FYI,

The MAF senses the amount of air that enters the engine. It uses hot wire sensing element to measure the amount of air entering the engine. As the air passes over the wire it cools. The amount of current required to keet it at 200°C above the ambient temp is proportional to the amount of air flowing into the engine.
The MAF then sends a voltage signal to the PCM based on the intake air mass.
THE PCM then calculates the injector pulse width. When you play with the MAF you must compensate for the above. Some PCMs have the ability (from the factory) to compensate for the modified MAF. Matt is trying to discover which ones do.
Now back to the survey

Regards

Jean Marc Chartier

 

JMC and neal know what they are talking about...calibration of the maf..and the ECM has some room to adjust for the lean condition from the feedback of the oxygen sensor...

 

HI!... Sorry if my last post was a bit confusing. I was trying to put it into "LAYMANS" terms, so everyone could understand. JMC went the opposite route and put it into the "TECHNICAL" terms!LOL! JMS is exactly right, but of coarse I have to agre with him, he's from WINDSOR also! O'k, sorry to interupt this thread so much. Let's get back on topic.

 

Well if you want to know why porting does not mess the calibration, look at the back of the stock MAF.

There is plate there that diverts the air flow through 2 90* bends. That is going to slow the amount of air down through the sampling tube. Now when you open up MAF by removing the centerpost and the backing plate you are forcing the element to sample more air. So when you gut the maf and remove the post, you are really just canceling out the incalibrations.

Obviously it does not work on every MAF 150. Why? as JMC figured out to find out if it is certain computer calibrations or different MAF units. Obviously the computer codes are EASY to get, drivers door jamb and so I am trying to compile this list for a knowledge base.

I only have 3 people so far. I know of others that tried removing the backing plate and that failed. So lets hear the combination you have with motor, tranny, computer code, chipped and success or not.

 

Matt,

I think because of the partial success rate people have been scared away from doing this mod. FWIW here is my info
MAF# XL3F-128579-BA AFH80-06C Cal 9J26
Truck: 00 F-150 XLT 4x4 4.6 w/5spd 3.55 diff 255/70 R16 tires.
Unsuccessful mod.

Regards

Jean Marc Chartier

 

What is all this belt Squeal I hear about with these shift kits? From most of those kits I seen the front pump takes a great strain do to the increase line pressure.. Also that increase in line pressure is actually robbing more power do to having to spin under a greater load. Its a double edge sword The engine should never rev between shifts.. only chirp tires . Perhaps I am too old school used to vacuum modulated transes. I know Ford on the lightning computer it cuts out three injectors between 1-2 shift which, allows the the trans to" Lock up" after the shift causing that momentary rev you all aquire.. Over all the 4r100 trans is good but not great //If your an all out drag racer I'd recommend contacting Level 10 Transmissions if you think I am just talking trash on here.. www.levelten.com or 1-973 827-1000.. I am just quoting what I have learned to help other f-150 owners and lightning owners beware of the pros and cons of chips .. Keep on eating Gm's and Dodges.. If any of you get Muscle Mustang and Fast Fords its in the november Issue 2001 pg 102-113. I just wanna see ol fords ahead of the competition thats all take care all.

 

Matt,

I forgot the PCM code in my post. Would you believe PCM2. How could i have forgotten such an easy code?


JMC

 

Hello, sorry I took so long but it's been hectic 'round here. I found a sticker that might be the computer code, it reads as follows.

Calibration
Etalonnage

7-48R F7AE-6E061-TZP


I'm not sure if that's the one your looking for but if not I can remove the driver's side kick panel and try to get it right off the 'puter itself.

FWIW, I can't believe that gutting the MAF would make the engine run lean, if any thing it should run richer. The plate and post forces sampled air to make two 90 degree turns (that's equivalent to a 180 about face turn) this must slow the sampled air considerably. By removing the post and allowing the sample tube to blow straight through it should read much more air and compensate by richening the fuel charge. I know that others here have more knowledge of such things than I do but I am concluding this through simple logic and physics.

I have no proof to offer supporting my theory but if anyone can make heads or tails of it I can post my emissions readout from a recent trip to the Motor Vehicles Inspection station. For those who are not aware, the DMV in this state puts your truck on a treadmill of sorts and takes a pollution test while the truck or car is running at a simulated predetermined speed.

Hope this can be helpful to someone.

