I just purchased a 2006 Corolla S with 85,000 miles. I drive about 25 miles to work each way...mostly highway. Im currently getting 30 mpg and feel like it should be alot more. I just had my intake gasket replaced, thinking that was the problem but my first tank gave the same results in mpg. Any ideas???
My 2003 (auto) averages about 32-34 in the summer and 30-32 in the winter. (30.5 last tankful). This is about 10 miles highway, 7 miles city each way each day. It's not unusual to see 28-30mpg on a semi-regular basis.
My 2005 LE with automatic gets 40 mpg in summer without ac running and in the winter 34 becuase I normally have the defroster blowing and that engages the ac compressor. If I run without defroster, I get 40 in winter too
My 2005 LE with automatic gets 40 mpg in summer without ac running and in the winter 34 becuase I normally have the defroster blowing and that engages the ac compressor. If I run without defroster, I get 40 in winter too
My Festiva gets at least 46MPG.
I could probably get those numbers if I was the only driver of my 'rolla but with it having multiple drivers I'm not going to complain about 30-34.
I just purchased a 2006 Corolla S with 85,000 miles. I drive about 25 miles to work each way...mostly highway. Im currently getting 30 mpg and feel like it should be alot more. I just had my intake gasket replaced, thinking that was the problem but my first tank gave the same results in mpg. Any ideas???
mpg's are very dependant on driving conditions, driving style, speed, hills, and wind. Even if you are mostly highway it doesn't take too many stop lights to bring you back to 30mpg overall. Test your mpg on a 100-minimum mile road trip on flat terrain, there and back, keeping it at 65-70. You should be in the 34-37 mpg range, as long as the cross winds are not too bad. Also make sure your tire pressure is not low.
The first few dips are from resetting the ECU after cleaning various sensors. My recent crappy gas mileage is probably due to the really cold weather. This car feels like it should get about 37 MPG if you just get onto the highway and don't drive like a bat out of hell (like me).
The first few dips are from resetting the ECU after cleaning various sensors. My recent crappy gas mileage is probably due to the really cold weather. This car feels like it should get about 37 MPG if you just get onto the highway and don't drive like a bat out of hell (like me).
There is also the switch to oxygenated fuel for winter months in many states, that can lead to lower fuel mileage as well.
There is also the switch to oxygenated fuel for winter months in many states, that can lead to lower fuel mileage as well.
Absolutely true. My mileage is invariably highest right around when they change the gas formulation but before I have to use my air conditioning (and the opposite in the fall).
By reading many posts on this website and others, I have determined that my intake manifold gasket is leaking. My car frequently idles at over 2000 rpm when it is very cold outside (especially below freezing), revving up and down at times as the fuel injectors cut off. I will change it this weekend and see how my mileage changes. I looked at my car's service record and indeed, the original owner appears to have never gotten it replaced under warranty or otherwise.
Certainly, if this turns out to be a real problem, it would explain the direct correlation between cold weather and my gas mileage dropping. I will confirm this before I go throwing out any suggestions for fellow Corolla owners to look into this issue. It may end up being a purely "cosmetic" engine issue...then again, there must be quite a lot of air getting into that gap to make that idle go up like that.
It's also important to understand that colder weather in itself can reduce fuel economy:
Since colder air is more dense it requires more fuel to maintain the stoichiometric 14.7:1 air/fuel ratio in order for the vehicle to run properly. Also since the air is more dense it creates more wind resistance as you drive down the road. Also colder temperatures means the oil is thicker which creates more friction, especially when the engine is cold and just starting to warm up.
Granted the difference is pretty minute but over several hundred miles it can add up to a significant decrease in fuel economy.
And of course there's also the extra load of the wipers, rear defroster, blower, and of course warm up time.
Granted winter temperatures here in STL has been in the 50s-60s (very odd not to see any significant snow yet) but it still doesn't help any.
Nobody ever told me that there was a reason other than the gasoline formulation change for worse mileage in colder weather. Thanks for explaining all that. I do have a question, though: why would a lower air temperature cause you to have worse mileage? I know that engines monitor their fuel to air ratio, and while it would be putting in more gas per cycle than in the summer, wouldn't the corresponding detonation also yield a larger force, ie, a "bigger bang"? Further, why do people install aftermarket "cold air intakes" on their cars instead of, say, the opposite scenario...where you were to install the air intake near the radiator so that the air temperature going into the engine were higher? And even further, why do some engines feature turbochargers to increase the amount of air going into the engine?
