I think I see what you are refering too. I recurved the top. This is a graph with my old factory MAF curve on the right. I left the bottom anomolies in the curve as I felt they were the result of measured data.
ED
Maf curve
I think I see what you are refering too. I recurved the top. This is a graph with my old factory MAF curve on the right. I left the bottom anomolies in the curve as I felt they were the result of measured data.
ED
This forum is lucky to have someone with Joecar's knowledge. One of the ways Joecar probably learned was that he logs almost every day. It would be real easy to do the experiment Joecar was referring to and then see which Table is controlling.
Try making one Table richer and then see. Some OS's may differ (as I found in the 2002 Camaro). Try his experiment. Thats the best way to learn.
Good luck..
Thanks for the kind words
I don't know that much, but I do log every day, and I read everyday, and I compare other people's observations/experiments with my own... it is an on-going learning experience, I see myself continually doing this until my very last day
I've done that experiment in SD (MAF-less) mode, I will repeat it in MAF mode, soon.
Can you post a picture of how the MAF is installed and the air box mods? My guess is your getting some poor airflow due to placement. If your MAF is close to a sharp edge leading in or right after a 90 degree bend you can get some goofy reading like that. Some times simply rotating the MAF is enough to get it in cleaner air flow. Other time moving the MAF so there is at least 6" of straight tube in front of it helps a ton. That is not always possible. In my 2004 Suburban the is an air lense before straighten out the airflow before it enters the MAF. The MAF is less that 2" form the opening in the air box that is less then friendly to airflow. The Lens straightens out the tumble and allows the MAF to do its job.Originally Posted by BRD-PREY
Airbox
The output of the airbox going into the MAF tube has a honeycomb laminar flow straightner. The Original F-body never had the required straight sections before and after the MAF sensor. That's why they had a screen on their MAF. I totally agree that uneven airflow is the culpret for bumps or anomalies in my maf table. If no anomolies existed you could just use a formula instead of a flow table.
In the big scheme of things why would you want a setup that adds accuracy to a sensor but decreases the amount of air that is availiable for cylinder filling.
A section of straight pipe in front and behind the maf would have to be how big before adding no flow resistance to the air mass that reaches the 92MM throttle body.
Most vehicles where the person adds a bigger intake and throttle body they use close to the same size intake plumbing.
My Airbox has seals that seal it to the hood when closed and the hood has the 2 original ram air scoops and 2 additional ovals on the bottom side. The airbox output is 104.1mm into the 100mm MAF into the 92mm TB. My goal was that the TB actually the TB Blade be the only restriction to airflow.
I'm not sure but I have evidence now thanks to EFI_live that I'm on the right track:
(but only if I read the evidence correctly)
The table for the MAF I purchased for my application states that I will have at:
1500 hz 3.18 g/s
4500 hz 37.62 g/s
My application has:
1500 hz 5.06 g/s
4500 hz 76.39 g/s
Now I realize my motor is still only taking in what in neededs but the MAF tube is the same diameter in both applications.
In fact the table for this MAF Sensor with a 441cuin LSX stroker had very similiar numbers.
1500 hz 5.21 g/s
4500 hz 69.16 g/s
I don't know what type of intake plumbing the other 2 applications had.
I don't have any definitive reasons for the numbers maybe air velocity, maybe airflow while straight because of my laminar flow straightner is not equally distributed.
I don't have all the answers, in fact very few of them so and thoughts or discussions are welcomed and encouraged.
Ed
At least I get good honest discussions here, on LSTech they want to know where I bought the black wrinkle paint!
Hi Ed,
Question: you're only using 4 wires on the MAF connector...?
Your plumbing looks sufficiently straight (i.e. no bends).
You can try an experiment: clock the MAF sensor (i.e. rotate it), see if it reads different when clocked to 45° and 90°.
The Calc.VET tutorial corrects the MAF table, the Calc.MAFT tutorial calculates the MAF table from the corrected VE (each of those uses LTFT/wideband, but the procedure can be modified to use wideband only, if required).
BTW: are the ram air hood grilles aluminum (did you make them...?)...? [ sorry, I had ask
]
The MAF airflow numbers depend on engines actual VE ability (i.e. cylinder airmass ability), and how well behaved the air is flowing thru the MAF (laminar vs turbulent).
No all 5, I probably took the picture when I was doing the AUTOSD ve.
I already tried the clock thing, it's now at 1:30.
No they are plastic and broken I just got a set of SS ones in, but my time is split between getting ready for Sunday when I pull the t56 and rebuild it and finishing up the custom rain baffle I'm designing for inside the hood.
ps I looked good catch, yah the wire was unpluged and folded back while I was doing the SD tune. I don't think its necessary but their was enough people saying it had to be unplugged even if you killed the MAF with fail freq I didn't want to take a change.
Ed
PSS It's hooked back up
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