 

First of all....everything that I will state here IS my opinion,
but it is based on FACT. Furthermore, it also reflects the tuning
philosophy of all the chipmakers who use the M. Wesley hipmaster.
You're the kind of guy who likes to experiment, fool around and
learn things on his own. That's all well and good, but there are
some things that will work and other things that will not work
when it comes to tuning an EEC computer. Lets start with the mass
air meter (MAF). The EEC uses the MAF to accurately determine the
quantity (mass) of air entering the engine at any given instant.
The MAFs duty is to do the measuring, that's all! Within the EECs
programming logic, there is no place for altering the MAF
calibration as a tuning aid. Period. Ford flow tested all of
thier MAFs on a flow bench and with the data they obtained, a
plot of air flow in Kg/hr vs voltage output is constructed. This
is called the mass air transfer function and it is incorporated
into the EEC as part of it's software. While in operation, the
EEC looks at the MAFs output voltage, goes to the MAF transfer
function and converts this output voltage into an actual air flow
(mass). It then ratios this measured airflow over what the engine
can hold at 100% volumetric efficiency. So if the engine is
injesting air at 50 Kg/hr, but could injest 100 Kg/hr for
complete cylinder filling at that given instanteneous RPM, the
ratio is 50/100 or 0.50. This is equal to the LOAD. Once the EEC
has a load number, it references a fuel load table where a given
A/F ratio is selected as a function of load vs RPM. A similiar
calculation is used to determine the spark timing from a spark
load table where timing is given as a function of load vs RPM. In
the case of the fuel load table, once an A/F ratio is determined,
the EEC knows the correct pulsewidth to use because THE INJECTOR
SIZE IS PROGRAMMED INTO THE EEC SOFTWARE. So you can see that it
is not the MAF that is calibrated for a particular injector size,
THE EEC IS. The proper way to tune for an injector change is to
reprogram the EEC for the injectors. This way it will continue to
correctly calculate the load and thus, properly read the fuel
load table. In this case, the proper A/F ratio will be selected
and with the proper injector size now known, the EEC will give
the corect pulsewidth. Now if you alter the MAF by "recalibrating"
it, the transfer function can no longer be used to accurately
determine what the MAF is measuring. Therefore, the EEC will
incorrectly calculate the LOAD. This error is then carried over
to the spark and fuel load tables where incorrect fuel and spark
timing are thus selected. In the case where you use a MAF
recalibrated for, say 30# injectors, the MAFs output voltage is
lowered by 19/30 or almost 37%. With this alteration, the EEC may
never read the high load areas of the spark and fuel load tables.
And this is assuming that the meter's output follows the curve
for the transfer function. It is possible to modify a meter
whereby it's behavior does not even follow a linear relationship
to the transfer function, but instead deviates differing amounts
depending on where you are on the curve. Now consider the FMU.
The FMU is actually a second controller overlaid on the EEC. Here
you are taking the EECs calculated fuel delivery and modifying it
with a mechanical boost sensative device. The FMU will not
necessarily give you the best fuel curve becuase, at best, it is
limited by a linear relationship of boost VS fuel psi. Who says
that this will necessarily produce the best fuel curve? Ideally,
the fuel curve should be based upon the LOAD. The EEC already
performs this load calculation and here, the best way to go is to
use a reprogramming chip. With regard to Pro-Ms calibrations, if
there is actually a difference, why couldn't they tell you?
Remember, any change in the MAFs calibration not only effects
fuel delivery, but spark timing as well. I don't dispute that
perhaps you can recalibrate the MAF to give decent results at
WOT, but not over the entire performance envelope which is where
you drive 95% of the time. All of these tricks, ie: recal. MAFs,
boost timing retards and FMUs do not work because they try to
defeat the programming logic of the EEC. Any tuning modifications
or updates should instead be incorporated into the EEC. This will
give you the best possible results. First of all, both the HO and Cobra processors have the same mass
air transfer function as part of the factory software that
enables use of the SAME MAF calibration, 19#. No ford MAF was
ever "calibrated" for a specific injector size, the EEC was. Ford
flow tests thier mass air meters on a flow bench and records the
output voltage vs actual air flow in Kg/min. With this data, a
graph of the output voltage vs mass air flow is constructed and
this is called the MASS AIR TRANSFER FUNCTION. It is part of the
EEC software. In operation, the EEC reads the MAF output voltage,
goes to the mass air transfer function and converts this output
into an actual quantity of air mass that's entering the engine at
any given time. Remember, this was all done beforehand on a flow
bench. Now that it knows the actual mass of air entering the
engine, it ratios this over what the engine could hold at 100%
volumetric efficiency for that given RPM. So, if the engine is
ingesting 50 Kg of air, but could ingest 100 Kg of air at 100%
(complete cylinder filling) volumetric efficiency for that given
RPM, the ratio is 50/100 or 0.50. This is equal to the LOAD.
Thus, so far the EEC has read the MAF output voltage, used the
mass air transfer function to convert this into an actual mass
air reading, ratioed this over what the engine could hold at 100%
volumetric efficiency and thus determined the load. Once the EEC
has a load number, it references a load vs RPM fuel load table.
In it, this table graphs air/fuel ratio as a function of load vs
RPM. Here, the EEC takes the calculated load and using the
instantaneous RPM, selects an A/F ratio from the table. The EEC
knows the required pulsewidth to give this A/F ratio because the
injector size is part of the EEC programming. Within the EEC
software, there is also a spark load table where similiar
calculations are used to determine spark timing. It should now be
clear that the MAF is not calibrated for injector size, the EEC
IS. The EEC uses the MAF to determine LOAD. Recalibrating the MAF
changes the load calculations and this error is carried over to
the fuel and spark load tables where incorrect A/F ratios and
spark timing are selected as a result. Any change in injector
size must accompanied by a corresponding change in the EEC
calibration for injector size. This way, the EEC will continue
to correctly calculate the load and the corresponding timing and
A/F ratios, but will vary the pulse width to match the injector
size. Now if you change the MAF or modify it in any way, the
transfer function can no longer be used by the EEC to determine
ACCURATELY what the MAF is actually measuring. To restore this
accuracy, the MAF will have to once again be flow tested and with
the data collected, a new transfer function constructed AND THEN
INCORPORATED AS PART OF THE EEC SOFTWARE, REPLACING THE ORIGINAL
TRANSFER FUNCTION. Changing the MAF "calibration" simply does not
work because you are trying to defy the EECs programming logic.
To make programming changes that will allow the use of a
different MAF (the 80mm Ford, for example) or different size
injectors, a reprogramming chip must be used. This allows such
changes to work with the EECs programming logic. A chip can
further be used to alter the A/F ratio or spark timing whereby an
increase in performance can be realized. This is significant in
cases where modifications have changed the operating enviornment
and tuning requirements of the engine. An extreme example is the
use of a blower.

