Descreening the MAFS?
Registered User
Joined: Jul 2005
Posts: 1,783
Re: Descreening the MAFS?
Don't, the screen straightens the air and does not slow it down any. I descreened and ported mine and a ton of people replied with negative things 
. Plus it makes it really hard for someone to tune. Just leave it there.
. Plus it makes it really hard for someone to tune. Just leave it there.
Registered User
Joined: May 2005
Posts: 478
Re: Descreening the MAFS?
the after market MAF's work really well if you have a lot of mods, along with a computer tune... however if you dont have that many mods, an aftermarket one wont be worth you buying... 
good luck...
good luck...
Registered User
Joined: Nov 2003
Posts: 48
From: PA
Re: Descreening the MAFS?
I had mine tuned tonight and the guy had to run it in speed density mode, because the MAF was throwing the mixtures around so bad. too bad unlike my lt1 where i could pop the screen back in. off to buy a stock one. Although this guy told me that hes had alot of problems and the entire speed shop said the Granetelli was junk and threw the mixtures way out of wack. dunno maybe a bad MAF? Anyways let it alone. It richened my low end and leaned out my top end. loss of 50miles per tank. M.H.O.
Registered User
Joined: Jan 2005
Posts: 2,592
From: N Falmouth MA
Re: Descreening the MAFS?
Originally Posted by Injuneer
The 3rd GEN Bosch MAF sensors are dogs.... they have two metallic screens and all the internal cooling fins, and removing the screens and the fins can eliminate a bottleneck as HP increases. However the 4th Gen LT1 and LS1 cars use a GM MAF sensor, with a single formed paper/foil honeycomb in the MAF inlet side. That device is provided to smooth the airflow through the MAF sensor, making it more uniform across the full open face of the sensor. That way, the small amount of air that actually touches the sensing element is more representative of the true flow through the entire MAF. The factory assumed the screen was there when they set up the MAF calibration curve in the PCM. If you remove the screen, you alter the calibration.
Removing the screen isn't going to increase flow by 180cfm. It will eliminate a tiny pressure loss, increasing what's left of the barometric pressure by the time it gets done filling the cylinder volume. That's effectively a tiny increase in volumetric efficiency. IF you assume that removing the screen reduces the pressure loss through the MAF (it might actually increase the pressure drop if it screws up flow ) by about 0.1"Hg the resulting flow increase is 0.33%.... or on an engine consuming 400cfm, you would gain approx. 1.34cfm. Not worth it, if it screws up the meter calibration.
Originally Posted by IROC-T
I took mine out in '89 an I've never had any problems,as for sucking things into the engine, isn't that what the air filter is for. It doesn't make a noticable differance,but I believe every little bit helps to a point. If you do it keep a good air filter in line and you should be ok.
I took mine out in '89 an I've never had any problems,as for sucking things into the engine, isn't that what the air filter is for. It doesn't make a noticable differance,but I believe every little bit helps to a point. If you do it keep a good air filter in line and you should be ok.
The 3rd GEN Bosch MAF sensors are dogs.... they have two metallic screens and all the internal cooling fins, and removing the screens and the fins can eliminate a bottleneck as HP increases. However the 4th Gen LT1 and LS1 cars use a GM MAF sensor, with a single formed paper/foil honeycomb in the MAF inlet side. That device is provided to smooth the airflow through the MAF sensor, making it more uniform across the full open face of the sensor. That way, the small amount of air that actually touches the sensing element is more representative of the true flow through the entire MAF. The factory assumed the screen was there when they set up the MAF calibration curve in the PCM. If you remove the screen, you alter the calibration.
Removing the screen isn't going to increase flow by 180cfm. It will eliminate a tiny pressure loss, increasing what's left of the barometric pressure by the time it gets done filling the cylinder volume. That's effectively a tiny increase in volumetric efficiency. IF you assume that removing the screen reduces the pressure loss through the MAF (it might actually increase the pressure drop if it screws up flow ) by about 0.1"Hg the resulting flow increase is 0.33%.... or on an engine consuming 400cfm, you would gain approx. 1.34cfm. Not worth it, if it screws up the meter calibration.
Or check THIS.....
I'm putting my screen back in when I get home! It'll make it easier for my tuning guy! And I don't want to have the Teke184 Incident and forget about a nut and have it sucked into my engine.
I'm a little forgetfull myself...
Last edited by Bayer-Z28; Jul 29, 2005 at 12:06 PM.
Re: Descreening the MAFS?
Registered User
Joined: May 2000
Posts: 501
From: Chesapeake, VA USA
Re: Descreening the MAFS?
If you have a good tuner, porting the MAF is fine. Again, I wouldn't bother unless you are making big power as the stocker is good for at least 500HP. You could always try some ported ends first, that way if you have probs, you can switch them out.
Registered User
Joined: Feb 2004
Posts: 4,800
Re: Descreening the MAFS?
http://web.camaross.com/forums/showthread.php?t=386134
Thread on the recent Granatelli magazine AD.
A MAF is a sensor and a highly calibrated one at that it is entirely possible to tune for almost any porting of it and the like but it can be a lot of work and since it is not restriction it ends up not gaining you anything. If you port it the stock calibrations are no longer accurate, does it sound like a good idea to give your pcm false info to base fueling off of?
Thread on the recent Granatelli magazine AD.
A MAF is a sensor and a highly calibrated one at that it is entirely possible to tune for almost any porting of it and the like but it can be a lot of work and since it is not restriction it ends up not gaining you anything. If you port it the stock calibrations are no longer accurate, does it sound like a good idea to give your pcm false info to base fueling off of?
Registered User
Joined: Aug 2000
Posts: 1,901
From: Houston, Tx USA
Re: Descreening the MAFS?
I have seen more bad than good come from aftermarket MAFs..
I would leave the stock one alone as its not a source of power gains.
If you want to just spend a few hundred on something how about suspension..
I bet you dont have an airbag in your right rear spring.. Get and AirLift airbag and pop it in your right rear spring, set at 21psi.. Enjoy better launches.
Or subframes.. or LCAs... do mods that will make the most of the power you already have instead of adding pissant mods that do nothing.
I would leave the stock one alone as its not a source of power gains.
If you want to just spend a few hundred on something how about suspension..
I bet you dont have an airbag in your right rear spring.. Get and AirLift airbag and pop it in your right rear spring, set at 21psi.. Enjoy better launches.
Or subframes.. or LCAs... do mods that will make the most of the power you already have instead of adding pissant mods that do nothing.