MAF Descreening
Team Owner
Joined: Aug 2004
Posts: 21,543
Likes: 3,216
From: Park City Utah
Originally Posted by timd38
I am not the engineer that decided the screen was needed, you should ask him or her why it is there.
An engineer didn't "Decide" that the C6 needed a screen, rather, a budgeteer decided that it was not worth removing the screen from the "parts bin" MAF used for the C6.
Le Mans Master
Joined: Nov 1999
Posts: 7,695
Likes: 51
From: Imperial Beach CA
Originally Posted by SpinMonster
And the same engineer removed it on the C5 Z06....so I guess when labor is involved on the high performance model, it gets removed. It being on the LS2 is because they didnt do the labor to remove it. It was cheaper to keep it.....like the ex.
Melting Slicks
Joined: Jun 2006
Posts: 2,208
Likes: 1
[QUOTE=Jim_H]I found this link on MAF screen removal, not sure what to think, but I probably won't be messing with it.
[URL="http://www.gmtips.com/3rd-degree/dox/tips/maf/maf-screen.htm"]http://www.gmtips.com/3rd-degree/dox/tips/maf/maf-
I've read similar text and believe them. The screen is there for a purpose and removing it degrades the functionality of the key sensor in the car. I don't want to run so lean I burn a piston, or so rich I kill every flying insect in 5 miles with black smoke. And it is not logical that any gain of any value is going to come from doing it. If somebody swears they got a gain, good for them. But still pass. 
[URL="http://www.gmtips.com/3rd-degree/dox/tips/maf/maf-screen.htm"]http://www.gmtips.com/3rd-degree/dox/tips/maf/maf-
I've read similar text and believe them. The screen is there for a purpose and removing it degrades the functionality of the key sensor in the car. I don't want to run so lean I burn a piston, or so rich I kill every flying insect in 5 miles with black smoke. And it is not logical that any gain of any value is going to come from doing it. If somebody swears they got a gain, good for them. But still pass.
Team Owner
Joined: Aug 2004
Posts: 21,543
Likes: 3,216
From: Park City Utah
[QUOTE=Whiterock1]
I little melodramatic aren't we? Yes.
The above link is writen by whom? Some guy. What makes them more credible than anyone on this board?
Dave Hill said that they discovered that w/the relatively straight path of airflow in to the MAF in the Vette, they were able to remove the screen w/no ill effects, and did so for the Z06. That is why trucks, F-bod's and GTO's understandably have screens. Because the rest of GM's fleet has 90* intake tubes GM's MAF vendor builds MAF's w/screens. GM spent the money on the Z06 for a different MAF, but not on the C6.
I agree that tuning make sense for a screeen removal though. On the other hand, I've had great luck removing screens on a previous '86 TPI Trans Am, and my current DD, a '96 Chevy Silverado 1500 w/a 5.7 Vortec. Both had/have 90* bends in the intake and ran/run perfectly w/no screens AND no tuning. No "hesitation", not "black smoke", no "rough idle", no "burned pistons" (lol), etc. To wit, my 1500, x-cab, 4x4 truck gets me over 20 mpg on the highway, consistently and matches my friends 305 hp Nissan Titan -even though mine is 50 hp short on paper. Seems to me like the MAF is working fine, sans screen.
Originally Posted by Jim_H
I found this link on MAF screen removal, not sure what to think, but I probably won't be messing with it.
[URL="http://www.gmtips.com/3rd-degree/dox/tips/maf/maf-screen.htm"]http://www.gmtips.com/3rd-degree/dox/tips/maf/maf-
...I don't want to run so lean I burn a piston, or so rich I kill every flying insect in 5 miles with black smoke.
[URL="http://www.gmtips.com/3rd-degree/dox/tips/maf/maf-screen.htm"]http://www.gmtips.com/3rd-degree/dox/tips/maf/maf-
...I don't want to run so lean I burn a piston, or so rich I kill every flying insect in 5 miles with black smoke.
The above link is writen by whom? Some guy. What makes them more credible than anyone on this board?
Dave Hill said that they discovered that w/the relatively straight path of airflow in to the MAF in the Vette, they were able to remove the screen w/no ill effects, and did so for the Z06. That is why trucks, F-bod's and GTO's understandably have screens. Because the rest of GM's fleet has 90* intake tubes GM's MAF vendor builds MAF's w/screens. GM spent the money on the Z06 for a different MAF, but not on the C6.
