I got to thinking about this thread a little more. On today's fuel injected engines, a less restictive air cleaner could make for more power (although possibly leading to shorter engine life due to larger openings in the filter media). However, an air cleaner won't affect gas mileage on a fuel injected engine!!!
The reason is that fuel is measured into the intake manifold based on the amount of air that has already made it past the filter element. After all, the mass air flow meter is after the air filter. If you need 60 hp to move along at 70 mph, you need to burn so many pounds of air mixed with so many pounds of fuel. If you have a restrictive air cleaner, you will open the throttle a little farther to reduce the restriction at the throttle body to make up for more restriction at the air cleaner. The net result is the same total amount of restriction from the air intake to the intake valve---------and the same number of pounds of air flowing-------------and the same amount of fuel being added----------and the same amount of hp being produced----------------and the same gas mileage.
The MAF doesn't care where the restriction is, it just measures the air flowing by it and sends a signal to the computer. The computer then injects a predetermined amount of fuel into the manifold and, voila, the same amount of hp. Of course, at WOT, an engine with a restrictive air cleaner will make less hp-----but it won't get worse mileage, not with a fuel injected engine.
If you see improved gas mileage after changing an air cleaner on an fuel injected engine, something else caused it.
A carbureted engine's MPG may be affected by a really bad air cleaner but we're talking about the MM here.
The reason is that fuel is measured into the intake manifold based on the amount of air that has already made it past the filter element. After all, the mass air flow meter is after the air filter. If you need 60 hp to move along at 70 mph, you need to burn so many pounds of air mixed with so many pounds of fuel. If you have a restrictive air cleaner, you will open the throttle a little farther to reduce the restriction at the throttle body to make up for more restriction at the air cleaner. The net result is the same total amount of restriction from the air intake to the intake valve---------and the same number of pounds of air flowing-------------and the same amount of fuel being added----------and the same amount of hp being produced----------------and the same gas mileage.
The MAF doesn't care where the restriction is, it just measures the air flowing by it and sends a signal to the computer. The computer then injects a predetermined amount of fuel into the manifold and, voila, the same amount of hp. Of course, at WOT, an engine with a restrictive air cleaner will make less hp-----but it won't get worse mileage, not with a fuel injected engine.
If you see improved gas mileage after changing an air cleaner on an fuel injected engine, something else caused it.
A carbureted engine's MPG may be affected by a really bad air cleaner but we're talking about the MM here.
Ross
Senior Member/Rice Eater
Haven't done any dyno runs, so I can't post numbers. However, I have a conical K&N and have this to say about the "360 degree" air intake. When I clean my filter, which I do often, the BOTTOM of the filter is always MUCH dirtier than the top. In fact, when the bottom is visibly dirty, the top is almost always very clean. Now I'm no engineer, but this tells me that in our cars, the airflow is coming up from the bottom and the vast majority of air is coming into the filter from the bottom. I could probably block off the top of my K&N and still get about as much airflow. Just my humble observations and .02.
Let the flames begin!!!! Air cleaners (especially K& N) are almost as sure to get a discussion going as an "oil topic".
First a little background. I've been a member of SAE (Society of Automotive Engineers) for 40 years (ever since engineering school). I've spent a lot of years working with off-highway equipment (forestry and ag tractors). There's nothing worse than an ag tractor pulling an implement at 5 mph with a 5 mph tailwind. The engine suppliers were all very fussy about the air cleaners that were used with their engine installations----and oil wetted designs disappeared quickly in the 50's with the advent of carefully engineered and manufactured paper media filters.
Second, if you want more air flow through a filter, you have just 2 choices. One is to increase the surface area (pleats or just a bigger air filter assembly). The second is to make the holes in the filtering media bigger (one doesn't even need engineering school to figure this out).
Thirdly, I own one of the few cars (if not the only one), produced in the last 50 years, that has an oil wetted air filter----the tri-carbed Vett.
Fourthly, the Ford engineers want all the power they can get out of an engine like the Marauder's (yes, they also don't want it to get "dusted out" too quickly either).
Finally, I doubt that any after market air cleaner will flow more air (comparable overall package size) than a new, stock air cleaner will------unless it has bigger passages for the air AND DIRT to come through!!!
If you're interested in performance, stick with the paper element and change it often.
Bring it On!!!!!
First a little background. I've been a member of SAE (Society of Automotive Engineers) for 40 years (ever since engineering school). I've spent a lot of years working with off-highway equipment (forestry and ag tractors). There's nothing worse than an ag tractor pulling an implement at 5 mph with a 5 mph tailwind. The engine suppliers were all very fussy about the air cleaners that were used with their engine installations----and oil wetted designs disappeared quickly in the 50's with the advent of carefully engineered and manufactured paper media filters.
Second, if you want more air flow through a filter, you have just 2 choices. One is to increase the surface area (pleats or just a bigger air filter assembly). The second is to make the holes in the filtering media bigger (one doesn't even need engineering school to figure this out).
Thirdly, I own one of the few cars (if not the only one), produced in the last 50 years, that has an oil wetted air filter----the tri-carbed Vett.
Fourthly, the Ford engineers want all the power they can get out of an engine like the Marauder's (yes, they also don't want it to get "dusted out" too quickly either).
Finally, I doubt that any after market air cleaner will flow more air (comparable overall package size) than a new, stock air cleaner will------unless it has bigger passages for the air AND DIRT to come through!!!
If you're interested in performance, stick with the paper element and change it often.
Bring it On!!!!!
Glenn
Atlanta Trilogy #1
Easy HP Gain
If your running at the track pop the MM air box cover up about 1 1/2 - 2". When I was dynoing my MM last month opening the air box cover gained 6 HP and I have a K&N and it was clean. There is still more HP to be gained from a better air box and filter. What happened to the K&N air box that was reported in the works??????
Glenn
If your running at the track pop the MM air box cover up about 1 1/2 - 2". When I was dynoing my MM last month opening the air box cover gained 6 HP and I have a K&N and it was clean. There is still more HP to be gained from a better air box and filter. What happened to the K&N air box that was reported in the works??????
Glenn
:lol: