K&N Air Filters - Better or Worse

[dkvasnicka]

I'm one of those who threw in a K&N but are having second thoughts... I've read almost everything that can be searched on the net on K&Ns before I put it there but decided to go with it because I had a (subjective) very good experience with it in my turbocharged V6 Saab 9-5. Forced induction engines like airflow.

However I'm now not so sure it's worth it. What I would love to know is whether the airflow is really bigger enough to e.g. help the torque converter stay locked up longer in hills simply because the engine needs to work less in order to suck the air in... Some people report that (or staying in higher gears longer).
Is the throttle body open enough for the increased airflow to actually matter in regular driving? Can it be really that harder for the engine to breathe with the paper filter?

Some people report lower MPG, some higher
I think I'll just put in the old filter and try it for some period of time.

 

[Mooseman]

I could see in the old days of carbs it would have mattered but I don't think that in a modern naturally aspired engine it would do much, if at all really. On top of that, oiled filters can screw up the MAF sensor.

 

[dkvasnicka]

So I threw the original filter back in. It's a barely used FRAM CA9345, which should be more than enough. I'm curious whether I'll notice any difference or not. I hope I'll be able to resist the placebo effect

 

[dkvasnicka]

My observations after a few drives (all types of road). Maybe a little less noisy, pickup basically the same (doesn't feel sluggish at all compared to K&N) and I have a feeling that it locks the converter a liiiiitle bit later in very low "lockable" speeds, like 75 kph or so (no difference on highway). But I probably don't have enough observations to be sure about that and it may very well be the case that I'm just kidding here

Anyway, the K&N's not going back in for sure. No need to. I think the biggest reason is that the airbox is exceptionally high-flow in this car.

Just my $.02 for people thinking about buying the drop-in filter.