MAF

burgundyz71 · February 1, 2006

I was searching here for reviews on the AEM Brute Force air intake system and while reading someone posted they descreened their MAF. I thought this was a bad thing to do, am I wrong and if so is there an advantage to doing this ?

fmjhp594 · February 1, 2006

I was searching here for reviews on the AEM Brute Force air intake system and while reading someone posted they descreened their MAF. I thought this was a bad thing to do, am I wrong and if so is there an advantage to doing this ?

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I did it on mine with my brute force, it susposedly aided in the throttle response, but only to a point. The TM will limit the response anyways on newer trucks, but if you have a tune with the TM toned down or removed, then it will help even more. It is bad to do if you put an intake on that uses an oiled filter. The oil will get all over the sensors and possibly ruin it, or make your truck run funny and so you have to take it out and clean it. My AEM uses the new dryflow filters that have no oil on them, so I removed it. I cant tell you how much I gained from just removing the screen becasue I put the intake on at the same time. But here in a few weeks I will be getting a wait4me tune that will limit the TM, so then there might be a bigger difference.

Nick99Chevy · February 2, 2006

Leave it in.

BlueTahoe · February 2, 2006

I removed mine on the Tahoe and had no issues until I got a tune. With the tune the goal is to move it closer to the edge. The tune in combination with slightly inaccurate metering by the MAF took mind over the edge to mild detonation. I replaced with a new MAF and the tune was perfect. I say leave it in. It may add a small performance gains for some but could cause allot of problems.

drumset5994 · February 2, 2006

I second that "leave it on with an oiled filter"...

My brother did that to his S10 with the 4.3L V6, and with his cold air intake, it made the thing run like a piece of garbage.

Wait, that was past tense. It STILL runs like a piece of garbage.

vhato · February 3, 2006

I can say I have done this before, on my old '00 Z-71.

I used AutoTAP to pull some MAF sample data and discovered Ignition Timing increased (I don't remember how much) on the average when compared to the average of several previous rides using my work commute as reference.

Throttle response improved and at times the truck did feel stronger under part throttle acceleration.

The disadvantage I saw was my LTRIMS (Long Term Fuel) actually changed by 8% (10% is GM spec, 5% is custom tune spec and 2% is perfect). The computer was constantly trying to correct my fuel mixture. I don't remember if it was rich or lean though

I later installed Dynomax exhaust as well as K&N Intake and HyperTech Tune. Ignition timing was WAY too high during part throttle driving and my LTRIMS were ~15% off. The High Ignition Timing made my engine ping *ALL* the time and the LTRIMS being off led to nasty gas mileage and power during part throttle acceleration was all over the place. During acceleration it felt like the truck would sometimes bounce from a little acceleration to more to less. It was weird.

So I grabbed a factory MAF from a friend just to see and my engine ping went away, LTRIMS were around 3% and acceleration was smooth.

Needless to say I replaced it.

Now that I am customing tuning my 2004 myself I have learned the MAF is nothing to play with. It comes with a very specific calibration and any change will GREATLY through it off. Even a K&N drop-in filter *can* change the calibration for the worse. Just switching the exhaust creates a major change in its calibration.

To make a long story short, *ANY* change in air flow to an engine should require an updated PCM to accurately take advantage of it. People with Intakes and Exhaust should take note and get a Predator programmer or custom PCM.