Understand how MAF works - DON'T DE-SCREEN IT!!
10-13-2004, 07:48 PM
#41
TECH Addict
Join Date: Feb 2004
Posts: 2,826
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by jimmyblue
Not really, nothing so fancy; just a single scaling
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.
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.
10-14-2004, 11:16 AM
#43
Launching!
Join Date: Mar 2003
Location: Castaic Lake, So. Cal.
Posts: 238
Likes: 0
Received 0 Likes
on
0 Posts
The SLP MAF is the same as the 6L truck and the LS6. I am using an SLP unit without the resistor and have my MAF table set to the 6L truck settings. It runs great, no need to remove the screen, as it helps the MAF read more consistantly and offers final protection for the engine air. If you change or port or descreen your MAF without changing the MAF table, something will change in your engine calibration, for better or worse, depending on your mods.
10-15-2004, 12:56 AM
#45
TECH Enthusiast
iTrader: (8)
Join Date: Feb 2004
Location: In my garage
Posts: 579
Likes: 0
Received 0 Likes
on
0 Posts
Jimmy, I love reading your posts. Always on the money. I nominate you to write a tuning book... I'll publish it and will split 50/50. 
The screen simply makes the velocity profile more linear. In other words, the flow rate near the outside is closer to the flow rate at the middle. Fluid mechanics 101. If anything, the screen adds more turbulence. Albiet the structures are smaller scale and spread out across the diameter.
My guess is that GM initially saved money with the screen as it would require less tuning. But as the tuning got better, the screen could be dropped.
Cool thread, now I got to get back to making my car pass smog.
The screen simply makes the velocity profile more linear. In other words, the flow rate near the outside is closer to the flow rate at the middle. Fluid mechanics 101. If anything, the screen adds more turbulence. Albiet the structures are smaller scale and spread out across the diameter.
My guess is that GM initially saved money with the screen as it would require less tuning. But as the tuning got better, the screen could be dropped.
Cool thread, now I got to get back to making my car pass smog.
10-15-2004, 03:22 PM
#46
10 Second Club
iTrader: (4)
Join Date: Feb 2004
Location: Marysville, WA
Posts: 9,448
Likes: 0
Received 0 Likes
on
0 Posts
Interesting thread. Old subject, but with some newer info. Many people that descreen their factory MAFs have toubles. That is why I bought a GMAF. And tho my car was .25 seconds faster, it too had issues as Jimmy told me it would. James @ RWTD tried tuning around it, but I ended up going back to the stock electronics to make it go away. But I still use the Granatelli ported descreened ends with NO issues. I figured out that is where the extra power comes from. The engine flows 5% more air......
10-22-2004, 07:57 AM
#47
Teching In
Join Date: Mar 2004
Location: Central NJ
Posts: 32
Likes: 0
Received 0 Likes
on
0 Posts
Just want to make sure I understand this (newbie here) - all I have to physically do on the SLP is unsolder the resistor (no resistors back)? Then use the 6 liter MAF truck tables? The of course check my A/F's.
10-22-2004, 08:26 AM
#48
Moderator
iTrader: (11)
Join Date: Mar 2002
Location: East Central Florida
Posts: 12,604
Likes: 0
Received 6 Likes
on
6 Posts
Yes, the truck tables will be dead-on or very close,
if the after-factory resistor is removed. The other
85mm Delphi vehicles' tables are not that far different
but I prefer the truck as it's the richest in effect of
the bunch (err that way on an A4 car unless you
know better). In fact my WOT commanded AFR is
right on the money by the wideband using that table.
Though I did have to twiddle the low end VE table a
bit to get idle not to be a couple of points lean in
the trims.
if the after-factory resistor is removed. The other
85mm Delphi vehicles' tables are not that far different
but I prefer the truck as it's the richest in effect of
the bunch (err that way on an A4 car unless you
know better). In fact my WOT commanded AFR is
right on the money by the wideband using that table.
Though I did have to twiddle the low end VE table a
bit to get idle not to be a couple of points lean in
the trims.