 

Keep in mind that there are several factors involved in the
dynamics of the way your car now runs. First of all, for the same
given airflow, the Cobra MAF will give a slightly lower (<10%)
output voltage than the original MAF. This will in turn cause the
EEC to calculate a slightly lower load number for the same given
airflow. Now when you are running at less than approximately 3/4
throttle, the EEC is operating in closed loop. Here the A/F ratio
is under lambda control and will continually seek ~14.7:1. But
when it comes to calculating the spark timing, the EEC uses the
load calculation to determine the timing by referencing the spark
load table. Since your MAF gives a slightly lower load number in
the calculations, the EEC will tend to read the lower portions of
the spark load table for any actual given load. This will result
in the EEC giving MORE spark timing under light load conditions.
Now when you progress to higher actual loads, your engine is able
to flow more air because the Cobra MAF is less restrictive.
therefore, the engine's volumetric efficiency has increased. But
remember we said that the Cobra MAF outputs a lower voltage for
any given airflow. The end result will probably be a load
calculation that is nearly the same or slightly HIGHER under
medium load conditions. As you approach WOT and higher RPMs, this
difference will become greater until you reach the top of the RPM
scale (>4000 RPM) where the decreased restriction and greater
airflow really make a difference. Here the actual load
calculations will in all likelihood be higher. These effects will
result in the EEC reading the higher portion of the fuel load
table with no drop off to lower loads at high throttle and high
RPMs, thus producing a slightly lower (richer) A/F mixture. Under
these conditions with greater than about 3/4 throttle (open
loop), the EEC references a seperate spark table that is no
longer based on load and here your timing remains unaffected. So
the overall effect would tend to be more spark timing at low
speed until you go into open loop. This increase in timing will
make your car seem stronger at part throttle. As you approach
mid-throttle settings at medium loads, the engine performance
will be nearly the same. As you approach WOT at high loads with
RPMs above approximately 3500-4000 RPM, you will have more power
due to increased volumetric efficiency and the mixture will tend
to richen up a little. So to go back to your question, the
differences will depend both on load and RPM. I personally
wouldn't modify a mass air meter in any way because in doing so,
you will most likely degrade it's accuracy...

