quantfutur

Been thinking of downgrading to 87 from 91/3 and found this article in USA Today, which includes opinion of an oil industry engineer from Chevron...

http://www.usatoday.com/money/autos/...emiumgas_x.htm

kiwi

what the article fails to indicate, is that if your vehicle has a knock sensor (which i am pretty sure ours does) and you use regular fuel, you may here the engine knock or ping.

by all means if your owners manual say use regular then use regular. i had a 1997 accord and used premium for a long time til the prices went up to 150 per liter. i switch to regular, and my mileage increased to almost an extra 50km per tank. should have used regular like the manual said.

lexus114

The 3MZ-FE has two knock sensors.

lexus114

Here is how I see it. Premium is recommended by Lexus, It comes out to around $4.00-4.80 a tank more than regular,and in some locations,it`s lower than that. Isnt your vehicle worth it?

kickin8

iTrader: (1)

but $70 a tank is really killing us....

kiwi

132.9 per litre up here, so about 83 bucks a tank, and for that i get 400km (250 miles) city, 450km (275 miles) hwy. hoping when i remove the winter tires it gets better.

i would love to switch to regular

quantfutur

I did 87 octane on my 99 RX300. There was no mention of a higher octane recommendation in the owner's manual, to my recollection. The catalytic converter started to go bad around 165k miles.

My '05 RX330 owner's manual says minimum 87 octane. It has always been run on premium but gas prices are ridiculous now. I plan to switch to 87 this week and will monitor it, including the gas mileage. Apparently if there is problem I will hear knocking, and if I do I will switch back to 91/93 for sure.

xfirechief

I was thinking of mixing but I can get 93 for only 10 cents more then 87 here on Mondays so for only $1.60 more per tank I'll stick with 93 Octane. I have tested in the past & I get 2+ MPG more with 93 too.

quantfutur

xfirechief - for 10 cents more I'd stick with 93, too. Unfortunately more like 35-40 cents here.

lexus 114 - I agree is worth it to use 93 if I start hearing a knock or see any indication that I could be harming my car with 87. I suppose I wouldn't even try this if it weren't for the fact that my '99 RX300 ran on 87 without problems

kitlz

I used 89 on the 330 even though it could take 87. Didn't have any problems with knocking. Now I need premium for the 450h. Can't complain though, I paid $3.61 yesterday for 93, Shell too. They don't jack up prices like other stations do.

cdnewton

I can be the guinea pig for running normal octane in the RX. I am in Colorado and run 85 octane (equivalent to 87) and our RX just surpassed 140,000 miles. I will report back when we hit 200,000 miles (or sooner) if we have experienced any issues. For the '04 model, I think it says "for optimum performance, premium is recommended". As usual, YMMV.

HtownBlue

The major factor people fail to realize is the combustion between 87/89/ etc. etc. is so small in the 330 engine it rarely effects performance. The higher octane is said to prevent premature ignition, but that is a rare event in an engine that is well taken care of. And in respect to higher octane fuel being "cleaner burning", that is a complete farce. The same amount of detergents go into regular and premium levels of fuel as regulated by the EPA and FTC.

To really understand the "value" of premium fuel, you must know about engine knock, engine combustion, and fuel injection /EGR/Mass Airflow? etc. and how those components of your vehicle operate together.

I'm sure others may feel differently because the Lexus manual says use premium, but the ECU of the LEXUS fine tunes the injection and timing of the engine to a point where it is extremely rare to have knock due to engine fuel alone. Not saying knocking can't happen, but I have a combined 350K+ on two Lexus RX's and have used regular and have NEVER had a knock, or knock sensor code. Take care of your engine (oil, timing belt change at 130K, etc. etc.) and it will take care of you and your wallet with regular fuel.

infinirx

I am gonna give it a try Been hurting $$ wise lately..

billy44bo

I put 77k miles on my 05 330 never ran anything other than 87. Car ran fine. Like that car so much order a 2011 450h with all the things that I wanted in the car. I run 89 in the 450h and I am getting 30mpg per tank right now with just 3k miles on the car. Try the lowest grade of gas If you do not like it then change one grade up to see if that is a better grade for your needs.

lexus114

No it isnt, My tail pipe is clean as a whistle using premium. If your using regular, I bet your tail pipe has an indication of a richer mixture/carbon in it. Check it out. If the motor benefits from using premium as ours does, It just makes sense to use it.