Boomer01

I've always used premium gas but the owner before me told me that he used mid grade (plus). I experimented with it for a few tanks after I bought the car seeing how the mpg was affected. It seemed like I was consistently getting better gas mileage with premium. The driving was mostly in the city so it could never be consistent though.

This weekend we took a trip to St. Louis and I decided to try again since I would be driving the same stretch of road and would go through at least two tanks of gas. On the way there I used premium and drove just over 500 miles before filling up. I drove anywhere from 65-85 mph depending on the road and I averaged exactly 25 mpg. On the way back I filled up with mid-grade gas. I drove just under 500 miles and averaged exactly 24 mpg.

Doing the math tells me that a full tank of gas would equal around 1 extra gallon of gas. Since gas is around $4 now, the $0.10 difference in grades (around $2 for a full tank) would not be in my favor. So you actually save money in the long run by using premium gas and it's better for your car. I'll be sticking with premium gas from now on.

CarGuy89

Thanks for doing the experiment and sharing your results!

BlueLS

haha haha haha

Jabberwock

That has been my experience also, the lower octane content produces slightly lower mpg that basically nullifies any $ savings of using lower octane gas. The computers running the fuel air system on the LS can certainly deal with lower octane gas by retarding the ignition but there doesn't seem to be any $ benefit to running lower octane gas in a relatively high compression engine.

warminwisc

Toyota puts how many millions into engineering cars, and on and on we go about questioning them? I am fortunate I have a bunch of money but I would be ashamed to run other than OEM and buy this expensive car. This is the last time I ever glance at this thread so bash away.

Marklouis

for you guys that your display in the dash constantly shows low MPG numbers -

Be sure to reset your data especially "avg mph" and also "avg mpg" after refueling - I reset mine right after fill up and when I am driving on the most level part of the hwy/interstate doing about 60/70. I do this because for some reason my "avg mph" will get stuck on 27-35 mph even when im on the interstate for some time. so I try to be sure and reset that before I leave the house and I seem to get more accurate MPG readings. it will usually jump from 21 - 26/27 on the interstate and stay there when I do the reset. I just like to know what my MPG is often on different stretches of road and weather conditions - the "Current mpg" option is just too erratic for my taste.

Viper6

Sorry to debunk the myth. Based on my understanding, high octane gas has the same Joules of energy as low octane gas for a given volume. I just tried a tank of 87 vs. the 93 I normally use... I usually get 25-26MPG on 93 Octane and got 25.5 mpg for that tankful of the low octane fuel... no measurable difference in mpg, measurable difference in my bank account however.

I guess my driving style did not miss the approx 1-2% increase in peak HP and Torque that 93 octane would have delivered. I'm not smarter than Lexus R&D center, I just did a simple non-scientific experiment to test an hypothesis... use your own judgement to interpret the results.

Jabberwock

Viper I think you are exactly correct in that the energy content between high octane and low octane gas is the same. The higher amount of octane content in "premium" gas is there just to retard early ignition. Premium is not a better or stronger gas, its just slightly different combo (formula) of the various hydrocarbon distillates - the "tanes" that are mixed together to make up what is commonly sold as automotive gas.

I do think there is an MPG difference in the high compression engine on the LS because the fuel air computer has to retard ignition which makes the engine run below its peak performance and peak efficiency since it was designed to run on higher octane gas. For me at least I have observed about a 10% decrease in mpg...although that's an admittedly highly unscientific estimate as the amount of ethanol content in the gas is unfortunately something that is unknown from one tank of as to the next. Up to 10% ethanol content is what the pumps say around em and that can also cause 10% less mpg all by itself.

But for someone running a low compression engine there would be no difference in energy achieved or mpg derived from running premium versus regular gas formulas. "Moving up" to premium on an 8.5/1 engine is a waste of money.

Boomer01

About $4 per tank is a measurable difference in your bank account? Driving a LS430, I hope not. Especially when it costs around $75 to fill it up.

Marklouis

getting closer to $80 to fill up now. Im just very careful and only drive when I absolutely need to. the Gas will be going down though the closer to the elections we get - happens every time.

So Philly1

Gas prices suck..



that is all.....

philboyj

Its funny when you read forum posts from 6 - 7 years ago that complained about gas prices when it was $1.89 a gallon and they found a pump that sells it for $ 1.75 a gallon

We are still better off than Europe and a lot of other third world countries. A large part of that is the taxes - nearly 3-5 dollars per gallon as tax alone. That hopefully would never happen in the US. Third world countries with a much lower per capita income pay almost 50% to 100% more than the USA. Here is an interesting link - http://www.theatlantic.com/business/...238226/#slide2

Venezuela - 10 cents per gallon ??? WTF
Saudi Arabia - 45 cents per gallon
Denmark - 9.69 per gallon.
India, China, Bangladesh, etc - $ 4:25 per gallon (not in article above)

I certainly wish that we did not depend on the Middle East or anybody else for oil and we make the switch to some other form sooner than later. (Hybrid, Electric, etc etc).

Viper6

I said Measurable (more like $5/tank difference), not "Material"... however with Gas being the highest running cost for my vehicles (I perform my own routine maintenance), the extra $250/yr saved to grab a different nozzle at the pump is something I and others would consider.

Go stroke your ego elsewhere... read the thread title.

Have a great day!

LexusFan09

Hello everyone. I was just wondering can you put "Plus" gas in a Lexus LS 430. I only use Shell V-Power(93) gas but I always wondered if you can put plus in these cars. Also, does anyone put sheetz or WaWa gas in their LS?

caddyowner

I also only use Shell V-Power 93 in my LS and LX. I figure I'd listen to the Lexus owners manuals. My Prius gets Shell regular, per the specs.