I have a 2010 Lexus RX350. The dealer is telling me that I have to always put premium gas. Has anyone put in any other gas grade beside premium on the 2010 RX 350?

Thanks

 

OLD ISSUE. Many ideas on this subject but my 2 cents worth is use premium all the time. I do with our '09 & get more MPG & better preformance with it.
Its a Lexus & most people do not buy a Lexus that can not afford the best fuel available. Lexus says u need it so get it.

 

It's recommended, not required, to use Premium Gas. That's what I was told by my dealer and I'm pretty sure I read it somewhere too. Although I have to agree, why risk using anything but Premium?

 

With the engine's compression still at 10.8 to 1, I think you can go either way.

 

at least use PLUS if not premium

 

Curious! How much can we save if using non-premium gas? $300 per year (fill a tank every week)?

 

For what it's worth, we have been using 89 octane (10% ethanol blend) for my wife's RX400h for the past 4 years and I have also been using this same blend for my LS460L. There have been no problems whatsoever. Here In IA, 10% ethanol is 13 cents cheaper than 87 octane (regular) and 30 cents cheaper than premium. I have tried premium (91 to 93 octane) once in a while for testing purposes and I have not seen any real difference in fuel efficiency or performance. Unless we are absolutely told that we have to use premium for the new RX450h, we will continue to use the 89 octane ethanol blend.

 

You should not use cheap gas in your LS to save $200 to $300 a year? The engine in the LS has a much higher compression ratio then the RX. 11.8 to 1 compare to 10.8 to 1.

 

I think no one says that using non-premium gasoline will hurt the engine. Engines in this era have been set to adjust itself when using the varied of common octance. Your engine will keep running "well" until you stop maintain it.

For those higher compression rate engine, car makers "only" suggest to use Premium to get the better efficiency and performace. If drivers don't feel the difference, don't use premium.

Someone would like to spend $$ on his stereo and speakers; I don't mind spend $$ on premium gas. Everyone has their own choices.

 

rets, I know that on engines such as the GS350 or the IS-F, premium is require, not recommanded.
You are right that the engine will adjust timing when it senses knocking from the low octane gas. The issue is that it will slowly advance timing until it detect a knock again, at which time , the engine's computer pull back timing again. Imagine this happening over and over again, that little bit of a knocking must not cause any damage if it only happens once a while, but if you let it happen over and over again thru out the life of engine, it may cause damage over time.
Thats why most turbo chraged engines requires premium fuel, its because of their high compression. I would say a good cut off point is about a 12 to 1 compression ratio. The RX which has 10.8 to 1 should be ok with cheap gas, but the GS, LS or the IS350 which has 11.8 to 1 is a good candidate for 91 octane.

 

Its your car put what ever you want in it that will float your boat. I live on the gulf coast and can get away with the low octane gas because we have no hills here and the on load I ever put on the motor is getting on the Interstate.

 

I used 89 octane (10% ethanol) on the LS430 I owned for 4 years and I had absolutely no problem. I have been using 89 octane on the 2008 LS460L that I have owned since Dec., 2007. I am not doing this to save money but ethanol is suppose to be better for the environment.

 

I have no problem with it. Unless the gasoline is up to $5 per gallon, I can afford it. I'll use the one I think it's right. To me, I do feel the difference between Premium and non-premium.

To those who don't feel the difference, I understand their points and wish them good luck and enjoy their rides.

 

Is gasohol all made by 89 octane only? There is Premium gas with ethanol, right?

 

I am not sure about other parts of the country but here in IA, ethanol only comes with 89 octane. The premium does not have ethanol. I believe that in TX all the gasoline has some ethanol in it, but I could be wrong.