MAF vs SD: List PROS and CONS
TECH Senior Member
Joined: Nov 2001
Posts: 7,036
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From: Lake Zurich, IL
SD Pro: Limited sensors, less room for error due to skewed sensor readings
SD Pro: No Restriction, especially if running a larger TB than 78mm
SD Neg: As conditions change , requires some tweaking to stay 100% dead on
MAF Pro: at higher RPMs accurately measures air entering
MAF Pro: No need to adjust once locked in as weather changes
MAF Pro: Lets you runa dry nitrous kit
MAF Neg: Any changes prior to MAF can cause the reported values to be skewed high or low
MAF Neg: Restriction to air from airbox to TB
SD Pro: No Restriction, especially if running a larger TB than 78mm
SD Neg: As conditions change , requires some tweaking to stay 100% dead on
MAF Pro: at higher RPMs accurately measures air entering
MAF Pro: No need to adjust once locked in as weather changes
MAF Pro: Lets you runa dry nitrous kit
MAF Neg: Any changes prior to MAF can cause the reported values to be skewed high or low
MAF Neg: Restriction to air from airbox to TB
Thread Starter
Launching!
Joined: Nov 2002
Posts: 275
Likes: 0
From: Miami
Originally Posted by horist
SD Pro: Limited sensors, less room for error due to skewed sensor readings
SD Pro: No Restriction, especially if running a larger TB than 78mm
SD Neg: As conditions change , requires some tweaking to stay 100% dead on
MAF Pro: at higher RPMs accurately measures air entering
MAF Pro: No need to adjust once locked in as weather changes
MAF Pro: Lets you runa dry nitrous kit
MAF Neg: Any changes prior to MAF can cause the reported values to be skewed high or low
MAF Neg: Restriction to air from airbox to TB
SD Pro: No Restriction, especially if running a larger TB than 78mm
SD Neg: As conditions change , requires some tweaking to stay 100% dead on
MAF Pro: at higher RPMs accurately measures air entering
MAF Pro: No need to adjust once locked in as weather changes
MAF Pro: Lets you runa dry nitrous kit
MAF Neg: Any changes prior to MAF can cause the reported values to be skewed high or low
MAF Neg: Restriction to air from airbox to TB
MAF con: can't handle reversion at low rpm.
SD pro: histograms make VE table easy to tune, MAF table is harder
SD con: if you have an auto, you need a maf for the transmission to work right
SD con: 1998-2000 run on the secondary VE table
Slow, SD won't keep you from going FI. HP tuners can change your operating system so it can read a 3 bar map.
SD pro: histograms make VE table easy to tune, MAF table is harder
SD con: if you have an auto, you need a maf for the transmission to work right
SD con: 1998-2000 run on the secondary VE table
Slow, SD won't keep you from going FI. HP tuners can change your operating system so it can read a 3 bar map.
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Thread Starter
Launching!
Joined: Nov 2002
Posts: 275
Likes: 0
From: Miami
Originally Posted by P Mack
MAF con: can't handle reversion at low rpm.
SD pro: histograms make VE table easy to tune, MAF table is harder
SD con: if you have an auto, you need a maf for the transmission to work right
SD con: 1998-2000 run on the secondary VE table
Slow, SD won't keep you from going FI. HP tuners can change your operating system so it can read a 3 bar map.
SD pro: histograms make VE table easy to tune, MAF table is harder
SD con: if you have an auto, you need a maf for the transmission to work right
SD con: 1998-2000 run on the secondary VE table
Slow, SD won't keep you from going FI. HP tuners can change your operating system so it can read a 3 bar map.
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TECH Addict
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Originally Posted by P Mack
You're not wasting your time, you just have less resolution. Unless of course you're only making changes to the primary and not the secondary, then you're wasting your time.
Right, I realize he would see the changes to the primary table when/if he plugs the maf back in. But while tuning in SD you have to make changes to the secondary ve if you want to see results while you're still in SD. I made that mistake once, and was getting pissed off when I was tuning in sd, i would make changes to the primary table, but the fuel trims wouldn't change. If he leaves it in SD like a lot of people do, he'll always be running of the secondary table.
