How does a C&L Maf work on our cars?

[poboys 94]

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?

 

[final5-0]

Soo....you can tell the pcm actual airflow via the 30 pt. maf transfer sheet yes?

Yes ... 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

 

[poboys 94]

Yes ... 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

Man, I do appreciate the time youve taken to explain this all, thank you Just one more ? Suppose we update the flow specs and change the tables for the MAF via the tuning device-- and it flows more air (of course)-- could you actually keep a smaller injector on the engine because the PCM would increase the injector pule rate/ on time? NOT planning on skipping out on the 30lbers, just OR use bigger injectors with,say,-- a stock MAF-- and change ? tables or info thru the tuning device? Your site is VERY informative, and just the kind of info I was looking for, shouldve went there in the first place!

 

[final5-0]

I kinda got lost with your Question

I ran the OEM meter and 30's as you see it in the sig when I went to
the dyno for my baseline evaluation.

I'll give you this info as I think it might be what you seek

Lets use my combo for an example

We will need to break it down in two parts of Airflow & Inj's Size

INJECTOR SIZE

Most Tweecer tuners try to emulate Fords method of tuning with OEM
values of fuel pressure, dizzy setting, etc

Most non pcm tuners do just the opposite with elevated fuel pressure

When using OEM fuel pressure levels you must remember two things

1) The inj's rating was designed at a value higher than Fords supplied
39#'s and IIRC ... its like 41 or 42#'s

2) At a pressure of 39#'s ... the inj will supply less fuel
so ... when you compare this method to the mainstream method
of elevated fuel pressure ... the inj acts smaller

See how 1 & 2 makes any size inj you choose be ... conservative :Word:

Also ... please remember this ...
Those formulas to estimate inj size are usually based in FWHP
and not RWHP most Stangers relate to

You can look at fuel needs any way you want to
but
Elevated fuel pressure will only band aid things ... so much.

You need a good pump to supply adequate volume
and
You need enough inj to pass all that volume

having said all that ... I ran the numbers and 30's were chosen

AIR FLOW REQUIREMENTS

Simply put ... would my combo peg the OEM meter

At first it did
but
I found some head room with a different transfer curve
and
A little scalar value fudging on my part

It was just enough to barely make it work

It was not optimum
but
It did work until I could upgrade meters

Summing up with a final thought

Most Stangers are gonna run out of fuel W A Y before they are gonna run
out of air flow with the OEM meter :Word:

HOWEVER

If they don't have pcm access ...
they gotta go with a new meter when its time to upgrade inj's
cause
they got no choice but to rely on the cheat method of the meter's cal
matching the size of inj choice.

Hopefully ... I've answered your Q
If not ... ask again differently

Grady

 

[blksn955.o]

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

Yes C&L uses the stock electronics. However, the housing/tube interchange is how they fool it. It is a mechanical means to cal/fool the meter for a bigger inj. They are good meters just not the best for the 94-95 peeps IMHO. You tend to see more drivability issues with the C&L meters on our cars. They seem to work better on the fox cars.

First hand exp. I had a part throt. bucking issue, rich idle, cold weather idle stall issue from the C&L back before I got the tweecer.

 

[rj95svt]

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.

 

[blksn955.o]

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.

 

[rj95svt]

If the meter is cal'd for stock injectors then the transfer function would have to be very close to the stock ford meters because the meter is not trying to fool the computer into thinking that there is less air entering the motor to compensate for a larger injector than stock. Therefore with a stock injector if the meter did not have a very similar transfer function as the stock meter the air fuel ratio and load would be very fouled up and the car wouldn't run right and have drivebility problems. I know the transfer would not be exactly the same as a stock one but they would have to be close. I know that the meter is physically able to flow more air therefore less restrictive but for a given amount of air both meters would be very close in voltage output. Somebody please correct me if I'm wrong about this.

Don't get me wrong I'm not trying to argue but this is the way understand it and I would like to know if I'm wrong about it.

