Understand how MAF works - DON'T DE-SCREEN IT!!
10-13-2004, 10:00 AM
#22
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I've only heard complaints from people with A4s that have descreened. I descreened my M6 Camaro and have no complaints. Fuel mileage came down about 1-2 mpg at highway speeds, but this may be secondary to aging spark plugs and the recent addition of LT headers.
10-13-2004, 10:03 AM
#23
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F-body guys seem to generally get away with taking
the screen off the stocker. Though some also report
that changing lids messed their calibration up. Do not
know, how many of these are also descreened. The
deal is, though the air has only one place to go, if
everybody sits on the right side of the airplane it is
going to be an interesting flight.
Porting is a whole 'nother matter, there you are making
a gross deviation (mechanical airflow) from the sensed-
to-total airflow ratio that the MAF electronics were
trimmed to. I guess the resistor mod is fighting that.
But every port job is a brand new guess for calibration.
Here is the Holden table (starts at 1500, runs out to
12000 with -real values- unlike the F-body table, but
in the middle, where you live, they appear identical).
2004 Holden Monaro
2.14 2.59 3.07 3.59 4.15 4.74 5.4 6.1 6.85 7.67 8.55 9.48 10.5 11.59 12.76 14.02 15.34 16.95 18.66 20.52 22.29 24.16 26.16 28.26 30.48 32.83 35.3 37.91 40.66 43.54 46.57 49.74 53.06 56.55 60.19 63.98 67.95 72.09 76.41 80.91 85.58 90.45 95.5 100.74 106.2 111.84 117.7 123.76 130.04 136.54 143.26 150.2 157.38 164.79 172.44 180.32 188.46 196.84 205.48 214.38 223.53 232.95 242.64 252.6 262.84 273.37 284.17 295.27 306.66 318.34 330.33 342.62 355.21 368.13 381.35 394.9 408.77 422.97 437.5 452.37 467.58 483.13 499.02 511.99 511.99
the screen off the stocker. Though some also report
that changing lids messed their calibration up. Do not
know, how many of these are also descreened. The
deal is, though the air has only one place to go, if
everybody sits on the right side of the airplane it is
going to be an interesting flight.
Porting is a whole 'nother matter, there you are making
a gross deviation (mechanical airflow) from the sensed-
to-total airflow ratio that the MAF electronics were
trimmed to. I guess the resistor mod is fighting that.
But every port job is a brand new guess for calibration.
Here is the Holden table (starts at 1500, runs out to
12000 with -real values- unlike the F-body table, but
in the middle, where you live, they appear identical).
2004 Holden Monaro
2.14 2.59 3.07 3.59 4.15 4.74 5.4 6.1 6.85 7.67 8.55 9.48 10.5 11.59 12.76 14.02 15.34 16.95 18.66 20.52 22.29 24.16 26.16 28.26 30.48 32.83 35.3 37.91 40.66 43.54 46.57 49.74 53.06 56.55 60.19 63.98 67.95 72.09 76.41 80.91 85.58 90.45 95.5 100.74 106.2 111.84 117.7 123.76 130.04 136.54 143.26 150.2 157.38 164.79 172.44 180.32 188.46 196.84 205.48 214.38 223.53 232.95 242.64 252.6 262.84 273.37 284.17 295.27 306.66 318.34 330.33 342.62 355.21 368.13 381.35 394.9 408.77 422.97 437.5 452.37 467.58 483.13 499.02 511.99 511.99
10-13-2004, 10:36 AM
#24
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Im using the SLP 85mm Maf the 2001+ one. Any ideas on what the Maf table of that is and if anything needs to be changed with LS1 edit to accomodate it? The car was ls1 edit dyno tuned already fwiw and the a/f showed 12.5 on the dyno.
