Soo....you can tell the pcm actual airflow via the 30 pt. maf transfer sheet yes?
Soo....you can tell the pcm actual airflow via the 30 pt. maf transfer sheet yes?This maf calibration thing can be kinda mind blowing
You can see very simple but detailed info on my site
and
I think Wes has some good stuff on the Wiki site as well
Try to think of a meter in this way
One made by Ford (OEM) for a stock Stang
and
One of the same for a Lightning
Each one has to be able to accurately report V E R Y different amounts
of air flow and each one only has a voltage range of 0 to 5.0 volts that
is used to represent that airflow.
btw ... both use an electronic method of sampling airflow
Now ... the Stang uses 19# inj's because they are the size needed to
support the amount of air flow that motor can produce
The same can be said about the Lightning's greater air flow and
much larger 42# size inj's
Each meter in these example cars here has its own unique transfer
curve contained in its respective pcm.
That is how Ford does it :Word:
these meters are not caled for a certain size inj.
these meters are designed for a certain amount of air flow
The after market meter companies like ProM and C&L base things
upon the fact the info in the pcm is unchanged. That is what is
referred to as ... a calibrated meter.
Those companies came up with that concept ... which some
call ... the cheat method ... in an attempt to allow their
customers to use their meters with larger inj's without
the need for a custom tune.
Worked kinda sorta good for the fox rpm based pcm's
but
Not all that great with the 94-95 load based pcm's
Now ... if you have pcm access
All that cheat method goes out the window
and
You now can do it no differently than Ford did it
because
You now have the ability to tell the pcm you are running 30's
and
You now have the ability to tell the pcm actual air flow
Grady
Soo....you can tell the pcm actual airflow via the 30 pt. maf transfer sheet yes?
Man, I do appreciate the time youve taken to explain this all, thank youYes ... That is correct
and
You tell the pcm the actual size of injectors being used
The two M U S T go hand in hand
but
Using our two example cars above
You would N E V E R be able to use that OEM 94-95 Stang meter with an
application like a Lightning.
You would reach its limit of airflow at SOMETHING LIKE a half to two thirds
of the trucks rpm range. Thats obviously so because of the huge amount
of air flow generated by the larger motor and it's blower.
That situation is what a lot of peeps call ... pegging the meter
A self tuner interface or chip can do nothing about that
Now take your proposed 30# application with a ProM meter.
Even though that meter has a 30# cal
Always ... Always ... Remember this
Meters are about Air Flow ... NOT ... inj size :Word:
ProM will deliver that meter to you with the ability to support the
air flow a motor will produce that has fuel requirement needs of
30# size injectors.
See where I'm going here... the meter has to be built to report
more air flow yet still stay within the mandatory 0 to 5 volt range
that the pcm uses to determine air flow
This is most likely the most misunderstood part
of the whole tuning concept when peeps try to get a grasp on ........
How does my Stang work
I do confess to spending a good bit of time
before I saw it clearly
Once again ... the meter being caled for a certain size inj ...........
That is for those who don't have pcm access
thus
They're forced to use the OEM meters curve contained in the pcm
AND
The 19# value of inj size contained in the pcm
TRUTHFUL info for the pcm is more ACCURATE info for the pcm :Word:
and that ... boys & girls ... is why
Custom tunes can give most combos ... Stock Like Drivability
Listen to my idle with the sig link
Sure ... its got a bit of cam lope
but
More importantly ... it has a very stable idle
That was obtained with a cam that has a lsa of ... less than 110
Grady
how can you rank stock #1 and c&l last it is a aftermarket housing with stock internals so i would say if stock is your first pick then c&l should be right under that
Yep still 19lbs, back when I did the HCI I shouldve at least gone 24s butAs always Grady is really good at explaining things. Armed with all the info grady provided you see the reason I said that if your combo isn't pegging your current maf there is no reason for changing it if you get the tweecer. All you have to do then is tell the computer what size injectors you are running and plug in the correct transfer curve for your current maf. That is somewhat oversimplified I'm sure but is basically what you have to do.
What size injectors is your current pro m meter cal'd for? It is possible that if it's cal'd for stock 19lb. injectors you could peg it like the stock one would if you go over 300rwhp but I'm unsure of this. I'm assuming that a stock injector size cal'd maf would peg at about the same hp levels as the stock ford meter.
As always Grady is really good at explaining things. Armed with all the info grady provided you see the reason I said that if your combo isn't pegging your current maf there is no reason for changing it if you get the tweecer. All you have to do then is tell the computer what size injectors you are running and plug in the correct transfer curve for your current maf. That is somewhat oversimplified I'm sure but is basically what you have to do.
