I heard that on a 01 Z06 there is a honeycomb filter on the maf. Was curious if we could remove it for a little more hp not expecting much just know that the new years Z06 dont have this honeycomb filter?

 

The '01 MAF screen is an air flow 'straightener' that was overlooked till '02 by GM engineers. Because of the relative straight air flow from the air box , engineers in '02 deterimed it was not necessary and restrictive. By removing the screen and adding the '02-'04 ZO6 air box GM engineers say its worth 5 hp.

NOTE*** Some '01 ZO6 owners report problems with idle speed after removing the screen.

 

No way you'll get 5 HP from de-screening the MAF. The air filter is WAY more "restrictive" than the "screen". The only time the MAF becomes a "restriction" is if you've put some "monster" cam in the car and are flowing WAY more air than the GM MAF was built for.

And for 2002 the GM engineers installed a new MAF calibration table in the PCM for the descreened MAF. If you search the archives you will find that MANY of the people who took out the "honeycomb" were getting codes for the engine running too lean.

De-screening the MAF turned out to be about as good an idea as a Granatelli MAF ... again do a search and see how many people found that there was no gain, and many had codes for running lean.

 

I'm not necessarily advocating descreening the MAF on an 01 Z06, but am confused by your comments above. Seems somewhat contradictive............If the screen is not restrictive, then why would owners get a lean code condition following it's removal????

I believe GM engineers said that the 02 Z06 got a 5hp bump up, as a result of the screen removal, and the additon of the larger air box on an 02 and later ZO6.

 

I am having the car retuned so would u guys just take it off i cant see any harm in gaining 1 or 2 hp or tq. It seems like it had to take some power away or they would have left it in the 02.

 

The reason people see lean codes, and/or driveability problems, after de-screening the MAF is because the screen affects the way the air flows over the sensor wires - but not neccesarily in a way that affects "power". For example, while we usually think of air flowing through the MAF at a "constant" velocity, at idle that isn't the case. The air flow through the intake system tends to "pulse" through at idle speeds. The screen on the MAF actually helps to lower the "pulse" effect as incoming air tends to "bunch up" on the screen on an intake pulse, and so the screen causes the air to flow both more constantly through the MAF, and it also causes the air to flow more evenly measured at the center of the MAF and at the outer diameter of the MAF. The heated wires react differently to a pulsing airflow that tends to pulse down the center of the MAF body versus how they react to a more "smoothed" out airflow that is more evenly distributed across the bore of the MAF.

Now in the above example, I can "adjust" for the descreening by updating the MAF table in the PCM to reflect the "new" frequency the de-screened MAF is reporting at idle. The adjustment won't affect engine power (we're talking idle here) but it will help the PCM get a correct reading of the airflow through the MAF, and therefore a better A/F ratio at idle.

The same is true at higher engine speeds ..... the air flows differently through a screened MAF versus an unscreened MAF .... for the same amount of air (say 10 grams) one MAF may report a 10,000 Hz signal, while the other may report a 9,500 Hz signal. neither is wrong ... the key is in the MAF table in the PCM. If the PCM expects 10,000 Hz is 10 grams, then when you switch to a MAF that reports 9,500 for 10 grams, the PCM is gonna think there is less air coming through the MAF and lower the fuel injected accordingly ... BUT ... you actually still got 10 grams of air, and less fuel .... LEAN ....

It just happens that descreening our MAFS tend to make the car generally run lean because de-screening changes the level of "turbulence" in the MAF, and therefore changes the frequency the MAF reports for a given weight of air.

I figure GM has spent a lot of time and money engineering these engines. I'm not gonna try second guessing GM Powertrain and de-screen my MAF for what is likely to MAYBE be a couple of HP difference, and trade off running the engine lean in exchange.

One of the things a "good" tuner should be doing is ensuring that your PCM's MAF table is correctly matched to your MAF, especially if you change your MAF or other parts of the intake system. To give you an idea how sensitive the MAF is .... on the Pontiac GTO's with the LSx engines the MAF table is different than the Corvette's (even though the engine and MAF are the same) because the intake system (air cleaner and other parts to the MAF) are different enough that the Corvette MAF table was found to not work to Powertrain's satisfaction.

 

Thank you for taking the time to provide a very detailed and understandable answer to my question. I have not removed the MAF screen on my '00, even though I have installed both the Z06 intake manifold, and the '02 air box lid. Driveability and idle is good, and don't want to risk degration of same as a result of MAF screen removal.

 

I have a 01 Z06. I de-screened the maf myself, and its been that way for 5 yrs. with no problems, its also backing up a modified radiator shroud, Blackwing air filter assy, and a powerduct with a Diablo tune. No codes rough idle no issues.

 

My 01 is running with a descreened MAF. I have no issues what so ever related to it.

 

Apparently BlackZo6 your are more knowledgeable than the Asst. Chief Engineer of Gen 3 engines for General Motots who was reported to say at a Z06 press conference that descreening the Z06 MAF with the addition of the '02 Z06 air box larger opening( reread my post please) is worth 5 hp. Don't kill the messanger, if you have problems with this statment take it up with GM.

"Dr" John Juriga went on to say that Gm did what hot rodders have be doing for years , descreening or removing the "air strainghtener" the MAF. Because of the relatively straight passage bewteen the air box and the MAF the screen/ air straightener was not needed.

I did mention that here have been reports from forum members of idle problems . I have swapped out he '01 MAF for the '02 with out apparent problem but after some substanial upgrades in induction and exhaust , the PCM was modified for a greatly improved responce.

Please in the future could folks please reference their sources.