On a basic bolt on car (mods in the sig) are you guys running them screened or de-screened? Their website says that they'll flow 895 cfm screened and over 1000 cfm de-screened...something tells me with my setup it won't really make much difference. Is it the same situation as the stock MAF (de-screening ok, but f'ing with it otherwise is a bad idea)?

TIA,
Brent

 

I descreened mine ('01-'02 model on an '02 SS). This
did not seem to hurt anything. Stayed pretty neutral
(no positive LTFTs). Descreening wasn't as easy as the
stocker I did, I had to damage the screen on this one
(no going back).

I filed off some of the flash on the nose-end casting,
and this made my car meter about 5% lean (positive
LTFTs).

I dicked around with different resistor values for the
one they solder in there, and ended up with 3300 ohms
putting me back right on mixture, vs. the original 2700.
Back to -1 LTFTs, +10% spark and +3% PE on top of a
Predator canned tune, 900mV O2s and no knock.

That's one neat thing about this MAF, for the cost of a
soldering iron (I've got half a dozen) and a Radio Shack
resistor assortment (or a few luckily-chosen values),
you can tune it +/-20%. Way more than enough for any
intake / exhaust mods you might make.

Now, when anyone tells me a piece flows XXX CFM and
doesn't bother to tell me at what pressure drop, I figure
they're a bunch of fertilizer salesmen. The stock MAF
with the screen in place will flow 1000 CFM too. At some
drop.

(drop/ambient)*325HP [correct this for your year & mods]
is the peak HP left on the table at any given
flow. The relevant one being what your engine can
pump, at the top end. Like 600CFM at 6000RPM.

Never seen a straight-up flow bench comparison of
any two MAFs nor frequency@flow fidelity comparisons
in such a setup neither. I guess if it were to their sales
advantage one of the many outfits selling MAFs would
have published it.

Or maybe they're just making MAFs without having a
clue about that kind of stuff. Gee, ain't that a warm
fuzzy scenario, too?

Get yer fertilizer... nice, warm, fertilizer....

 

Awesome info, thanks a bunch Jimmy

 

Is there some kind of good manual for adjusting the MAF resistor? How do I know it is set correctly? Please don't say get LS1 Edit!

 

You will have to have some means of telling if the
tune (MAF calibration) is right. At a minimum, a
Predator scanning real-time LTFTs or an AutoTAP /
EFILive scan. Whatever FTC Cell 15 says for LTFT,
is your MAF error pretty much. Need to have this
trim settled out and then it will tell what the PCM
needs to do, to make it true. Right answer is a
-1 - -2 LTFT value. Cell 15 is your 3/4 throttle,
>2400RPM operation, so go hit the on-ramp and
see what is going on at barely-sub-WOT.

 

I just kept my screen on. SLP suggests keeping it on! Thus, I figured I should just keep it on. I'm sure it wouldn't hurt nothin though if you discreened it.

 

Super info. Thank's very much.

I think you hit the nail on the head--if there was an advertising advantage, they'd be touting it. The absence of specific numbers by all indicates they aren't even interested in such specifics. Sorta like Alfred E Newman, "What me Worry?"

Steve

 

i decsreened mine, and just driving around, i havent noticed any kind of a difference. the car has been running fine ever since i have taken it out tho. like jimmy said, if u decide to do it, theres no going back, because 99 % chance u will damage it

 

I lost to much power to even think about putting it in without some sort of dyno tuning. The stock MAF flows plenty of air for a bolt-on car, even H/C cars up to 450rwhp. If you aren't adjusting the resistors or having them dyno tuned in, your prolly losing power.