What size injectors is your current pro m meter cal'd for? It is possible that if it's cal'd for stock 19lb. injectors you could peg it like the stock one would if you go over 300rwhp but I'm unsure of this. I'm assuming that a stock injector size cal'd maf would peg at about the same hp levels as the stock ford meter.
The way I understand it from what others have experienced with the Pro-M/PMAS style maf is this.
They do flow more than the stocker, a 77-80mm Pro-M running with 19lb inj. will flow more than the stocker will. IIRC as the inj. size goes up...that "peg" point comes down as the electrical offset to "fudge" what the eec see's grows.
I also think that is why like Grady mentioned as you drift further and further away from the stock inj. size you run a greater chance of drivability issues.
Yep still 19lbs, back when I did the HCI I shouldve at least gone 24s but$$ got tight after all the mods,. So from what you say I shouldnt waste time/money on sending the meter for a recal, instead save the $ for the Tweecer--Get the 30s- and start tuning?
Another issue is the "cold air tuning " option that they asked me when I ordered the Pro-m, from what I understand when theybench flowed the meter, they put a 90degree elbow in front of it to simulate the turbulence of my Densecharger Cai-- does any of that come into play when tuning if I were to say--straighten that 90 to a 45 degree--Im guessing then I might have have a rich/lean issue. AH--- but then that would be when the wideband Grady talks about come s into play
This is one of those ... It depends upon ... kinda deals
I'll answer your Q
and
Propose another Q based upon the same subject
Keep your current 19# ProM meter and see if you peg it.
Once more ... driving home the point
Its all about the amount of A I R ... not ... inj size
If you don't peg that meter ... you can use it :Word:
and
You can use 19's, 24's, 30's, 36's, or 42's
Would you wanna use 19's or 24's ... NO ... too little
Should you use 36's or 42's ...
For your NA application ... you could ... but ... more tuning work
I'd stick to 30's
Now ... if you peg it
That meter has got to be setup to be able to report more air flow
This is a non-negotiable kinda deal here
The pcm can deal with a voltage output from the meter in a range
of only 0 to 5 volts
All ProM does is alter those tiny wires to deal with more air flow
but still stay in that mandatory 0 to 5 volt range
Its no big deal and the meter doesn't become any less effective
cause
You're gonna update original pcm values to current REAL values :Word:
Of course ... if you had a C&L ... you would swap tube doo-dads
Now ... All this talk has been about pegging a meter
or
Getting V E R Y close to pegging a meter
Lets talk about a different option thats been mentioned here
The Lightning Meter
Remember ... Ford setup this meter for a 351 cubic inch motor
and
It had a blower forcing large amounts of air flow through it
You're not gonna be generating anywhere near that amount of air flow
You might only use 2/3 of that meters transfer curve
Here is my Q
Are there any SN members here with a similar NA combo
using a Lightning meter that can share how much of the
curve they have used
Grady
Good question. Also..Would you be able to bolt the Ligtning meter on with the matching injectors, and roll with it as is? I would think to do it proper you would want the flow specs etc.. to load into the tuner right? The way Im going to go about this so far is Im not touching the meter or swapping injectors till I get the Tweecer.I've got another question about this. If the stock 94-95 mustang GT makes only around 180 rwhp and the stock meter will work well all the way to somewhere around 300 hp aren't we only using 2/3 of the stock maf's curve in stock form. I would think that the there woundn't be a lot of difference between the two scenarios. Additionally I hear that the lightning maf has a better resolution than the stock mustang maf. I have no practical experience with these so I'm only working with what I've read, but if that's so wouldn't there be a possibility to get better than stock like driveability using one of these meters?
Ok... Im still on the hunt for the 30s...and thanks Grady, for clarifying these issues for meIve been to your site and that initself has eliminated most of the apprehensions about using the tuning device, Ive tried to learn from past mistakes by RESEARCHING AS MUCH AS I CAN before jumping into something I might regret later BTW.. just saw a deal on a Lightning meter and 39lbers but there was mention about rigging the wiring harness Hmm...
Good question. Also..Would you be able to bolt the Ligtning meter on with the matching injectors, and roll with it as is?
the lightning meter has a totally different transfer function and can not be used without a tweecer or custom tune at all. So you would have to load the lightning transfer curve before you installed the meter. the lightning meter isn't a bolt on meter either it has a different flange the the stock mustang meter and you have to either splice a late model wiring connector on or buy the adapter harness.
I am in the same boat as you with this stuff as I haven't actually put a aftermarket maf on my car yet but I'm learning all that I can about this stuff so that when I do it I'm not going to be flying blind. I haven't actually even bought the tweecer yet either but I'm gonna be getting one very soon. I have been reading this stuff for months trying to learn as much as possible before making the plunge.
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