RedHardSupra

iTrader: (1)

uncalibrated to me is when SD/VE and MAF modes behave differently. my method of tuning MAF is exactly matching DynamicAirflow values onto a MAF table, that's why it's crucial to have the full VE table done perfectly.

Willem @ Fuel Injection Concepts

iTrader: (2)

fwiw i did the same on my vette, was running SD tune with maf still on intake and took maf off on back to back dynos and picked up 15 ft/lb of torque and 8 hp.

Sport Side

iTrader: (6)

Yelo, when you completely remove the MAF, what are you doing for an IAT sensor?

Zick

iTrader: (18)

I believe he said that he just left it in the MAF hanging next to the intake tube so that it would still get a close reading.
He's got a thread on this on PT.net too.

02sierraz71_5.3

iTrader: (2)

Thats got to be from the afr changing. Redhard said it best

Zick

iTrader: (18)

But Yelo is running in SD, so wouldn't the MAF play no part in the fueling anyways?

GuitsBoy

iTrader: (4)

Sounds to me like he had disabled the MAF via tuning before he remove teh physical restriction, so Tune does not play a roll in the gains here. It could however play a roll in how the computer figures out delivered torque.

I definately believe the stock 75mm f-body MAF is a big restriction on a modded car, which is why im such a big fan of ported MAFs, assuming theyre recalibrated afterwards. I do find it a little difficult to believe that an 85mm de-screened maf would restrict you to the tune of 20 rwtq though.

ZL1Killa

iTrader: (17)

tuning...its all in the tuning.. you can get the same power both ways, its already been proven. some people can't get CL tuning done right... others can do MAFless and get it dialed in fine...


i'm sticking to this.

GuitsBoy

iTrader: (4)

I agree with yoru answer, but your answering the wrong question here.

He was already in speed-density mode. The tune did not change and was not altered. The MAF was not functional, it was only along for the ride... Any gains would have come from removing a physical restriction.

I do agree with you that there should be no difference between properly tuned MAF and SD setups, all else being equal, ie. unplugging the MAF but not removing it.

txhorns281

iTrader: (12)

LOOK HERE

Willem @ Fuel Injection Concepts

iTrader: (2)

my car was in SD already before i removed the maf completely.. so the only difference made was removing the maf from the intact tract. a/f remained the same.

txhorns281

iTrader: (12)

I'm sure the twin snails is the difference, the MAF is not an obstruction for MOST vehicles out there....

ZL1Killa

iTrader: (17)

GuitsBoy this is exactly what I was talking about.

maybe i referred to the wrong person in my first post... or something IDK,...

but this thread is what I was talking about, HumpinSS tested this.

GuitsBoy

iTrader: (4)

The original poster was already using SD, even though the MAF was physically in place, its was not being read by the ECM. This is why its not a tuning issue. Its a questions of SD vs. SD, not a question of MAF vs. SD as you and most others have assumed.

For all intents and purposes, its as if the MAF has already been unplugged, but he realized the gain when he physically removed the MAF, even though it had been unplugged and rendered inoperable for some time.

SMOKINV8

iTrader: (6)

Why is this thread going in circles...?

GuitsBoy has had to repeat himself like four times. Obviously the guy's MAF was a restriction.

txhorns281

iTrader: (12)

Ported stocker vs straight bellows yielded nothing drastic on my old setup, as mentioned earlier, the difference would be minimal, a couple HP at best, which is certainly not inteligible by SOTP.... I "love" the SOTP dyno....

SMOKINV8

iTrader: (6)

I don't think anybody would disagree with you about your results, you pretty well covered the variables with your expirement. I know I don't need to tell you this, but you did good work for verifying it. But at the same time, your car is but one car, and it can't represent every LSX vehicle out there for how it responds to a certain mod. I really don't think a car with a 75mm lid opening would gain much by even using a bigger MAF, so removing it wouldn't help much more. A bottleneck is a bottleneck.

Do I think this guy's results were extreme? Yep, sure do. I'd even feel confident saying something (unknown) impacted the dyno result. Maybe the shop prankster was squeezing off a little nitrous in the cooling fan during the run, I dunno. But he made one change in a tight enough time span that the weather didn't likely change, and made a big power increase.

I'd personally like to see the same thing done another time or two on the same dyno just to verify or disprove that the MAF in the intake path was what was holding it back.

txhorns281

iTrader: (12)

well, when we talk about how the MAF he took out was a screened stocker, that can certainly make difference, we all know the screen is a hinderance in airflow velocity draw, which affects airflow volume over time unit. Take that screen out, and the MAF unit is virtually no different than running a straight bellows in terms of airflow requirement for most setups.

I am not saying that in this case there is not a power increase. I'm saying the MAF housing itself (the area of the section plane) if unrestricted, offers no sizeable benefit when removed. The title of this thread is a bit misleading in that it will have unexperienced tuners rushing to remove their MAFs and once again there will be a useless debate about which is better b/w MAF and SD. The numbers compared here are merely estimations the PCM outputs in order to reference saver functions, certainly not to be held for any real word comparison. I am not the only one to verify these concepts, just trying to keep us all on earth.

Black02SS

iTrader: (36)

I have personally only see one true comparison between MAF/SD and the results speak for themselves. This is even with a 90/90 and a 85mm MAF. Get it on a dyno and see what it does.

SMOKINV8

iTrader: (6)

You mean you don't want to start round two of the SD craze?

I think we're all in agreement here.