MAF Screen removal Dyno results
Thread Starter
Safety Car
Joined: Jul 2000
Posts: 3,596
Likes: 37
From: Orange County CA
MAF Screen removal Dyno results
I have heard so much about removing the MAF screen that I decided to do a test at the last So Cal Dynoday. I removed the screen from my MAF and ran the car for a couple of weeks. In this configuration my best run was 315.9 HP with 321.1 ft/lbs of torque. My car is a '99 A4 with a cold air intake (custom), Powerloader, Bassani x-pipe, and Corsa touring exhaust. I then replaced the MAF end with another unit that still had the screen in (thanks Tome), and had my friend drive the car for about 25 miles (thanks again Tome). Then we re dynoed the car (about two hours after the first dyno runs) and got 315.6 hp and 320.5 ft/lbs of torque. With the screen removed the car did appear to have an increase of about one or two additional HP between 4700 and 5100 RPM but the peak numbers are nearly identical (within the accuracy of the dyno). I will post the dyno charts after I receive the electronic files from the dyno operator and have some time to evaluate the data in greater detail.
In my opinion removing the screen is of marginal (if any ) benefit.
I hope this information is helpful.
In my opinion removing the screen is of marginal (if any ) benefit.
I hope this information is helpful.
Le Mans Master
Joined: Jul 2000
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From: Fort Worth Texas
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Re: MAF Screen removal Dyno results (Charley Hoyt)
Thanks Charley. Did you happen to get an Air/Fuel Ratio on the runs?
[Modified by kewlbrz, 11:32 AM 7/18/2002]
[Modified by kewlbrz, 11:32 AM 7/18/2002]
Thread Starter
Safety Car
Joined: Jul 2000
Posts: 3,596
Likes: 37
From: Orange County CA
Re: MAF Screen removal Dyno results (kewlbrz)
Thanks Charley. Did you happen to get an Air/Fuel Ratio on the runs?
[Modified by kewlbrz, 11:32 AM 7/18/2002]
[Modified by kewlbrz, 11:32 AM 7/18/2002]
[Modified by Charley Hoyt, 2:06 PM 7/18/2002]
Race Director
Joined: Jun 1999
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From: Dallas TX
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Re: MAF Screen removal Dyno results (Charley Hoyt)
I get this question almost daily...I tell the customer it's not worth the risk of damaging the stock unit while taking it out, for what you get. You've shown that here again.
RG
RG
Le Mans Master
Joined: Jul 2000
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From: Fort Worth Texas
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Re: MAF Screen removal Dyno results (Ryan2002C5)
I think its a great mod (with tuning) for power levels at 350+RWHP. So does GMs Cheif powertrain engineer John Juriga :yesnod:
[Modified by kewlbrz, 1:34 PM 7/18/2002]
[Modified by kewlbrz, 1:34 PM 7/18/2002]
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Melting Slicks
Joined: May 2001
Posts: 2,596
Likes: 120
From: East Tennessee
Re: MAF Screen removal Dyno results (Charley Hoyt)
I made 457 rwhp with the screen still in, even though I did grind around the sensor a bit so the sensors 'saw' less air... I just pulled the air cleaner off this 99 C5 with 76K I just bought, there were 2 or 3 good sized pebbles laying in front of the screen, why take a chance for no gain.
Instructor
Joined: Jun 2002
Posts: 140
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From: Houston Tx
Re: MAF Screen removal Dyno results (kp)
We are all aware that the Z06 has no screens right ;) They are not there to protect the intake from small pebbles, they are there to straighten out the airflow. If you want to take them out, do it. If you are worried about it don't. You will obviously see a *tiny* improvement if it is a mostly stock car. Perhaps if the car is seriously hot-rodded, the removal of the screen would help.
Chevy's design team noted the restriction the screen created and that's why it was removed as part of the Z06's enhancements.
Do what you please and drive happy :yesnod:
Russ
Chevy's design team noted the restriction the screen created and that's why it was removed as part of the Z06's enhancements.
Do what you please and drive happy :yesnod:
Russ
Melting Slicks
Joined: May 2001
Posts: 2,596
Likes: 120
From: East Tennessee
Re: MAF Screen removal Dyno results (77-4speed)
Of course the screen is there to straighten the airflow not to protect from debris, but if it keeps junk out of the maf/intake why remove it for no gain. Some people may see a big jump in performance when first removed because the car will be a little lean until the pcm adjusts the ltrims, other than that its a useless mod - imo anyhow..
I dunno, if a stock maf with a screen can easily flow enough for 457rwhp (probably more if I didnt run a 'safe' 11:1 a/f) I cant see how it can hurt a stock Z06, considering its even larger diameter than an LS1 MAF.