I agree that tuning make sense for a screeen removal though. On the other hand, I've had great luck removing screens on a previous '86 TPI Trans Am, and my current DD, a '96 Chevy Silverado 1500 w/a 5.7 Vortec. Both had/have 90* bends in the intake and ran/run perfectly w/no screens AND no tuning. No "hesitation", not "black smoke", no "rough idle", no "burned pistons" (lol), etc. To wit, my 1500, x-cab, 4x4 truck gets me over 20 mpg on the highway, consistently and matches my friends 305 hp Nissan Titan -even though mine is 50 hp short on paper. Seems to me like the MAF is working fine, sans screen.
Last edited by Tom400CFI; Sep 26, 2006 at 04:29 PM.
Le Mans Master
Joined: Feb 2006
Posts: 5,762
Likes: 4
From: Chandler Arizona
[QUOTE=Tom400CFI]
Melow Dramatic? Does that mean that you are kind of (mellow) dramatic.
I think you meant melodramatic.
Sorry, couldn't refuse.
Originally Posted by Whiterock1
I little melow dramatic aren't we?
I think you meant melodramatic.
Sorry, couldn't refuse.
Safety Car
Joined: Dec 2004
Posts: 3,565
Likes: 5
From: stafford country, va. Avatar: Me on turn 3 @ Bristol (The World's Fastest Half-Mile)
Originally Posted by midnite902
I descreened my MAF[/IMG]
if removing the screen improves airflow so will aligning the MAF air diffusor with the throttle body.
the maf has a built in air diffusor that is aligned vertical (90 degrees out-of-phase with the throttle body butterfly).
the throttle body butterfly opens horizontally.
wouldn't aligning the maf diffusor (air flow director) with the throttle body opening permit better airflow into the intake ?
instead of air being directed into the butterfly plate it would be directed into the opening.
oh, wait, just noticed.. you've installed a 100mm maf, does that even have a diffusor ?
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Melting Slicks
Joined: Jun 2006
Posts: 2,208
Likes: 1
[QUOTE=glennhl]
Melow Dramatic? Does that mean that you are kind of (mellow) dramatic.
I think you meant melodramatic.
Sorry, couldn't refuse.
You beat me to it...Yes, I am mellow (with 2 ls...) and often dramatic, but when it comes to price performance, I've often found that when it doesn't cost anything to do, it also doesn't do anything--at least good.
Originally Posted by Tom400CFI
Melow Dramatic? Does that mean that you are kind of (mellow) dramatic.
I think you meant melodramatic.
Sorry, couldn't refuse.
Le Mans Master
Joined: Nov 1999
Posts: 7,695
Likes: 51
From: Imperial Beach CA
Originally Posted by SpinMonster
When I bought a replacement it was there.
Tech Contributor
Joined: Mar 2003
Posts: 12,094
Likes: 197
From: Colorado Springs, CO
St. Jude Donor '08-'09-'10-'11
Originally Posted by jimman
The part number for the C5 Z06 and Chevy truck MAF are the same. Had them both in hand and neither had a screen, can't say any more than that.
Racer
Joined: Jun 2006
Posts: 309
Likes: 0
I am so confused. If you remove the screen there's more airflow but the sensor see's the airflow as being unchanged so it should lean the motor out. In closed loop the computer trims the fuel delivery back to what it wants so that would be OK. At WOT the motor should be leaner right? I'm assuming that since rich is safe than at WOT (as delivered by the factory) the motor's too rich anyway. I know this is simplistic but I'm still confused as to why this isn't the case.
Team Owner
Joined: Aug 2004
Posts: 21,543
Likes: 3,216
From: Park City Utah
[QUOTE=Whiterock1]
Sorry for the type-o. Fixed.
I couldn't disagree w/you more about cost vs. gains. No offense but people who think the way you do, spend too much to get too little.
Porting an intake costs nothing. Are you going to argue that it does nothing? Advancing the ignition timing in many engines costs nothing, and in some engines it makes a HUGE difference. Innovation and experimentation is what "hot rodding" is all about, and applying reason and logic can get you a looong way, for very little.
