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Discussion Starter #1
Hey everyone. So I have a 2001 N/A Forester S, and I've been researching for air intake options that wouldn't break the bank. Eventually I came to the conclusion of just doing some custom work because as it stands, anything is better than the way my car is currently getting air (it is drawing air inside the engine bay behind the passenger headlight without any air duct). SO, I came to the conclusion that maybe I could just get piping that would go from the throttle body to an air box behind the passenger headlight with a cone filter inside, and then have an air duct from the fender drawing air directly into the air box that the filter would be drawing air from. However, I am a bit lazy, and making a box and mounting it and such seems a bit meh. So continuing my search, I learned that Spectre Performance makes a cylindrical shaped "air cylinder", if you will, that functions like an air box. I figured, what if I could make a larger version that could fit a cone filter, and then all Id have to worry about was connecting couplers to the bottom and top of the cylinder. MUCH easier it seems. My question to you all is, would this work? Any thoughts are appreciated.

Some things I've considered:

1. Making the cylinder large enough to fit a cone filter (allowing enough room in the cylinder so the filter does not suffocate)
2. How would I mount it ( if I need to)
3. Would this work the way i'm intending? (air duct into cylinder> filter takes air from cylinder into engine).
4. Thickness of the cylinder, or possibility of heat wrap/heat reflective tape.
 

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Discussion Starter #3
@Magic Pepto What do you hope to accomplish or gain by doing this?
Before I say this, I do understand that I wont get much out of an N/A..BUT
Im hoping to:
  • increase airflow (by having shorter and different material intake piping)
  • increase air quality being inducted (by gathering air through an air duct rather than from the engine bay)
  • saving money
  • increasing performance/mileage (even if close to nothing, it is still something).
 

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Sooo...I don't have any advise regarding the changes to the airbox or ducting. But depending on your driving style and where you are driving. It is not likely you will see any changes regarding MPG, definitely not see any change in performance. If anything, these changes you are making will yes make the "engine breathe better" and therefore a very slight increase in HP, maybe 1HP or less?. But in doing so, you are actually going to decrease the torque at the bottom end, meaning off the line performance will actually get worse. This is a very heavy vehicle due to the weight of the AWD bits and pieces, and therefore you actually want to increase torque and not HP.

Try this test, since you have a Forester S, and I assume it's the 4EAT Auto. Plug in the FWD fuse in the engine compartment. Drive around, you will notice without the AWD turn on, the vehicle leaps off the line as it has crazy amounts of torque off the line.
 

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Discussion Starter #5
Sooo...I don't have any advise regarding the changes to the airbox or ducting. But depending on your driving style and where you are driving. It is not likely you will see any changes regarding MPG, definitely not see any change in performance. If anything, these changes you are making will yes make the "engine breathe better" and therefore a very slight increase in HP, maybe 1HP or less?. But in doing so, you are actually going to decrease the torque at the bottom end, meaning off the line performance will actually get worse. This is a very heavy vehicle due to the weight of the AWD bits and pieces, and therefore you actually want to increase torque and not HP.

Try this test, since you have a Forester S, and I assume it's the 4EAT Auto. Plug in the FWD fuse in the engine compartment. Drive around, you will notice without the AWD turn on, the vehicle leaps off the line as it has crazy amounts of torque off the line.
Thank you for your insight! Do you happen to have any information about increasing low end by modifying the intake? There has to be SOMETHING. My car is sort of a daily driver/adventure vehicle. I do abuse it a little (within reason). Thank you.
 

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Thank you for your insight! Do you happen to have any information about increasing low end by modifying the intake? There has to be SOMETHING. My car is sort of a daily driver/adventure vehicle. I do abuse it a little (within reason). Thank you.
Torque requires couple of things: longer stroke and larger combustion. Neither of which will be gained by modifying the intake.

Short of installing turbo kit? Not really anyway to increase performance. Given this is a flat 4, meaning no more room in the engine bay, you have no way of increasing stroke length and therefore increasing torque/bottom end. Turbo allows you to create a bigger combustion, but that's a very expensive undertaking. But given the EJ251 is an open-deck design it also would not stand up to the bigger combustion from the turbo and you would end up with all kinds of head issues, piston and crank issues.

Just live with what you got. And enjoy it. There are not many other vehicles out there that does what this vehicle does. And it's cheap and easy to maintain. Just change the oil regularly and a few other things and it just runs. I have nearly 217,000 miles on my 2001 Forester S. Other than 2 head gasket jobs, I got no complaints.
 
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