Small Air Filter

[nolig2278]

Does the size of the air filter make a real difference in a BPT setup?

Will it slow my spool up? Will it limit my top range boost when I stop my wastegate?

[torpedan]

This is almost like a trick question, in reality though there are too many factors to considered for me to give you a good answer.

Best said though, Yes it will make a diffrence. It will affect the amount of filter surface area for the engine to draw air threw and might offer a point of restirction in the intake system. I use restriction liberally though.

Spool times will be drastically affectged by velocity as well though, this brings into questions a lot on intake and filter design. Its not a simple question to answer.

[ModMX3 - (Carmaster2005)]

I have heard of people saying that a big intake on a turbo slows your spool time. but i have no idea if this is true or not. I would think it would be similar to an over sized exhaust as it would hurt you low end power air flow. But like torpedan said, this is a really tricky question bueause there are so many factors like CFM, air temp, PSI , # of x amount bends, ect. I think as long as you dont go to big youll be fine. example turbo inlet = 1 in. intake pipe = 3.5 in. = not good . hope this helps a bit.

[Kuromu]

I don't see why a larger filter would slow your spool time. The turbo will only take in air as it needs it. It isn't like a larger filter is going to FORCE more air in just because it is bigger. In actuality, a larger filter with quality breathing elements would help insure that your turbo gets good clean air when it needs it.

I think the breathability of the filter would be the deciding factor over size. Cheap cone filters are more restrictive than say and HKS or K&N because the materials are usually cheaper and not well engineered.

[torpedan]

I don't see why a larger filter would slow your spool time. The turbo will only take in air as it needs it. It isn't like a larger filter is going to FORCE more air in just because it is bigger. In actuality, a larger filter with quality breathing elements would help insure that your turbo gets good clean air when it needs it.

I think the breathability of the filter would be the deciding factor over size. Cheap cone filters are more restrictive than say and HKS or K&N because the materials are usually cheaper and not well engineered.

In thoery it will draw in the air it "needs" but the velocity of the air going at it and the turbulnce and eddies it creates and encoutners along the way pay a big facotr as well. Either way its a simple question with an answer that is application specific and a general reply will not meet everyones needs.

[WingleBeast]

think of it this way... its not about volume its about speed...

with the greater surface area of a larger filter, the suction of the turbo has to act over a wider area, therfore the force the turbo is enacting per inch of filter will go down. and it will get to the point where the force cannot effectively overcome the filter elements ability to stop the flow of air (friction) but the bad thing about this is there are no set number because on differnt filter elements come different friction and flow characteristics. however foam and metal mesh filters have less resistence on moving air but they also filter less efficently

with reguards to the intake... your turbo cant be selective on what air its sucking up, by laws of physics even if the turbo sucks what it needs in a 3 inch pipe, it will still have to move the whole column of air to replace what it took

so basically in a tube, no matter how big the turbo, the same amount of air is going to be moved, its just a matter of how fast the turbo can effectively do it. if you were really smart and found out the airflow numbers on your turbo for your set boost, you could figure out the right diameter and length of tubeing that will give you the best velocity to volume ratio