Apparently the "newsflash" to the original poster is that Mercedes come with maintenance schedule booklets that define all kinds of things, including the air filter replacment interval.You say this as if it's a news flash.
The right amount of air and fuel determines the good gas mileage at optimum power.Air filters are one of those things that usually don't get too much attention. Even if they look ok, they still should be replaced with every oil change IMO. My car's city fuel economy was progressively getting bad over time. I was down to around 9-10 MPGs in the city. My filter looked OK but I replaced it anyways as I had an extra one lying around. My city fuel economy doubled immediately!!!:thumbsup: I am now getting b/w 18-19 MPGs now in the city! (32 highway, an increase from 28).
My advice: Spend the few $$$ and change the air filter at every oil change. You will more than make it up via much better fuel economy.
Oh yeah, my car has 99k miles on it. 2000 E320. Will do spark plugs one day as soon as I find the time and motivation and energy to do so.
Were this true, there would be no need to ever change an air filter, or for any throttle body to be larger than 1 mm.I think j99xj is completely right.
A clogged filter will reduce the volume or air entering the cylinders.
Thus the volume of fuel injected will also be reduced by the injection system in order to respect the optimal air:fuel ratio (14:1).
So a clogged filter reduces the engine's power but not the mileage.
The mileage will only decrease on old engines that use carburators.
Yeah, but computer sensing less air, will deliver less fuel, what in first stage might actually save fuel as you won't be able to accelerate fast, nor drive at top speeds.Were this true, there would be no need to ever change an air filter, or for any throttle body to be larger than 1 mm.
Not accurateThe more throttle would apply to carburated engines, although even there it is the air flow that sucks fuel from the nozzles.
On computerized engine, pushing the gas pedal is just a wish you are giving to computer. Computer analyze how much air comes to the engine and with restricted air will restrict fuel.
Therefore you come to the point when it will take 2 minutes to reach 60 mph.
All wit top fuel efficiency.
Works the same for any otto cycleSir K had been on at the very beginning.
For carbureted engine, it was true that a partially clogged air filter affects both fuel economy and performance. That was the conventional wisdom so people always think a modern (injected and computer controlled) engine works the same way.
Fortunately or unfortunately, that was really not the case in a modern engine. There had been several tests to prove that there is very little, if any, difference in terms of fuel economy between new and partially clogged air filters. (Otherwise, K&N sale would go over the roof.)
I know many in the forum do not trust Consumers Report so I will spare their study. However, let's try one done by real scientists.
The most authoritative study was done by scientists from Oak Ridge National Labs. I guess the government (think DOD) must own a lot vehicles so this is a significant things. They tested a lot of different engines and found no real fuel economy difference between new and partially clogged air filters in modern cars. There is, however, a performance difference.
I saved that info and here is their conclusion: (the 1972 reference was to a carbureted engine)
Results reveal insignificant fuel economy and emissions sensitivity of modern vehicles to air filter condition, but measureable effects on the 1972 vehicle. All vehicles experienced a measured acceleration performance penalty with clogged intake air filters.
For the starters, my engines do not have tps, nor do they have throttleAnother thing to consider
Engines run open loop ie tb position tps