My father-in-law has a 2000 Avalon and says that the onboard computer that calculates his gas mileage only works up till he turns off his car. Then it resets. Every car I've seen that has an mpg calculation on board has both instant mpg and average mpg (which you must manually reset). Is this true that the average mpg on an avalon is reset each time you turn off the car? If so this is a pretty worthless piece of information.
Yes it is true for the 2000 and 2001. One of many crappy features about that car that no one notices when reviewing it. Too bad they can't make seatbelts that wind back up by themselves and auto climate control that works.
I have a 2000 Avalon but it does not have the feature. I also have a
03' 4-runner that does.... The reason I'm telling you this is in my experience the mpg computer is very inaccurate. My 4 runner says I get
19.2 mpg consistently. My math at the gas pump is closer to about 16 mpg. The 16 is much closer to the mark. Tell your father in law to just do the math... its more accurate anyway. Darren
I've never bothered to check but someone else posted that their Toyota readout matched their math perfectly mileage wise. I zero the trip odometer every fill up and a quick look at the gas pump each time indicates 20 mpg as a rough average.
I have a 2000 Avalon and I get about 24-25 mpg on the highway (I drive fairly fast) and about 15 in town (mostly very short trips). That is on premium fuel.
I have a 2000 Avalon. I get 20 MPG city and 30 MPG highway. I have never used anything but regular gas. The average MPG calculator on mine is exactly correct. I checked it on 5 different gas tank fills. It is too bad that it resets on every trip, but it is useful on telling how you did on that trip.
What the owners manual actually says is to use 91 octane for best performance, but the minimum acceptable is 87 octane. If you use the 87 octane (regular) the timing will be automatically retarded by the knock sensor (as necessary) to prevent detonation (pinging, knocking), and mileage will be slightly worse (less cylinder pressure, less efficiency). But that only comes into play when the engine is working hard, such as climbing a steep grade or under heavy acceleration. Since the price difference is less than 10% (20 cents) between premium and regular, I choose to use premium so it is there when I need it (when you are retired, money is no object--grin).
I know about octane ratings and what they do as I am a retired Naval Aviator and I used to teach aircraft powerplants. Aircraft reciprocating engines are very sensitive to the proper octane fuel. AvGas comes in different colors so you know for sure what octane you are getting.
Your quote is not exact. On page 192 the manual says: "Select Octane rating 87 or higher. For improved vehicle performance the use of premium unleaded gasoline with octane rating of 91 or higher is recommended."
The manual calls for 87. It says you can use higher. What car is this not true for?
Than to paraphrase it says using less than 87 will cause knocking. The manual does not say any of the other things that you mention. The manual does not suggest what the improved performance might be.
I interrupt the manual to say that 87 is fine. I have driven the car 100,000 miles and have never felt a need for any more performance. This has included to pretty tall and steep mountains up to 14,000 feet. I consistently get
20 MPG city and 30 MPG highway. On one tank of regular gas I actually got 40 MPG. The circumstance for that was following my son who was driving an overloaded UHaul truck.
Once I accidentally did fill with premium and noticed no difference.
So I am open minded what performance improvement can I expect to see? What sort of gas mileage can I expect to see? I am a retired engineer for the past
13 years so the needless extra expense of $.20 per gallon is a factor. The oil company profits are high enough.
From my engineering education I seem to remember that higher octane gas contains fewer BTU per gallon and unless the engine is designed to need the higher octane the result will be poorer gas economy.
Excellent post Merritt...after I had released that post I was a bit concerned that it might have been too abrupt, I'm glad that you didn't take offense at it.
What you say is exactly right, I, too taught aircraft recips to students after spending many years operating them as a Flight Engineer.
My last stint was 7 years as an Argus F/E, big momma recips,
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