Most EFI systems don't use the fuel pressure to vary delivery. Although it is not uncommon. On the Ford CFI system, I believe the fuel pressure is not dynamically varied, as in a "rising rate regulator" system.

In either case, the fuel pressure will have a drastic effect on correct operation, so be sure to set it appropriately. Think of it more as a baseline adjustment. The newer ford MPFI system does vary fuel pressure, but that is not the primary factor in delivering fuel flow.

In modern EFI systems injector pulse width is varied to affect fuel delivery according to calculated airflow ("speed-density", as in the CFI) or by direct measurement of airflow ("mass airflow" systems).

Quote:
I have never bothered looking for a fuel reg on a low pressure Throttle Body Injection system, But every Multi Point EFI system I have ever worked on has had a fuel reg.
Fuel regs have been discussed on here many times before.
What do you suggest a fuel reg is used for?
It regulates fuel pressure/return flow according to manifold pressures.
Without a fuel reg, what do you think fuel delivery will be like during varying manifold pressures? Fuel pressures and delivery rate would be all over the place and the ecu's fuel map would be all over the place and it would be very hard to have a fuel map that would be stoichiometric during various engine speeds and loads.
But yet its still been said a reg isnt used to vary delivery of fuel.
Fuel line pressure is regulated by varying return flow. If fuel pressure wasnt regulated - what do you think fuel delivery would be like?

Dont sit there and think, just because the computer doesnt adjust fuel pressure - that fuel pressure isnt used to control fuel delivery
Fuel pressure in conjunction with injector pulse widths is used to control fuel delivery.

If you yourselves cant understand factory fuel delivery - its pointless you yourselves trying to modify a system to work on another motor.

I think the idea of useing 2 of these ford Throttle Body Injection setups is more about sounding good, rather than being well thought out.

If you havent gathered im not a EFI specialist. but i got a few basics and i am open to critisim as it helps me learn a bit more. I wouldn't have thought that a little bit of vacum would make a differance to a 40psi fuel system. from what i got told a fuel reg keeps the pressure at 40psi roughly. i would think 15 psi boast would make an impact though thus needing a rising rate reg.???????? like i said i dont know i am just putting in a few ideas

for what your going to save, i would think it would be worth going to the extra effort of making a manifold...

sure it's not easy but not that expensive...

all the high costs involved in going for injection are still required for this setup (i.e. fuel system and computer)

Hey guys, I've been through this all before with an apprentice who wanted to inject his 1200 coupe. We adapted the CFI throttlebody from a N13 pulsar and used all of the sensors (adapted), fuel pump and computer that came with it. The computer is a Delco (GM) that is easily reprogrammed by most performance shops. I think that the main problem was adapting electronic ignition for the injector drive (still needs to be timed to the intake stroke)seem to remember an aftermarket system being used in the end. As this system is designed for a 1.6, it performed very well in the 1200 and an A14 that was swapped in later after a dynotune/program. Bottom line is that the ford unit will most probably overfuel the system- don't forget that with a carb you have a much higher incidence of unburnt hydrocarbons (fuel) passing straight through- hence the need to time the injectors with the engines firing sequence. Too much fuel can be just as bad in performance terms as not enough.

Just a quick note also that we played around with two of the pulsar throttlebodies on a 186 red but ended up putting a blue head and VK injection on instead.

Hope this helps!

http://www.perfectpower.com/Technical_info/throttle.asp

The main reason for the Ford version is because it is almost a bolt on compared
to the others available.
For those who must know who else made
throttle injection from factory cars 80-90s
Honda, Mitsubishi, Daihatsu, Ford and Suzuki.
However they are all difficult to adapt
compared to the Ford unit hence those
where simply scraped from the start of my
search as they also have pollution gear and
connections, tubes & solenoids everywhere.
The idea came simply from the Fords clean
and simple setup, although not as sophis as
MPFI its a cheap alternative to bolt to the
standard manifold with little difficulty.
However from the information Ive gathered
so far the Ford computer is a no go unless it
can be reprogramed by a piggy back device.
Using a custom computer will always allow
the possibility to upgrade to Multi point
system in the future as funds arise and if
you are chasing higher performance but in reality for the street, the Ford CFI on the
small four cylinders is more than enough. You have twin 36-40mm inlets similar to the
old Capri twin barrel 38mm dgv or something.
Ive pmed with the owner of the mazda 1300 with turbo and ford cfi and he runs
microtech for 127rwhp and hes very happy
with the CFI unit. Also another previous
owner of a 1200 ute with a12 turbo also
expressed the same but 110rwhp.
The ford CFI engines run well but are a
underpowered compared to MPFI because
the engine in the end is 3-4litres and you
never see since the 80s a big 6 with such a
small cc induction. Even my old 67 berz with
a 2.8 litre six had a 600cfm four barrel.

