JLeffler

Yes, this would be really interesting in Colorado for sure. I use an app called Gas Cubby...you enter fuel cost, gallons purchased, current odo, and some other things and it calculates and charts a nice graph on your iPhone. My Saturn which I no longer have, would range from 17-21 mpg on any given fuel up. My wife's car too, goes as low as 18 and high as 23. With all the hills and wind, I don't really know how I would be able to calculate whether or not it is a true savings. It would almost need to be a month to month or year to year study.

Colorado is also known for you being able to use A/C on an afternoon when you used the heater in the morning which can really mess up mpg.

JLeffler

Currently, after our first week with the Lexus ( I love saying that btw ! ) we are getting 19mpg. Now, I am not certain what kind of gas the dealership put in it. I'm sure with their "bottom line" they gave me 85. It's my wife and baby's primary car, so they are not speed demons. Plus, she's still getting used to driving it.

In the next few days when it comes time to fuel up, I will try 87 and then maybe 89. Next weekend we are going on a mountain trip.... speed limit will range from 35-55mph and increase about 2500 feet. And then back home. Usually this trip gives awesome gas mileage on the way home, when it's downhill the whole way. In two weeks we will drive to Denver on the interstate which will be a solid 75mph the whole way and a much slighter increase in elevation. I know completely different sceranrios will warrant different results.

I do appreciate the input. It does seem like it sparked some interesting conversations.

jfelbab

While I'm not a fleet owner, his example matches my experience with my RX330. I've taken over 18 cross country excursions with my RX330 each at least 1,500 miles in length. I can confirm his experience. I continually see much higher measured MPG using premium on the freeways over identical routes but not in city driving. In the city, I can feel more power as evidenced by less downshifting on hills and just a more spirited vehicle but I don't see this reflected in the MPG. On the freeway, improved performance is immediately evident in my RX330. I travel further per dollar spent when using premium and I've done this test repeatedly over the 10 years that I've owned this vehicle, most recently just 5 days ago.

The Lexus has a computer that slightly de-tunes the engine to accommodate 87 octane fuel. This results in lower power and less efficiency. This is spelled out in the owners manual.

DPJ

Thanks for the info, I'll try 93 on my next freeway trip. I was disappointed not to see any improvement driving around town.

JLeffler

I guess I'll do the same !

PeterJ63

I have been using Premium Gas in my newly purchased 2008 RX 350 because that is what I assumed the manual was suggesting. HAS ANYONE tried using ETHYNOL FREE GASOLINE in their RX?

jfelbab

Yes, I usually burn real gasoline in my RX330. I can get ethanol free gasoline 5 miles from where I live. I do see 1-2 MPG improvement which stands to reason as that fuel has higher energy than ethanol blended gas. I also live just inside an area that requires vehicle emission testing and I get the same results no matter which fuel is in the vehicle. I always burn premium and the ethanol free gas is only available here in premium. Over the life of my RX330 (10 years) I have averaged 23.1 MPG measured. I do 80% highway/expressway driving and see 25-27 MPG there. I've not seen much difference in MPG in city driving with either fuel or any octane rating but on the expressway at a steady 60-75 mph I see a nice gain, especially with premium ethanol-free gas. Not sure what the 350 will do but I'm about to find out as I'm planning to get a 2014 RX.

Pmkettler

I just purchased a 2007 RX 350 last week and was curious if I can use regular unleaded instead of premium gas? Thanks!

kiwi

as per the owners manual, YES

Pmkettler

True, but I know lexus owners who only put regular unlead and say it makes no difference.
I just want to make sure I won't hurt anything if I do this..

RX330inFL

Welcome to Club Lexus, Pmkettler.

As stated in your Owner's Manual:

Fuel types Use unleaded gasoline. (91 Octane rating [Research Octane Number 96] or
higher)

http://drivers.lexus.com/t3Portal/do.../sec_01-05.pdf

Please keep in mind that this is different than the requirements for the 3.3L engine in the RX330 from 2004-2006.

This is a topic which has been discussed previously here at CL and at great length. For example:

https://www.clublexus.com/forums/rx-...ne-rating.html

In short, you can try running several tanks of regular unleaded in your RX350 to see how it performs and get an idea of your MPG. One tank is not a sufficient test sample. However, from past experience here on CL more individuals who own 2nd Generation RX350 have had problems running regular fuel and have switched back to premium. It is what your vehicle was designed to use and in this case probably will prefer. You might get away with it and notice no difference. Only you can make that decision.

Rainbird

Lexus recommends premium fuel for the RX350. Follow the manufactures recommendation. It all balances out, you will get less MPG burning regular fuel. Here are several link discussing fuel.

https://www.clublexus.com/forums/rx-...emium-gas.html

https://www.clublexus.com/forums/rx-...nsumption.html

Pmkettler

Thank you for the info.

ejb222

I honestly dont think it's that much difference from 87 to 93. I personally run 87 in my 05 RX330 with 235k on it. the previous owner(my dad) only ran 87 in it as well. I've compared the mileage and it really doesn't pay off at all. In fact some gas stations are so inflating the premium gas that it actually is worse for your wallet.

RX330inFL

Let me reiterate my comment above...

While the 3.3L engine in your RX330 can run on 87 octane, as it is stated in the Owner's Manual, this is NOT the case for the 3.5L engine in the 2nd Generation RX350. These are two different engines and you cannot compare one to the other for such a comparison.