You know that it's only us truck guys that leave the MAF installed when we go speed density right??....ALL of the other LSx based vehicles have the MAF removed when converted to SD. Once the MAF has failed it's ignored completely as far as I can tell from the searches I've done both here and on 'tech about this topic.

 

that's not true... I have a firechicken, been in SD for a year and a half and still haven't removed MAF out of the the tract. Why? becuase I like to compare numbers, see how they differ day to day, since dynair is calculated from dynamically changing variables, but MAF table is fixed. I have my MAF calibrated, so I can switch to MAF any time I want to. People been saying that MAF is a restriction, but HumpinSS had a thread like a month or two ago about how he removed the MAF completely and the whole dyno curve was within 0.5hp, so no it isn't a restriction at least on a 430rwhp setup.

as per earlier thread, the PCM really doesnt' care if you're getting airflow from SD calculations, MAF measurement, or a ouiji board, as long as it's correct then it just proportions fueling accordingly.

 

I stand corrected....I was kind of generalizing and trying to make the point that the MAF doesn't HAVE to be in the intake tract for the motor to run right.

All I intended to do in this thread was post my observations between having the MAf in the tract and out of the tract...and the visible results that occured because of this change. MY belief here is that it's not the MAF that's resctrictive...it's the combination of the MAF screen , the 90º turn in the intake tube, and the shape of our intake tubes...I saw an airflow gain be removing the MAF, whether this translated into a power gain or not I can't prove (my butt-o-meter isn't very well calibrated sometimes) but I CAN prove the increase in delivered torque caused by thi change (again...I KNOW it's not accurate, but it's a calculated number based upon airflow that will change proportionally with airflow)

Y'know....I might consider giving the ouija board thing a try though....it's gotta be easier than the other ways we use to tune these things sometimes

 

I am here to tell ya, at least MY butt-o-meter has fooled me many times. However I agree, rather you want to admit to it or not there is something to the delivered TQ reading. Maybe your difference is only .5HP, and that your increase in that reading was an actual reflection of that (doubt it though). Out of curiousity, ever think of putting a short intake right on the TB? Just a test and research thing. I imagine heat soak will get to it, but w/o a MAF and practically no intake tract. Just like the vette right?

As far as the ouija technique...I have been using that on my spark table for a while now. Don't trust it.

 

I dont want to hijack your thred, but have a question. I have tried a few times to go to SD. Zero the MAF, and cancel the code. My truck will start just like normal, but then die, and wont re-start till I go back to the MAF. I still have the stock tube on the intake but was thinking of mounting the filter directly to the TB, figure thats about the straightest airflow I can get.

Any ideas to try to get my truck to run in SD?

 

Keep trying. It can take a few minutes sometimes for the MAF failure to take effect. When I unplugged mine it did the same thing til it registered that it was no longer there.

 

I have actually driven around for a few minutes before it would throw the code.

 

If the VE table is too far off the truck may not run is SD mode at all....

 

so? if maf table is way off it won't run either. again, you gotta think about getting correct airflow, not concentrate on what's a more correct source to get it. use whatever works better for you. if you got reversion or boost, you're better off in SD. if you got a simple NA or dont wanna mess with it ever again, MAF is a safer bet.

 

What I was getting at is that if he's trying to run in SD with the MAF unplugged and it's not even idling the VE table may be too far off for the truck to function properly (the trims will only do so much)...and since he's only got ONE source of fueling in SD mode (the VE table) if that's really screwed up the truck won't run