I've run a de-screened MAF in my '88 C4 . I have now added a 2001 Vert to the stable and was planning to de-screen the MAF. Any cons to doing this?

 

Don't do it. Unless you are having your car re-tuned by a professional immediately.

 

Leave it alone. You wont gain anything but headaches. The stock PCM is calibrated for the maf the way it is from the factory.

 

Been there, done that

 

OK, but how does that square with people using hi flow air bridges, blackwings air intakes, vararams and the like?

 

The maf is a 'meter'. It measures the amount of air going through it. By taking the screen off you change the amount of air it responds to.
If you look at the MAF tables in the computer you will see that at each given frequency in each cell you will have a mass value. If you remove the screen that will allow more volume to pass through, but the extra volume won't be measured because the MAF actually measures velocity. Put more volume through it at the same velocity and you will have a greater air mass and an 'out of cal' condition. The 2002 Z06 has no screen but the values in the cells are different to compensate for this. There is a way to remove the screen and recalibrate the maf, but it entails scanning several PCM parameters and air/fuel ratio and then changing the mass values to put them back into the proper scaling.
What will happen if the screen is taken off and the PCM not recal'ed? Most likely you will run a little leaner and you will have different spark advance lookups that could lead to knock which would consequently kill some performance.
All that stuff like Vararams and Blackwings and high-flow airbridges are valid because they increase efficiency of the engine to fill the cylinders with air because they are less restrictive, but they don't change the calibration of the maf.
Listen to Chris. He is one who knows.

 

Sounds like the same answer my performance shop gave. I was set on a de-screen, so he had his work cut out for him to set me straight. I really wanted to belive him . But, de-screening just sounded so right . I chose to listen to the expert, my MAF is untouched

 

Uncle!
and thanks !
rich

 

Sorry, it was late and I had a case of verbal diarrhea.

 

It was a great explanation and convinced me not to do it.... It was exactly what I needed to get me off the track I was on.

I should apologize to you if my reply suggested you were verbose.
thanks again
rich

 

I descreened my 2002 MAF and it does help some, BUT you must have the 02 Z06 MAF tables down loaded for this to be beneficial. As was mentioned earlier, the screened MAF and the screenless MAF have different tables in the PCM which will affect drivability to some extent. My rationale was if the factory did it , it must have a beneficial effect.
JMHO.

 

I pulled the screen out when I first got my car and didn't have any trouble whatso ever.

 

I have the Halltech (old style) snorkle system, and the Halltech MAF ends (polished). I removed the screen, and carefully hogged out all the un-necessary plastic. That was over 60K miles ago! no problems. My 98 was running quite rich when I bought her (inn 98), and it put it right in the ball park. She idles and runs great and now has 120k+ miles. If you do mess with it be very careful they are fragile! And yes get a tune. I now also have a Z-oh-sex manifold on as well, and runs even better.

Mine is a little 98 A4 with a rag top.

 

The best place for the MAF screen is in the garbage!!

Also no need to retune the PCM after its removed..

 

Here we go again with 'MAF screen wars'.

 

I just returned your PM, I checked your sig and wanted to ask how you like the 410's cause I am still undecided about 390 verses 410.