So for a small 4 cylinder it hasnt presented problems for the two setups mentioned or the one mentioned by Ding Dang on this thread. However it looks like a cheap setup for those who cant afford to muck around with MFPI and parts cost me less than 50 dollars from pick-a-part. I dont see a better setup using a factory manifold. Phunkey It will obviously never outdo your setup or any MFPI but it could be a nice alternative for that factory look as it can take a normal factory stock looking airfilter assembly with little effort.
As for the link above it states that the emmissions and burn is supposed to be cleaner thanks to better mixing with air before it enters the combustion. Great if true for those chasing economy with still more oomph.
As for the using a twin CFI setup... yes it does sound good and why not when these things are so available, cheap and can be mounted on their side also. Using 2 to have quad 36-40mm throttles with a custom computer? Its just an idea and with the price of the throttles it can be a cheap one for chasing performace.
DD the 80s for unit on the v8s have much larger cfm and different design but I know that the custom aussie 2 x CFI setup can make some serious hp with an aftermarket computer on an old cleveland XD Falcon (however your pic setup looks thirstier than the one Ive seen although the XD runs a clean 14.4).
As for the amount of posts, should have already packed my bags at 1000

Quote:
I dont believe DingDang said the ford throttle was ever used.
Do you have any website links that explain about the other 2 mentioned. I only see pics of one in the first link. Would be good to read about what was done.
So whats your plans for injectors?
I do believe the ford setup was good at the time for emissions, This was only better than the multi point setups that used injectors that squirted fuel. Multi point setups with injectors that spray, provided a more combustable air/fuel mix.
The exact difference can be shown in a little experiment.
* Splash fuel on a fire
* Spray fuel on a fire.
The difference can be seen 10 fold

The Ford CFI is not a low-pressure system. It maintains a 40 psi in normal operation. Call it medium-high if you wish. It's certainly not high pressure like a diesel injection system. Nor low pressure like carbureted systems.

Yes, the CFI uses a regulator. It is used to maintain a constant 40 psi.

The beauty of this idea comes from inexpensive, readily available parts, easily adapted to a stock manifold. If you can use a factory Ford computer, then the total cost could be very low. How much would the modification to a Delco unit run? The Delco controllers are available by the millions at junkyards around the world.

And don't forget its "sneaker" quality. Hide it under a stock air cleaner for a stealth effect.

Quote:This is an emissions-control problem and a slight fuel-economy problem, but not a performance problem. Most multi-port injection systems are not timed to the firing sequence. The Ford multiport "sequential" V8 system was, but the GM multiport system was not. The GM smallblock V8 made just as much horsepower.

Quote:
Maybe it might be worthwhile researching D's chosen CFI = EA,EB 3.9 6cyl ford falcon.
Might then rethink your stated pressure and then add a 1 to the front and drop the 0 off the end, leaving 14.
Quote:
And what effect does this have on varying fuel flow.
What effect would be shown if this fuel system wasnt regulated to vary flow.
On most fuel regs (cfi unknown to me) there is vacuum signal. Hows this effect pressure? and if pressure wasnt effected, why wouldnt the reg just be a pressure valve controling fuel return?

Picture:
"X" pressure in fuel line
"X" pressure exceeded - some fuel is bled off to maintain "X" pressure in fuel line.
Now put a vacuum signal like a normal reg
No vac - " X" pressure manitained like above
Vac - "X" now becomes less as it takes less than " X" pressure to bleed off fuel.

Show me a reg that maintains a constant fuel pressure and I will show you a pressure release valve.


Now back to my original post containing fuel pressure.
I dont care how this CFI setup originally controlled fuel.
I said." The original injectors will flow to much for a 1.5 litre engine. If you were to attempt to reduce this fuel flow by reducing fuel pressure. How much scope do you think you will have to reduce it considering the chosen CFI's original low fuel pressure."