Actually colder air is more dense.. which means there are more molecules in the same volume. Because of this you need more fuel to maintain the 14.7:1 air/fuel ratio. If extra fuel wasn't added to compensate for colder air then the car would have a hard time starting and performance would be very poor if it did start.. which is the reason that carburetors had chokes. Fuel injection systems compensate this by holding the injectors open for just a little bit longer to spray more fuel in lieu of having a mechanical choke.
The drawback to this is that more fuel = less fuel economy.
The upside to this is that more fuel = more power and performance.
The reason cold air intakes are popular is that they are supposed to pull cold air in from outside of the engine compartment instead of the hot air in the engine compartment in order to be able to put more fuel in and create more power. Unfortunately most people who install them don't think about this and they simply install an open filter inside the engine compartment which kind of negates the whole reason for doing so.
Some people purposely install "warm air intakes" for fuel economy purposes that specifically uses the warm air in the engine compartment.
I can tell you from experience that unless you have exhaust and engine modifications to support it, any kind of performance air intake is more for show and less for go. Yes it may sound like you have more power but I can assure you that the very tiny gains that might be had are not enough to even be noticed - of course the extra noise that it creates often makes people think otherwise.
You're backwards with your train of thought. Theoretically in the summer time less fuel is used. The hot air doesn't require as much fuel. Unfortunately cars also tend to use more electrical power during the summer due to radiator fans and air conditioning being on and that creates an extra load on the alternator which makes the engine work harder and use more fuel.
"Forced Induction" which is in the form of turbo chargers, super chargers, or in some cases "ram air" increase power by compressing the air before it goes in the engine. Since it is compressed a LOT MORE FUEL can be pumped in to the same volume. Since more fuel = more power (due to stronger combustion) this SUBSTANTIALLY increases the amount of power produced. It also substantially decreases fuel economy when you're on the gas as opposed to a "Naturally Aspirated" (or NA) engine.
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my 05 corolla s 5 spd currently gets 27 mpg 90% city driving. This is actually down from my 30-32 mpg because i have winter tires on now and they cause more rolling resistance. With my previous all seasons the ride was quiter and obvioulsy better mpg. same driving condtions 90% city driving. i keep the pressure at 40
Again, the explanations are really appreciated. I was told by a friend at one point that a turbocharger would increase fuel economy by harnessing unused energy from the exhaust. The way you're explaining it, it sounds like the more air you put into the cylinders under any circumstances, the worse your gas mileage. That explains to me why turbochargers often use coolers...to maximize the amount of air going into the cylinders and therefore maximize the power, at the expense of some fuel.
So...people adding cold air intakes and turbos to their Corollas are actually defying the nature of their "efficient" commuter car. Why did I ever have any reason to believe these people were being logical?
So I drove without the defrost on for a full tank...no change, still getting 30 mpg. I guess I will wait until spring to see what kind of mileage Ill get.
Right a turbocharger/supercharger basically increases the displacement of the engine. In its basic form it's a pump used to force more air into the engine then the engine could suck in on it's own by design.
So if a 1.8 liter could suck in 100 liters of air by it's design then adding a turbocharger could make it suck in anywhere from 50 liters or more air into the engine. This is like making that 1.8 liter a 2.5 or 3.0 liter instantly. The increased air is matched with an increase in fuel and therefore you make more power with a smaller engine.
This is why a non turbo supra in 1995 made 221HP while a Supra with 2 Turbochargers made 320HP even with lower compression pistons and a nearly identical engine.
The only way to get an increase in fuel mileage with a turbo is to stay off boost. The issue with this is during city driving the car will have no power as the car not on boost will be even less powerful than a non turbo charged variant. On the highway this isn't the case which is why a car like Supra Turbo cruising at 65MPH will likely be better than the non turbo variant crushing at the same speed. While the turbo is spinning slow the engine is not forcing air and thus does not need the added fuel to avoid running lean.
As far as cold air intakes remember that the factory intake is cold air. Cold air being more dense increases power. Which is why some cars will have a little extra oomph on a slightly colder day vs. blistering summer heat. And why short ram (hot air intakes) reduce power and fuel economy. The reduced power means the engine has to try harder to the same task which comes at the expense of fuel economy.
My car never does less than 35MPG. I use cruise control strictly, use 0W30 synthetic oil (less drag on cold starting since it thickens less at startup but acts the same when driving), and make sure to always check my tire pressure.
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