what is SD tuning?
SD tuning, ignoring the MAF and entering the amount of air into a rpm vs map table, calling it a "VE table" so the computer can assume the mass of air entering into the motor, instead of using a sensor designed to measure the mass of the air to provide this data to the computer.
A slightly biased answer based on my point of view, but a factual representation of the process.
Maf = good
Ryan
A slightly biased answer based on my point of view, but a factual representation of the process.
Maf = good
Ryan
SD is Speed Density. The LS1 uses both MAF and SD and alternates them as needed. SD tuning eliminates the MAF's input from determining timing and fuel requirements. All timing and fuel is determined off the VE table by using the MAP and RPM input. If your car is fairly stock I would leave it alone. Many times with highly modified motors, the MAF can make tuning a bit of a pain in the ***. By eliminating it you have more direct control over the PCM. This is something very beneficial on forced induction motors. Not to mention it removes another restriction from the intake.
TECH Senior Member
Joined: Nov 2001
Posts: 7,036
Likes: 1
From: Lake Zurich, IL
everyone pretty well explained it... there's more info in the stickies
I personally prefer speed Density... it's easy to tune and eliminates a restriction (If you choose to remove the MAF... especially useful if you have a FAST 90or LS2 intake manifold ... since they don't make a 90mm MAF... it eliminates a restriction)
seems some prefer to run on a MAF others prefer SD ... SD is really a failover mode in our cars..
One thing that's kinda funny ... alot of mustang guys (5.0 mustangs) do anything they can to switch over to a good MAF setup .... whereas seems late model GMs are the reverse.... heh
once you have an SD tune done, then you can also calibrate your MAF if you choose (a properly calibrated MAF will make idle tuning and regular tuning considerably easier ... or you could stay SD and it's still pretty easy)
I personally prefer speed Density... it's easy to tune and eliminates a restriction (If you choose to remove the MAF... especially useful if you have a FAST 90or LS2 intake manifold ... since they don't make a 90mm MAF... it eliminates a restriction)
seems some prefer to run on a MAF others prefer SD ... SD is really a failover mode in our cars..
One thing that's kinda funny ... alot of mustang guys (5.0 mustangs) do anything they can to switch over to a good MAF setup .... whereas seems late model GMs are the reverse.... heh
once you have an SD tune done, then you can also calibrate your MAF if you choose (a properly calibrated MAF will make idle tuning and regular tuning considerably easier ... or you could stay SD and it's still pretty easy)
Yeah, it is kinda funny that the ford guys love maf, and the gm does not. Seeing how both pcms work, I can understand why, the ford is more of an alpha-n system with tp vs rpm vs VE, where the LS1 uses a map sensor and has a real speed density setup, knowing more about the engine load that the vehicle is under.
I do like tuning a ford vehicle correctly in about 30 minutes with a maf. 30 points and your done.
Ryan
I do like tuning a ford vehicle correctly in about 30 minutes with a maf. 30 points and your done.
Ryan
Trending Topics
Ive Seen What A Tuner Can Do With Sd, And The Truth Is That The Car Pulls Harder Then With Maf.. Dunno Why.. My Question Is I Wanted Sd Tune On My Car 408ci With 240/247 639/647 @114 But Ive Been Told That It Cant Be Done Because Of The Cam, Why Cant Tuners Do Sd Tunes With Radicall Cams??
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Originally Posted by pewter 01 SS
Ive Seen What A Tuner Can Do With Sd, And The Truth Is That The Car Pulls Harder Then With Maf.. Dunno Why.. My Question Is I Wanted Sd Tune On My Car 408ci With 240/247 639/647 @114 But Ive Been Told That It Cant Be Done Because Of The Cam, Why Cant Tuners Do Sd Tunes With Radicall Cams??
Bill
Originally Posted by pewter 01 SS
Ive Seen What A Tuner Can Do With Sd, And The Truth Is That The Car Pulls Harder Then With Maf.. Dunno Why.. My Question Is I Wanted Sd Tune On My Car 408ci With 240/247 639/647 @114 But Ive Been Told That It Cant Be Done Because Of The Cam, Why Cant Tuners Do Sd Tunes With Radicall Cams??
I'd call you tuner and tell him someone on the internet raised the
flag on him 
My cam is slightly larger than Bill's and I'm running OLSD no problem.
TECH Enthusiast
Joined: Nov 2004
Posts: 600
Likes: 0
From: Coppell,TX
the large cam can cause problems with a proper MAP reading. However, unless you've got a huge cam it shouldnt be too erratic to tune well in SD. Dont know what this is called but i know there is a name.
Teching In
Joined: Sep 2005
Posts: 49
Likes: 0
From: Sydney Australia
SD, Wish the world would be so simple.
1. MAF and VE is used under 4000rpm.
2. MAF is a restriction, depending on size, to the intake so limits HP. Note: not a concern on mildly modied cars. Note: if you port you maf you will need to re-calibrate the PCM.
3. SD, you can do this Wideband or NarrowBand! You can also turn of LTFT and limit close loop mode. The drag racers uses this method as they can command the AFR to 13/1.
