pemarsh

My lx 470 took 87 gas for 4 years without a hiccup. Dealer actually told me when I bought it new it would not be a problem.
Now, with the 570, it of course says premium fuel. Has anyone tried 87?? Also, when it says premium, are they talking 92, or 89??
Silly questions, as im sure the only gas meant to go in this is 92.
Here in Chicago, 92 is already over $4.15/gal. Ugh. Just curious to what you guys think.

pagemaster

I am sure you will do fine with 87 octane. The Land Cruiser with the same Japan sourced 5.7 does not recommend 91. 91 octane will likely give you the full 383 hp and most likely wil be a little smoother.

ggebhardt

I can tell you for sure that the mid grade will run just fine, heck I am betting the full tank the dealer gave us was not high test.

My VP just bought a fully loaded Tundra with the exact same motor and hp and his says 87 is just fine in his manual.

Why would Lexus say we have to use high test?

I do not mind paying the extra money for the extra octane if it gives me something in return.

pagemaster

The ratings of the Lx570 were achieved using 91 octane or higher. The manual should state that if premium is not used performance will decrease.
The Lx570 makes a little more hp and tq than the Tundra and likely is set up with a different exhaust ect. Also the 5.7 in the Lexus/LC is not the engine made in Alabama.

luxury1

We had the same discussion on the LS forum. Someone said that you need to use premium because of the high compression ratio. I really didn't understand it but the consensus for the LS was to use premium.

pemarsh

i guess the best thing i have heard is that someone driving the 570 is using 89. The manual does state 91 or higher...for whatever that is worth.

Da Hapa

You can use any grade you want but you will not get the maximum power or torque and therefore likely not the maximum MPG if you don't use the recommended 91+ octane fuel in your LX.

Simple as that.

pagemaster

For best performance the manual states 91 or higher if I am correct but not required.

I don't think car manufacturers make cars than require 91 only anymore. I know my brothers Pathfinder and dads old Cadillac required it but the next engines adjust themselves when lower than 91 is used.

pagemaster

I always thought that the MPG didn't get affected by octane?

pemarsh

Per Lexus LX 570 instruction manual, p 684.

"Premium unleaded gasoline only"
"91 (Research Octane Number 96) or higher"

Then we have another gasoline tidbit on page 692:

"If 91 Octane cannot be obtained, you may use unleaded gasoline with an Octane Rating as low as 87 (research octane number 91). However, use of unleaded fuel with an octane rating lower than 91 may result in engine knocking or drastically reduce output to protect itself while driving a heavy load. Persistent knocking can lead to engine damage and should be corrected by refueling with higher octane unleaded gasoline."

Also, on page 692, it says:
"Premium unleaded gasoline with an octane rating 91 or higher required for optimum performance."

Bottom line, who the heck knows.

tigmd99

The way that i read it is: use premium or else knocking may occur which will damage engine. So, i don't think that you have any choice here if you plan on keeping your LX a long time.

For my G, i use premium because i want to keep it a long time...and my OM says the same thing...premium required! Bright side for you guys, i get 13.5-14 mpg on the highway with my slightly oversized all-terrain tire (BFG AT KO 32").

luxury1

Thai, you sure have an interesting collection of cars! You usually don't see the G5 next to you other two more civil cars.

tigmd99

The other two are definitely more sensible choices for daily drivers. I buy cars to serve a purpose.

trusso

gas is a staple and like milk, bread, etc, you gotta buy it.
It's only about a $5 difference to fill the 570 from 1/4 full. This is from the least expensive gas to the most expensive gas.
If I need to fill it once a week, it only comes to about $20 a month...not too bad.
I hate that gas is so pricey but I still get the highest octane, it's worth it to not have to question it.

I used to run a Sunoco race fuel (mixed) in my Corvette and motorcycles. It's about $20 a gallon now

2007es350

This is a great topic!

I have driven my LS about 7,000 miles and have always used Premium fuel as recommended. I decided to try a tank of Regular fuel just to see if I could feel a difference. Now I'm sold on Premium. Running Regular, my car hesitates from a start and can tell that torque is diminished; it feels like a different car. It's definitely not worth saving $4 per fillup (which is about once every 3 weeks).

If you are skeptical of the Premium fuel requirement, I suggest trying Regular fuel. If you are happy with the performance of Regular fuel, you don't tow, and you take it easy, then go for Regular. To me, there's no point in drivng a vehicle with a nice V8 only to cripple it with cheaper fuel.