10-13-2004, 11:07 AM
#25
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It's "supposed" to drop in with the stock table but I am
suspicious about the realism of that. If you desoldered
the resistor, and used the truck MAF table for the older
ZL-1 6.0L I think you would be good to go. It just seems
pretty farfetched to me, that truck MAF + generic 2.7K
resistor just magically fits the F-body MAF calibration
curve all across the airflow band. Ain't nobody knows,
as far as I've seen, what the -proper- cal table is for
that piece. I'm suspecting SLP just tried some values,
and stopped at "good enough" without ever putting it
to a flow bench and frequency counter (that being a
several hundred dollar exercise, and few places willing
and able to do it to 1% level of absolute accuracy).
suspicious about the realism of that. If you desoldered
the resistor, and used the truck MAF table for the older
ZL-1 6.0L I think you would be good to go. It just seems
pretty farfetched to me, that truck MAF + generic 2.7K
resistor just magically fits the F-body MAF calibration
curve all across the airflow band. Ain't nobody knows,
as far as I've seen, what the -proper- cal table is for
that piece. I'm suspecting SLP just tried some values,
and stopped at "good enough" without ever putting it
to a flow bench and frequency counter (that being a
several hundred dollar exercise, and few places willing
and able to do it to 1% level of absolute accuracy).
10-13-2004, 11:30 AM
#26
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Originally Posted by Mike K.
Im using the SLP 85mm Maf the 2001+ one. Any ideas on what the Maf table of that is and if anything needs to be changed with LS1 edit to accomodate it? The car was ls1 edit dyno tuned already fwiw and the a/f showed 12.5 on the dyno.
I posted the link a few posts ago.
10-13-2004, 11:47 AM
#27
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The c5howto page has the '01 (screened) and '02+
(no screen) 'Vette tables. But those don't play with
the SLP, unless you remove the resistor.
I favor the truck tables because they are a bit richer
in effect and seem to have put my car to the most
realistic result (as judged by final LTFTs and the
fidelity of open loop commanded to wideband AFR).
But this also has to do with intake tract setup and
your mileage may vary, as they say.
In any case I think removing the resistor and using
the natural MAF and one of these, is a better way to
go than using the as-delivered SLP MAF and the stock
F-body table.
Interestingly the F-body MAF calibration (in Holden
form) runs out to a higher mass air flow than the
85mm MAFs (511.9 g/sec vs roughly 460 at 12KHz).
But I am well short of that number so it makes me
not care, and prefer the big hose, for the present.
(no screen) 'Vette tables. But those don't play with
the SLP, unless you remove the resistor.
I favor the truck tables because they are a bit richer
in effect and seem to have put my car to the most
realistic result (as judged by final LTFTs and the
fidelity of open loop commanded to wideband AFR).
But this also has to do with intake tract setup and
your mileage may vary, as they say.
In any case I think removing the resistor and using
the natural MAF and one of these, is a better way to
go than using the as-delivered SLP MAF and the stock
F-body table.
Interestingly the F-body MAF calibration (in Holden
form) runs out to a higher mass air flow than the
85mm MAFs (511.9 g/sec vs roughly 460 at 12KHz).
But I am well short of that number so it makes me
not care, and prefer the big hose, for the present.
10-13-2004, 12:20 PM
#28
De- Screen MAF It does not hurt to de-screen a MAF as long as you get it tuned, I have tried a stock MAF then removed the screen and the A/F went lean a full point. After tuning and bringing the A/F back to the proper ratio, horsepower was gained and idle and driveability was not affected. Porting though is not recommended since it will affect the airflow causing turbulence. This in turn will affect the idle and driveability.But again I have noticed that all LS1's are only equal to themselves.It may work in one but not the other.But definitely stay away from porting the MAF..
10-13-2004, 12:50 PM
#29
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At least I know a little more than you, as the article you have posted says that the corvette intake was smoothed out FIRST to justify/allow the removal of the screen. And the Z06 tunning is different too. Your argument doesn't apply to f-bodies.
Originally Posted by crainholio
I guess you know more than the GM and Delphi engineers who design these...they removed the screen on the '02 and up Z06 system...
http://www.c5registry.com/2k2z06/page3.htm
-Kevin
http://www.c5registry.com/2k2z06/page3.htm
-Kevin
10-13-2004, 02:13 PM
#30
For what its worth, my car runs noticeably stronger when I switch from my stock MAF to my ported MAF (and swap tunes accordingly). Drivability is not noticeably affected.
