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LS maf vs speed density


pontiacfreak142

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For the guys that have experience with both, after a good tune, is there really much difference?. I ask because i picked up a vararam intake for the gto, but they are meant for the ls2 cars and i guess due to throttle body and maf length, its much harder to get these on an ls1 car. Im not even sure just going to an ls2 maf will work either, so i also picked up a cam and will be getting long tubes shortly, so im thinking just wait, do it all at once and just get rid of the maf so the intake will work.

 

Opinions?

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I've seen tuners/owners who run each and swear by it. I don't know that there is really any power to be made/lost on a NA setup assuming intake duct has the same flow SD vs MAF. Its my understanding that MAF can be trickier to tune especially with a big cam. My car has a LS7 MAF and the tuner didn't have much of an issue dialing it in.

 

Really all comes down to the tuner.

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The MAF in most cases is the better tune and is why GM uses them in the first place. SD can be almost as good to the point it is unnoticed by most people, and has its place for certain applications. MAF just does a better job of measuring the air entering the engine rather then calculating it like SD so it isn't effected byaaltitude, air temp, and the like nearly as much. SD takes much more time to be nearly as seemless and any changes to your car's volumetric efficiency will throw it off.
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Let me elaborate a little, the car's computer has to know how much air is in the engine. It can do this a number of ways, MAF, SD, or Alpha-N to name a few. Many manufacturers use a combination of them in the way GM actually uses MAF and SD on it's cars together to kind of double check itself. This process not only gives you the ability to tune in just SD or just MAF, it makes it a more involved process then most people realize to make a modified car operate the way GM designed using the MAF with SD as a back up. A lot of tuners see the benefits of the way GM originally designed it and tune it that way whenever possible. That doesn't mean that everything can be tuned that way, but most can. Cars that have a blower added is a good example of just going SD being much easier to tune.

 

Ultimately if the engine has a good calculation of the air inside it, then it can properly fuel it. If MAF and SD are each tuned properly they each will do that well. It's taking the time to properly get SD to modify it's calculations for the dynamic altitude that makes the MAF better in most cases, because it measures the air as it enters, SD calculates various sensors and then modifies those values based on other variables. SD can be done, but not in a couple hours on the dyno in one day. It may only be a few percent off when you run it in sub zero temps versus the mid eighties you originally tuned it in but it won't be the same. Lots of things go into how far off, mostly engine combination, and how you adjust you modifiers.

 

Bottom line is very few people will take the time to read books and learn everything that goes on, even certain tuners. In my opinion it's worth doing what you need to in order to keep the MAF. If tuned right it can be done very accurately relatively quickly and doesn't really need to be fucked with later.

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Crap not what i wanted to hear lol. Not that its my full time "racecar" or anything, but sounds like bracket racing wouldnt be so good with sd. Guess ill try to make this fit lol.

 

Aussie, if you do find it, can you take pics so i can see if its any smaller than mine?

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I seem to have lost my tape measure. Shell is 2 3/4 for reference

 

 

http://i140.photobucket.com/albums/r39/aussiek2000/Pontiac/AE08DAFD-6B77-47FD-B7D7-BC8798BA5B6A.jpg

 

http://i140.photobucket.com/albums/r39/aussiek2000/Pontiac/5120CBE5-5143-4346-A801-835AC3F9DC61.jpg

 

http://i140.photobucket.com/albums/r39/aussiek2000/Pontiac/F85259E4-46BA-47A7-8294-B4B483429808.jpg

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I'm on a SD tune and the car runs good enough. I had idle surge issues and some weird graph on the dyno with my maf still in the intake (disconnected) and the stock accordion pipe. I replaced both with a simple 4" hose and it runs much better. I do agree with maf tuning being better, but this works for me and the car makes great power (440) for an NA ls1 while being safe up top. It's also a fair weather only car so it doesn't run in extreme cold.
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  • 5 weeks later...

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