Well I don't have an answer for ya there. Almost all tuners I've talked to swear by a MAF for an NA application.

 

Personally, MAF tunes are much easier.....I would only go for SD on a N/A car if you maxed out the MAF as I don't like raping the PE table.

 

Pretty sure 90% of the NA guys keep mafs. All the SD threads seem to be boosted guys having problems moving to it for specific reasons, as I did.

 

Silly question my tuner has my truck running in speed density mode how do i turn the 02's back on? he turned them off due to a 02 issue which ended up being a cracked header sucking air in on one side. headers fixed

 

Possible reasons I see:
1) One less thing to tune (MAF)
2) Possible air inlet restriction
3) Maxed out MAF

 

Phantom, the only times I convert and tune sd only is when the maf actually becomes a restriction (maxing out). Another would be for forced induction. Lastly in cases like my buddy the woodhauler where we put a vic jr and 4bbl tb, we used a conventional air cleanier with an iat plumbed in it.

SD does seem to be a bit more responsive, but the maf does a great job of adjusting for varying conditions.

OLSD is where a good street or dyno tune should start, and most people that run olsd have software to keep an eye on it. I like having o2 trimming to compensate for any potential problems like vaccum leaks etc.

In the end, the MAF on a MAF tuned vehicle is in full control at wot, it blends with ve at part throttle. It is more of a backup so to speak and not needed, I think it helps make vehicles more versatile in all conditions. It certainly doesn't enchance performance but at the same time, it doesn't hurt performance either on 90% of na vehicles.

 

Its mostly about not having to " fool " the fueling / air flow tables as bad .

Most of you guys are just fine with a MAF,

I ran a MAF up to about 10 psi on mine, but we were still fooling the tables pretty heavy.

SD is a more precise way to go about tuning.

I'd like to see a professional tuner enter this thread and explain it to us better.

My truck runs the best its ever has with My SD tune, and thats also under no boost, driveability is excellent.

 

The MAF sensor is quite an amazing and accurate device for measuring airflow. They react very well to changes in weather, humidity, temp etc.... in respect to fueling. Steady state fueling is also improved with a MAF.

However talking about N/A and speed density in a number of cases involving bigger or BIG cams, where the "big" cams do cause reversion back thru the intake and this can cause irregular fueling at idle in particular with a MAF in place. This is where speed density can prove to be a good option.

 

I have to respectfully disagree that sd is more precise as the maf is a direct measurment of airflow unlike manifold pressure. Every street tune should start as sd to nail the ve first. At 97 kpa at wot, you can be at 6700 hz on the maf or 9700 hz. The maf isn't a table that has to be fooled. Gm calibrates the maf table by predetermined flow figures of the maf. When you change what goes on in front of or behind the maf, you likely will have to alter the maf table.

As Klug mentioned on big cam setups, sd may control idle fuelin better depending on where the maf is located. Also, sd may prove to be a little more responsive in most cases because a lot of people don't nail the ve, and the maf. Then you have 2 tables having to blend to get fueling correct at cruise and transient stages, it can cause it to be less responsive.

That being said my dd (99 cavalier) is sd from the factory. A lot of vehicles are. It doesn't have to have the maf, but on vehicles originally equipped with it, it is great.

 

I have always run a MAF, i have never had issues until my died... Now i am in the process of replacing it with the new card style MAF... My truck has always had insane throttle response, ask anyone who as ever driven it... Tuning the VE and MAF tables together helps.... My regular tune with the maf enabled has alot better throttle response than my SD tune... From all my research tuning the maf comes down to 2 different things...

1. the placement of the maf.... Since the MAF directly reads how much air flows past it, the shape of the intake path is really important... Having bends before or after cause issues... these issues can be resolved by monitoring the MAF output on a scanner and rotating the MAF housing in the tube...

2. The actual software/tune... People who say you should never touch the maf table are *** clowns. People who say you should only scale up or scale down the maf table are also *** clowns... If you look at the maf table the units are Grams/Sec. Tuning the MAF table similar to the VE table is a must, at least in MY OPINION.... Basicaly when you tune the MAF table your are adjusting the sensor for you intake/filter setup.... As i mentioned previously the output of the MAF and its accuracy directly depend on it placement within the airstream....

Now when tuning the maf you need to be REALLY REALLY slow on the throttle transitions and also you must filter out all the throttle transitions afterwards...