Is it normal for you car to get less gas mileage with midgrade than regular?
(2011-06-14 14:25:20) 1. Says: Okay, I have a toyota that just requires regular gas.I heard putting midgrade to premium helps improve gas milage.
So I put some midgrade in the last time I filled up.
Well first thing I noticed was the car engine seemed to have a lot more horsepower and seemed to work harder.
Then I noticed about a 5 to 10 mile drop in gas mileage.
Is this normal>?
I don't think I'm ever going to put midgrade in the tank again.
Seems to run better on lower octane fuel for some reason.2. Says: Switching gas would not cause that kind of drop in mileage, there is no reason it would cause any drop at all, either you changed your driving style during that period, or you have some other issue going on.
zxc0903. Says: I found this.http://addlife.info/57127/car-engineGooooood luck (:4. Says: Read some about octane. What it is and why there are different ratings and for what purpose. You have fallen for an urban myth by thinking midgrade to premium helps improve gas milage.
+1 mad jack5. Says: A 5-10 mile drop on a full tank? That's nothing. My wife's car gained almost 3mpg going from mid grade to premium...That's almost 60 miles on a single tank more. But her car is also high compression that calls for premium fuel.
The fuel itself won't help gas mileage, unless the fuel you're currently using is inadequate. As the others said, it's a myth, though if you actually lost 5 or more mpg, and you felt more power, you probably took advantage of that and didn't drive the same way, so you burned more fuel. I don't judge it based on one tank. If you want to get a true idea of how it is to drive, fill up with mid grade for 6-7 tanks. The last 4-5 tanks of mid grade will give you the real mileage, because the first couple tanks could be swayed because you either conciously or subconciously alter your driving style to get a specified result.6. Says: It is not bad for your engine, but is a waste of your money.
The only difference between regular fuel, mid-grade fuel, and premium fuel is the octane rating.
Octane has nothing to do with the amount of energy in the fuel. High octane fuel will not give any significant increase in performance in a low compression engine. You do not see any benefit from high octane fuel unless you have a high compression engine.
The octane rating is the fuel's resistance to spontaneous combustion under compression. The higher the octane rating, the more compression it takes to make the fuel spontaneously ignite.
A high compression engine requires higher octane fuel to prevent detonation. Detonation is a condition where the fuel air mixture ignites while being compressed before the spark plug fires. Detonation can cause serious internal damage to an engine. You can usually hear when detonation is occurring. With the engine under a load or hard acceleration, you will hear a knocking noise coming from the engine compartment. Sometimes this noise can sound like a bunch of marbles rattling around in a tin can under the hood. When you ease up on the throttle this noise goes away.
You usually won't hear this knocking noise on a modern computer controlled engines because they have a knock sensor to detect detonation. When detonation is detected, the engine management computer will adjust the fuel / air mixture and ignition timing to stop the detonation and protect the engine. When this happens, there will be a loss of power and fuel economy.
In some instances, an engine will not run as well on higher octane fuel. This is because higher octane fuel has a slower burn rate. If it is not compressed enough before it is ignited, the fuel may not completely burn in the combustion chamber of your engine. It would finish burning in your exhaust system where it does absolutely no good.
On some occasions, you may feel an improvement in performance and fuel economy when using premium fuel in an engine designed to run on 87 octane regular fuel. Most times this improvement is slight. Many times, it is a placebo effect. You may even get a slight improvement in fuel economy. However if you do the math you will usually find that the improvement in fuel economy is not enough to make up the increased cost of the fuel. Try this. Calculate your MPG with both fuels and keep a log. Include the price per gallon for the fuel in your log. Calculate the cost per mile for fuel by dividing the amount paid for the fuel by the miles per gallon.
You don't really need to use a higher octane fuel until you go over 10 to 1 compression or if the engine is equipped with a turbocharger or supercharger.
The higher octane fuel will not make a low compression engine run any better or last any longer. You are only giving the oil companies more money than you need to. I think they make enough money already.
If you are in doubt, follow the fuel recommendations found in your owner's manual and you won't go wrong.
The link below will tell you all about how gasoline works. The 4th page of the article explains octane. Tag: Is it normal for you car to get less gas mileage with midgrade than regular?