if you take the filter out of your stock box at the drag strip, you'll actually will go slower than leaving a clean filter in the airbox.

also, you'll dyno higher with the filter in.

just thought I'd let you know.

It's got to be clean filter though.

 

Is that more due to the ECU pulling timing or what not, cuz the air/fuel ratios are off?

 

thats my guess

 

thanks for the tip plokivos

 

i've gained 10whp with the filter in and took off 2 tenth of a second at the track with the filter in.

 

classic

 

would it hurt the engine/ filter if i take the cover off the filter from time to time just to hear the BOV ?

 

Try it.

 

one must not forget about dust and dirt!

 

I'm not disagreeing with you but I just don't belive in using dynos to accuratley measure HP cause they're to easy to munipuliate. And the ET part of the 1/4 mile would be the driver, so I'll ask what happened to your MPH on that run in the 1/8th and at the big end???

So far with the stock filter and no airbox cover I've trapped 104 and I'm 100% stock with the exception of a MBC set at 19psi. today I was going to try running no filter with just a nylon stocking to stop small debris and see how that goes. I usually run around with top of the air box off to hear the BOV better and I noticed a little quicker spool like that. I think with no filter at all you will see an even better spool but I don't know how the MAF will react to the air not being as straight as with the filter.

 

On my 667 whp evo - taking off the filter makes a ZERO whp difference - I tested it

 

yeh, i have 2 mods, and it bogs or something if i take the filter out.

sounds cool, but that's about it.

 

your car is MUCH different then a normal evo, I wouldn't say thats a good example.

I just got back from doing some testing of my own. I took out my factory air filter which was just changed 4,000 miles ago at the dealer (15k service) and used a nylon stocking my gf had laying around. Since it wouldn't fit over the air filter opening I put it over the scoop going into the top cover.

Instantly I could tell a big difference... spool up was much faster almost instant and throttle response was almost like an all motor engine. I'd be in vacuum @ 2,700 rpm, go WOT and by 3k I was seeing over 1.2 bar... anytime I pressed the gas above 3k I was flung back in my seat and it just pulled hard.

The only other thing I noticed was the turbo wouldn't spin down as fast... usually when I let off the gas the car would decel faster then it was doing with no filter.

I wouldn't drive around all the time like this however, i've seen some things stuck in my stock filter that would rip a hole threw the nylon sock with ease. I'm going to see if this makes any difference where it counts, at the track.

 

Are you using the stock airbox?

 

IIRC, you are running speed-density...no MAF...different from a regular Evo setup...