Also, before HPTuners, I ported my MAF and did the resistor mod and used a MAFT to fine tune it. My LTFTs were pretty solid. Swapping from a stock air lid to an aftermarket lid (stock MAF) skewed the LTFTs more than the ported MAF did.
Also, before HPTuners, I ported my MAF and did the resistor mod and used a MAFT to fine tune it. My LTFTs were pretty solid. Swapping from a stock air lid to an aftermarket lid (stock MAF) skewed the LTFTs more than the ported MAF did.
10-13-2004, 02:22 PM
#31
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Originally Posted by jimmyblue
It's "supposed" to drop in with the stock table but I am
suspicious about the realism of that. If you desoldered
the resistor, and used the truck MAF table for the older
ZL-1 6.0L I think you would be good to go. It just seems
pretty farfetched to me, that truck MAF + generic 2.7K
resistor just magically fits the F-body MAF calibration
curve all across the airflow band. Ain't nobody knows,
as far as I've seen, what the -proper- cal table is for
that piece. I'm suspecting SLP just tried some values,
and stopped at "good enough" without ever putting it
to a flow bench and frequency counter (that being a
several hundred dollar exercise, and few places willing
and able to do it to 1% level of absolute accuracy).
suspicious about the realism of that. If you desoldered
the resistor, and used the truck MAF table for the older
ZL-1 6.0L I think you would be good to go. It just seems
pretty farfetched to me, that truck MAF + generic 2.7K
resistor just magically fits the F-body MAF calibration
curve all across the airflow band. Ain't nobody knows,
as far as I've seen, what the -proper- cal table is for
that piece. I'm suspecting SLP just tried some values,
and stopped at "good enough" without ever putting it
to a flow bench and frequency counter (that being a
several hundred dollar exercise, and few places willing
and able to do it to 1% level of absolute accuracy).
Thanks for the input, I am looking at my SLP maf and there are several small resistors and 1 large one, I imagine you are saying desolder the large one and then it becomes a truck maf right,, i.e I dont have to solder something back in its place? At that point use ls1edit to alter the MAF tables for the ZL1 6.0 ltr right? Couple more questions do you guys know were to get the tables for the 6.0 ltr MAF? And I take it with this MAF I should leave it screened?
10-13-2004, 02:49 PM
#33
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Originally Posted by HumpinSS
Mike to my knowledge the 6.0 l maf is the same as the ZO6 MAF you can use the tables from the link above if you want those tables
cool if its the same I will use those ones.
10-13-2004, 03:36 PM
#34
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My collection of MAF tables:
http://home.cfl.rr.com/jimmyblue/MAF...s_20040914.xls
Stuff about SLP MAF:
http://community.webshots.com/album/95429402bLraTX
http://home.cfl.rr.com/jimmyblue/MAF...s_20040914.xls
Stuff about SLP MAF:
http://community.webshots.com/album/95429402bLraTX
10-13-2004, 04:22 PM
#35
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The sole purpose of a MAF screen is to keep **** from hitting the filament while it's removed during engine servicing. It has nothing to do with improving airflow.
10-13-2004, 04:30 PM
#36
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Originally Posted by YellowToy/A
The horsepower lose with the screen is small. .
Like 30-50rwhp difference without the screen. And I am sure that sucking air would really **** off the sensors but sure seems happy on my gto.
10-13-2004, 04:44 PM
#37
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Originally Posted by jimmyblue
My collection of MAF tables:
http://home.cfl.rr.com/jimmyblue/MAF...s_20040914.xls
Stuff about SLP MAF:
http://community.webshots.com/album/95429402bLraTX
http://home.cfl.rr.com/jimmyblue/MAF...s_20040914.xls
Stuff about SLP MAF:
http://community.webshots.com/album/95429402bLraTX
10-13-2004, 06:54 PM
#40
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Originally Posted by Bads02Z28
Great info. Is that a home made MAFT?
element (like the MAFT base adjustment). But I
haven't bothered with it since getting into the
HPTuners, as you have total flexibility once you
can table-edit stuff.