I recently bought a 2009 Mazda CX-7 with a 2.3 turbo engine.

I do not speed or do jack rabbit starts.

I wonder why the E.P.A. rating of a 4 cylinder only gets an average of 20 m.p.g. ??

So far I have driven 260 miles and the gas gauge is at 1/2 full.

Any thoughts or experiences ?

i think this is only for computing, more specifically linux.
find a new site maybe

Is it all wheel or just front wheel drive? The reviews indicate EPA fuel ecomomy for AWD at 16 mpg city/22 mpg highway (or 18 mpg combined), while the two-wheel-drive version gets 17 mpg city/23 mpg highway (20 mpg combined). However, one of the review cons was bad fuel economy. The turbo does not help and who knows how the previous owners drove the car...

This forum is for any topic.

20 is BAD

take it in and have the engine checked out

( is it burning oil for 20 seconds on start up ? )


now think about this
i had a 1968 302 Mustang with a holly 4150 4 barrel carb
0 to 60 in 4.5


i was getting 18 highway ( 11 city )

Car is 2 wheel drive.

Previous owner took great care and kept meticulous records.

I am happy with it.

It is a 2 ton, gas powered only Sport Utility Vehicle.

20 is NOT bad for that vehicle, the EPA listings for it range in the 17-23 range, and therefore you're right down the middle.

You want great gas mileage, drive something smaller.

The other thing is what you said was not that you're "getting" 20 MPG, but instead that you've driven it "260 miles and the gauge is at 1/2". And then asked what people's thoughts are.

My thoughts are that you ought to actually compute your mileage rather than just "look" at the gas gauge, probably the most inaccurate device possible and instead drive it for a few tanks worth and compute the actual mileage. If you were full before, you know how far you've driven, next time you fill up, take note of the amount of gas you added and the mileage you've driven. Then you can compute what you're actually getting.

I submit that the rating is poor because of the type and size of vehicle.

I believe whenever I've computed mileage, I usually get better than the EPA estimates, in general, not just for a specific car.

I know how to calculate exact m.p.g.

I was just estimating until I fill it up again.

I will post the exact figure in a week or two.

Looks to be about 24 m.p.g which I am happy with.

That's with mid range octane gas.

When I fill up with premium gas, I will see if it gets better gas mileage.

And see if the extra 20 cents per gallon is worth it. :-)

The extra 20 cents per gallon is not worth it. I've tried it, with several vehicles. Use the lowest octane (read cheapest) gas the manufacturer recommends. And almost all recommend regular gas, not premium and not midrange. Straight regular.

Thanks for the money saving advice.

Recommendations:

Check your manual for what fuel types you can use. Some engines (especially turbocharged ones) cannot handle octane below 90 without knocking, which damages the engine. I always use supreme gas for this reason. In fact, it says in my manual that the octane should be 90 and up.

Keep your tires properly inflated.

Change your oil on time.

An ECU reset may help if you change altitudes where you reside at.

I drive a Subaru Impreza 2.5 RS. The gas mileage I usually get is 23-24 MPG. Newer vehicles get higher gas mileage than this, but the most I have experienced myself with rental cars is 34 MPG, and that was way below the listed value of 46 MPG (Chevy Cruze). I doubt any normal car can consistently get 40 MPG and up. You might be able to get that with specially designed hybrid cars in certain conditions. The car manufacturers just lie about the MPG. They run the tests with special tires, high tire pressure, and all sorts of other tweaks to get the totally unrealistic listed gas mileages.

Most people won't get EPA numbers. EPA had nothing to do with those numbers. The company that made the car told EPA the numbers.

Premium may increase mileage but at a cost. It would take tanks of it to cause long term computer map change unless you have a flex fuel. If the thing does "require" a certain octane then you must use it. My car detunes for regular and drops total horsepower.

20 sounds about right. Remember your fuel is part corn. It does help the air quality but slightly reduces mileage.

Car makers are doing quite a lot to raise corporate mileage by using higher compression, variable valve timing, super and turbocharging. Transmissions are cvts and 9 speeds. Next step may be that all will have some electric assist.

I drive a 2013 Ford F150 5.0L and have averaged 19.3mpg over 44K miles. That is a huge jump up from a 78 454 running 6 mpg.

Take all the junk out of it you don't need. Everything from old maps to shoes and even carpets if you don't use them.

I forgot about the lower energy value of ethanol.

The ethanol in fuel also degrades rubber faster. Cars made before the year 2000 will have their engines damaged by 10% ethanol. You will probably also need to increase the octane of your fuel if you don't want your engine to knock with 10% ethanol. Engine knocking occurs when the fuel fails to ignite in one of the cylinders, usually due to low fuel grade. This puts extra pressure on the crankshaft.

I believe my car has knock sensor and will change timing based on the octane value of the gas.

It will probably also reduce boost pressure, and you will lose power.

Also:
http://www.misterfixit.com/deton.htm