Re: 4.6L Ford MAF was Re: Heat crazed mad scientist

[Mike Wesley <mwesley@mediaone.net>]

Bruce Plecan wrote:
> 
> > One reason people switch to MAF is the ease
> 
> Oh, ease as in lazy?
> 
> of tuneability over the Ford

Well, not really. It's just that the Ford SD implementation in the older
5.0 Mustangs isn't the best, which are the guys who do alot of the
swapping. And there is a lack of tuning tools for the 5.0 Mustangs ( I
have some, just haven't released all of them). The trucks do well
though...bit different SD system in those. We dropped a 514 Ford Crate
motor into a 1994 Lightning, needed a few tweaks here and there, nothing
serious, just told it the new injector size and tweaked the fuel/spark a
bit. Ended up going 11.63/118MPH on pump gas in the 1/4 @ 4700#'s with
driver. Now I don't like big blocks, but thats pretty good.

> > SD system and the range a Ford MAF (when tweaked) can have. The MAF I
> > run on one of my Ford engines can measure about 5100 Kg/hr of massflow
> > which is quite alot. You don't even really need to do anything to the
> > ECM, just pop in new injectors and the MAF and your good to go.
> 
> That sounds like it would easily support 1000HP, and you say new injectors,
> MAF and ready to go?

Exactly :) The MAF is calibrated for 83#/hr injectors. Stock the car
came with 19#/hr units. 
I also have a 107mm MAF setup that will measure around 7400 kg/hr of
massflow. That's for 160#/hr Ford injectors that I may run on a turbo
car we are building.


>  Gads. I don't see how, but, I'll admit to being fussy.
> That's a hellva setup, the more I think about it, runs injectors 4 TIMES the
> size of oem, and the same base timing table...

It's kind of a trick how it works. What you do is scale the voltage
output of the MAF by tweaking the electronics to sort of 'fool' the ECM
into thinking it's getting much less massflow into the engine. Then you
install larger injectors...say the Ford(Bosch) 36#/hr units (dark blue
tops). What happens is when the engine is running, the ECM 'sees' much
less voltage from the MAF, so when it does the conversion to massflow,
it ends up with a much smaller value. The real massflow into the engine
hasn't changed so the resultant injector pulsewidth (which is now alot
smaller than stock) works out to give you roughly the correct A/F ratio
you want. You program the Ford ECM with desired A/F ratio. It figures
out what the puslewidths need to be to get to your target. Makes things
REAL easy. But you actually don't need to tweak the ECM at all for any
of this to work. If the guys who re-calibrate the MAF's do it right,
they run great out of the box.

Mike....
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