the gas OCTANE question....

[colleyt]

ok I usually dont nickle and dime things when it comes to my cars but I live in LA and gas prices are getting to a point where its laughable. Paid $4.35 a gallon today for a grand total of $91.35 at the pump. That would put my gas expense for the month near $1,000. are you kidding me!!!!!!

THE QUESTION: I bought my LR3 and plan on keeping it for as long as I can! What do you think about putting lower octane gas in your LR3's?

I figured because of the weight and the modest power output that the higher octane would be integral to its operation. What are your opinions on running 91 vs 87?

 

[grommet]

Use search; you'll get many hits and we likely don't need another thread. For me, my MPG decreases with less than optimal octane... but I'm at sea level most of the time. "Your mileage/experiences may vary."

 

[roverman]

Dude, if you fill up 11 times a month, get a new car.

 

[joey]

You could be paying the equivalent of $10 a gallon like they are in the UK... shot it has been 10 years since they seen prices in the $4 a gallon range.

If you are spending that much in fuel, can I recommend buying a fuel sipping vehicle the fuel cost alone will pay for it.

 

[bobby]

I use 89 octane in mine as a middle ground. By trade I am a Petroleum Engineer working in upstream production, but with downstream production at the pumps there is usually a variance in the octane of +/- 3. This all being said…

Higher octane gas contains inhibitors that cause the "flash point" of the fuel to be higher to keep the fuel more stable and decrease premature combustion in the cylinder.

In today's modern engines there is what's known as a "knock sensor". This sensor detects the premature combustion of the fuel in the cylinders (causing a knocking sound) and will ****** timing and or change the air fuel mixture in the cylinder. Using the higher octane fuel in itself prevents knock so "normal" engine timing and performance can be maintained without the sensor backing things off.

Higher octane however is not required for normal operation of the LR3 engine despite what people have been saying. It's only RECOMENDED in the owners manual for the exact reason I mentioned above. If you want the best performance from your engine, if you're hauling a load, towing a boat or trailer, climbing hills or doing some serious offroading then you may want to go with the higher octane fuel during those time periods.

 

[bobby]

Just wanted to second what Joey said...

"You could be paying the equivalent of $10 a gallon like they are in the UK... shot it has been 10 years since they seen prices in the $4 a gallon range."

We still have it quite well here in the US.

Having also worked in Venz. and Indonesia where gas would be 0.3 cents a gallon I also feel part of the pain..

 

[broiler]

I also split the difference and use 89.

Some cars really do need 91 octane. My wife's Jag starts knocking if I put in 89 instead of 91. I had an old MR2 years back that was the same.

However, a lot of manufacturers want to be able to publish the best performance numbers for their vehicles (both mileage and horsepower), and to do that they do all of the tests with premium fuel, which gets them slightly better numbers. However, if they do their tests with that fuel, then the manufacturer MUST state that they recommend premium. This becoming a very common practice and is the main reason you are seeing so many cars now that recommend/require premium.

 

[Houm_WA]

The price of gas sucks balls right now. I don't care how much they pay in Europe, it sucks balls. I have made a lot of changes to reduce the pain. I drive the wife's Camry more and she rides the bus. I telecommute when I can. I even bought some shares of Exxon/Mobil...because I'm a stock market jinx and I figure that once I owned this stock, the government will regulate that industry and prices will get back to normal. So, I bought it not with massive profit in mind, but rather to take one for the team ! In that regard, as long as Bush and Cheney (oil men!) are in office, we will see no relief.

Colleyt...I'd seriously consider getting a 4-year old Toyota Corolla as a daily driver if I were you. Save the SUV for when you need it. Who knows...you may realize that you really don't need it at all; especially not in LA.

 

[Hollywood LR3]

Colleyt is a very cool guy ...... He can't be seen in a Corolla....

 

[richpike]

Higher octane however is not required for normal operation of the LR3 engine despite what people have been saying. It's only RECOMENDED in the owners manual for the exact reason I mentioned above. If you want the best performance from your engine, if you're hauling a load, towing a boat or trailer, climbing hills or doing some serious offroading then you may want to go with the higher octane fuel during those time periods.

I have often found that the LR3 manual is suspect - it appears to have not been thoroughly proofread. IMO, I'll take the info by the gas cap to be more accurate:

Having said that, I stand by my post in the V6 thread:

Why would you risk it? Gas is $3.20 a gallon right now for regular, $3.40 a gallon for premium. This is a 6% adder - nothing compared to when gas was $0.80 a gallon for regular versus $1 for premium (25% adder). If you drive 20,000 miles a year and average 15 miles per gallon, you are going to buy 1333 gallons of gas. This works out to

$4265 on regular
or
$4532 on premium

Or ~$270 difference. To me it is probably worth the $270 (or $135/ year if you only drive 10,000 miles).

At $4+ per gallon the % difference is even more minimal. I don't see it being worth it.

And the fact that you are putting $1K in gas per month in your LR3 is insane - I agree everyone else - I would highly suggest moving to a more fuel efficient vehicle (if possible) for your daily driver. But, even if you don't, at $4.35 a gallon and $1K a month, you are buying 230 gallons of gas a month. At an extra $0.20 a gallon, that is still only $46 a month. Buy the premium.

My $0.02 (or $46 for what it is worth ).
-Rich