Lexmex

Pemex 92 Octane here in Mexico, though the stuff is pure garbage, but with a monopoly you do not have much choice. A lot of my buddies just buy their gas, Sunoco, at the track and drive around on that, though 109 octane.

CarsFreak

I remember reading that a Sienna owner put in 91-octane fuel and the hesitation disappeared.

Could this be it?

Also, I heard that there's a new TSB out for all 3.3L. Anybody hear about it?

Legendman

What is the TSB about (what does it cover)?

dialleft

The term "premium" is misleading. There is no (as in zero) more energy in premium than in 87. It does not burn hotter and it does not burn cleaner. Higher octane gas has more of a chemical that retards gas from igniting, and that’s it.

That was important in cars before computers, because high performance engines were susceptible to premature ignition, i.e., engine knock. That knock meant a piston was igniting early, before it reached the peak of its cycle, and was actually working against the other pistons. That was very damaging to the car.

Modern cars have computers that detect engine knock and adjust the timing to stop it. An engine designed to run on premium will not perform quite as well on 87 because the computer timing adjustment will also impact horsepower and torque. I’m not sure whether the computer timing will increase performance of an engine designed to run on regular. My guess is slight, but I doubt it would be detectible.

So, basically you have been wasting your money on gas higher than 87. I use 87 in our 330 and premium in my 350Z.

I’m not an expert. When I first bought my 350Z I Googled the subject and found some excellent sites that explain it well. Here are some of them.

http://www.rxp.com/Octane.htm

http://www.ftc.gov/bcp/conline/pubs/autos/octane.htm

http://www.omegamotors.com/enjoy/gas...soline_06.html

http://mywebpages.comcast.net/rx300how2/

http://theserviceadvisor.com/octane.htm

Once you read them, please let me know whether I got it wrong.

mink92890

I dont know if it is just for RX or not (the poll) but my LS430 '01 RQ@UIRES ultra
It sucks because i pay like 2.30$ for a gallon.
23 gallon tank
You do the math



Mink92890

xfirechief

You really didn't buy a LS 430 & think about mileage did you? If one can afford vehicles like these, mileage should not even be on our mines.
There are other vehicles out there that get better MPG but we did not buy them.

Lexy GS430

Everybody on this thread so far has been very helpful with the gas pole but i believe that without hard facts on regular, plus or premium i'll still believe that premium burns cleaner, and less harmful to any gasoline engine, plus i don't mine paying $2.20 for premium where i'm at.

Kyosuke86

Even though regular is cheaper, I find that the car runs a hella lot smoother with premium. For some reason the RX my friend bought has an acceleration lag to it when she fills it with regular.

miltonlin

Is it running smoothly? Do you hear knocking?
Does changing the gas make any driveability difference?

I try to take the best care of my vehicles and my RX300 runs fine with 87.

Take that same 87 on my other vehcle, and ES300 (essentially SAME 1MZ-FE engine, and it's not as smooth, slight knock (especially noticable going slowly uphill, under load). When I switched to 93, that went away.

Rx13

Have tried Premium but couldn't find any difference other than the cost. I use Regular and haven't noticed any problems even in the Mountains (hills) of Vermont or Tennessee.

vpalacio

Although I would love to put premium in my RX, I can't justify buying $2.60/gallon every week. Maybe alternating between regular and premium would work?

TunedRX300

How does higher octane gas helps tranny hesitation? Gas burns in engines, not in transmissions. Engine is a power plant, tranny is just the transmission line.
The only possible explanation is when tranny shift to a higher gear, RXs that burn premium output lower power than those burn regular so you don't feel as big of a jolt between gears.
Higher octance means higher resistance to explosion. If you put higher octane to engines designed for 87 such as 1MZFE, you get unburned mixtures and lower power. Pay higher price, get lower performance, plus clogging up your catalytic converter with unburned carbon deposit, be careful here.

Jimbo2828

i dont think the RX300 required premium. besides its the same motor as a V6 camry and it doesnt require premium. but anyways i always used premium for my RX

mmahamm

Unless things have changed, no. I had a BMW 323i, and the owner's manual recommends premium but also states that it is designed to be able to handle regular. I only ever used regular in it, and it ran well.

mmahamm

Premium does not burn cleaner. All gasolines are designed to burn cleaner. Advertising has convinced us that only premium has all of the additives that make it burn clean, but on closer inspection, you will find that regular has the same additives.