How necessary is high octane gas for a 2006 Mazda 6?

Question

The manual says the car "requires" 87+ octane. In Utah, most standard grade gas is only 85 (I guess in some places, it's 87) octane. I'm wondering if I am wasting my $ on paying for mid-grade. Any mechanics or Mazda-savvy types, or others who consider themselves experts on gas grades who can comment?

Oh, it's a 2006 Mazda6 4 cyl 5 speed AT with no special trimmings.

Thanks.

Answer 1

Ping, knock, run on, engine damage.....use the recommended octane. It's recommended for a reason.

Answer 2

Real simple, put no more or less an octane rating in your gas tank than is recommended in the manual. If it takes 87 I would put 87 or higher in there. 85 may be bad for although mos tliekly not. If you want to err on the side of caution or performance than go higher. Do not put 91 in it because it is a waste of money and the engine will gain no benefits from it.

Answer 3

The mazda 6 needs 87 octane. 87 is low. I dont know how you guys get that crap (85). 90% of the country uses 87 as the lowest form. 90 as mid and 92 as high. Some even have 94 as super high. So stop yer bitchin and use the recomended 87.

Be glad you dont have a speed 6 you would need 92 octane.

Answer 4

The octane rating is a measure of the autoignition resistance of gasoline (petrol) and other fuels used in spark-ignition internal combustion engines. It's a measure of anti-detonation of a gasoline or fuel. Higher octane ratings correlate to higher activation energies. Activation energy is the amount of energy necessary to start a chemical reaction. Since higher octane fuels have higher activation energies, it is less likely that a given compression will cause knocking. (Note that it is the absolute pressure (compression) in the combustion chamber which is important - not the compression ratio. The compression ratio only governs the maximum compression that can be achieved). It might seem odd that fuels with higher octane ratings burn less easily, yet are popularly thought of as more powerful. The misunderstanding is caused by confusing the ability of the fuel to resist compression detonation (pre-ignition = engine knock) as opposed to the ability of the fuel to burn (combustion). However, premium grades of petrol often contain more energy per litre due to the composition of the fuel as well as increased octane. Using a fuel with a higher octane lets an engine run at a higher compression without having problems with knock. Many high-performance engines are designed to operate with a high maximum compression and thus need a high quality (high energy) fuel usually associated with high octane numbers and thus demand high-octane premium gasoline. The power output of an engine depends on the energy content of its fuel, and this bears no simple relationship to the octane rating. A common myth amongst petrol consumers is that adding a higher octane fuel to a vehicle's engine will increase its performance and/or lessen its fuel consumption; this is false—engines perform best when using fuel with the octane rating they were designed for and any increase in performance by using a fuel with a different octane rating is minimal or even imaginary. Using high octane fuel for an engine makes a difference when the engine is producing its maximum power. This will occur when the intake manifold has no air restriction and is running at minimum vacuum. Depending on the engine design, this particular circumstance can be anywhere along the RPM range, but is usually easy to pin-point if you can examine a print-out of the power-output (torque values) of an engine. On a typical high-rev'ving motorcycle engine, for example, the maximum power occurs at a point where the movements of the intake and exhaust valves are timed in such a way to maximize the compression loading of the cylinder; although the cylinder is already rising at the time the intake valve closes, the forward speed of the charge coming into the cylinder is high enough to continue to load the air-fuel mixture in. When this occurs, if a fuel with below recommended octane is used, then the engine will knock. Modern engines have anti-knock provisions built into the control systems and this is usually achieved by dynamically de-tuning the engine while under load by increasing the fuel-air mixture and retarding the spark. So, cutting the long story short, if your car is designed for high octane gas - use it. If it is not - you are not going to benefit from it.

Answer 5

It will be bad for your engine not to run the recommended octane,I have a 77 pontiac bonneville that requires mid grade and if I put in a lower octane the valves do not open and close properly which will reduce my mileage anyway so what's the point.Run a lower octane if you ansolutely need to but just remember that it is doing a very little bit of damage to your car.

Answer 6

Don't listen to wofford. Even if they use the same gas out of the same tank, different fuels have different additives. That's what octane ratings are (why do you think you can buy octane booster at the auto parts store?). Your car will probably run on lower grade, but if something happens to your car your warranty claim can be denied. The choice is yours though.

Answer 7

You needer higher octane in engines with a higher compression ratio. Reason being..higher compression engines can combust the fuel by pressure alone (versus by spark). You don't want this to happen. Higher octane fuel resists combusting under pressure. 87 will be fine for that engine, no need for higher, but I wouldn't go with 85.

Answer 8

I would say follow the guidelines. If you went with the lower octane, you may need to get some octane booster.

Answer 9

THE ENGINE IS A HIGHER COMPRESSION ENGINE AND NEEDS THE HIGH OCTANE TO RUN SMOOTHLY, 85 DOES NOT HAVE THE OCTANE NEEDED TO RUN THE ENGINE SMOOTHLY AND WILL LATER CAUSE PROBLEMS TO YOUR FUEL INJECTION AND FUEL PUMP.

Answer 10

When in doubt, follow the manufacturer's specifications. Using lower grade gas can void your warranty.