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What octane gas do you use? (The Mother thread)

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Old 09-03-12, 08:57 AM   #226
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Lucas makes snake oil and nothing else...
Check out bobistheoilguy if you want to delve further into the subject.
I don't know where you come up with that. User reviews are fantastic and I have had excellent experience with their products. Personally, I never use oil treatments but the fuel treatments works great.
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Old 09-03-12, 01:30 PM   #227
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It wouldn't cause any issues. It would just dilute the % of ethanol in the mix. I would run the 94 corn free alone if I could get it.

John
Thank for the info. Yeah I'd run 94 alone too if I had the $$$. Right now, trying to save a bit. Well in that case. I'll just switch back and forth.
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Old 11-09-13, 10:09 AM   #228
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if the prices for premium go over 270 then im switchin back to regular

its like 265 right now
x.x

chya

this forum requires that my message be longer
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Old 11-11-13, 01:17 PM   #229
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I have owned a 1997 LS400 coach edition for over 6 years. I obeyed the rules with my lst tank and put in premium fuel. At about one half a tank the second fillup I filled the car with regular and never noticed any difference. I have used regular fuel ever since and have never heard a "ping" and have noticed no difference in the engine over the six year period I have owned the car. I average 20 mpg city and have gotten as high as 29 hwy although I usually average around 27 hwy. All of this is with regular fuel which is arount 87 octane. I have only showered down on the accelerator twice in the 6 years I have owned the car and even under maximum acceleration I still never heard a "ping". I am convinced this "thing" about having to use premium is more hype than fact.
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Old 11-11-13, 01:33 PM   #230
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I have owned a 1997 LS400 Coach Edition for over 6 years. The first tank I filled with premium fuel, being hundreds of miles away from home and not knowing how the car would react to cheaper fuel.
At about one half tank I topped it off with regular fuel and noticed no difference. I have used regular fuel ever since (over 6 years) and have never heard a "ping". Last week I had to power out of a dangerous situation (lst time I ever had to floor the accelerator) and even under maximum acceleration I still never heard a "ping". The only repair I have had in over six years is an oxygen sensor I bought online for $36.00 and $41.00 for a small exhaust pipe leak. The flagship lexus LS is probably the best car ever built. Mine has over 200K and looks, runs, and drives like it has 50K.
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Old 11-11-13, 02:13 PM   #231
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do careful gas mileage measurements, I have done this and even if we ignore any possible pinging, the gas mileage difference was more than the cost difference, so premium actually saves me money over regular.
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Old 11-12-13, 01:27 PM   #232
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you bought a premium vehicle, it calls for premium fuel-give it waht it requires.
High compression, high cylinder pressures and advanced spark timing require a fuel with good pre ignition resistance. This is waht 91 is for. Advanced timing=higher cylinder pressure=higher torque=mileage.
Put in 87, it will knock, the computer will retard the spark timing. Less cylinder pressure, less torque, less performance.
91, nothing less.
These engines will most not likely ping-its not a chev 350 with a dizzy on it. It has knock sensors, which will retard the timing to knock threshold.
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Old 02-21-14, 10:19 AM   #233
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I only use non-ethanol premium fuel in my 98 LS400. If I cannot get the non-ethanol brand then I use Sunoco premium
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Old 02-24-14, 06:23 AM   #234
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I bought a 1997 LS400 coach edition in 2007 that was in mint condition. It was a one owner maintained at a Toyota dealer. My first tank was premium and then middle grade and I finally thought I would try regular to see what would happen. i absolutely could not tell any difference in fuel economy and I never heard it ping. I have used regular for the entire time almost 7 years) that I have had the car and I see absolutely no difference in the condition of the engine or the car. These incredible cars are not "hotrods" so I am convinced if these cars are driven like a luxury car should be driven you only need regular gas. I got in a situation one time where I had to power myself out of a situation to avoid a collision and I still never heard a "ping". I was impressed with the power. I get around 20 mpg city and 27 to 30 hwy--mostly around 27. In the 7 years I have owned the car I have spent a wopping $77.00 in repairs. Yes, not a missprint only $77.00 and the car now has 219 thousand miles and runs and drives like it has 50k. I have used sinthetic oil the entire time I have owned the car.
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Old 02-24-14, 06:31 AM   #235
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Originally Posted by charlesw62 View Post
I only use non-ethanol premium fuel in my 98 LS400. If I cannot get the non-ethanol brand then I use Sunoco premium
The problem is I can only get 90 octane corn free here in Atlanta. Do you think that is OK? I use 93 corn blend.

John
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Old 02-24-14, 07:36 AM   #236
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I get around 20 mpg city and 27 to 30 hwy--mostly around 27.
if you are getting 27-30 mpg, then something is off about how you are figuring gas mileage, the car didn't get that kind of mileage when new, and this probably also explains why you are not seeing the 10% or so drop in mileage using regular rather than premium that is normally seen by most folks here on CL, including myself.

Toyota didn't specify Premium fuel just for fun, or to be difficult, they had sound engineering reasons for doing so. In fact, manufacturers have every motivation to specify regular rather than premium, since premium kills their "cost of ownership" comparisons with competitors, so think about it logically!

and also think whether you believe it is reasonable that you are getting several more mpg on the hwy than all of the other members of Club Lexus.
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Old 02-24-14, 07:47 AM   #237
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The problem is I can only get 90 octane corn free here in Atlanta. Do you think that is OK? I use 93 corn blend.

