blazerbeam

Folks,

Lexus 04 RX330 manual recommends using 87 octane rating fuel and above.
I have always used 91. I want to re-think that with the rising gas prices.

Are there any obvious differences to mpg by using 87 instead of 91? any drops in mpg etc?
Furthermore, has anybody used 85 in the RX330?

bbeam

bizzy928

Hey Blazer,

There have been a few threads regarding gasoline and the RX. Most people use 87 and don't suffer any problems.

I wouldn't use 85 octane beceause that is lower than the recommened level of 87. (I didn't even know they sold 85...)

Lextranny

No difference in using the Premium Unleaded. I use mostly the regular unleaded and unleaded plus (rotate). Once....in a LONG....while I put the V-Power Premium from Shell or Premium Techron from Chevron just to clean up the fuel injectors.

blazerbeam

Thanks folks. Will give 87 a try.

NeverSatisfied

After filling up w/ 89 octane since Aug '03, I put in 87 today; I'll give it a try for a while... With all this BS about jerky shifts, clunks and what not, does this vehicle deserve anything higher?!?

Campbell

We are not tuning these cars for max power. The only variable to look for is air intake temps.
If 87 works for you all winter then thats fine. Pay more attention when it gets hot outside and if you have no problems in the peak of summer you are good to go.
These cars, like many, have a safety margin factored in. If Lexus says 87 is good, then not with-standing a bad tank of gas, you should have no problems in any conditions using that octane rating.
If anyone wants the long version of this issue I'll post it. Octane and detonation is an on going discussion in the performance world.


Octane is a stabilizer which gives a more controlled burn. Thus you can tune for more power based on it's prediictability. By just adding a higher octane, it will NOT give you more power, but will resist detonation better.

One issue to consider is whether the fuel companies add better detergents to their high octane fuels. The high octanes might also be cleaner with less contamiants. But, this is all hear-say.
Who really knows.

TunedRX300

I agree with Campell, higher octane does NOT equal to better gas for our cars. This topic has been discussed many times here and at the maintenance forum. Search button is a wonderful tool.

HarrierAWD

I used 85 in my RX300 when I moved to Colorado. The engine felt really weak so I went back to 87. Works fine and never a problem. With the rising fuel cost, I might try 85 again to see how it goes.

To: bizzy928 - In high altitude area like Colorado and Wyoming, the regular gas is 85 octane. It supposes to work like 87 due to thin air.

parula

I only use 87 as I think is recommended. Works fine here in the flatlands.

Ziggy09

93 thats it always and forever!!!

dmc888

I use premium 92-93 gas in all my cars. I like the extra Hp.

Campbell

It doesn't work like that.

dmc888

All of my cars run better on higher octane and it does provide little hp . But Not much .

TunedRX300

Higher octane means higher resistance to explosion, if your engine can not take advanage of the lower volitality nature of higher octane gas, you basically send gas unburned down your exhaust system. Incomplete mixture burn causes HP lost and clogging of your cat.
That is why "premium" does not equal to performance. You have to dyno the HP gain, not just "butt dyno" - feeling HP gained because you just spend extra $ per gallon.
I will stick with 87 since it is recommended by Lexus for RX's 1MZFE engine.

Ziggy09

no cheap gas for me i really can notice a difference