Topic: Airfoils/MAF Screens and Inj. flow rates
in Forum: C4 Fuel, Emission Control, and Exhaust Systems
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http://www.gmtuners.com/flow/index.htm
96LT1 2010-03-06 08:39:59
Found this online---these guys do ECM/PCM tuning---the tests are from a independent source (college)
I found it a very interesting and in my case suprising read...
Vaughn
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I removed mine last month. 
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Duncanville, TX - USA
Joined: 3/18/2009
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Vette(s): 1985 Coupe-L98/Auto,Bright Red/Carmine.
1974 Coupe-L48/4speed, Medium Red Metallic/Black Deluxe.
I removed the screens from my '85 years ago. As long as the air filter is clean, and the air box is well sealed, a screen-less MAF sensor is fine. 
Joel Adams 
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"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"
The screen is to straighten the air flow more than keep bugs off the MAF to improve the accuracy, particularly at low flow. It's hot enough to burn most dust that gets by the filter anyway. I'm running a Granatelli which comes without the screen and the output signal curve is calibrated for it. Also, there is a new digital MAF that you can find on Summit's web site. (on my wish list)
Notice they didn't post the differential across the throttle bodies or MAF's only that the density was adjusted to sea level. As I remember, carbs are generally rated at 4" Wg which is sort of where they'd run at wide open throttle on the street. So the numbers are only relative assuming they use the same base line differential pressure. Most air filters will create more drop than that so it's arbitrary at best. I've seen some hot rod articles that suggest a lot more than 10 HP remains in the induction inlet restriction.
My 85 already had an air foil in it. took the screens out of the bosch MAF added K&N airfilter and cut the center out of my breather cover over the filter to which they sell online for one hundred dollars took me fifteen minutes cost one cut off wheel and have noticed a big difference mostly when getting in to it. of course 85 was before ODBII but have not had any codes or lights come once since doing so and service light before would come on once a week before. Love My Vette!
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Duncanville, TX - USA
Joined: 3/18/2009
Posts: 2246
Vette(s): 1985 Coupe-L98/Auto,Bright Red/Carmine.
1974 Coupe-L48/4speed, Medium Red Metallic/Black Deluxe.
Gotta watch using a K&N filter with a MAF sensor..if you get too much oil on the filter, it will mess up the signal from the MAF. Can cause several driveability issues if that happens. It can happen too just installing a fresh, properly oiled filter, if the filter is put into use to quickly. GM has had several TSBs out on this issue, as have all the other car makers. 
Joel Adams
My Link
(click for Texas-sized view!) NCRS
"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"
in Forum: C4 Fuel, Emission Control, and Exhaust Systems
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