Hi All -

Have been researching the prior threads discussing regular vs. premium gas and found them interesting with arguments for and against on both sides. The CarGuys website thinks it's a myth that premium is required but erring on the safe side probably can't hurt other than the obvious additional cost:
http://www.cartalk.com/content/featu...ium/myths.html

My question is, being a relatively new owner of an '02 and an '06 Ls430, we're going to use premium but trying to decide whether 93 octane is all that better than 89. So far we've been using 89 w/ no noticeable negative results. Any thoughts?

Btw, our previous LS400's both had 87 fed to them for the last 50k we owned them, also w/o any problems.

Will and the Fur Crew

 

Required min octane is 91.

 

I go to Shell and the options in Michigan are 87, 89, and 93 octane. I run 93. I look at it this way:

- I drive about 25,000 miles per year at an average MPG, per the display, of 24.4.

- 93 octane costs $0.10 more than 89 and $0.20 (or less) more than 87.

- It costs me an extra $205 per year to run premium over regular, or $102 per year to run premium over midrange.

- If I drove 15,000 miles per year, the difference per year would be $123 over running regular and $61 over running midrange.

The sticker inside the fuel door says "Premium Unleaded Fuel Only". Following the manufacturers instructions is not going to impact my lifestyle.

 

The 2002 LS430 manual states "Select premium unleaded gasoline with an Octane Rating of 91 (Research Octane Number 96) or higher for optimum engine performance."

Does anyone know what Lexus means by "or higher"? Does higher = better performance? Can the ECU tune itself to take advantage of higher than 91 octane?

I've spent the last day researching information on Top Tier fuels versus Shell V-Power. A lot of forums have user reviews which are very subjective or biased to a specific brand, so it's hard to find real information.

My findings are:
1) you should only use the octane rating specified for your car
2) only get gas from a Top Tier retailer
3) some people say each brand's detergent package will leave behind gunk or deposits after awhile, and the best way to clean them is to switch to another brand, which will have a different detergent package and will "wash" away the old detergents.
4) for cars that require 91 octane, Shell V-Power with their patented nitrogen molecule is the best gas for keeping your engine components and fuel injectors clean. V-Power meets and exceeds the Top Tier specifications.

V-Power is theoretically better gas and should help keep fuel injectors and engine components cleaner than other brands. By keeping the fuel system clean all the time, fuel system additives and fuel injector cleaning service should never be needed.

From what I've read, the car may run a little worse when the detergents take effect, but after a few tanks, everything should be fine.

In Canada, V-Power does not contain any ethanol, so in theory, fuel economy should be 2-3% better. No ethanol should also mean less water going through your tank and fuel system.

Petro-Canada premium has been the only brand I would use, due to convenient locations and Top Tier certification, but I will switch to Shell V-Power after my current tank runs out. Since it is a nationally sold brand and heavily advertised, I don't see it causing any problems.

Unless I experience adverse effects that persist after several tanks, I'm making V-Power the only gas I will put in the car.

 

Thanks for the info, Stan -

Have been using Arco mainly for convenience sake + price, but it's not top tier. Think we'll switch to Shell as they're also close by AND top tier. Maybe a little more but not cost prohibitive.

Will and the Furry Ones

 

The sicker inside the fuel door of my 04 says, "Premium Unleaded Fuel Only, See Owners Manual."

The Owners Manual specifies 91 octane.

 

Only use 93

 

If i remember this correctly, if you go with octane rating lower than recommended the engine will misfire/detonate (but not enough to notice) which will lead to engine issues in the future (thousands of miles or years later) and oh yeah.. you loosing power and efficiency of the engine.

engines are designed for specific octane. octane rating is how fuel burns inside of the engine. (how quickly it burns)

most gas stations have additives. but, the cleanes burning fuel has always been BP. It was proven in many tests.

 

No joke intended (o.k., maybe some sarcasm towards BP) but it didn't look like BP burned so clean in the gulf spill when they'd set it ablaze.

On principle alone, I'd purchase any other fuel before BP.

Will and the Fur Crew

 

What principle...due to the oil spill?

 

Absolutely !