 

TW,

Thanks for the insite on the Varoius PCM functions. Saves me the trouble of looking all of them up. I know for a fact that Neal's MAF did not work in my truck. His had a different cal #. All I want is to fing a cheap way of removing the restrictive sampling tower without setting a code. I did partialy succeed. I cut mine down about 1/8th of an inch and I have set no codes. So I am on my way. One of these days I will have Mike T. correct my chip for the headers, MAF mod, Poor man's FIPK, Ported TB and the cat back.

JMC

 

Do any of you use a throddle body spacer like Poweraid, and does it affect the MAF in a positive of negative way?

 

Hello all,

Without commenting on Matt's comments about me or my knowledge, overall this is an interesting thread. I think that it is ultimately not going to be very productive in terms of anyone getting any appreciable increase in power by gutting the stock MAF, which is the real core issue here. At best, it's a risky move that can add only a little power, and roughly 70% of the people among our customers here at Performance who have done this on these F-150's have had to buy a new MAF as a result.

Our recommendation is very well known, we recommend skipping this idea altogether, as the risks are too great for the tiny potential gains *if* all goes well.

If your engine actually has need for more airflow capacity than your stock MAF can flow under demand (which takes very large power gains in these F-150's to outstrip the flow capacity of the stock MAF & TB, by the way), gutting the MAF isn't going to do the job anyway, it's time for a larger MAF.

Jstang's point & comments with regard to cfm's needed per hp is well taken, and should be considered here!

In addition, remember that all cfm ratings are measured at a certain pressure drop, usually 1G, or 28 inches of water column. If the engine requires more air, the components are actually capable of flowing more air with a stronger demand, it's just that this is the point at which significant power gains can be achieved by increasing airflow capacity in the MAF. In other words, a 650 cfm carb., for example, can and will actually flow more than it's "official" 650 cfm rating if the engine demands more air, but at that point the engine needs more carb., or in our case, a larger MAF.

In these 5.4's, the stock MAF is plenty large enough to support 350+ horsepower. There are plenty of 450 horsepower Lightnings running 80mm MAF's. Yes, the 2001 Lightning's have a 90mm unit, but that was primarily so that the owners would not install aftermarket MAF's because they lean out the A/F, rather than needing that much capacity. 90mm MAF size isn't needed until you're over 450 hp.

Ultimately, any real & sustainable power gain from gutting the factory F-150 MAF will come, in our humble opinion, from achieving a minor reduction in *restriction* thru the MAF. We discount the power gains achieved by the leanout of the A/F that happens many times with this mod as potentially being unsafe and not sustainable without being checked.

Matt's idea of various different catch codes being more "tolerant" of this procedure is interesting, and we wish him the best of luck in compiling his database! We'd be happy to contribute to that, but we've never kept track of which of our customers that have done this to their F-150 has which catch code, so unfortunately, we just don't have any data that would really be helpful to Matt in that regard, or we'd be more than happy to share it with him.

Plain and simple, you're just not going to see a significant power gain from "gutting" the stock MAF in these vehicles, dyno results over the past few years have shown usually not more than a 2-3 hp gain, and not more than 6-8 hp. Anytime someone undertakes this type of mod, they should have the A/F ratios checked to insure safe operation. Some would consider that overkill, as this whole idea was hatched to get "free" horsepower to begin with years ago, but with the price of engines these days, we don't.

Let's get this thread back to exchanging facts & ideas, and leave the personal crappola where it belongs, in the trash. Lively debate is one thing, casting aspersions, personal criticisms, etc. are another, and have no place here. I should also say a quick
thanks those that have contributed factual information to this thread, that's what F-150 Online is all about. Thank you!

We wish Matt the best of luck in getting his database compiled, and we do encourage anyone who has done this to their vehicle to help Matt out by letting him know your computer code. The bottom line is that Matt is just looking for facts, and whether you agree with him or not, facts are always nice to have, and since he's willing to do that "legwork", let's all please share that data if this applies to you, if you have gutted your factory MAF.

Our bests to all,

 

The MAF element do not self adjustment at all. It is calibrated and the computer or PCM/ECM does the adjustment.

YOu have to remember that you are not just adding more air by gutting the post. You are also increasing the amount of air sampled by removing the backing plate. So they should cancel each other out, but as we have about a 75% sucess rate (from those that I have gotten replies from) some calibrations for the PCM does not like this. That is what I am trying to discover, which codes work, which are like a "dont even try it" unit.

 

even though I have a small sampling, it is a 70% sucess rate.

So lets here those that have tried it and not worked.