According to this website:
http://www.gmtips.com/3rd-degree/dox...maf-screen.htm
the MAF screens and the resulting turbulence are necessary in some cases. I saw no problems when I removed my MAF screens. Has this been a problem for others? If so, what did you do about it?

 

Lots of people have problems after removing the screens, mostly from physically damaging the MAF itself. Its pretty fragile. I dont agree that the MAF cant measure correctly without the screens, its just a matter of some reprogramming. It actually results, most of the time, in a high reading and this is what sets off the code 33. To me, a code 33 is telling you just what you expected, there is more air flowing past the MAF than before, higher than the settings the ecm expects and it throws the code.

Lingenfelter and others do the same mod to the MAF and have been doing it for years. Its probably little if any gain on a stock engine, but on a modified engine it can help quite a bit.

 

Ok, but is the ECM able to adjust properly for the greater airflow or not? How is the "reprogramming" done to compensate for this?

 

I used to be on the side of the fence that didn't wanna cut the screens out, but trying it both ways run for run down the track, I seem to run a little better with them removed.


I also used to be a fan of "MAF" fuel injection.. I'm starting to think I shoulda went SD..

Maf _would_ work better, if the ECM wasn't so flawed. But I guess in 1985 GM didn't think people were gonna put blowers on these cars. All the hot rod guys hated fuel injection.


-- Joe

 

There is a table in the ECM for Max Airflow vs. RPM. I think this is used to generate a code 33.

But I converted to SD and got rid of the MAF sensor. You can see my post in the PROM board.

 

It appears that Mike has covered the bases in his article. He lists the reasons for having MAF screens, explains the theory of operation of the MAF, and warns that gains probably shouldn't be expected with stock or mildly modified engines.

The last question is really the best - if you're trying to run that much HP, why are you using the old MAF system instead of S/D or an OBD-II PCM?