Commercial systems

[Hadzic Muhammed]

On Mon, 29 Jan 1996, Bill wrote:

> Although I am keenly interested in diy_efi, the schedule of my current
> project requires that I purchase a commercial system.  I seems that the big
> players are Haltech, DFI, and Electromotive.  Does anybody have any
> experience with any of these organizations?  I've spoken with them over the
> phone and although all seem to be knowledgable, have imparted more than a
> little confusion.  I'm told by a competitor of Haltech, for example, that
> Haltech is a "bank-fired" system.....meaning that after the calculations are
> complete, all 4 injectors on 1 side of a V-8 are fired simultaneously, then
> the sequence repeats for the other side, and so on.   Has anyone ever heard
> of such a system?  
> 
> I'm also wondering about how the effect of manifold vacuum or pressure
> affects the rate of fuel delivery, all other factors being equal.  For
> example, if a given pulse width results in 10 #/hr of fuel with a given fuel
> rail pressure, does that mean "on the bench"?  What happens when the same
> injector is spraying into a 10" or 20" Hg vacuum?  Does that tend to suck
> extra fuel.  Or what happens when the boost is run up to 20 psig?  Clearly,
> its the pressure differential that is at issue here.  And nobody seems to be
> talking about modulating fuel rail pressure in response to manifold
> conditions in an attempt to keep the pressure differential constant.  Is
> this really an issue, or am I making this more complex than it has to be?
> 
> Lastly, does anyone know of a commercial system that is soon to be retired
> in favor of a later model?  Or does anyone have a funtional DIY_EFI for sale
> at this time?  My parameters are as follows:
> 
>       Small block Chevrolet motor (377 cu in) in flat-bottom V-drive boat
>        (2) AiResearch TO-4 turbos
>        Powerglide
>        Crank-driven ignition
>        Gasoline fuel with methanol enrichment at higher power levels (>5
> psig boost)
>        6000 RPM maximum

I being fairly new to the DIY_EFI group also used it to learn more about 
EFI.  Being in my fourth year in Mechanical Engineering at Queens 
University I decided to add EFI to my motorcycle. as my thesis.  However, I 
knew I would not have time to design the electronics myself.  This lead me to research 
various EFI companies.  These included Motec, Accel, Electromotive, 
Haltec, Hahn Racing, RB racing, and EFI technologies.  From this group I 
found Electromotive to be the best choise for the cost.  Thier options 
including timing control put then at a lower cost than most competitors.  
Big warning about Haltec, I hear they may be going through some major 
restructuring there or they might be going out of business.  These are 
only rumours I've heard.  Besides they have the worst reputation of all 
the EFI companies I heard of.  They also gave me a 8 week run around on 
triing to get a firm quote from them.  They eventually did get me one but 
the run around makes me wonder about thier product support and future in 
the market.  I have also read a lot of trash talk about then on the 
Formula SAE net.  Many of the teams in the SAE competition like and use 
the Electromotive system.  I did end up purchasing the Electromotive 
system and just recieved it in the new year.  I haven't installed it yet 
but I hope to by the end of Feb.  I have more on the systen comparisons 
and contacts if you need it.

As for the fuel rail pressure, you can keep it constant by using a 
pressure regulator at the return side for the rail that is pressure 
regulated from the intake manifold.  Bosch makes a nice one for only 
about 60 CND.  Have par number if you need it, but you need to get an 
adaptor to make it pressure regulated.

Let me know what type of project this is (ie educational, thesis, 
personnal) because most places will give educational discounts.

If you need any leads on finding things I will help if I can.

Muhammed Hadzic
Queens University
Kingston, Ontario
Canada