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SLP MAF or Stock MAF??

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Old Jun 9, 2005 | 04:55 PM
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Default SLP MAF or Stock MAF??

I just got QTP LTs & catted y-pipe installed and a tune.....i was told my SLP MAF that i have is basically useless, and the tuner tuned my car for a stock MAF and recommended i put the stock one back on.....i put down 339 rwhp and 360 rwtq....i'm wondering if my car were tuned for my MAF i would have seen a bigger HP number or if i need to finish polishing the ends of my stock descreened MAF, if i'll see a bigger HP number?? Is all the money i spent on that SLP MAF really wasted, or is it a good mod if tuned accordingly?
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Old Jun 10, 2005 | 07:35 AM
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I would think when he says stock maf, he means a "stock" maf with the screen and all. That is not the bottleneck everyone thinks it is. The gains people see from porting/descreening/polishing the maf are because it tends to lean the car out when you do it. Not because you're flowing more air. Sell the SLP maf and try to get some of your money back and see if you can pick up a "stock" maf. JMO...so take it for what it's worth.
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Old Jun 10, 2005 | 08:30 AM
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The screen -is- a restriction and by my measurements
it's on the same order as the stock lid. The body is not,
so it really doesn't matter much (other than aesthetically)
if you go to an 85mm. Though a bigger screen is less of
an obstruction than the smaller one. I took the screen
off mine, ported it out some, and substituted resistor
values until I got back to zero-ish fuel trims. This was
all before I had tuning software, just the Predator to
play with.

If you took out the resistor your tuner could hit you with
a truck MAF table and you'd be fine. Because it is a truck
MAF with a resistor soldered on, and a puffy SLP sticker
that falls off eventually.

I grew suspicious of the resistor "calibration" scheme, it
seemed to be "kinda right" in some places but it's just
very unlikely to make it dead right, all over.

Your tuner's problem is, there's no known-good cal table
for the SLP MAF unlike the unmodified Delphi ones, which
GM has provided (via PCM readouts and hobbyists sharing).
So it's off into the weeds trying to back-calibrate the MAF,
at the hourly rate. You probably don't want that bill.
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Old Jun 10, 2005 | 11:13 PM
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Originally Posted by slpss9723
I just got QTP LTs & catted y-pipe installed and a tune.....i was told my SLP MAF that i have is basically useless, and the tuner tuned my car for a stock MAF and recommended i put the stock one back on.....i put down 339 rwhp and 360 rwtq....i'm wondering if my car were tuned for my MAF i would have seen a bigger HP number or if i need to finish polishing the ends of my stock descreened MAF, if i'll see a bigger HP number?? Is all the money i spent on that SLP MAF really wasted, or is it a good mod if tuned accordingly?
if you can drive to KC.. I'l do the MAF recalibration for way less than the hourly rate standard....

of course..it will probably have to be sometime after I get back from tour
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Old Jun 11, 2005 | 01:13 PM
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so jimmy if i put my stock one back on with no screen and polished ends (not ported) will i be ok or what?? I didn't want to take the screen out but when i took it out to polish the ends it kinda BROKE on me......
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Old Jun 11, 2005 | 02:34 PM
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Originally Posted by jimmyblue
The screen -is- a restriction and by my measurements
it's on the same order as the stock lid. The body is not,
so it really doesn't matter much (other than aesthetically)
if you go to an 85mm. Though a bigger screen is less of
an obstruction than the smaller one. I took the screen
off mine, ported it out some, and substituted resistor
values until I got back to zero-ish fuel trims. This was
all before I had tuning software, just the Predator to
play with.

If you took out the resistor your tuner could hit you with
a truck MAF table and you'd be fine. Because it is a truck
MAF with a resistor soldered on, and a puffy SLP sticker
that falls off eventually.

I grew suspicious of the resistor "calibration" scheme, it
seemed to be "kinda right" in some places but it's just
very unlikely to make it dead right, all over.

Your tuner's problem is, there's no known-good cal table
for the SLP MAF unlike the unmodified Delphi ones, which
GM has provided (via PCM readouts and hobbyists sharing).
So it's off into the weeds trying to back-calibrate the MAF,
at the hourly rate. You probably don't want that bill.
I am in total agreement, I have debated/argued the screen as a restriction many times on a few different forums/areas (it's basic physics). I use the truck maf calibration on my '02 Z06 with some additional fine tuning. (using soundengineer's spread sheet).
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Old Jun 15, 2005 | 10:14 PM
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I descreened my 86 IROC MAF, not sure if it made a difference (although that 383 added so much torque). I originally bought a stock MAF, as I was originally planning on building a stock LS1. Now that I am almost done with my 396 stroker, I'm wondering if I should move up to a Z06 MAF, or stick with the stock one.

I have a Fast 90mm intake, and have yet to decide whether I will be using my SLP Airlid, or make a custom twin intake coming in from both fenders (since it is going in a 94 Camaro). Anyway, how many other people are running Fast 90mm with stock MAF?
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Old Jun 15, 2005 | 11:22 PM
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The problem I've seen with using a truck MAF table with a 85mm MAF(like the SLP one)is that if you do take the resistor out and use the truck MAF table your L Trims will probably look fine but the MAF will report less air coming in and then the PCM will use a different timing table that is usually used at a lower RPM. In other words if you do use the truck MAF table with a desoldered resistor you will have to retune your timing tables. JMO.
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Old Jun 16, 2005 | 08:42 AM
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for one i wouldnt buy anythign with slps name on it, they are just full of **** (sorry they sent a new mag out and i love the way they make it seem they are the best, when they are nothign close to it)

i had one of their "calibrated" ones on my car and it was a POS. IMO, stick with the stock TB, recalibrate it with the screen out and you will be good, or...take it off. thats waht i think, either stay stock or take it off. i took mine off and dont ever plan to go back, but of course you have to get it tuned for that and if you cnat do it yourself its more of a PITA to deal with a shop.
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Old Jun 16, 2005 | 08:55 AM
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Originally Posted by SmaknSS
The problem I've seen with using a truck MAF table with a 85mm MAF(like the SLP one)is that if you do take the resistor out and use the truck MAF table your L Trims will probably look fine but the MAF will report less air coming in and then the PCM will use a different timing table that is usually used at a lower RPM. In other words if you do use the truck MAF table with a desoldered resistor you will have to retune your timing tables. JMO.
That's SLP's "calibration" game. Especially on their
'98-'00 model they under-report airflow so you run
more spark advance, woo-hoo!

If you're able to jam a new MAF table in then you
are also able to tune in the spark tables to get the
same (or, much better) result without the ill effects
of underreporting true airflow.
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Old Jun 16, 2005 | 02:41 PM
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Originally Posted by jimmyblue
That's SLP's "calibration" game. Especially on their
'98-'00 model they under-report airflow so you run
more spark advance, woo-hoo!

If you're able to jam a new MAF table in then you
are also able to tune in the spark tables to get the
same (or, much better) result without the ill effects
of underreporting true airflow.
I agree except you say it better than I did.
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