I've been asked about mafs, inj's, and how a Tweecer makes any maf work with any inj.
Rather than answer in a pm, I wanted to make the reply available to all since we've had a new crop of noobs lately.
While I've given basic info about this subject before, and I've got what I believe is helpful info on my site, the article is a done in a lot of tech speak. I wanna lay it out one more time cause I think I've found a more simple way to present the relationship between all three ... but ... I guess you guys will have to be the judge of that.
I can't promise this will be short
but
I'm really gonna try and keep it ... SIMPLE ... sooooo ... here we go!
I'll answer the easiest Q first.
NO!!! The Tweecer can't make any maf work with any combo.
We all know the GT & Cobra use the exact same maf.
This maf was designed by Ford to report airflow a GT or Cobra can generate with a bit more breathing room up top as well. It just so happens ..........
for THAT amount of airflow ............
you need 19's or 24's.
Notice the maf was designed for airflow and NOT for inj size.
This is where we need to drive home the idea of ... mafs report airflow
and
That airflow is then converted to a voltage which is sent to the pcm
Say you bolt on a blower and you peg that oem maf.
That happened because at say 4500 rpm, you exceeded not only the amount of airflow a GT or Cobra could generate ... you as well exceeded the maximum amount of airflow Ford designed that maf to deal with.
For all practical purposes ... you generated airflow at 4500 rpm that was converted to a maf voltage of 5.0 volts. The pcm can only accept a maximum maf voltage of 5.0 volts.
The Tweecer can do nothing to make the oem maf work in this situation.
You now have to go to another maf that has the ability to
accurately report more airflow.
How about using a different oem maf?
How about using one from a Lightning?
Same kind of deal as above in the fact that Ford designed it to handle the airflow a 351 cubic inch blown motor can generate. Once more, just as in our example above, they did not design that maf to be used for 42 lb inj's. The deal is this ... if you've got a motor that can produce that amount of airflow, you are gonna need that size of inj's to adequately supply its fuel needs.
Here is where we bring in the Tweecer to help us make it all come together.
How we do this is we use data supplied from Ford about the Lightning maf that tells the relationship of airflow to voltage. This data can be called the meter's transfer curve you've seen so much talk about before.
We've now got a maf that won't peg or report 5.0 volts.
You could look at it as ... things are now similar to the original oem setup in the fact that we've got maximum airflow at say 75% of the capabilities of the maf.
Now ... The most important thing to see here is this .........
We've now got all this going on with the additional blowers airflow
and
We are ACCURATELY reporting airflow ........
Just as we did with the little oem meter and oem GT or Cobra motor.
We also will need to use the Tweecer to accurately report to the pcm about our new inj's size such as 36, 42, 55lb, etc.
So now we got the pcm understanding TRUE airflow in a voltage range of 0 to 5.0
and
It also understands that amount airflow will be used with 42's NOT 19's.
Well ... Thats about it!
and
I hope the info was laid out in a fashion that was relatable
At this time ... We'll not go into after market mafs and the method after market maf manufactures employ at an attempt to allow their customers to use their meters without a tune.
If anyone wants go go into that, we can always do it but ... I felt this was plenty to get across for now.
Also ... I used a Tweecer to manipulate the pcm values in this little example cause the Q came from a Tweecer user but other methods such as different self tuning interfaces or chips do basically similar things with airflow and inj values.
Grady
Rather than answer in a pm, I wanted to make the reply available to all since we've had a new crop of noobs lately.
While I've given basic info about this subject before, and I've got what I believe is helpful info on my site, the article is a done in a lot of tech speak. I wanna lay it out one more time cause I think I've found a more simple way to present the relationship between all three ... but ... I guess you guys will have to be the judge of that.
I can't promise this will be short
but
I'm really gonna try and keep it ... SIMPLE ... sooooo ... here we go!
I'll answer the easiest Q first.
NO!!! The Tweecer can't make any maf work with any combo.
We all know the GT & Cobra use the exact same maf.
This maf was designed by Ford to report airflow a GT or Cobra can generate with a bit more breathing room up top as well. It just so happens ..........
for THAT amount of airflow ............
you need 19's or 24's.
Notice the maf was designed for airflow and NOT for inj size.
This is where we need to drive home the idea of ... mafs report airflow
and
That airflow is then converted to a voltage which is sent to the pcm
Say you bolt on a blower and you peg that oem maf.
That happened because at say 4500 rpm, you exceeded not only the amount of airflow a GT or Cobra could generate ... you as well exceeded the maximum amount of airflow Ford designed that maf to deal with.
For all practical purposes ... you generated airflow at 4500 rpm that was converted to a maf voltage of 5.0 volts. The pcm can only accept a maximum maf voltage of 5.0 volts.
The Tweecer can do nothing to make the oem maf work in this situation.
You now have to go to another maf that has the ability to
accurately report more airflow.
How about using a different oem maf?
How about using one from a Lightning?
Same kind of deal as above in the fact that Ford designed it to handle the airflow a 351 cubic inch blown motor can generate. Once more, just as in our example above, they did not design that maf to be used for 42 lb inj's. The deal is this ... if you've got a motor that can produce that amount of airflow, you are gonna need that size of inj's to adequately supply its fuel needs.
Here is where we bring in the Tweecer to help us make it all come together.
How we do this is we use data supplied from Ford about the Lightning maf that tells the relationship of airflow to voltage. This data can be called the meter's transfer curve you've seen so much talk about before.
We've now got a maf that won't peg or report 5.0 volts.
You could look at it as ... things are now similar to the original oem setup in the fact that we've got maximum airflow at say 75% of the capabilities of the maf.
Now ... The most important thing to see here is this .........
We've now got all this going on with the additional blowers airflow
and
We are ACCURATELY reporting airflow ........
Just as we did with the little oem meter and oem GT or Cobra motor.
We also will need to use the Tweecer to accurately report to the pcm about our new inj's size such as 36, 42, 55lb, etc.
So now we got the pcm understanding TRUE airflow in a voltage range of 0 to 5.0
and
It also understands that amount airflow will be used with 42's NOT 19's.
Well ... Thats about it!
and
I hope the info was laid out in a fashion that was relatable
At this time ... We'll not go into after market mafs and the method after market maf manufactures employ at an attempt to allow their customers to use their meters without a tune.
If anyone wants go go into that, we can always do it but ... I felt this was plenty to get across for now.
Also ... I used a Tweecer to manipulate the pcm values in this little example cause the Q came from a Tweecer user but other methods such as different self tuning interfaces or chips do basically similar things with airflow and inj values.
Grady