For example, my first car was an '83 Trans Am with a Crossfire Injection 305. 170 hp stock. What a hopeless piece of junk...right? With $300 "headers" (Edelbrock TES) and "free mods" (similar to descreening a MAF), it went 14.5 @95 in the 1/4. That's TPI 350 'Vette territory.
Free mods work, and here's why; Because you can apply YOUR time/labor, to fix/adjust/improve something that the OE didn't need to spend the time (money) on to achieve their desired results.
Originally Posted by glennhl
You beat me to it...Yes, I am mellow (with 2 ls...) and often dramatic, but when it comes to price performance, I've often found that when it doesn't cost anything to do, it also doesn't do anything--at least good.
I couldn't disagree w/you more about cost vs. gains. No offense but people who think the way you do, spend too much to get too little.
Porting an intake costs nothing. Are you going to argue that it does nothing? Advancing the ignition timing in many engines costs nothing, and in some engines it makes a HUGE difference. Innovation and experimentation is what "hot rodding" is all about, and applying reason and logic can get you a looong way, for very little.
For example, my first car was an '83 Trans Am with a Crossfire Injection 305. 170 hp stock. What a hopeless piece of junk...right? With $300 "headers" (Edelbrock TES) and "free mods" (similar to descreening a MAF), it went 14.5 @95 in the 1/4. That's TPI 350 'Vette territory.
Free mods work, and here's why; Because you can apply YOUR time/labor, to fix/adjust/improve something that the OE didn't need to spend the time (money) on to achieve their desired results.
Burning Brakes
Joined: Oct 2005
Posts: 1,131
Likes: 0
From: Dallas Texas
Originally Posted by Zig
so why didn't you rotate it as well ??
if removing the screen improves airflow so will aligning the MAF air diffusor with the throttle body.
the maf has a built in air diffusor that is aligned vertical (90 degrees out-of-phase with the throttle body butterfly).
the throttle body butterfly opens horizontally.
wouldn't aligning the maf diffusor (air flow director) with the throttle body opening permit better airflow into the intake ?
instead of air being directed into the butterfly plate it would be directed into the opening.
oh, wait, just noticed.. you've installed a 100mm maf, does that even have a diffusor ?
if removing the screen improves airflow so will aligning the MAF air diffusor with the throttle body.
the maf has a built in air diffusor that is aligned vertical (90 degrees out-of-phase with the throttle body butterfly).
the throttle body butterfly opens horizontally.
wouldn't aligning the maf diffusor (air flow director) with the throttle body opening permit better airflow into the intake ?
instead of air being directed into the butterfly plate it would be directed into the opening.
oh, wait, just noticed.. you've installed a 100mm maf, does that even have a diffusor ?
Drifting
Joined: Jul 2003
Posts: 1,796
Likes: 1
From: Annandale VA
Have to agree about the free mods. When the LS1 first came out, it didn't take long for the F-body crowd to figure out that descreening the MAF would result in a few extra ponies. The screens are not there to catch critters, they are there to provide a more consistent laminar flow, at the expense of a slight airflow restriction. Removing the screen causes the MAF to mismeasure the airflow. THis makes the car run slightly leaner, and since the OEM tune is safely on the rich side, it produces a tad more power. Whether this is "logical" or not is beside the point --- it's been proven on the dyno countless times.
For some reason it can also result in a bit more timing. This really doesn't make sense to me, but again, it's a widely observed phenomenon.
Somewhat later, Granatelli brought out their descreened and "calibrated" MAF, and claimed certain HP gains. What followed was the familiar cycle of furiously worded forum debates about whether it was worth the $$$, yada yada yada. Then SLP chimed in with their 85 mm MAF, which kicked off even more debate.
Whether it works on the C6 LS2 the same way it did on the LS1 is a moot point. If you want to try it, it won't hurt, and you might even pick up a little power.
For some reason it can also result in a bit more timing. This really doesn't make sense to me, but again, it's a widely observed phenomenon.
Somewhat later, Granatelli brought out their descreened and "calibrated" MAF, and claimed certain HP gains. What followed was the familiar cycle of furiously worded forum debates about whether it was worth the $$$, yada yada yada. Then SLP chimed in with their 85 mm MAF, which kicked off even more debate.
Whether it works on the C6 LS2 the same way it did on the LS1 is a moot point. If you want to try it, it won't hurt, and you might even pick up a little power.
