Remove MAF screens on L98....
Thread Starter
Team Owner
Joined: Mar 2000
Posts: 83,383
Likes: 87
From: Boston, MA
....discuss this please while I wash my car. 
I saw an LT4 gain 5 rwhp between two dyno runs by doing this. I know they are supposed to help stop turbulent air, but so is the accordian thing in back of it. I also have a nifty difty do-nothing air foil in the throttlebody.
In theory is seems feasibly, remove the screens and more air can physically move through. Hell the 2002 Z06 MAF basically is a modified MAF.
Thanks, I'll do it this afternoon if I get more +'s than -'s.
I saw an LT4 gain 5 rwhp between two dyno runs by doing this. I know they are supposed to help stop turbulent air, but so is the accordian thing in back of it. I also have a nifty difty do-nothing air foil in the throttlebody.
In theory is seems feasibly, remove the screens and more air can physically move through. Hell the 2002 Z06 MAF basically is a modified MAF.
Thanks, I'll do it this afternoon if I get more +'s than -'s.
Burning Brakes
Joined: Apr 2001
Posts: 844
Likes: 3
From: Kennewick, Wa. USA
Scorp, I've run mine back to back with and without a screened MAF. I can't say there is any seat of the pants difference. However, if it did gain 5hp you would not feel it from the drivers seat...dosn't mean it isn't a good thing.
Thread Starter
Team Owner
Joined: Mar 2000
Posts: 83,383
Likes: 87
From: Boston, MA
Originally Posted by Ezgoin721:
[B
[B
I can't say there is any seat of the pants difference. However, if it did gain 5hp you would not feel it from the drivers seat...dosn't mean it isn't a good thing.
[/B][/color]
[/B][/color]
Advanced
Joined: Apr 2001
Posts: 50
Likes: 0
From: Morton Grove, IL
I think I saw something at www.c4vettes.com, which says to remove the two screens and make absolutely sure you clean the MAF device bore of all metal fragments from your screen removal activity but do not touch the wires on the inside of the MAF. You should get a 10HP gain by this. Check it out. Tom
Thread Starter
Team Owner
Joined: Mar 2000
Posts: 83,383
Likes: 87
From: Boston, MA
Originally Posted by Vash:
[B
[B
Scorp] remember to use a razorblade and cut the adhesive between the plastic ring with the screen and the MAF so you can reverse it if ou need to.[/B][/color]
Safety Car
Joined: Mar 2000
Posts: 3,620
Likes: 2
From: Hillsboro OR
You can also remove the cooling fins from the heatsink. These were added to the Bosch version by GM after some durability testing in death valley. Bosch never found them necessary when they did the original design.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)
Joe Kucinski
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!
Verdad Gallardo
Top 10 Corvettes Coming to Mecum Indy 2026!
Brett Foote
Drifting
Joined: Jun 2001
Posts: 1,704
Likes: 459
From: Mass Mass
Can tell you I did this a few years ago & after about 6000 miles the engine developed a stumble at part throttle. After replacing the burnoff relays, ignition wires and module, and setting the minimum idle speed about 5 times .... I bought a new MAF and the problem went away, put the modified one back in and it came back. I heard the screens do more than straighten the airflow, they attract/block small debree from hitting the wires. You'll also see the Block Lean numbers running around 132-138 (instead of 128). Controller is adding fuel which means the MAF is reading less air than is really going through it, I think...
Drifting
Joined: Aug 2000
Posts: 1,521
Likes: 0
From: West Islip New York
I've seen lots of numbers on improved air flow, but I gotta tell you, I really don't think removing the screens will add much performance (you can feel or measure) and you run the risk of killing the MAF should anything hit those wires.
