Cars that require premium fuel (91 octane) (luxury car, vehicle, MPG, mileage)

[tillman7]

I purchased a 2002 Acura RL, Acura recommends using at least 91 octane fuel in the car. I live down South and 91 octane isn’t sold here, only 87, 89 and 93 octanes. It is Ok to use 89 octane in the car? Or can I fill the car with half 89 octane and half 93 octane for an average of 91 octane?

[ninintothevoid]

For the money, I would just use 93 octane. High octane fuel delays ignition in the cylinder and is typically required for higher performance vehicles. Most modern cars can adjust for various fuels in the ECU for ignition timing, but this often results in diminished performance and lower fuel efficiency. It makes more economic sense to just use 93 octane fuel than to start playing around with mixing different types of gas.

[Nlambert]

Where down south? I see it everywhere between here and Mobile, AL. Either way, 93 is fine. 91 is the minimum. Sometimes you will get some detonation if you use a lower than recommended octane.

[MckinneyOwnr]

You can use 89, it's not going to harm anything, except perhaps retard the timing a bit in the ECU and you'll lose a little bit of horsepower.

My old Jeep GC Overland could run on 87, but it was optimized to use 91 or higher as it had the High Output engine. The difference according to Jeep was a loss of about 20hp by using 87 octane.

[C8N]

My car requires 91.... I just fill up with 93

[CCc girl]

Do not play around with octane on a newer luxury car. Find a 91 station or go with 93.

[ranger17]

i'd say be happy you can get 93; my daughter here has a modified/supercharged rsx that is tuned for 93 and most places now only serve up 91. So she drives a bit out of her way for the 93 or de-tunes a little.

But if it was my stock ride and i was in same position as the OP, i'd always run higher rather than lower on octane.

[z28lt1]

While there are some, very few stock cars REQUIRE 91 or higher octane. Most recommend it because they've tuned for it, and as mentioned, will decrease timing due to knock with lower octane fuel. It varies by car, and only a few cars have real published numbers, but the horsepower loss on lower octane for ones that have been published have been in the 3-15 neighborhood. So if you are ok with slightly less horsepower, check the manual to see if 91 is required or recommended. Higher is always ok (although after a point is just wasting money) Scientifically, higher octane shouldn't provide better mileage, but some people cliam they get better MPG with higher octane, and some with lower. Probably very vehicle dependent The OP's Acura talks about a slight decrease in performance when using lower than 91, but says it is ok.



Your Acura is designed to operate on
premium unleaded gasoline with a
pump octane number of 91 or higher.

If you are unable to find premium
unleaded gasoline, you may substi-
tute an unleaded regular gasoline.
The engine will compensate for the
lower octane, but you may notice a
slight decrease in power as a result.

EDIT:
I should add that mixing 93 and 89 will result in 91 if done properly and you want to go that route. For me, I would probably just use the 93.

[madpaddy]

You could safely mix 89 and 93 to get a 91 octane mix. But you only save yourself $1.13-$1.50 per fill up compared to just filling with 93 (assuming 15 gallons purchased and $0.15-$0.20 price differential between 89 and 93). For +/- $5 a month, I'd skip the hassle of blending; to do so would require two separate transactions every time you fill up.

Besides, it sometimes makes sense on an older car to "octane up" because carbon deposits on the pistons can increase the effective compression ratio. That's just one more reason to run strait 93 in the absence of 91 on a 2002 RL.

[brianjb]

Get the 93 octane. You're only talking a 10 cent difference in price between that and the other, right?