 

[poboys 94]

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.

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?

 

[final5-0]

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.

Well said

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 don't have any valid data to show an after market meter with a 19# cal
would be able to deal with more air flow than the little OEM meter.

Greg ... I know you have done a lot of work with various meters
so
I certainly don't doubt what you say one bit

I'm pretty sure John (WhiteDevil) pegged a 19# cal ProM meter with
his old OEM block Edel head based h/c/i combo

I can see how they might support more air flow
then again
If one was doing the ... no tune thing ...
they are limited to the original pcm curve and inj size values

I've never given it much thought ... because ... to me ........
A 19# caled meter seems so pointless
If you got a gain at all ... it would be small

Many other mods could give ... proven ... better ... gains for the money

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.

You bet Greg

Yes ... I was eluding to two main disadvantages to the cheat method
and
Once more this method is all about ... No Tune

1) It throws off the load factors in A L L the pcm tables

94-95 Stang Folks ... this is bad ... really bad
Our pcm's are based upon these ... load factors
and
Its the meter that is used to determine them

2) At low pulse width driving conditions (idle & cruise) they deliver
too much fuel

As you go higher with the inj size ...
1 & 2 become more and more noticeable

24's ... they are not too bad

30's ... they can be seen as a sitting on the fence kinda deal
For some ... they cause no issues
but for others
Issues can crop up

36's and larger ... most will have issues with them :Word:

Grady

 

[poboys 94]

Another issue is the "cold air tuning " option that they asked me when I ordered the Pro-m, from what I understand when they bench 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

 

[final5-0]

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?

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

 

[final5-0]

Another issue is the "cold air tuning " option that they asked me when I ordered the Pro-m, from what I understand when they bench 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

Always ... Look at all this from ProM's point of view

Their M A I N objective is to provide you with a tuneless meter :Word:

Small options they offer such as ..........
bends before the meter calibrations
supercharger calibrations
etc

They are a moot point for you cause you Self Tune

You're gonna Custom Tune to your S P E C I F I C combo needs

btw ... drivability issues
they can be dealt with quite nicely W I T H O U T a wb
you can use kamrf's & lambse
but
thats for another thread

Grady

 

[poboys 94]

Ok... Im still on the hunt for the 30s...and thanks Grady, for clarifying these issues for me Ive 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...

 

[rj95svt]

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

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?

 

[poboys 94]

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?

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.

 

[rj95svt]

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.

 

[final5-0]

Ok... Im still on the hunt for the 30s...and thanks Grady, for clarifying these issues for me Ive 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...

Others might disagree
but
I would tell you to consider this line of reasoning with those inj's

Not many peeps use 39's

If you stay with the main stream kind of parts ..........

You can get more help from other peeps
cause
They can relate more to what you are doing
cause
They have had experience with doing what you wanna do

Also ... You can find other combos using similar parts to yours
on the other sites :Word:

Hey ... When it comes to teaching yourself to self tune

You can ALWAYS find help through research MUCH quicker
than asking a bunch of Q's
AND
You learn at a MUCH faster rate as well

Well ... At least ... Thats how it was for me

Grady

 

[final5-0]

Good question. Also..Would you be able to bolt the Ligtning meter on with the matching injectors, and roll with it as is?

Go back and read this thread over again

You are still thinking like the masses

You need to unlearn all that junk

I am not pickin on ya

I am sayin ... Go over and over the info until you grasp it

You won't be much of a self tuner
if
You don't comprehend this stuff

Its that important :Word:

Again ... I spent a GOOD bit of time trying to get my head around it

Grady

 

[final5-0]

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.

By the things you have said and the Q's you ask

I can see you have put in some time to learn the basics

That kind of thinking
IMHO ... It will almost 100% guarantee your success with self tuning

You just have to expose yourself to all this stuff
and
Give yourself enough time for it to start and sink in

It really will make more and more sense as you go on :Word:

Grady