MAF Descreening
Burning Brakes
Joined: Mar 2003
Posts: 1,030
Likes: 0
From: Pittsburgh PA
I removed the screen on my C5. I didn't notice any difference good or bad. I haven't touched the C6-yet. This screen thing befuddles the hell out of me. It's more than a screen it's a honeycomb with some depth. The whole issue has been kicked around the C5 forum for years. If the idea was to protect the MAF a much simpler design could have been used. I don't think GM is right all the time but why spend money needlessly? Did the engineers think it was necessary (maybe for drivability) in the C5 & C6 but were willing to sacrifice for added HP in the Z?
My 2cents
My 2cents
Melting Slicks
Joined: Jun 2006
Posts: 2,208
Likes: 1
Originally Posted by aaaaa
I removed the screen on my C5. I didn't notice any difference good or bad. I haven't touched the C6-yet. This screen thing befuddles the hell out of me. It's more than a screen it's a honeycomb with some depth. The whole issue has been kicked around the C5 forum for years. If the idea was to protect the MAF a much simpler design could have been used. I don't think GM is right all the time but why spend money needlessly? Did the engineers think it was necessary (maybe for drivability) in the C5 & C6 but were willing to sacrifice for added HP in the Z?
My 2cents
My 2cents
Instructor
Joined: Jan 2003
Posts: 226
Likes: 0
From: debary fl
Originally Posted by glennhl
I have always thought that the screen was a flow straightener in order to make the MAF more accurate. But then GM went and descreened the MAF on the C5 Z06, so heck, it must be OK.
Race Director
Joined: Aug 2005
Posts: 13,592
Likes: 187
From: Hudson WI
NCM Sinkhole Donor
Originally Posted by SpinMonster
Please.....
The 2002-2004 Z06 has the exact same MAF as the 2001 and they deleted the screen. So what was it then, the engineers changed their minds again? I have 2 in the boxes they came in. Same number, same size, no screen.
You oppose every mod
The 2002-2004 Z06 has the exact same MAF as the 2001 and they deleted the screen. So what was it then, the engineers changed their minds again? I have 2 in the boxes they came in. Same number, same size, no screen.
You oppose every mod
I guess my exhaust, CAI, brakes and shifter aren't mods.
Last edited by timd38; Sep 22, 2006 at 07:04 PM.
Pro
Joined: Feb 2006
Posts: 690
Likes: 0
From: VA
The screen is for driveability. So your car idles and runs smooth. On higher performance app`s where power is the main goal they delete the screen such as the Zo6. As long as the computer is tuned for the increased air volume it will pick up power under WOT. However under part throttle, corrections made by the pcm could be a little off. Slight hesitation off idle, that kind of stuff as an example. Nothing to really bother most people, but don`t forget some people want there Vette to run like a Caddy...
Race Director
Joined: Jan 2000
Posts: 12,375
Likes: 406
From: Florida
My understanding is that the screen remains in the MAF because our MAF is shared with numerous other vehicles, including trucks and SUVs. In these vehicles, the screen is essential to straighten airflow because the air does a 90deg turn right before entering the the TB and MAF area and would owtherwise be excessively turbulent. That is not the case in the Vette.
The LS2 intake moves less velocity than the LS6 intake did, because displacement has replaced specific efficency. So my take on it is that it is not needed in the C6, but does not apparently pose enough of a restriction at stock power levels to warrant removal, or in this case the expense of a separate MAF part.
The LS7 has the same specific output as the LS6 did. So I would expect to see no MAF screen in there if it obstructs flow. Question: does the C6Z (LS7)MAF have the same PN as the LS2 MAF? If not, does the LS7 MAF have a screen?
The LS2 intake moves less velocity than the LS6 intake did, because displacement has replaced specific efficency. So my take on it is that it is not needed in the C6, but does not apparently pose enough of a restriction at stock power levels to warrant removal, or in this case the expense of a separate MAF part.