You will never have a MAF-only tune. The PCM uses
SD for a lot of things. You can get by without the
MAF at the cost of some adaptability. But getting
the SD tune right, or right enough, pays off even
if you keep the MAF, in areas like transient throttle
response and low RPM operation in particular.
SD for a lot of things. You can get by without the
MAF at the cost of some adaptability. But getting
the SD tune right, or right enough, pays off even
if you keep the MAF, in areas like transient throttle
response and low RPM operation in particular.
11 Second Club
iTrader: (20)
Joined: Sep 2002
Posts: 2,684
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From: Albuquerque NM - The Land of 8000ft DA
so, what I would like to know is what gains did you see at the track on back to back passes? 
tranny and diff are preventing me from finding out myself
tranny and diff are preventing me from finding out myself
Originally Posted by jimmyblue
But getting
the SD tune right, or right enough, pays off even
if you keep the MAF, in areas like transient throttle
response and low RPM operation in particular.
the SD tune right, or right enough, pays off even
if you keep the MAF, in areas like transient throttle
response and low RPM operation in particular.
Which is why I will never pay for a shop to tune my car. I'm not sure if any shops will take the time to get your ve table right, and I don't blame them cause it's time consuming. 
Originally Posted by P Mack
Right, I realize he would see the changes to the primary table when/if he plugs the maf back in. But while tuning in SD you have to make changes to the secondary ve if you want to see results while you're still in SD. I made that mistake once, and was getting pissed off when I was tuning in sd, i would make changes to the primary table, but the fuel trims wouldn't change. If he leaves it in SD like a lot of people do, he'll always be running of the secondary table.
Last edited by Flame Throwing SS; Feb 18, 2005 at 09:14 AM.
Originally Posted by jimmyblue
But getting
the SD tune right, or right enough, pays off even
if you keep the MAF, in areas like transient throttle
response and low RPM operation in particular.
Which is why I will never pay for a shop to tune my car. I'm not sure if any shops will take the time to get your ve table right, and I don't blame them cause it's time consuming. Really good points. Also, you need days with different intake temps to get the IAPark right. I some areas of the country you could wait months for warm weather and in some it never get cold. A tuner would need a lot of time to do it right.
SD Pro- You can get a smoother idle by running it richer.
MAF Pro- Not that much harder to get it running and transitioning well and will hold the tune.
But getting
the SD tune right, or right enough, pays off even
if you keep the MAF, in areas like transient throttle
response and low RPM operation in particular.
Originally Posted by P Mack
Which is why I will never pay for a shop to tune my car. I'm not sure if any shops will take the time to get your ve table right, and I don't blame them cause it's time consuming.SD Pro- You can get a smoother idle by running it richer.
MAF Pro- Not that much harder to get it running and transitioning well and will hold the tune.
Originally Posted by Flame Throwing SS
That is actually how it should be done to keep the Primary resolution, then just copy the required (every other MAP row) cells over to the secondary.
Thread Starter
Launching!
Joined: Nov 2002
Posts: 275
Likes: 0
From: Miami
Ok now whats up with this every other row thing? When I start to think I got a hang on this some new info comes up.
Ok today I will be going to the dyno. Yeah I should wait but I want to know what my numbers are before the tune and to see if I am running lean. Sunday I have a nice Autox on a 1.5 mile course and I want to make sure I'm not lean.
Should I go in there and get about 3 runs with the MAF on and 3 with the MAF off? And maybe get 2 runs at WOT as if I was at the track? All this recorded info can help figure out a lot things.
One thing I want to know is the SD or the MAF working the LTFT correctly when I match up against the A/F against the wide band.
Ok today I will be going to the dyno. Yeah I should wait but I want to know what my numbers are before the tune and to see if I am running lean. Sunday I have a nice Autox on a 1.5 mile course and I want to make sure I'm not lean.
Should I go in there and get about 3 runs with the MAF on and 3 with the MAF off? And maybe get 2 runs at WOT as if I was at the track? All this recorded info can help figure out a lot things.
One thing I want to know is the SD or the MAF working the LTFT correctly when I match up against the A/F against the wide band.
