unit213

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by 02BlackWS6:
<strong> When the screen is removed in A4's it reports less load therefore the PCM commands less line pressure to the tranny. </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">That is false. I have an A4 so I am experienced with one. Porting the MAF will lead to lower line pressure in the tranny, not descreening.

02BlackWS6

It is not false!!! I own a A4 to. for Over a year now and it runs 11's in full weight. So i think i know what i'm talking about. I installed a LS1 EDIT file into my PCM with no nother changes but bumping the line pressure. And when the screen was in the MAF it would chirp the wheels during 50% throttle or more during shifts. If i removed the screen with no other changes the tranny shifted real soft because of the reported lower inline pressure. Why do you think they increase line pressure when converters are installed? Why do people buy HPP3's to bump the pressure after making mods to their MAF's. Besides this was already debatted and in most A4 cars with descreened MAF, unported, slowed the air down enough to fool the PCM into thinking the engine was under less load, hence the PCM commanded lower line pressure to the tranny . MAkes perfect sense. On M6's cars there isn't no line pressure to worry about. And trust me, I had a '99 SS M6 and now i have a '02 Ws6 A4 and i do LS1 EDITTING on my '02 A4, and to get a A4 to shift as firm with a stock descreened MAF i have to bump line pressure up about 8% to make it shift as firm as it did before romving the screen. By removing the screen you are restricting the total air flow, but speeding the air going through the screen.The screen is there for 2 reasons: To straghten the flow over the sensors wires and to speed the air going past the wires. That's how the PCM gets a more accurate reading with it in. So with owning both models of cars and owning EDIT for over a year I think i know what i'm taking about!! This is why guys like Ed Wright ask if your MAF screen has been removed, especially in A4 cars. If the demand my heads and cam need plus my upcoming ATI kit i have my screen removed, but Ed bump my line pressure because specifically asked if my screen was in. So he pumped line pressure to to make sure i had the proper line pressure.

dug

iTrader: (10)

I did it a week ago. I couldnt believe how easy it was. Just poked the the screen out with my finger and it popped right out.

The car seemed to make more power and felt more torquey. Im guessing it leaned the engine out a bit because it runs stronger through out the rev range. I figure if there was a restriction Id notice more power at higher rpms.

If you have a manual poke it out. It wont hurt anything. At worse, you will just lose a few grams from the race weight.

unit213

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by 02BlackWS6:
<strong> It is not false!!! I own a A4 to. for Over a year now and it runs 11's in full weight. So i think i know what i'm talking about. </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">So by your logic, since you run 11's you have a better understanding of the MAF? Well, my buddy who happens to run 7.1@198 consistently removed my MAF for me. So he must be right since he's 4 seconds faster than you. (You can see a vid of it at http://www.wheelsup.net/videos/danmillenrec.mpg if you want)

FWIW, my intent in my previous post was not to attack you or your comments. I am merely discussing the topic and stating my thoughts.

02BlackWS6

That's a bunch of <img border="0" alt="[bullshit]" title="" src="graemlins/gr_bs.gif" /> First is you buddies car a LS1 powered f-body?? NO i doubt it. The fastest car on this forum runs 9.99 and that's Rob Raymers' car. And i could care less what your buddy runs, which is probably BS anyway. But I know from dealing both my LS1 powered f-bodies and especially the A4 version, a descreen or ported MAF softens shifts by slowing the air past the MAF therefore reporting less load which tell the PCM to apply less line pressure ..PERIOD. Most cars running in the 7's run speed density. Or have you never heard of that term neither??? With over 1,300 post i would think you would know how the LS1 and PCM work together in this car. And yes i do know what i'm talking about cause i have a LS1 and LS1 EDIT, i really doubt you have neither. And besides that 7 second car doesn't run with stock tuning. Like i said in my last post, to get a car to run that fast, plus being a LS1 powered f-body it would need extensive retuning. And IF , which i doubt, his car is a f-body with the LS1 he would definately need some type of tuning, big time.So just like i said the tuning definately had the line pressure pumped. I still say you aren't talking about a LS1 f-fody. NO WAY. So with me having a A4 and EDIT i think i'm more of an authority than you are.!! A stock LS1 PCM couldn't keep up with the demands a 7 second car would need. Lets stop talking pipe dreams and deal with reality. And if you really want another real opinion call Ed Wright or any other tuner and ask them. BTW...that link is down. And i'm just posting facts that i have noticed so don't attack me acting like i don't know what i'm talking about.
P.S. In your post you're stating your MAF was pulled? So you aren't even running a MAF?

unit213

I'm not here to argue. Congrats on your big bad 11 second car. My car will be in the 11's as soon as I get to the track. My current mods will put me there no problem. AND, I do have LS1edit for your info. I haven't got into it in detail yet. Why you would question wether or not I have an LS1 is beyond me. I'm not sure why you'd question my friend either who happens to be the world record holder in his class. Sure, it's a different ballgame with an LS1 and his car BUT he owns and operates a motorsports company and they do tons of LS1 work. He knows his ****. The only reason I brought him up is because I've gained a lot of knowledge from him as well as from my own personal experience. By no means was I trying to say, "Well, my friend has this...yada, yada, yada".

Anyway, I'm won't be a part of this thread getting ruined over some <img border="0" alt="[bullshit]" title="" src="graemlins/gr_bs.gif" /> because there is a TON of useful info here. Big thanks to Colonel for that. You won't see another reply from me. I don't want this thread to get locked.

