Just purchased an RX330 2004. One owner with 56000 miles. I love it.. Previous owner said she rotated between Mid grade and Premium octane gasoline.. Reading the manual it states 87 (regular) is fine for this engine. Anyone with experience in this regards?
Thanks!

Wow! Thanks fopr all the activity! Lots of good info out there.
FYI, I just pulled this off the Quick Trip web site;
"The word premium doesn't have anything to do with the quality of gasoline. It has more to do with the price.
Premium gasoline costs more for two reasons. It costs more to make. And, there's more profit added to premium by refiners and retailers. But, premium gasoline doesn't cost more because it is better.

Premium gasoline has a higher octane rating. Higher octane is only one thing: an index which indicates the gasoline's ability to overcome knocking or pinging in engines. That's all. If your car doesn't knock or ping on lower octane gasoline, paying for higher octane is a waste of your money.

Higher octane does not mean better quality and it will not result in more power, better performance, greater gas mileage or anything else.

Some high performance cars were designed to run on premium gasoline. In that case, the owner's manual will clearly state you should use only premium gasoline in that vehicle. That's what premium was made for.

Why does QuikTrip expose the premium myth? After all, we stand to make more money as long as some people continue to believe the myth.

The economics of doing the right thing are pretty simple. QuikTrip gives you the facts rather than trying to sell you myths. You test the facts and find they are true. You save money. You buy more gasoline from QuikTrip. We overcome any short-term loss by selling more gasoline.

You win. We win. It's that simple. "
End of quote

 

Welcome to Club Lexus. Keep in mind, some people in some areas don't have much of a choice in terms of octane (especially in high altitude areas), even if they wanted to use a better octane. However, there is a long story I have given about engine timing, octane and altitude before.

If you try our forum's search feature (use the word octane), there is quite a bit of information on this already.

Again, welcome to Club Lexus.

 

The manual actually says; I burn 91 octane or better. My RX has slightly better mileage and performance with premium gasoline and premium costs only about 20 cents a gallon more so that equates to about $2.50 a fill. More significant to me is that when I use premium the sulphur smell goes away. When I began having that strong sulphur smell under load, Lexus suggested I use better gas, i.e. gas with more detergent. I started burning premium from Top Tier suppliers and the smell went away.

Perhaps more important than the grade is the supplier. I now only purchase gas from a "Top Tier" supplier. <http://www.toptiergas.com>

Here is the currently published list of retailers who meet the "Top Tier" certification.

QuikTrip
Chevron
Conoco
Phillips
76
Shell
Entec Stations
MFA Oil Company
Kwik Trip/Kwik Star
The Somerset Refinery, Inc.
Chevron-Canada
Aloha Petroleum
Tri-Par Oil Company
Shell-Canada
Texaco
Petro-Canada
Sunoco-Canada

Surprisingly some rather prominent retailers (BP, CITGO) do not meet these Top Tier specs with their grades.

 

uh oh, not another mpg thread. i have an 05 rx330 and i use 87 octane all the time. the dealer said that putting more expensive gas is useless. since so many people on this board swear that putting in higher octane gas is better and that not doing it is just insanity, i tried putting in a full tank of 91 octane and from a shell station. My mpg for a full tank went from around 280 to 265, which is weird that with higher octane gas my mpg actually went down. oh yeah performance didnt change at all either.

 

Mexico is probably one of the places where it is not insane (but U.S. and Canada have some of the best gas on the planet). At higher altitude here, I would prefer to use 87 instead of 92, but the 87 sold here chock full of sulfur (great for cooling engines) but not for combustion or emissions. Whereas the 92 octane premium is much closer to U.S. sulfur levels (unlike what it was for years).

