mpg
Member
Joined: Feb 2011
Posts: 93
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From: Oklahoma
Ok so I'm new here but gonna call myself one of the idiots who spent the money on the 77 series chrome K&N CAI system...but has def paid for itself I gained 2 to 3 mpg went from 13 to 16 but my biggest gains came after I installed the poweraid tbs I now get 20 on the highway with a steady pedal but I have a fully functional cowl induction hood which popes air straight over the top of my k&n
Senior Member
Joined: Aug 2010
Posts: 268
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From: Shamokin PA.
K&N has a lot of claims but I notice they don't mentoin a fuel increase on there series 77 cai. You think a 2-3 mpg increase would be a huge selling point wouldnt you? Yeah they look good but it does'nt flow any better than a factory intake and a high flow filter. Hell you can go on ebay and get a adapter and a oiled gauze filter for $10 and a complete aluminum cai for $30.
They will not improve mileage on a closed loop OBD-II car. All passenger cars sold in the USA since 1996 are OBD-II.
The reason it cannot improve gas mileage is that OBD-II cars sense both the amount of air, post filter, going into the engine and the state of combustion of the exhaust gas. The fuel/air ratio is dynamically adjusted to keep it at what the car thinks best at the moment.
A more restrictive filter will simply lower the air flow, and the car will compensate by either lowering the fuel flow, or slightly opening the throttle butterfly.
The only time a less restrictive filter has an effect is at or near full throttle. In this case a less restrictive filter will let in more air when the throttle butterfly valve is fully open, which will burn more fuel making more full power output. If one races a Prius than a K&N filter might make sense in order to win the races, otherwise it is a waste of money, or worse.
Worse? Yes, worse. UOA have often shown that some oiled K&N filters may let in more dirt than paper filters. This shows as elevated silicon from road dirt. Silicon is highly abrasive to the metal in engines and may increase engine wear and decrease service life. For racing cars which are rebuilt often this doesn't matter. I would prefer never to have to have my Prius's engine rebuilt.
Test evidence that these filters, and that clog filters have no effect on gas mileage:
www.fueleconomy.gov/Feg/pdfs/Air_Filter_Effects_02_26_2009.pdf
They will not improve mileage on a closed loop OBD-II car. All passenger cars sold in the USA since 1996 are OBD-II.
The reason it cannot improve gas mileage is that OBD-II cars sense both the amount of air, post filter, going into the engine and the state of combustion of the exhaust gas. The fuel/air ratio is dynamically adjusted to keep it at what the car thinks best at the moment.
A more restrictive filter will simply lower the air flow, and the car will compensate by either lowering the fuel flow, or slightly opening the throttle butterfly.
The only time a less restrictive filter has an effect is at or near full throttle. In this case a less restrictive filter will let in more air when the throttle butterfly valve is fully open, which will burn more fuel making more full power output. If one races a Prius than a K&N filter might make sense in order to win the races, otherwise it is a waste of money, or worse.
Worse? Yes, worse. UOA have often shown that some oiled K&N filters may let in more dirt than paper filters. This shows as elevated silicon from road dirt. Silicon is highly abrasive to the metal in engines and may increase engine wear and decrease service life. For racing cars which are rebuilt often this doesn't matter. I would prefer never to have to have my Prius's engine rebuilt.
Test evidence that these filters, and that clog filters have no effect on gas mileage:
www.fueleconomy.gov/Feg/pdfs/Air_Filter_Effects_02_26_2009.pdf
Member
Joined: Feb 2011
Posts: 93
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From: Oklahoma
You seem very knowledgable bob101770 but I didn't claim k&n said it'd improve fuel mileage just said I noticed an increase. Anyways the 77 does claim for an increase in horsepower and torque not great substancial gains but some yes.
Now let's say just for theory the reason one chooses a cai is for colder air, it's said that colder air is similar to giving your vehicle a shot of nitrous the colder air makes for a better air/fuel atomization which gives a little more punch to your combustion chamber.
Now this punch is where the torque and horsepower come from. But we all know that more horspower doesn't necessarily mean better fuel mileage in theory should be worse right? Now here's another question that will support this theory also when you have a little more horsepower and torque it's like stepping from a V6 motor up to a V8 won't the V8 work less than the V6 hench which just maybe increase fuel mileage just a little bit more?
Now let's say just for theory the reason one chooses a cai is for colder air, it's said that colder air is similar to giving your vehicle a shot of nitrous the colder air makes for a better air/fuel atomization which gives a little more punch to your combustion chamber.
Now this punch is where the torque and horsepower come from. But we all know that more horspower doesn't necessarily mean better fuel mileage in theory should be worse right? Now here's another question that will support this theory also when you have a little more horsepower and torque it's like stepping from a V6 motor up to a V8 won't the V8 work less than the V6 hench which just maybe increase fuel mileage just a little bit more?
Senior Member
Joined: Jul 2010
Posts: 8,544
Likes: 2,552
From: Alaska
The CAI is only as good on a Ford as the plug in tuner you have to adjust the air/fuel mix. Without a tuner, the air fuel mixtures don't change with a CAI installed. Only by using a tuner can this be achieved. Some owners claim that SCT, Evo, Diablo, Hyper, etc give you the absolute best result. Everyone has their preference. I have a Superchip for my p/u and a Diablo for my '07 Mustang. The truck shifts better and runs much smoother since I installed the tuner, but the gas mileage didn't go up much if any. The power and the improved shifting was a pleasant surprise tho. With the Mustang, the Diablo makes that pony jump. Without it its got plenty of power, but with the tuner it's in another world. The difference in power with just a tune installed, is phenomenal on the Mustang. I was never a fan of a tuner until I tried one on the '07. Now I'm sold on the Diablo tuner. The Superchips not so much. 