kjcole

I have cars with 150K miles of running gas/ethanol. Never any problems. Cars are designed for this gas. Older marine engines or older utility engines (lawnmowers, etc), that's a different story.

tromly

Correct, today's engines will not have problems with ethanol.

Harold57

I forget what the proper wording is in the automotive industry but some cars are recommended and others are required to use premium. For those that it is recommended, the car can deal with either octane without causing problems. For those that are required, problems may arise from the use of regular gasoline.

I've been driving my '02 on regular gas since '06 without any issues, nor pinging. I did drive it for 6 months to a year on premium when I thought some problems were developing but that turned out to be a well placed rock between the bottom faring and the engine. It sounded just like pinging and fortunately a mechanic finally tracked it down.

The main differences that I saw were slightly less performance and slightly less mpg, neither were that major. However, I don't hot rod around either. So there should be no need to worry whether you damaged your engine with regular gas, they can take it.

Moonstruck

Harold57,

Ya, I also remember reading something about recommending and requiring the use of higher Octain. I think that I am going to use the 93 just to be safe, especially since the extra cost is not going to amount to much because our Rochester climat prevents me from driving the car more than 6 month each year.

LexusinTex

There is no need to use 93 octane. I had an SC430 for 2 years and it ran fine on 89. An advanced engineer once explained this on a Mercedes forum-- Some parts of the world only have 88 or 89 octane gas, all cars are made to be sold worldwide---so you get the picture.

The two cars I had that really needed, begged, wanted 93 octane was a C5 Corvette and a 64 Thunderbird with a 429 V8, those cars were super pingy without it.

Cars that didn't--- 2002 GS400, 2004 SL500.

Moonstruck

LexusinTex,

Thanks for the info, I'll keep that in mind when I get the car out of storage at the end of the month. Right now we are having a snow storm here in Rochester so it's tough to think about my summer toy.

danielxxxx

I own a 2010 RX350, and even though the owner's manual says to run on super gaz, I fill it up with less expensive regular and I haven't seen any difference. My dealer told me the sensors in the motor will detect the difference and adjust accordingly. Premium gaz is more compulsory with motors with a turbocompressor, like the new NX200.

ShawnOk

iTrader: (1)

I've only used premium gas since I purchased my SC430 in 2002. I've heard that using less than premium quality gasoline in a car that requires premium can lead to engine knocking with time. Not sure if there's truth behind it, but I didn't want to be the guinea pig on that myth.

danielxxxx

If you not sure if you want to try regular instead of premium, just fill in a quarter of a tank with regular and run with it to see if you hear any knocking. If you hear something wrong, fill up the rest wth premium. Personnally, I have never heard any knocking with regular, but I agree it depends on the kind of motor.

If you want to save money on gaz, you can also go with mid-grade, which is half-half.

Harold57

I've used regular gas almost the entire time that I've owned the car, which is over 9 years and 60k miles. No knocks and no smoke. The engine handles it just fine. The only difference that I've seen is slightly better acceleration with premium.

tromly

I too run regular in both my RX's, no difference!

ShawnOk

iTrader: (1)

Yeah, i guess it's just a personal choice. I used to own a 1999 Chrysler Sebring LXi (albeit with a Mitsubishi engine) and it would knock horribly after about 2 years (using only regular gasoline). I hated that sound to my core. Didn't want my Lexus to end up in the same boat and after i heard the "myth" about using less than premium leading knocking over time, I made the decision that it was only premium for The Lex.

texsexlex

iTrader: (3)

I too only use premium in my Sc.... I figured with the 30-60 cent difference between regular & premium, it's only an additional $6-10 per tank to play it safe

Prasha

High Octane gas has shorter shelf life, loses its octanes on storage in gas tanks?

Moonstruck

A trusted mechanic told me that if your car runs OK on regular gas and does not ping during hard acceleration there is absolutely no reason to spend the extra money for higher octane. I do use the highest octane for filling up my tank for winter storage, but primarily because it does not contain ethanol.