John
a little ethanol will not hurt your LS400, in fact it is an excellent fuel system drier, in case any residual moisture exists in your tank from living in the humid Southeast
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Old 02-24-14, 07:58 AM   #238
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read this thoroughly..its best if u totally understand what octane is.
http://www.nicoclub.com/archives/gas...ane-myths.html

higher octane does NOT equate to higher mileage..its that simple.
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Old 02-24-14, 08:01 AM   #239
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Almost all luxury cars require premium based on the compression ratio of the engine. Higher compression rations work better with higher octane. Improved fuel economy. My old 99 was 10:5:1 My LS430 is the same. Not sure if the older LS400 have a slightly less compression ratio.

All I know is I DO get slightly better fuel economy when using premium. But this is a moot point. Avoiding preignition is more important.

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Most internal combustion automobile engines, whether they're four, six or eight cylinders, operate on a four-stroke cycle known as the Otto cycle. The four strokes are: intake, compression, combustion and exhaust. To put it in the simplest of terms, each of the vehicle's pistons moves up and down within a cylinder. As the piston moves to the bottom of the cylinder, a mixture of fuel and air flows in. The piston then moves upward, toward the top of the cylinder, compressing the air and fuel mixture as it does so. Just as the piston reaches the top of the cylinder, that cylinder's spark plug ignites. The spark creates a small, controlled explosion that forces the piston to the bottom of the cylinder. In the final stroke of the cycle, the piston moves upward to push the exhaust gas out of the cylinder. Once the exhaust gas has been pushed out, the entire cycle begins again. For a much more in-depth look at how an internal combustion engine operates, you may want to read How Car Engines Work.

As long as this process works as described above, the engine runs smoothly. But occasionally the pressure of the piston itself will cause the air and gas mixture to ignite prematurely during the compression cycle, creating a smaller, less powerful explosion. This is called preignition and it's the cause of engine knock, the erratic rattling or pinging sound you may occasionally hear underneath your car's hood. A little bit of engine knock isn't necessarily bad for your engine, but it's not desirable, either. It means that your engine isn't running as efficiently as it could be, and left unchecked, it could eventually cause damage. Engine knock reduces your car's performance, too, so you definitely want to avoid it. How, you may ask? Well, low-octane gas is more likely to ignite under the pressure of the piston alone, so it's also more likely to produce engine knock.

Does this mean you should always use high-octane gas? Not necessarily. It really depends on the compression ratio of your engine. This is the ratio of the volume within the cylinder when the piston is at its lowest point to the volume within the cylinder when the piston is at its highest point. The higher the compression ratio, the more compressed the air and fuel mixture becomes and the more likely it is to ignite before it's supposed to due to pressure alone. Cars with a low compression ratio don't need premium gas because there's little danger of the air and fuel mixture igniting improperly. But high-performance engines, which have a high compression ratio, are more prone to preignition and can truly benefit from premium fuel. This would include the engines in most luxury cars.

Modern engines use a device called a knock sensor to detect the rattling and vibration within a cylinder that signals preignition. These sensors send a signal to the vehicle's Engine Control Unit (ECU), sometimes called an Engine Control Module (ECM), which then adjusts the engine's timing -- when the spark plugs fire -- to reduce or prevent the knock. Because these sensors are so effective, cars with knock sensors rarely experience engine knock, even when running on regular unleaded gasoline. However, because the timing is slightly adjusted when low-octane fuel is present, the car's performance and fuel efficiency is diminished slightly, too.

Is the loss in performance dramatic enough to notice? For most people, the answer is probably no. According to one estimate, a car running on regular unleaded instead of premium will take about a half a second longer to accelerate from zero to 60 mph (97 kilometers per hour). Unless you're drag racing, it's unlikely that this will matter. Still, it's conceivable that you might find yourself in a situation where that half second just might matter -- merging safely with highway traffic, for instance. So, it's really up to you to decide if this is important.

Some experts claim that the loss in fuel efficiency when using regular gas in a luxury or high-performance car will be so great that it will actually cancel out the savings you get from buying cheaper low-octane gas. This point is debatable, but you should keep it in mind.

Another reason that people use premium unleaded fuel is that they believe it will keep their car's engine cleaner. This is because some fuel companies advertise that they add special detergents to their higher grades of gas. However, U.S. Environmental Protection Agency regulations require that all grades of gas have detergent in them. Yes, the premium grades often have more detergent, but the lower octane fuels can keep your engine clean, too. If you have reason to believe that an unusual amount of buildup has collected in your engine, simply buy a detergent additive at your local auto store and add it to the tank yourself.

So, unless your owner's manual says that your luxury car "requires" premium gas, it isn't going to hurt your car if you don't use it. And regular gas isn't going to have a significant impact on your engine's performance, either. Basically, it's up to you to decide whether the small impact that it does have is worth the extra cost of premium fuel.
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Old 02-24-14, 09:02 AM   #240
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The problem is I can only get 90 octane corn free here in Atlanta. Do you think that is OK? I use 93 corn blend.

John
Try to find a Resco or Pure fuels distributor. They typically carry non ethanol fuel. Non ethanol fuel is more expensive. I pay 4.20 a gallon but it's worth it in an aluminum engine. Alcohol is a corrosive. Small amounts are okay that's why it's only 10%. But after looking at the spark plugs they look new. No carbon deposits (very little). And I actually get approximately 27 miles to the gallon on the highway. Based on a 22.5 gallon gas tank if I use 20 gallons at 27 miles per gallon I have an effective cruising range of 540 miles. This means I can drive from Rocky Mount North Carolina to New York City on $84 worth of fuel. And this car is 15 years old. Lucy is very well-maintained at the Lexus dealer and gets all the recommended service at the recommended mileage intervals.
Of course if I'm driving hard and fast my mileage drops to 20 miles per gallon. As long as I don't go over 110 mph I'm fine
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Old 02-24-14, 09:02 AM
 
 
 
 
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