How much air does a screen stop? I'm not doing mine
How much air does a screen stop? I'm not doing mine
Intermediate
Joined: Sep 2000
Posts: 47
Likes: 0
From: Valdosta Georgia
Here's more food for thought...this has been discussed lots on thirdgen.org...
http://www.thirdgen.org/messgboard/F...ML/000585.html
http://www.thirdgen.org/messgboard/F...ML/001566.html
http://www.thirdgen.org/messgboard/F...ML/002312.html
My MAF is gutted and descreened and I haven't had any problems with it, plus it's the original sensor since the car was new. But I didn't see any loss or gain by doing so. Some have had good luck with it, and some haven't, as SuperL98 can attest to. It's your call...
http://www.thirdgen.org/messgboard/F...ML/000585.html
http://www.thirdgen.org/messgboard/F...ML/001566.html
http://www.thirdgen.org/messgboard/F...ML/002312.html
My MAF is gutted and descreened and I haven't had any problems with it, plus it's the original sensor since the car was new. But I didn't see any loss or gain by doing so. Some have had good luck with it, and some haven't, as SuperL98 can attest to. It's your call...
Team Owner
Joined: Dec 2000
Posts: 90,675
Likes: 304
From: SE NY
Cruise-In II Veteran
I've had the MAF on my IROC fully modified (screens & fins gone) for 4yrs and on the Vette for 1yr with no problem and possibly a performance gain.
I believe the air flow numbers in TPIS "Insider Hints" so I modified the MAF. Of course the screens at least tend to protect the sensor wires, so I always run with an air rilter in place. Nothing will get through my K&N that wouldn't pass those screens too.
I think that as we push into the 350 HP range and above this mod becomes effective. If someone has a spare stock MAF for an '88 L98 I'll be glad to make some back to back runs and compare time slips.
I believe the air flow numbers in TPIS "Insider Hints" so I modified the MAF. Of course the screens at least tend to protect the sensor wires, so I always run with an air rilter in place. Nothing will get through my K&N that wouldn't pass those screens too.
I think that as we push into the 350 HP range and above this mod becomes effective. If someone has a spare stock MAF for an '88 L98 I'll be glad to make some back to back runs and compare time slips.
Drifting
Joined: Jun 2001
Posts: 1,704
Likes: 459
From: Mass Mass
Might be a simple answer to all this. Look at the MAF values with a scanner. Only an 8 bit output, I beleive, it can only read 254 grams/sec. If your full throttle runs read below this, don't expect gains by playing with the screens. Most stock to mild L98 read about 200 to 211 grams/sec at high rpms. My supercharged L98 hits the 246 grams/sec at around 5600rpm. Seams like the stock MAF has all the airflow it needs for most of us.
By the way, you can plot out the MAF values of a full throttle run, and see the shape of your horspower curve vs rpm. You can also use these to compare effects of modifications, by comparing these curves. After all it measures airflow, just like an engine dyno.
If your a real nut you can take the injector pulse width readings, your injector flow rate, and the MAF air grams/sec values, and figure your full throttle fuel mixture pretty close.
By the way, you can plot out the MAF values of a full throttle run, and see the shape of your horspower curve vs rpm. You can also use these to compare effects of modifications, by comparing these curves. After all it measures airflow, just like an engine dyno.
If your a real nut you can take the injector pulse width readings, your injector flow rate, and the MAF air grams/sec values, and figure your full throttle fuel mixture pretty close.
Safety Car
Joined: Jun 1999
Posts: 3,641
Likes: 2
From: Southern California
So if a LT4 gained power by removing the screen how much more power do the '92 and '93 LT1's have over the '94-'96 LT1's? The '92 and '93 have no MAF and no accordian hose while the '94-'96 do.
Pro
Joined: Jan 2001
Posts: 602
Likes: 0
From: Aliso Viejo CA
The screens are to straighten the air. On my Trans Am, there is a 90* bend right in front of the MAF, so the screens are needed (though many still remove them). On ours vettes, the path is straight. Take 'em out.
Melting Slicks
Joined: May 1999
Posts: 2,037
Likes: 0
From: Sarasota FL
There may be a gain to doing it, but the MAF is going to read less air than is actually going through. This will lean your A/F. On a stock car, I wouldn't mess with it. On a modified car, I'd switch to MAP.