me in my civic, which increases the ratio to the point of chancing a rod through the sidewall. but the hp and tq go up dramatically. not worth it to me unless i had a spare motor sitting around to put in when i busted it up. in the end i bought my civic for the mileage and longevity it has, not the potential as a gokart racer.
 
I just wish 93 octane was more fully available across the country. If I run 91 instead of 93, I get bad knocking, but then my engine management pulls back timing. I've created more conservative tunes to run on 91 when going on road trips to avoid this.

Oh, and I'm a stock-looking Honda/Acura owner with 250whp (~300hp) in my 2750lbs car. Confuses the hell out of STI's / Evo's / Z's / big V8 cars.. I have way too much fun 🙂

OP, since you are not cheap, just use 93 and call it a day.
 
SuperSix said:
A riend of mine bought a new Nissan Murano when they came out. Had it for ~3mo, and asked me how to adjust the valves. Turns out he was using 87 the whole time (91+ Manufacturer recommendation) and the clattering from the preignition made him think there was a problem with the valves. He switched to 93, ran like a new car.
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Then your friend had a problem with his Murano.


From the Murano's owner's manual:

Use unleaded regular gasoline with an octane rating of at least 87 AKI (Anti-Knock Index) number (Research octane number 91).

For improved vehicle performance, NISSAN recommends the use of unleaded premium gasoline with an octane rating of at least 91 AKI number (Research octane number 96).
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So, the minimum Nissan recommends for the Murano is 87 octane with 91 being preferred for full power. While the Murano's engine is the same as a Maxima, it's detuned slightly and can operate quite well on regular.
 
Yeah, the Murano shouldn't have pre-ignition with 87 even if it required 91 octane because it uses a modern engine that will simply hear the knocking and back off of the power until the knocking quits.

A Murano that's knocking on 87 octane is broken.

Many people confuse the ratings. 91 RON is 87 octane at the pump in the US.
 
The only reason I know is that our recently purchased 2003 Murano had an almost empty tank when we bought it and, not thinking, I immediately filled it up with a tankful of regular. No pinging, no knocking......but didn't seem to have the power I expected from a Maxima/Z engine.

Of course, after reading the owner's manual later that evening, I discovered it is tuned for premium, which it got on its next tankful. Did make a difference with power generation.
 
jlee said:
Qualify "bad"...I'd run 104 in my cars before I ran 87. 😉
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oh cmon you know jlee 😛

if your car isnt properly tuned for higher octane fuels, you can actually retard detonation, which is also bad for the engine



OP - run whatever your owner's manual recommends (which i assume is 91 octane or higher). running anything lower can cause knocking (premature detonation). if your car has a knock sensor, it will reduce engine performance to accommodate the lower octane fuel. however, it is not optimal.

you bought a vehicle costing tens of thousands of dollars, and now you're going to cheap out on a few cents/gallon of gas? seems awfully stupid to me that people would consider this.
 
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Fenixgoon said:
oh cmon you know jlee 😛

if your car isnt properly tuned for higher octane fuels, you can actually retard detonation, which is also bad for the engine



OP - run 91 octane or higher. running anything lower can cause knocking (premature detonation). if your car has a knock sensor, it will reduce engine performance to accommodate the lower octane fuel. however, it is not optimal.

you bought a vehicle costing tens of thousands of dollars, and now you're going to cheap out on a few cents/gallon of gas? seems awfully stupid to me that people would consider this.
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I have yet to see an engine damaged by running a higher octane fuel than recommended. ..sure, it's unnecessary, but it's not going to hurt anything.
 
jlee said:
I have yet to see an engine damaged by running a higher octane fuel than recommended. ..sure, it's unnecessary, but it's not going to hurt anything.
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Well it's not like you have a lot of time out there in the field.

Premature catalyst failure is one cause.

You do realize what octane means right and that if you aren't burning the complete fuel deposit that that is bad mojo.
 
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