The US Department of Energy's fueleconomy.gov website has a PDF Article about a recent study showing that Newer fuel injected vehicles don't lose any MPG from a dirty/clogged air filter. All the dirty air filter did was cause a performance drop compared to a new OEM filter.



Carbureted engines showed a 2-6 percent drop in MPG with a dirty air filter.



So does this mean a performance air filter on a newer car won't give you any increase in fuel economy just better performance?



What are your thoughts on this?

 

I think I like my power AND fuel economy at optimal levels so I'll continue to keep my filter clean. OTOH I don't see how you could lose one without the other but then I never looked at the maths in that study.

 

Dont forget to keep your tires inflated too for best mpg's! haha



[/Obama voice]

 

a performance air filter? pah. just get a new oem paper filter and be done with it!



but yeah, a clogged filter is just going to let less air past the maf, so the computer will inject less fuel. it makes sense now that somebody else said it

 

The way I always thought it worked was that the car using less throttle would be the car getting better MPG's compared to the same car with a dirty air filter requiring more throttle just to keep up with the other car.

 

i suppose there would be a slight difference due to WOT enrichment, but if your air filter is dirty enough to require anywhere near WOT...