This being my first post and after seeing alot of pictures I am confused. I picked up a 5.3 that is missing the ECU, MAF but otherwise complete. I am deabating on the twin or single turbo road but have been searching about the MAF sensor. I see some people changinf to speed density other keep the MAf. Since I dont have one should I buy one (which one) or should I go the SD path? I guess at this point since I have no ECU I could do either but I want to make sure the street manners are good. thanks for any input on this and this is a great site.

 

No Maf, street manners are very good with speed density.

 

This thread topic coes up ~ once a month. Somebody should write a sticky...

Unless you're using one of the late model ECU's (e38/ e40/ e67) then go speed density. There are electronic limits of the older ECU's that requires some "less-than-preferred" workarounds. The new ECU's have raised these limits making them easier to use the MAF.

More people are running SD tunes than MAF tunes (on these engines). Good tuner + SD tune = well proven setup, even on the street. In most cases no retune required for altitude (as would be expected).

MAF tunes are touted as easier to tune, and you'll have absolutely no worries about altitude compensation. Care has to be taken for the location of the MAF in the intake piping, as they are susceptible to flow disruptions from things like bends, throttle blades, etc. There are flow straighteners (honeycomb) available for ~$15 that are rumored to work well.

Regards,

Kurt Betton

 

I disagree somewhat. MAFs have come a long way since the late 1990s. I am currently running a MAF setup with my 2000 PCM. It does well adjusting to altitudes changes making 850ish rwhp. Find a tuner not stuck in the early 2000s.

 

X2 on this subject. I have a very reputable tuner kinda local who strongly suggests me sticking with a maf(98 pcm& car goes over mountain passes).for my application I see why,besides altitude changes I have a limited pcm. Either the 2 bar SD or maf will have to be scaled. But I have yet to ride in a SD tuned car so I don't know how driveability really is.

 

Not to thread Jack,but what's the typical recommended maf for blow threw for fbodys?

 

That is because your tuner wants to get paid the same amount for doing half the work. LOL

 

LOL may be true. I'm still undecided but leaning towards SD. I may have Turbo technology tune it,then learn to modify the tune from there

 

x3 lol

 

I have a really good tuner also that thinks im stupid fot wanting to run SD on my turbo 370 car. He says why calculate the air when you can read it with a maf.

 

My Car was tuned speed density by Frost. He's in VA.. Look him up. It's mostly a street car and driveability is still awesome.

 

What in particular do you guys disagree with? My understanding is if u're making enouigh power to peg the MAF on the old style, ECUs there's going to have to be some kind of workaround (that most people desire less than just going SD).

I'm likely missing some information but my understanding is that using MAF on the older ECUs results in either:

• Loss of resolution over the whole range
• Loss of resolution at low rpms
• Loss of resolution at high rpms
• Switch from MAF to SD when the MAF is pegged

(The amount of resolution needed is certainly debatable...)

Feel free to correct me or add new info!

Regards,

Kurt

 

Im get a tune very soon, and I need this info also! Turbo LQ4.

 

For me I am still as confused as when I posted it. I think that since I will only drive mine when around town I could go SD or MAF as I am not planning on making a ton of HP. My thoughts were if SD was good why did cars like the mustang go away from it? Maybe for now I will keep the MAF and later on I can always change.

 

That make two of us, but I got to chose soon!

 

I have both of this guys videos. http://www.calibratedsuccess.com/
You can tune a boosted motor with a MAF and not run out of MAF if you know what your doing. The older systems are limited to 512 grams per sec of air.

You can scale the system and accurately tune beyond that point.
It can be done.

This guy goes into great detail on how to do this.

I was told for a long time that SD was the best option for FI tuning in older 512/gm LS
PCM's.

Tuning for max power is one thing, but making it have silky smooth drivability is another.

 

Still running stock MAF here. Been Mid 9's/145mph 4850lbs with it. I drive truck back and forth from Ca to Colorado altitudes from sealevel to 11,500' with no problems. Just have to adjust boost to keep the AFR in check. Also hot day to cool night will need boost backed off or fuel added in tune. Works for me but can't say that I recommend this setup lol.

 

i had a maf tune on both of my twin turbo setups...I thought the tune was great. They drove just like stock. I dont know how a SD tune could make it any better? Maybe a little more power?

 

All good info to know. I think ill stick with the maf because the silky smooth driveability is more important to me. Plus I am gonna get a copy of HP tuners so I can adjust my tune any ways. For me its a win win

 

Just be sure to keep a steady eye on the AFR gauge at all times. It's basically like your running a carburetor once you hit 10psi and 5K rpm. Cool night or lower elevation it will lean out. Up the boost 2psi you have to add fuel.