02BlackWS6

And just to give you an example...We took a Ed Wright tuned PCM that had line pressure pumped, idle raised, and fans lowered, and a little more aggressive timing and fueling. Juts for fun we decided to pop that PCM into my stock WS6 A4 and with my screen in the car shifted so hard it chirped the wheels during shifts. Plus ATAP showed a bump in line pressure. After i pulled the screen the shifts softened up? WHY? Well just like others have stated in other post as well, its the speed of the air moving the air faster over the MAF wires giving the PCM the true reading that GM intended. Why does Vortech still tell you to use the screen? Makes ya think.
For your information it's not <img border="0" alt="[bullshit]" title="" src="graemlins/gr_bs.gif" /> I'm basically saying the same thing Colonel is saying. The biggest restriction is the screen.So whether it's ported for descreened it's almost the same. Almost. The screen is there to speed up the air through the MAF. After a certain power level and with tuning that descreened MAF is fine. BUT not without adjusting things for an A4.

Colonel

I have an idea. Why don't we start with a stock screened MAF. Let's go out and make about 5 Autotap runs with the car at FULL operating temperature while monitoring the TPS, RPM, and MAF Air Flow Rate. Then, without even letting the car cool, pop that screen out and make 5 more readings while monitoring the same parameters. If there is a change in the load reading you will see it. Dispute settled! <img border="0" title="" alt="[Cool]" src="gr_images/icons/cool.gif" />

"The fastest car on this forum runs 9.99 and that's Rob Raymers' car."

No. I'm faster than that and I'm running NA. The fastest LS1 is in the 8s (ARE's car.)

Bass98WS6

I am obviously overwhelmed by the amount of replies as well as the detail of the answers. My question this time is if for some reason it does't work, can i replace the MAF with a new one, and resolve the problem, or is this something that may cause any type of permanent damage?

Thanks

unit213

You can definitely replace it. No permanent damage will come from descreening your MAF. From what I've read in this thread, there are people who will dispute that. The only problem I can forsee is tranny issues with an A4. That comes from porting the MAF though, not descreening it. Once again, I'm sure that'll be disputed. That's fine though. That's the purpose of these threads really. As a result, I'll state that that is only my opinion.

Dan

Ray

Damn you guys know alot about cars! This is free too? I feel real lucky here! I'm very confused and I say why risk it? I have a 2001 A4 SS and I was thinking of descreening my MAF but now...... no way.... knowing me I will set off the SES and have to go back to my dick dealer. Hell with it.... plus you may throw out your back taking it off! <img border="0" title="" alt="[Roll Eyes]" src="images/icons/rolleyes.gif" />

onyxxtreme

iTrader: (4)

great topic! <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />
i WILL be taking my screen out as soon as the rain goes away <img border="0" alt="[cheers]" title="" src="graemlins/gr_cheers.gif" />

unit213

If anything, listen to the Colonel. You don't run 9's NA without picking up a thing or two. <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" />

wild_willy

I've been trying to keep up on the discussion about MAF's and this one has been very informative.

Unfortunately, it doesn't answer another question I have. I've been wanting to get the SLP MAF and keep the screen in it. A friend of mine has a 2000 Z28 AF that's been descreened and he's not had any problems with it. We both have been using LS1Edit to tune our cars.

I've got a 2001 SS A4 and I've found a few posts that have indicated that my car (with the Torque Management crap) can't accurately calculate load and some people are having problems burning out clutches.

Comments?? <img border="0" alt="[worship]" title="" src="graemlins/gr_hail.gif" />

Colonel

"I'm very confused and I say why risk it? I have a 2001 A4 SS and I was thinking of descreening my MAF but now...... no way.... knowing me I will set off the SES and have to go back to my dick dealer."

And that's the danger of threads like this. One or two people discourage people from doing what thousands have well proven to be a perfectly safe free mod. Oh well, at least in the case of this mod you're not talking much power at all. No big deal if you leave it in there.

Bass98WS6

Mine is coming out tonight <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />

Lastyrss

Mine is also coming out. <img border="0" alt="[burn out]" title="" src="graemlins/gr_burnout.gif" />

StalkerLS1

You guys pulling your screens be sure to let us know how it went!.

<img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />

Toxic Texan

Geeez it is just a screen. <img border="0" title="" alt="[Roll Eyes]" src="images/icons/rolleyes.gif" /> I've had mine out for 3 1/2 years and no problems. If you don't feel comfortable doing it then don't do it. <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />

2000WhiteZ28

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by SSLink:
<strong> Just one last thought. Air being forced through the openings in a screen could be moving at a slightly higher velocity than the same amount of air flowing through an open orifice, although I have no proof of this (any physics majors out there?). </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">The colonel is about right. Removing the screen will barely affect flow amount. It will barely effect flow velocity. Porting will slow velocity and barely affect flow amount. I believe I hear somewhere the MAF flows 805CFM (think about your carbuerator days). The funny thing is, that is plenty of air considering your TB flows maybe 850cfm and so does the LS1 intake. I would leave the porting alone until you have passed 450HP or so, then port the intake pieces (MAF, TB, Intake) and use your MAFT to correct any wild A/F ratios in part throttle or WOT.

The tough question here, is how do you get 805CFM of air available to your MAF? That's hard to do without a great ram air set-up, large filter area, and high vehicle speed. It takes a lot to top it out. You shouldn't need a bigger MAF or TB until you have (I believe someone mentioned before, this word...) DEMAND for that much at the mouth of the MAF. At that point, you also need to compensate with injectors that can keep up. Forced induction (Turbo,SuperC) cars really have to think about this air flow amount and computer/injector tuning.
I have a de-screened MAF and A4, works fine!

Sincerely, Physics Major UNF