The LS7 has the same specific output as the LS6 did. So I would expect to see no MAF screen in there if it obstructs flow. Question: does the C6Z (LS7)MAF have the same PN as the LS2 MAF? If not, does the LS7 MAF have a screen?
Drifting
Joined: Jul 2005
Posts: 1,533
Likes: 0
From: az
Originally Posted by TTRotary
Question: does the C6Z (LS7)MAF have the same PN as the LS2 MAF? If not, does the LS7 MAF have a screen?
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Tech Contributor
Joined: Mar 2003
Posts: 12,094
Likes: 197
From: Colorado Springs, CO
St. Jude Donor '08-'09-'10-'11
Originally Posted by timd38
Only telling you my experience, but if you want to remove it, that's your choice.
I guess my exhaust, CAI, brakes and shifter aren't mods.
I guess my exhaust, CAI, brakes and shifter aren't mods.
Tech Contributor
Joined: Mar 2003
Posts: 12,094
Likes: 197
From: Colorado Springs, CO
St. Jude Donor '08-'09-'10-'11
Originally Posted by GMRULZ
The screen is for driveability. So your car idles and runs smooth. On higher performance app`s where power is the main goal they delete the screen such as the Zo6. As long as the computer is tuned for the increased air volume it will pick up power under WOT. However under part throttle, corrections made by the pcm could be a little off. Slight hesitation off idle, that kind of stuff as an example. Nothing to really bother most people, but don`t forget some people want there Vette to run like a Caddy...
Tech Contributor
Joined: Mar 2003
Posts: 12,094
Likes: 197
From: Colorado Springs, CO
St. Jude Donor '08-'09-'10-'11
Originally Posted by cbrf4i1
no different part#, ls7 maf is made by hitachi, ls2 maf is made by delphi. if the software is written into the ecm with the screen there, and the screen is removed, the ability to measure the correct amount of air flow by the maf could have been alter, which would lead to incorrect a/f that would require the ecm to make st/ltft adjustments. again this adjustment by the ecm isn't exactly perfect since it relies on the o2 sensors (of course they are not wide band) if the "ability" to measure by maf isn't affect by the screen weather it is there or not, then without the screen, air flow will increase without any possiblity of incorrect a/f situation. of couse you can always fix this situation by rewritting the ecm software / tune.
Race Director
Joined: Aug 2005
Posts: 13,592
Likes: 187
From: Hudson WI
NCM Sinkhole Donor
I go back to what I said previously, why would GM spend money on the screen if it didn't serve a purpose.
These are the same guys that took the hood lamp out in 2007 to save money.
These are the same guys that took the hood lamp out in 2007 to save money.
Race Director
Joined: Jan 2000
Posts: 12,375
Likes: 406
From: Florida
Originally Posted by cbrf4i1
never stated that, if you are referring to me. ls7 doesn't, ls2 does.
Race Director
Joined: Jan 2000
Posts: 12,375
Likes: 406
From: Florida
Originally Posted by timd38
I go back to what I said previously, why would GM spend money on the screen if it didn't serve a purpose. These are the same guys that took the hood lamp out in 2007 to save money.
The LS7, being a maximum effort with a $25K pricetag increase, warrants a screenless MAF.
Melting Slicks
Joined: Sep 2005
Posts: 2,670
Likes: 134
From: merritt island fl
C1 of Year Finalist (stock) 2019
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Originally Posted by TTRotary
My understanding is that the screen remains in the MAF because our MAF is shared with numerous other vehicles, including trucks and SUVs. In these vehicles, the screen is essential to straighten airflow because the air does a 90deg turn right before entering the the TB and MAF area and would owtherwise be excessively turbulent. That is not the case in the Vette.
The LS2 intake moves less velocity than the LS6 intake did, because displacement has replaced specific efficency. So my take on it is that it is not needed in the C6, but does not apparently pose enough of a restriction at stock power levels to warrant removal, or in this case the expense of a separate MAF part.
The LS7 has the same specific output as the LS6 did. So I would expect to see no MAF screen in there if it obstructs flow. Question: does the C6Z (LS7)MAF have the same PN as the LS2 MAF? If not, does the LS7 MAF have a screen?
The LS2 intake moves less velocity than the LS6 intake did, because displacement has replaced specific efficency. So my take on it is that it is not needed in the C6, but does not apparently pose enough of a restriction at stock power levels to warrant removal, or in this case the expense of a separate MAF part.
The LS7 has the same specific output as the LS6 did. So I would expect to see no MAF screen in there if it obstructs flow. Question: does the C6Z (LS7)MAF have the same PN as the LS2 MAF? If not, does the LS7 MAF have a screen?
Instructor
Joined: Jun 2005
Posts: 124
Likes: 12
From: Rye N.H.
It's Saturday morning and I've nothing at the moment to do - so
in support of SpinMonster and TT Rotary, here's my experience regarding the MAF discussion.
1. My C5 and C6 MAFs have the same part #s.
2. I replaced C6 MAF with my desreened C5 MAF ( same as ZO6)
PRIOR to dyno tune. No changes in drivability.
3.At the dyno, initial pull revealed LTFTs were out of wack -
-8 t0 -18.( Car has LPE intake, Callaway exhaust and 1 3/4" AR
headers).Note: Tuner using HP TUNER's program
4.After tune; 374 RWHP and 371 RWT.
5.Car runs great from idle to WOT.
6.Conclusion;if DESCREENING you'll need a proper tune. The descreening
probably helped the top end, keeping in mind that at WOT you're
NOT using the VE table - it's essentially a SD tune.
in support of SpinMonster and TT Rotary, here's my experience regarding the MAF discussion.
1. My C5 and C6 MAFs have the same part #s.
2. I replaced C6 MAF with my desreened C5 MAF ( same as ZO6)
PRIOR to dyno tune. No changes in drivability.
3.At the dyno, initial pull revealed LTFTs were out of wack -
-8 t0 -18.( Car has LPE intake, Callaway exhaust and 1 3/4" AR
headers).Note: Tuner using HP TUNER's program
4.After tune; 374 RWHP and 371 RWT.
5.Car runs great from idle to WOT.
6.Conclusion;if DESCREENING you'll need a proper tune. The descreening
probably helped the top end, keeping in mind that at WOT you're
NOT using the VE table - it's essentially a SD tune.
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 SpinMonster
.. If you unplug the MAF and you have a reasonable tune, you wont even know it isnt working unless you see a check engine light. That alone proves the screen an insignificant variable.
huh, you did this ?? i accidently left the maf unplugged once, and it didn't like it at all. bunch of bucking, and finally died. but then again, that was with the 'stock' tune.
Pro
Joined: Feb 2006
Posts: 690
Likes: 0
From: VA
Originally Posted by SpinMonster
I removed it on my C5 and had to use the Z06 MAF table for the driveability. Since the car drove equally as smooth without the screen, I dont know what you guys are talking about. The screen was removed on the 2002-2004 Z06 and that cars runs smooth and has great driveability, what is your point?...other than to repeat another ongoing false myth.
If you noticed I said some have experienced some loss of drivability. It seems to be a hit or miss thing. My LT1 F-body drove like crap w/ it out. It would hesitate when taking off so forth. Put back in wala all better. Go search cz28.com it happened to a lot of LT1 F-bodies. In my LS2 Vette it didn`t cause any problem at all. It leaned the fuel out slightly. Which actually was a good thing. The LT1 has a lot of bends in the air intake on a Fbody so perhaps thats why the screen was important. I just know there are some people who have very minor driveability problems and those that don`t.
My 2 cars 1 did and 1 didn`t. So don`t act like this doesn`t happen as it does on some cars. If yours was like my LS2 then great. Bottom line, its not a myth, just because your 2 cars haven`t had a problem. Do you disbelieve that some Ls2`s are losing their crank bolt just because yours hasn`t???