Race Director
Joined: Jan 2000
Posts: 12,375
Likes: 406
From: Florida
Well, I think we need to be cautious in calling this a free mod. What I am getting from those who have tried it is that you need a tune to see the effect or for the car to run right. That's $300 or so. I also recall a thread a while back where some (not all) got CELs from de-screening.
Personally, I will de-screen, but will do it at once with other mods so I spend my tuning money once. That is why I have had a Vortex rammer sitting in the box for 6 months.
Personally, I will de-screen, but will do it at once with other mods so I spend my tuning money once. That is why I have had a Vortex rammer sitting in the box for 6 months.
Drifting
Joined: Jul 2003
Posts: 1,796
Likes: 1
From: Annandale VA
Your choice. I would say that the lesson learned from the F-body guys who did this was that it was useless to do it if you planned to get a tune anyway, but for guys who were pretty much bone stock, you might get a slight gain. Ditto for the Granatelli and/or SLP MAFs.
Team Owner
Joined: Feb 2001
Posts: 27,254
Likes: 136
From: Short Hills, NJ
Originally Posted by Tom400CFI
I couldn't disagree w/you more about cost vs. gains. No offense but people who think the way you do, spend too much to get too little.
Porting an intake costs nothing. Are you going to argue that it does nothing? Advancing the ignition timing in many engines costs nothing, and in some engines it makes a HUGE difference. Innovation and experimentation is what "hot rodding" is all about, and applying reason and logic can get you a looong way, for very little.
For example, my first car was an '83 Trans Am with a Crossfire Injection 305. 170 hp stock. What a hopeless piece of junk...right? With $300 "headers" (Edelbrock TES) and "free mods" (similar to descreening a MAF), it went 14.5 @95 in the 1/4. That's TPI 350 'Vette territory.
Free mods work, and here's why; Because you can apply YOUR time/labor, to fix/adjust/improve something that the OE didn't need to spend the time (money) on to achieve their desired results.
Porting an intake costs nothing. Are you going to argue that it does nothing? Advancing the ignition timing in many engines costs nothing, and in some engines it makes a HUGE difference. Innovation and experimentation is what "hot rodding" is all about, and applying reason and logic can get you a looong way, for very little.
For example, my first car was an '83 Trans Am with a Crossfire Injection 305. 170 hp stock. What a hopeless piece of junk...right? With $300 "headers" (Edelbrock TES) and "free mods" (similar to descreening a MAF), it went 14.5 @95 in the 1/4. That's TPI 350 'Vette territory.
Free mods work, and here's why; Because you can apply YOUR time/labor, to fix/adjust/improve something that the OE didn't need to spend the time (money) on to achieve their desired results.
100%
Originally Posted by HITMAN99
Have to agree about the free mods. When the LS1 first came out, it didn't take long for the F-body crowd to figure out that descreening the MAF would result in a few extra ponies. The screens are not there to catch critters, they are there to provide a more consistent laminar flow, at the expense of a slight airflow restriction. Removing the screen causes the MAF to mismeasure the airflow. THis makes the car run slightly leaner, and since the OEM tune is safely on the rich side, it produces a tad more power. Whether this is "logical" or not is beside the point --- it's been proven on the dyno countless times.
For some reason it can also result in a bit more timing. This really doesn't make sense to me, but again, it's a widely observed phenomenon.
Somewhat later, Granatelli brought out their descreened and "calibrated" MAF, and claimed certain HP gains. What followed was the familiar cycle of furiously worded forum debates about whether it was worth the $$$, yada yada yada. Then SLP chimed in with their 85 mm MAF, which kicked off even more debate.
Whether it works on the C6 LS2 the same way it did on the LS1 is a moot point. If you want to try it, it won't hurt, and you might even pick up a little power.
For some reason it can also result in a bit more timing. This really doesn't make sense to me, but again, it's a widely observed phenomenon.
Somewhat later, Granatelli brought out their descreened and "calibrated" MAF, and claimed certain HP gains. What followed was the familiar cycle of furiously worded forum debates about whether it was worth the $$$, yada yada yada. Then SLP chimed in with their 85 mm MAF, which kicked off even more debate.
Whether it works on the C6 LS2 the same way it did on the LS1 is a moot point. If you want to try it, it won't hurt, and you might even pick up a little power.
I remember those 'early days' of LS1 freemodding, it was fun and I utilized a lot of those tricks to get my Z28 into the 12s.
