I've never noticed this before. I'm an attentive driver and I know what my vehicle normally feels like. Today I replaced my air crappy APC filter with a nice K&N that was exactly the same size. I closed the hood and went for a drive. When I first started the car all was fine but then I pulled into the street and it stuttered, stumbled and stalled. I restarted and it was better but a stutter step was still there for a few seconds. I was a bit worried but my tranny has been acting up lately and thought it could be related.

So, I head out to the country for some Sunday driving. I was pushing it and seems totally fine up top. So I'm on a deserted road and decide to break it down and see if that clogged filter was holding back my low end. To my suprise I felt a very noticable loss in power from the day before. WTF? I did it many times. Normally on a cool day the tires chirp on a launch but they didn't and it felt extremely sluggish. But all the sudden at just over 3K it drops the hammer and RPM's begin to fly.

Has anyone experienced a similar situation? This is really bugging me. Why would replacing a filter result in losing low end? I was toying with the idea that its my mind playing tricks on me but I don't think so. Maybe I've been suffering from such a poor upper power band for so long that I'm used to the power/tq band to be very static across the rev band. Now it feels like someone hit a small nitrous switch or something. Even if I was used to the low power it doesn't explain why the tangible result of power(tire chirp) isn't apparent any longer.

 

Same happened to me, i got a kn filter also and the first day it seemed fine but the second day the car got slowwwwww. i didnt know what was going on either then i got pissed and returned it for a regular pos filter and it fixed the problem.

 

Maybe it had too much oil? Screwed with your MAF? I dunno

 

yah, my jwt sucks down low compared to stock air box and Nissan panel filter.
Jae

 

idk man, bump

 

Broaner,

I also have the K&N panel filter and budget Y-pipe. I haven't had my regular filter for so long so I can't say anything about it, but I don't think I am losing power down low.

The surge at 3.1k up to 5.5 is stronger when you have a Y-pipe, which you do.

 

my car seems to have a power surge at around the same rpm's. i have the stillen intake with the k&n cone filter.
of course, its been on there since i bought the car, so i thought maybe it was normal. i never felt the stock intake. i always thought it was a little weird that it would do that, though.
so what can i do to make up for that weaker low end? or is it actually that it just opened up the top end that much? the low end is actually just normal?

 

This thread is exactly why I kept my stock air filter stepup when I installed the y-pipe. Normally we don't keep the rpms in the 3.1-5.5 range for the K&N to help out much. The stock filter retains the monster torque this motor puts out down low and Y-pipe lets the motor breathe on the highway. The best of both worlds!!

 

I think they do have the stock airbox...just a K&N panel instead of the $3 one...

 

Let me clarify the situation. I had a ram air setup already and replaced the cone w/ a K&N unit. I don't understand why a clogged filter would increase TQ. The only restriction that would effect TQ should be on the exhaust side. Maybe it is that my up top was just suffering extremely. I have been having trouble lately getting above 125 so... In racing situations there is never a time that power is needed so low. To me it doesn't matter if I lose a bit down low. I'll be 5Spd by the end of next season and will be able to launch above the low power band. I consider the gain in power up top much more benificial because anytime you wanna go fast you need that upper pull.

Sober you have a good point. Is it possible to clean the MAF's thermo-resistor thing without damaging it. I'll take a look at it today.

I guess there is only one legit way to determine whats going on; dyno.