What type of gas do you put in your GX
 

My new GX is my first ever luxury car....I'm used to driving around in my 1996 Honda Accord :)

Should I be using a higher grade of gasoline, or is it unnecessary?

Thanks in advance,

Welcome to ClubLexus!

You'll find many of the questions you have may have been asked before so try the search feature! I looked for 'premium gas' in the GX forum and found the following threads among others. Instant answers, no waiting :)

https://www.clublexus.com/forums/sho...ht=premium+gas
https://www.clublexus.com/forums/sho...ht=premium+gas
https://www.clublexus.com/forums/sho...ht=premium+gas (older thread pre-release)

How about the 05's what is there recommondation?

regular unleaded
www.edmunds.com
great place to find this type of info on any vehicle.

Per Lexus website, Octane 91 or higher is required on 05 GX (it used to be regular on 04's). However my 05 users's manual states:

"Select Octane Rating 87 (Research Octane Number 91) or higher. For improved vehicle performance, the use of premium unleaded gasoline with an Octane Rating of 91 (Research Octane Number 96) or higher is recommended "

I called Lexus customer service to find out why the website and the user's manual were not on the same page about this. Well all they could tell me was
"the engine can run fine on regular gas, but for improved performance we recommend premium"

I guess It's a matter of personal choice.

Orclex

... or how much you like paying an extra $.20-$.40/gallon for basically nothing. Consumer Reports did a study on this a few years ago and they concluded that you gain almost nothing by putting in a higher octane than that which is required by the manufacturer. The engine will probably advance the timing a bit if you put in 91 (or higher) octane, but you'll never notice the difference.

If your car pings with 87 octane then you'll need to put in higher octane until you can get Lexus to fix the problem. Otherwise save your money and put in 87 octane as recommended in the owners manual.

But in what context was the CR report (i.e., what kind of engines)? The compression ratio of the 2005 GX is 10:1 which, from articles I have read, generally should "require" or prefer the higher octane. The lower octane may combust to soon.

Which one would hear if it actually occurs. If so, higher octane will probably help. If it doesn't, you're paying an extra $4-$6 per fill-up for nothing by using a higher octane than recommended by the manufacturer.

I think you are right, if you aren't getting any knocking you are probably o.k. :) If you don't mind the cost I suppose it could be worth peace of mind! :D

This is true if 87 octane is recommended for the car.

I have to do the research, but there was another study that stated that if you put a lowere octane fuel in a car that requires 91 octane or higher, the timing will be retarded and gas mileage may suffer to the point of negating the monetary savings of going to a lower grade fuel.

Bottom line. Use what the manual recommends.

I think that's true, that it could be bad if you are using the lower octane than what is required. If the higher compression causes the fuel to ignite too soon, you end up burning more gas.

The question is probably more like what happens if 91 octane is used instead of the recommended 87 octane, as opposed to using a lower octane than specified in the owners manual. I started the ES330 out with 89 octane and went back to the recommended 87 octane with no noticeable reduction in performance or mileage. The engine has VVT with intelligence. Back a few years ago, there were some GS400 owners who were severely chastised for even thinking out loud about using 87 octane instead of the required 91. They were asked why someone that could afford a $50K car would feel a need to save $250 a year by using cheaper gas.

This afternoon I was taking one of my friends to a BMW dealership. He owns a 3 series beemer and when I kicked the accelerator down to merge onto the freeway, his eyes got real big and he said, "Wow, this truck really moves out". I use 87 octane.

The octane has NOTHING to do with more power or better acceleration. It is to prevent knocking in high compression engines.

Also, just because the ES had VVT also has no bearing. Again, it's what the manual recommends.

Hello? Didn't I say there was no noticeable difference in performance or mileage on the ES? You should have quoted the first paragraph, not the second. The fact that the ES has VVT is only a statement not an argument.

Well that's the issue. The manual says Regular (Octane 87) while the specs on the website says Premium (Octane 91 or higher).

which one should we trust? The manual or the website? Could that be a misprint? :confused: