Ported MAF
I have both actually, my stock and the ported one. Why do you say dont port it? Theres not a whole lot of material taken off. Its mostly just has the fin thing removed and smoothed out a bit. I was actually thinking about putting the screen on the "de-fined" one.
Listen to Damian, I have learned the hard way on porting a maf. The devider is there to direct the air to the little wires. Without that it doesn't get the correct air metering and will make it go way lean and cause spark knock. The only way it will ever work right is if you can find a tuner and have them recalibrate the maf. I have never had a problem removing just the screen but the devider is a no no. I know alot of people do it but they are just lucky they havent burnt a piston yet.
It was in fact the problem on both of my cars. Honestly just driving it seemed just fine but after a log using EFI Live it was enough to scare me. I changed back to the unported ends and logged again and everything was good. A tuner once told me what I was talking about above and made sense to me, also fixed my problem. Maybe some cars react differant, who knows
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Verdad Gallardo That does make sense. Don't know how well you know how the pcm works but once the O2s see a very lean condition they will try to correct it buy adding alot of fuel. So yea that very well could happen. I don't want to get in some fighting match but honestly I would find a buddy with EFI or HP tuner and have them run a log on how your car is reacting. You would be surprised what is going on. But like I said if you tune the maf tables to run a ported maf then it will be fine. It's not possible for an engine to run and perform correct if you have a modified maf when the maf table is set to stock. It's like runnng a cammed car on a stock tune. The pcm doesn't know what has been changed. To the original poster, if you want go ahead and try it but make sure that somebody can log it after just to make sure you aren't getting lean spikes or KR under a load. Let us know how it worked out
Staging Lane
Joined: Oct 2008
Posts: 62
Likes: 0
so how much hp did u make destroying ur maf?
why do u people do stupid mods like this and expect any good from it?.. let me ask you something... if the car companies could save a quick buck would they do it??... uhm i think so. so if things like the maf screen werent important, you think it wouldnt be there? not to mention the engineers who put alot of time and effort to build a machine that works and LASTS. despite what you may think youre not making ur engine perform any better when youre really just causing a strain and a burden on it. shaving ur maf for ur stock isnt very logical imo. do all this stupid stuff to ur cars and then yall wonder why the car next to u passes u by and u run into so many problems and have such poor performance. sry dude im havin a bad day but its all still true
why do u people do stupid mods like this and expect any good from it?.. let me ask you something... if the car companies could save a quick buck would they do it??... uhm i think so. so if things like the maf screen werent important, you think it wouldnt be there? not to mention the engineers who put alot of time and effort to build a machine that works and LASTS. despite what you may think youre not making ur engine perform any better when youre really just causing a strain and a burden on it. shaving ur maf for ur stock isnt very logical imo. do all this stupid stuff to ur cars and then yall wonder why the car next to u passes u by and u run into so many problems and have such poor performance. sry dude im havin a bad day but its all still true
That does make sense. Don't know how well you know how the pcm works but once the O2s see a very lean condition they will try to correct it buy adding alot of fuel. So yea that very well could happen. I don't want to get in some fighting match but honestly I would find a buddy with EFI or HP tuner and have them run a log on how your car is reacting. You would be surprised what is going on. But like I said if you tune the maf tables to run a ported maf then it will be fine. It's not possible for an engine to run and perform correct if you have a modified maf when the maf table is set to stock. It's like runnng a cammed car on a stock tune. The pcm doesn't know what has been changed. To the original poster, if you want go ahead and try it but make sure that somebody can log it after just to make sure you aren't getting lean spikes or KR under a load. Let us know how it worked out
+1,000,000. This post & the others that have explained what needs to be done to the tuning after modifying the MAF are correct.
I have tuning software & can say that MAF mods without re-scaling the MAF table are a mistake. The fuel trims will be maxed out. If a PCM's trims are set to max @ +/- 5% then it will show +/- 5% even though it may need to be +/- 20% in order to properly account for the change. Further, it's usually not just the MAF that an owner modifies. It's also a CAI & a TB. Every intake modification should be tuned in order to take full advantage of the modification & to leave the PCM's fuel trims available for any driving conditions that may require trim. Just because some have gotten away w/ it, doesn't make it correct.
I've seen ported MAF ends work in person, on my car. With ported MAF ends and an underdrive pulley, my car picked up 13 rwhp without tuning. Pretty sure the pulley did not account for all 13 rwhp.
Over the years it seems that a ported Maf works best on m6 cars, NOT Auto cars. When I brough my LTS,3.73's,CAI, in for a tune, it was running WAYYYY lean at idle because of the ported maf, and was actually causing me to run slow BEFORE the tune. He is a very good tuner and currently has the LSX nitrous record, told me that I should look for a stock UNported maf to use instead. I trust what he says.
Thanks to those that replied with out being *** holes. There was no need for that. It was a spare MAF so no harm done. It was fun to do it any way so 
. I'm getting the car tuned any way and was just looking to squeeze every once out of it I could. But I do see what people are saying about the fin thing. But as for the screen, the way some one explained it to me a long time ago was that the screen is there for stock cars to straighten out the air flow after it goes through the air silencer box thing thats after a stock lid. Because, that thing causes all kinds of turbulence, so...since I'm not going to have the stock lid no need for the screen. Right?
. I'm getting the car tuned any way and was just looking to squeeze every once out of it I could. But I do see what people are saying about the fin thing. But as for the screen, the way some one explained it to me a long time ago was that the screen is there for stock cars to straighten out the air flow after it goes through the air silencer box thing thats after a stock lid. Because, that thing causes all kinds of turbulence, so...since I'm not going to have the stock lid no need for the screen. Right? Thanks to those that replied with out being *** holes. There was no need for that. It was a spare MAF so no harm done. It was fun to do it any way so . I'm getting the car tuned any way and was just looking to squeeze every once out of it I could. But I do see what people are saying about the fin thing. But as for the screen, the way some one explained it to me a long time ago was that the screen is there for stock cars to straighten out the air flow after it goes through the air silencer box thing thats after a stock lid. Because, that thing causes all kinds of turbulence, so...since I'm not going to have the stock lid no need for the screen. Right?
. I'm getting the car tuned any way and was just looking to squeeze every once out of it I could. But I do see what people are saying about the fin thing. But as for the screen, the way some one explained it to me a long time ago was that the screen is there for stock cars to straighten out the air flow after it goes through the air silencer box thing thats after a stock lid. Because, that thing causes all kinds of turbulence, so...since I'm not going to have the stock lid no need for the screen. Right? Precisely, same goes for GTOs I would assume. My car is running just fine with the ported ends and no screen, so you'll be just fine. Just FYI, my ported MAF ends are the aluminum ends from Thunder Racing.
Over the years it seems that a ported Maf works best on m6 cars, NOT Auto cars. When I brough my LTS,3.73's,CAI, in for a tune, it was running WAYYYY lean at idle because of the ported maf, and was actually causing me to run slow BEFORE the tune. He is a very good tuner and currently has the LSX nitrous record, told me that I should look for a stock UNported maf to use instead. I trust what he says.
Thats true..the auto cars use the MAF to calculate load so the PCM can add
the proper line pressure. You only need to remove the screen..even then
the tranny might shift alittle soft. Some cars need to have the tranny line pressure bumped up alittle after messing with the screen. Good luck.
Oh i thought of something...more than likely a tuner can reduce that pushing effect that i mentioned above.
Last edited by BlackNiteWS6; Nov 14, 2008 at 01:44 PM.
