If it was truly restricted to "Premium ONLY!!", what happens if you simply can't get Premium in someplace isolated like Death Valley or Yellowstone because the only gas station ran out? You're going to park the car, get a room, and wait overnight for the delivery truck?
What if they just got three feet of snow? Your small car or SUV can easily get out by following the first plow, but it'll be several days till the roads are totally plowed and dry enough to handle a rolling bomb (gasoline tank truck) safely...
If you can't get Premium, you put in Regular. The computer is constantly monitoring the knock sensors. If you put in Regular fuel, it simply retards the ignition timing and/or cuts back the fuel shot till the knocking stops. The effective power level is lower because the retarded timing effectively gives the burning fuel less time to push on the piston before the exhaust stroke starts.
But for people who read the manual religiously and follow only the words therein, if Toyota failed to put in the magical phrase "use of lower octane fuel won't hurt the system, but you can expect lower performance" (as they did in 1994), they're stuck.
While the gasoline probably did come out of a common tank somewhere, I'll bet you that the Shell additive packages are way different than the BP additive packages.
You mean, the requirement that was written by marketing people so as to make sure the buyer knows that it must be a "premium" car because it requires "premium" fuel?
At one point, Lexus made sure to point out that use of lower octane fuel would not damage the engine.
Then one year, they took that out.
Trust me, use of lower octane fuel will not damage the engine. The car doesn't NEED it. Marketing NEEDS it, because stupid buyers think that higher octane fuel is "premium". And of course a "premium" car would naturally require "premium" fuel, right?
Even though the base engine is sold in millions of Camrys.
You are correct, over the years many small 4cy Japanese engines were designed to run on higher octanes as they were spun up, so that they could advertise higher HP figures. Unfortunately spinning up an engine to gain HP also lowers the torque curve relationship, separating the torque and HP curves results in cars equipped with an automatic tranny being a slug when one needs that torque to get going and maintain speed on grades. The 4cy in a Camry is a prime example
Modern microprocessors can easily de-tune an engine by adjusting the F/A ratio and timing to run on a lower octane fuel that for which it was designed, however it will not run as efficiently as it will if run on the fuel for which it was designed. When an oil company implies your car will run better or premium fuel, they are not being disingenuous because they are not referring to all cars, rather those designed to run on premium, not running your 89 octane car one 93 octane
Engines designed for higher octane's can easily run satisfactorily on 87 octane fuel. Modern microprocessors can do-tune to compensate for fuels with an octane rating lower than the 93 or 91 octane rating for which the engine was designed to be the most efficient, as long as the result does not cause excess pollution. At that point the check engine light might eliminate as the O2 sensor detects insufficient O2 content. The microprocessor does the same to run on engines that use 89 octane gasoline's when fueled with gasoline's that contains up to 15% ethanol but the result is fewer MPGs
You will win that bet! Current environmental laws do not allow different type of gasoline to be stored or transported in the same container at different times. I E Today a tank truck that loaded regular can not be reloaded with premium etc, without first being purged and the purge medium disposed of environmentally. When the seasons change from hot to cold for example and the volatility must be changed every thing must be purged as well. One of the reason gas cost so must today are those types of federal regulations. Companies need to buy more trucks as a result. The same is true of the gas lines. A company can not pump gasoline through a line that is different than what was pumped before. The days of pumping a given number of gallons of one brand, to a tank farm, and then a given number of gallons of another brand, are long gone. In the old days they would simply draw of the last, say 50K of the one brand and 50K gallon of the next brand, or one octane rating and another, to purge the line. The draw off, known as "plug" gas was sold of to independent stations.
Today all of the gasoline(s) pumped, designed to meet the environmental requirements of a given area, or a state, are the same. The gasoline sold at brand X station in one state or area is different than the gas sold by brand X in another state or area, as well. The oil companies refer to it as "57" varieties compliance. For example one does not get the same brand X gas in Nevada as they do in California. Sunoco gas in New Jersey contains
15% ethanol by law and in Pa it does not necessarily contain ethanol.
Today the gasoline is drawn off at the different brand terminals, the different additives, coloring and such for that brand are added at their terminal giving them their "own" gasoline. After Katrina, and the loss of production causing a shortage was ramping up the price of gas, President Bush issued an order suspending "57" varieties compliance for two weeks allowing any gas to be transported to any were and that brought the price back down
"Elmo P. Shagnasty" wrote in message news: snipped-for-privacy@nntp10.usenetserver.com...
Your Tacoma has a knock sensor, so the knocking should go away after about 3 seconds. If it continues to knock, check out the knock sensor and base ignition timing.
In a vehicle that is programmed to use 87 octane, there will be no performance improvement by using higher octane fuel unless there is a problem with the engine or engine programming. Ignition timing is programmed to advance based on engine RPM, and the ECM will retard ignition timing if it starts getting a signal from the knock sensor. In the absence of a signal from the knock sensor, the ignition timing will advance by its programmed amount, so there is nothing to be gained by higher octane fuel.
replying to Elmo P. Shagnasty, Tom Obrien wrote: I disagree with that line of thinking. Toyota does not sell gasoline so what benefit is it to them if you pay more for fuel? I would think it would be the other way around. "Yes, this is a top quality car but, it runs on regular unleaded gasoline. BONUS!!" The manual for my 2015 Avalon states "87 octane".
replying to Tom Obrien, Elmo P. Shagnasty wrote: You aren't a marketer. It is not good marketing to make people who bought a premium product, think that their product isn't premium. You'll hear it all the time in the car forums: "if you can't afford the service, you can't afford the car!" People use that excuse to make themselves feel better about having spent the money on the car to begin with. "Sure a Toyota oil change is $40, but that Lexus oil change is $150--therefore it's better, and of course it is, because it's a much higher level car!" People love to fool themselves, and marketing people are in the business of helping them fool themselves so they'll happily pay more money.
I hold by my statement that at one point, Lexus actually put it in the owner's manual explicitly that lower grade fuel would not hurt the car. That's still the case; they just don't write it down, that's all. The engine electronics are designed to protect the engine.
Does the Lexus have different performance maps built into its computer, to take advantage of higher octane fuel? Yes. But the protection systems in the sensors and computer are all still in place. You could use Mexican piss gas for a tankful, without damage.
In no way does Lexus want their buyers to think that their premium car uses "ordinary" anything, from the service schedule/pricing to the gasoline.
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