How much power can a cheap air filter rob?
Posted: Tue Mar 19, 2013 6:40 pm
83rwkw.
Yeah, I was surprised too. Car in question was a Datto 910 with S15 SR20. Owner had just fitted a TD06SL2-20G, ext WG, Poncams, 850cc injectors and HPX AFM in a 3" tube.
I ran it up and started feeling my way around at low boost. Seemed a little weird but I forged ahead. Once I'd got things beaten into some sort of shape I tried turning boost up. Couldn't get any more boost! 10psi was it.
Hmmm. After much messing about with a very hot WG the offending air filter was spotted. It was collapsing any time the engine came on boost. Pulled the filter off and the first pull it woke up and started to deliver like it should! Slipped on an old K&N style filter and it made the same power. All good.
Here's a dyno graph showing a pull before and after removing air filter. No other changes.
Now, the guy only buys good stuff and paid $90 for the air filter. A Jap name brand item. I can only imagine that it was a fake. I have no proof either way though.
Anyone else seen this happen?
PL
Yeah, I was surprised too. Car in question was a Datto 910 with S15 SR20. Owner had just fitted a TD06SL2-20G, ext WG, Poncams, 850cc injectors and HPX AFM in a 3" tube.
I ran it up and started feeling my way around at low boost. Seemed a little weird but I forged ahead. Once I'd got things beaten into some sort of shape I tried turning boost up. Couldn't get any more boost! 10psi was it.
Hmmm. After much messing about with a very hot WG the offending air filter was spotted. It was collapsing any time the engine came on boost. Pulled the filter off and the first pull it woke up and started to deliver like it should! Slipped on an old K&N style filter and it made the same power. All good.
Here's a dyno graph showing a pull before and after removing air filter. No other changes.
Now, the guy only buys good stuff and paid $90 for the air filter. A Jap name brand item. I can only imagine that it was a fake. I have no proof either way though.
Anyone else seen this happen?
PL