Granted thats under boost but I have seen many n/a LS1 cars dyno at 400+ with the stock MAF. I think they left out the screen on the Z06 because it simply just wasnt needed..
I have a simple theory, dont fix what isnt broke :)
I dunno, if a stock maf with a screen can easily flow enough for 457rwhp (probably more if I didnt run a 'safe' 11:1 a/f) I cant see how it can hurt a stock Z06, considering its even larger diameter than an LS1 MAF.
Granted thats under boost but I have seen many n/a LS1 cars dyno at 400+ with the stock MAF. I think they left out the screen on the Z06 because it simply just wasnt needed..
I have a simple theory, dont fix what isnt broke :)
Pro
Joined: Aug 2000
Posts: 573
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From: EAST ROCKAWAY NY USA
Re: MAF Screen removal Dyno results (Charley Hoyt)
I am having the same problem and I never did anything to the MAF.I did change my 2.73 gears to 3.42 changed my Traque Converter to a ProTrque2400 ,PowerLoader,TransGo Shift Kit.After these changes my RPM started surging a little.I found a TSB about this problem .As I remember it had something to do with the Alt.I will try to find my notes with the TSB # and I will post it to the net. :flag :flag :flag :U :U :U :blueangel: :blueangel: :blueangel: :flag :flag :flag
[Modified by GLENN43, 7:21 PM 7/18/2002]
[Modified by GLENN43, 7:21 PM 7/18/2002]
Le Mans Master
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From: Fort Worth Texas
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Re: MAF Screen removal Dyno results (GLENN43)
My 2001 would sometimes surge up to 1100 RPM when depressing the clutch coming up to a stop with the screen in place. Since removing the screen, it hasnt done it since.
[Modified by kewlbrz, 9:59 PM 7/18/2002]
[Modified by kewlbrz, 9:59 PM 7/18/2002]
Le Mans Master
Joined: Nov 2001
Posts: 7,033
Likes: 0
From: Cincinnati Ohio
Re: MAF Screen removal Dyno results (77-4speed)
We are all aware that the Z06 has no screens right ;) They are not there to protect the intake from small pebbles, they are there to straighten out the airflow. If you want to take them out, do it. If you are worried about it don't. You will obviously see a *tiny* improvement if it is a mostly stock car. Perhaps if the car is seriously hot-rodded, the removal of the screen would help.
Chevy's design team noted the restriction the screen created and that's why it was removed as part of the Z06's enhancements.
Do what you please and drive happy :yesnod:
Russ
Chevy's design team noted the restriction the screen created and that's why it was removed as part of the Z06's enhancements.
Do what you please and drive happy :yesnod:
Russ
Team Owner
Joined: Sep 1999
Posts: 20,054
Likes: 44
From: Swansea IL
Re: MAF Screen removal Dyno results (Charley Hoyt)
During my last dyno my car was VERY RICH AFR's down to 10.9:1 After removing the screen my car feels like a rocket. I must have leaned it out just enough to get a major bump in HP. I'm going to put it back on the dyno to check.
Also we had a dude pull his screen and collapsed it down on itself, it looked like half a circle almost exactly half the size of it's diameter. That tells me the screen reduces air flow considerably from an un-restricted MAF.
My 99 MN6 with Blackwing and Corsa Indy's dyno'd in at 293. So for Charley Hoyt's car to dyno in at over 315 tells me his car was already "tuned" close to perfect. I'd be willing to bet his AFR's were close to 13.0:1 so removing the screen would only lean out his car and thus not produce any noticeable affect.
But the bottom line is you have to know your AFR's to know if your going to benefit from this mod. Cars running very RICH will benefit greatly.
Tom
USAF Retired
[Modified by AFVETTE, 6:38 PM 7/18/2002]
[Modified by AFVETTE, 6:39 PM 7/18/2002]
Also we had a dude pull his screen and collapsed it down on itself, it looked like half a circle almost exactly half the size of it's diameter. That tells me the screen reduces air flow considerably from an un-restricted MAF.
My 99 MN6 with Blackwing and Corsa Indy's dyno'd in at 293. So for Charley Hoyt's car to dyno in at over 315 tells me his car was already "tuned" close to perfect. I'd be willing to bet his AFR's were close to 13.0:1 so removing the screen would only lean out his car and thus not produce any noticeable affect.
But the bottom line is you have to know your AFR's to know if your going to benefit from this mod. Cars running very RICH will benefit greatly.
Tom
USAF Retired
[Modified by AFVETTE, 6:38 PM 7/18/2002]
[Modified by AFVETTE, 6:39 PM 7/18/2002]
