told not to use anything but regular gas..... true?

This debate is kind of a waste.

I mean, Toyota RECOMMENDS regular. So clearly that is what you should go with.

I personally don't think an occasional tank of Premium will do any damage. Given the fact that most locations sell Regular, Mid-Grade and Premium, I hardly think Toyota would design an engine or system that would self-destruct if a slightly higher Octane occasionally appeared in the tank.

Fuel Injection and Fuel System cleaners like Techron, temporarily change the Octane in the tank. Cars don't suddenly blow up.

Use regular....but don't sweat it if you should accidently get Premium.

 

By that logic why not put in a tank of diesel since it's at the same gas station?

 

Tht's because mid-grade has more ethanol in it to achieve a higher octane rating. Ethanol has less energy than gasoline. Less energy=less mileage.

 

The 3rd Gen runs fine on 105 octane E85 blended with 87 octane gas. I proved that What I have read somewhere on this forum is running 89 octane will give the car slightly better gas mileage. Run what you want as the car has huge fuel injectors and the software can handle even E85 blended with gasoline. Maybe someone can chime in that has run straight E85 and tell us if the software corrects for it without any check engine light. As far as running 92 or 93 octane, if you like it run it. It will have no adverse effect on the motor.

Mike

 

Running premium for extended periods will build up higher carbon deposits in the engine too. Engines that use forced induction need this higher octane but the Prius does not. Premium also has less energy in it due to the higher octane as pointed out, so why waste your money? Will a single tank hurt it, ot at all but there is no need to waste the few dollars & the lower mpg. For those that think the higher octane helped with mpg, it would be easier to think it could have been from normal changes that we all see from tank to tank. The simple fact is that less energy content in premium gas will produce less mpg.

 

This is something one hears often, "nothing but the best" for my car/motorcycle whatever. There is an assumption made that since it is called "Premium" it is some how better. It is not "better" some engines are designed to use it. It actually "retards" the gas from from detonating from the compression of the engine until the spark plug fires.

A high compression engine requires the use of Premium fuel so that the gas does not fire prematurley (due to the compression) which can lead to what is called engine knock. My wife's Miata requires Premium fuel.

The Prius was designed to run on "Regular" fuel, it will run on Premium but it is a waste of your money and there are really no benefits.

 

Where do you get from my comments that has ANYTHING to do with my logic?

The whole debate is Premium vs. Regular. I'm assuming most fully functional adults would know not to put Diesel in their Non-Diesel automobile.

And nowhere in my commentary do I suggest Diesel could or should be used.

But it is TRUE that at the majority of gas stations gasoline is sold in 3 grades...regular, mid-grade and premium.

That has NOTHING to do with the fact that at some gas stations they might also have a Diesel Pump. And it would be brain damage idiotic to suggest that the mere appearance or availability of Diesel would in anyway compare with the reality of 3 grades of "standard" gasoline being available at most stations.

The OP was asking about Regular vs. Premium....I kinda default to the base assumption that everyone would know NOT to put diesel in their vehicle.

That doesn't have anything to do with logic....just reality.

 

I have noticed a 4-5 MPG increase with premium gas, I live in Michigan. Not sure if the winter blend has something to do with it but i have tryed reg and compared the two...

 

I

I'd really like to see how you made the comparisons. Can you provide details?

 

If, (in his location) Premium has no ethanol (E0) and Regular has 10% Ethanol, (E10) he may be getting 4 to 5 MPG more with 'Premium' but because it is E0, not because it is Premium.

In other locations, where both or neither are E10, he will not get 4 to 5 MPG better with Premium.

 

I like 105 octane

Mike

 

what i did is filled up with regular, averaged how many miles i went on that tank then the next tank used premium and did the same thing. reated that twice to make sure my math was right. NOTE: i drive the same way to and from work everyday, and have a luxuary SUV for driving for pleasure when not commuting.

 

87 Octane is good, 10 % ethanol is good, high altitude 85 octane is good. Premium gas will not improve MPG and may trigger an emissions sensor.

 

Did you monitor weather and environmental conditions for each trip then return to regular unleaded and monitor for that tank? We call it ABA testing. It helps reduce variables.

 

One could just read their owners manual.

Yeah, I know crazy talk. What was I thinking? Continue on........

 

For the month that i did it the weather had almost no changes and nothing drastic at that. I continue to get 5 more mpgs with premium. It isnt a huge savings but every little bit helps. As long as its only .20 differance ill keep putting it in. And if it goes down ill re evauluate whether I want to try regular.

 

It may have something to do with Michigans winter blend, not sure at this point

 

I

I should have asked you when you did this test. If it was around the time of the winter blend switch you may have went from winter blend regular and left over summer blend premium. Who knows.

 

thats true, but to my knowledge we have been on winter blend for over a month, but depends what they had in their tanks. the shell station i use is pretty busy so id like to think that it wasnt, but anything is possible.

 

92 or greater is popular in Mark's part of Michigan as there are a lot of fast street cars around there. Those cars would be stored in the winter so the stations may still have summer blend in their premium tanks. Keep testing Mark and maybe we'll see a change or maybe you are onto something there. I myself don't run 87 octane in anything unless it is a blend

Mike