MAF is good for emisions and fuel, SD is the way to go for racing. SD narrowband is in between.
1. MAF and VE is used under 4000rpm.
2. MAF is a restriction, depending on size, to the intake so limits HP. Note: not a concern on mildly modied cars. Note: if you port you maf you will need to re-calibrate the PCM.
3. SD, you can do this Wideband or NarrowBand! You can also turn of LTFT and limit close loop mode. The drag racers uses this method as they can command the AFR to 13/1.
MAF is good for emisions and fuel, SD is the way to go for racing. SD narrowband is in between.
Thanks For The Info. Indeed My Car Was Tuneable With Sd Even With The Huge Cam 240/247 639/647 @114.. The Tuner Used The Sd Tune To Correct The Ve Table Then Put Back On The Math.. I'll Try To See If We Can Do Sd Alone. Does Anybody Know If U Can Do Sd Alone In 408ci With This Cam And Nitrous?? Can A Sd Tune Be Done For Nitrous Applications?
many people do not understand how important the VE table is...
IF you still have a MAF you still need the VE for Part throttle.
basically anything under 4000 rpms and changing throttle conditions is VE. your MAF is only used in Steady State conditions....which is defined under airflow-dynamic airflow...
so if you dont tune your VE, you have tip in knock and crappy throttle response.
You dont need the MAF at all...you car relys on your IAT...which means that cars with IAT in the MAF need to buy a seperate IAT if they want to get rid of MAF totally...
I have been in SD for almost 8 months now.....
there has been no changes to my VE LTFT's in that time..climate here changes a lot
was 70*F outside 3 days ago...very next day it was 20*F!!! no change in trims as I was working on a writeup for tuning Open Loop Table..still in teh works....trying to get a definate way to do it..have tried 3 different things.....geting a lot closer now...think I have it...just need to do an actual writeup now...
many tuners put back on teh maf after doing VE tuning..and forget to recalibrate the MAF to match the VE that they just tuned....LOL
and to the comment above that says the MAF pulls harder....
Try My car....or any SD tune that I have done....
for the mods on the car...pulls way harder than with MAF on
IF you still have a MAF you still need the VE for Part throttle.
basically anything under 4000 rpms and changing throttle conditions is VE. your MAF is only used in Steady State conditions....which is defined under airflow-dynamic airflow...
so if you dont tune your VE, you have tip in knock and crappy throttle response.
You dont need the MAF at all...you car relys on your IAT...which means that cars with IAT in the MAF need to buy a seperate IAT if they want to get rid of MAF totally...
I have been in SD for almost 8 months now.....
there has been no changes to my VE LTFT's in that time..climate here changes a lot
was 70*F outside 3 days ago...very next day it was 20*F!!! no change in trims as I was working on a writeup for tuning Open Loop Table..still in teh works....trying to get a definate way to do it..have tried 3 different things.....geting a lot closer now...think I have it...just need to do an actual writeup now...
many tuners put back on teh maf after doing VE tuning..and forget to recalibrate the MAF to match the VE that they just tuned....LOL
and to the comment above that says the MAF pulls harder....
Try My car....or any SD tune that I have done....
for the mods on the car...pulls way harder than with MAF on
not sure if he did it with the wideband, he fixed my idle problem then drove around minewhile he turned of the maf and went for a few runs going through the gears therefor getting the VE readings for each RPM in everygear.. we ran out power in the comp and there interegrated the VE of the maf and the VE readings that were acquired while the car was in SD mode. the car hasnt been on the dyno. the only thing that i was wondering about was that can a car be tuned with out MAF(SD) for a nitrous application?
Originally Posted by pewter 01 SS
Thanks For The Info. Indeed My Car Was Tuneable With Sd Even With The Huge Cam 240/247 639/647 @114.. The Tuner Used The Sd Tune To Correct The Ve Table Then Put Back On The Math.. I'll Try To See If We Can Do Sd Alone. Does Anybody Know If U Can Do Sd Alone In 408ci With This Cam And Nitrous?? Can A Sd Tune Be Done For Nitrous Applications?
no problem
the cool thing with nitrous is that its usually fuel controlled by the jets...
so you just tune VE like normal(with a wideband)
and then you can use a controller to take out timing for spray...or you can do it in the IAT correction table using 284* and wire a resistor up to the IAT with a relay switch based on your Nitrous window switch...and you can do it without an extra controller
Originally Posted by pewter 01 SS
not sure if he did it with the wideband, he fixed my idle problem then drove around minewhile he turned of the maf and went for a few runs going through the gears therefor getting the VE readings for each RPM in everygear.. we ran out power in the comp and there interegrated the VE of the maf and the VE readings that were acquired while the car was in SD mode. the car hasnt been on the dyno. the only thing that i was wondering about was that can a car be tuned with out MAF(SD) for a nitrous application?
TECH Enthusiast
Joined: Nov 2004
Posts: 600
Likes: 0
From: Coppell,TX
but has anyone done dry nitrous? lol. i like dry n20 and feel that it would be cool to do with the right tuning software might even save money over the window switch, wot switch, and a progressive controler. Only problem might be real time demands.