I wanted to report that I have successfully removed the screen from my MAF w/o any adverse effects to the tune or fuel trims. I know that Mellon has done this and reported similar findings. My STFT & LTFT's are still hovering + or -1 and my open loop fueling is still solid w/ pulls to redline. I have no new knock to report or any quirkiness, just wondering if that screen is really necessary? All I did was remove the plastic retaining piece surrounding the screen, removed screen, and epoxied the plastic retaining piece back in. I then logged the car at idle & cruise to see if anything funky was going on. I then lowered the boost to check for open loop fueling and all was good. I then upped the boost to normal levels and did some more pulls; everything stayed consistent to logs w/ the screen.

Note: I don't recommend this mod to those running stock framed turbos, the only reason I attempted this was in anticipation of a much larger turbo that I will be installing and I didn't feel like sucking the screen into the turbo. Is anyone else running around without the screen in the MAF?

 

bump

 

your load will be slightly lower and you may be in a different fuel/timing cell

 

i have noticed this! i am on the stock turbo BTW.

any ideas on fixing this? when i try to dial in timing i often cannot locate the particular cell with "ease"

 

I did notice slightly lower load <10 overall; nothing too significant though that would cause me to re-tune my maps.

 

you wouldn't tune it any differently...just adjust the appropriate column/row like normal according to what you see in the logs

 

did you notice any sooner spoolup differences???

 

no, there were no gains in power...it's only done for turbo safety.

 

Does the car want to do things like stall out when the cooling fan kicks on at idle?

 

Nada, I imagine that as long as your MAF is properly scaled for whatever intake setup you are running and your fuel trims are in check it shouldn't make much difference. I didn't notice any stumbling when coming to a stop or when the fans kicked on.

As far as spoolup or power differences, I haven't noticed any difference in my most recent logs. I'm just happy that I can drive w/o worrying if my turbo is going to suck the screen in for lunch

 

Well the reasoning for the straightening is so that the air flows through the sensor straight everytime and the sensor body itself induces the eddy currents that are picked up by the internal microphone. I was just wondering if the AC fan on the evo was able to disturb how straight the air flowed into the filter and then into the air sensor thus possibly artificially causing eddy currents that aren't truly representative of air speed. I mean this is basically how the karmon vortex sensor works. Air speed, baro pressure, and air temp are calculated by the ecu to figure out air mass in lbs/min or whatever unit your head likes.

 

Any change in Baro readings with the 'restriction" removed?

 

Removed mine friday afternoon after discovering that it was twisting itself out, I have noticed a couple of things that I haven't spent time tuning out (yet):

Crank/warmup is all good
transitional stuff is all good
Idle is fine (+- 5 hz @ idle vs having the screen in, I didn't pay much attention to it before hand, I think it idled at around 40hz before and now its 37ish).
It made everything richer, I would have expected the opposite from a slight shift downward (except perhaps at idle).

the only thing it does that is annoying (and I have messed with it a bit to alleviate the issue) occasionally clutching in or putting the car in neutral from mid-rpm range, it will hit the target idle of 1k and then dip down to about 400 for a second. It hasn't stalled yet, it just acts like it now and again. A/c on or off doesn't seem to matter (altho ironically, its less prone to do it with the a/c on).

I expected more transient inconsistencies than it has demonstrated. If you have the tools and the ability to tune your vehicle, this should not be something to be feared. I did not notice any change in performance, nor did I really expect one, it was more a measure of preventative maintenance when I realized that my maf screen was moving about.

 

i have had mine removed for a year now....

no change really occassionally my AFRs (off my wideband) would got to 12 for a second then swing back up to 14.7.

nothing else really.

 

if im on a fp green or fp red can i still use the maf with the comb or am i not safe ??