thronson

I know this has been discussed before, but with current gas prices I thought it would be interesting to revisit which octane provides the best mileage\power\cost benefit. My 2007 LX runs fine on either 87 or 91, although seems to get about 2 mpg better on 91. Power seems about the same with either grade, maybe a little better with 91.

I will have a chance next week to more scientifically evaluate this, but at $4.20 a gallon for 87, and assuming 16 mpg highway (on the computer), that works out to $.2625 cents per mile. Assuming 18 mpg highway for 91 octane (again on the computer), that works out to $.2416 cents per mile. So 91 would seem to be more cost effective. What I haven't tried is 85 octane, which the engine would doubtless run on, but is nowhere recommended I don't think.

I would be interested in other's experiences.

V8_Fan

x2 here. I get 1.5-2mpg better on 91 vs. 87, which is 10-15% better. Since premium is $4.10 vs. $3.90 for 87, that 20 cents extra per gallon is only about 5% extra cost for 10-15% extra gain in fuel economy. Gas would have to drop to $2/gallon (in other words, never) to make it cheaper to run 87.

LXPearl

It seems the 03-07 LX gets better mileage with 91 octane. My 01 LX gets close to the same mpg with either 91 or 87. However, the driveability of the 91 is better (torque improvement) and my mileage is about 0.5 mpg better with 91. I always run 91 when fully loaded, so not sure if the difference would be more pronounced in that condition.

In contrast, the 98-00 appears to require 91 octane, even has a sticker on the gas lid stating to use premium only. I expect greater difference in such vehicles.

My Lexus dealer stated they returned to requiring premium because people complained about performance issues when using 87 octane. The Lexus/Toyota training manual states that although the newer Toyota engines are designed to adjust to octane, they optimally are designed to run on premium and are very sensitive to octane changes.

kyoso23

I've always run 91+ in mine, especially with it being a '98 and "requiring" it. Only in a pinch one time I had to use 87 for about 100 miles and although it seemed to run fine, my mileage dropped drastically.

AKoch

I had a 98 one for like 8 years, and almost always ran it on 87. Never was an issue, and no engine issues after 8 years.

The 'feel' of the engine response was a bit better on the 91 though.

Now I am on the 06 - same thing.

davidsong

why bother buying cheap gas...?? the price difference aint that much either. and in the long run, higher octane gas is always better for the engine....

pagemaster

Toyota recommends premium fuel for the 4.7. I would go premium.

osomoso

I always run 93 octane Ethanol free from a local Place when they have it. But generally run 91 or 92 with Ethanol. I do notice less response and mileage loss with Ethanol added fuels (up to 10%). You are only buying 9/10 of a gallon already. So now is it 8/10 of a gallon? Just rambling.

dougjohn

if premium is recommended, then use premium.
if it's not recommended, then don't use it.

the main difference between premium and the regular stuff is that the premium retards engine knocking. if your engine doesn't knock/ping with the regular, then use it.