 

My 04 seemed to run and shift much better running the Premium stuff. I could tell a differance between the 2

 

err from the first day to now, which is just 4 years now, ive been putting Chevron Premium in there (91 octane cause we dont get anything higher). I dont want to "try" putting anything else down there just cause i have OCD where i dont want different gasses to mix. ONLY CHEVRON! lol

at this point, the only real difference that you can probably tell would be the price difference. but for 20 cents a gallon, thats at most a dollar something extra at the pump. so...you cant even buy a cup of coffee at starbucks for that much. really there isnt much of a financial impact.

however, im sure 87 would be totally fine. at least use mid grade though. Treat your cars like you want to be treated. think of it like your feeding them. the cars like high octane...lol

 

I agree that it shouldn't matter. I usually just do the math. I seldom can tell the difference between mid-grade and premium when it comes to performance and mpg (I just know it's best to fill up on premium in just about any car before going for smog testing). However, there is a significant difference I noticed when going down to 87. So I just do the math. If I am not filling up, and only getting a few gallons, then I go premium. If I do fill up I decide at that time is it worth the extra money. Most of the time I go with premium.

Yesterday I was at the Chevron just north of Cahuenga and Franklin in Hollywood and my JAW HIT THE GROUND. 87 - $2.99/gal, 89 - $3.19/gal, and 91 - $3.29/gal. My instincts said fill up on Premium, it must be close to an election or something. To fill up on 87 would have cost me $41.86, 89 - $44.66, and 91 - $46.06. So for peace of mind, I just paid an additional $4.20, the cost of one coffee from Starbucks.

 

I would have still gone to starbucks and got my Grande-Skinny mocha/extra hot/no foam--MMmmmmm good
Or the wifes Grande Skinny/2-pump sugar free vanilla latte/extra hot/no foam-MMmm good too

 

Experts need to chime in, look at the article on Wiki about sulphur content in diesel, less sulphur means less pollution but also note from the article, diesel is also produced from crude oil though the distillation process at refinery is different

The refining process that removes the sulfur also reduces the aromatic content and density of the fuel, resulting in a minor decrease in the energy content, by about 1%. This decrease in energy content may result in reduced peak power and fuel economy. The reduction is only slight and will likely go unnoticed.

WikiArticleAboutSulfur

 

I think affordability has nothing to do with the actual need or no need for premium. Most people would love to have both Starbuck coffee and meet the octane requirement for the same $ spend. Why spend more if one does not have to?

 

err, well...

im not saying that i can tell a difference in the premium gas versus regular, but id like to think its better for the car. my car is an investment, and i want to keep it in the best condition possible, engine wise.

 

That is a pretty bad cruising range. We used to get a estimated cruising range of about 385-395 on a full tank of 92 on our 04. We would easily get up to about 330-350 miles before we would fill up. It wasn't until I went to 20" rims with over sized tires and our state switched to E10 that I saw 285-295 miles on a full tank.

 

umm...WTF?

how are you guys getting over a 300 cruising range...

do my wife and I need to relearn how to drive? When she primarily drives it, it says 255 after a fill up with an avg of 14-15 mpg. (we do mostly city driving)

shes been on vacation for two weeks so i filled it up, again the 250s and then for the rest of the week, i kept the navi on the trip info screen. I was watchng it meticulously and pretended it was a game. I seriously was very careful. this is mix city and highway since ive been using it. Well when the yellow light came on, i went to refill the car. The computer said 280...which is the highest ive ever seen it. lol with an avg of 18.5 mpg.

am i missing something here? I have a 2004 and i only use premium. 18" wheels with the performance package. (i also want to add its very hard to be fuel efficient in a city like San Francisco. The hills are a real killer.

 

We probably had about 60% highway and 40% city. To be honest, it was more like 40% highway because my wifes commute on the highway was spent in peak morning and evening bumper to bumper traffic which pretty much wiped out the fact that you were actually on the freeway

In pure stock forum we would see 385-395 on the estimated cruising range, but we typically would fill up between 330-350 miles with about 15 gallons of gas. We easily would get about 22 MPG combined average. Then, when I put the 20" rims on with oversized 255/50/20 tires, our MPG dropped to about 20MPG, but I never got less than 20. Then in 2006 our state mandated E10 gas and that dropped my MPG another 2 MPG to about 18MPG which really sucked.

What is odd is I'm difinitely not a casual driver as I'm much more aggressive than my wife. I've been driving sports cars for my daily for a while so I don't baby it. But I generally got better over all MPG than my wife did when she drove the RX.

Honestly, if I only got 18MPG combined average in the RX from the start I'd be pretty pissed considering that our 99 LS400 with 290HP V8 gets about 18MPG combined average as well.