[DML] Re: EFI? Megasquirt?

["content22207" <brobertson@xxxxxxxxxxxx>]

Thought some more about dual fuel metering:

The absolute easiest setup would be to use the carbureted manifold for
both metering systems. If you installed a carb with a rheostat on the
throttle plate shaft you could even use it as the EFI throttle plates
as well. In carburetion mode, simply unplug EFI injectors. In EFI
mode, simply turn or cap off the carburetor fuel line. Unfortunately I
don't know if such a direct route into the heads would deliver the
performance you want.  Fuel injection tends to route the air around
its elbow before dropping into the heads, whereas carburetion sends it
straight in. Would be a unique setup, however.

Other thoughts:

Even if you swap out the entire manifold, there's no need to swap out
the EFI fuel rails. Simply unplug them. Idle injectors will seal the
heads as well as bolts would. Just ensure the EFI rails don't overlap
the manifolds so you can easily swap them.

If you use two different throttle devices the accelerator cable will
need to be modified to reach two different positions. Easiest way to
do that would be to cut its sheath at the point of the closest
throttle. When that device is installed, pull off the remaining sheath
and attach the throttle plates to the cable now exposed. When you
switch to the other device, put that piece of sheath back in place and
attach the throttle plates to the cable further out. You might need to
solder the cable end to prevent it from fraying as you insert and
remove a piece of sheath.

To plumb two different metering devices, simply put a tee in the
outbound fuel line. One side of the tee would pass through a regulator
that cuts the pressure to 4-6 PSI before going into the carb. The
other side of the tee would send full tank pump pressure to the EFI
system. When the carb is installed, simply unplug the injector rails
so they don't fire. When the carb is removed, simply plug its side of
the tee with a bolt (4-6 PSI is very easy to cap off). Remember that a
carburetor does not need a return line to the tank -- you only need
one tee. High pressure fuel passing through the idle EFI rails and
back to the tank while the carb is active won't bother a thing.

I still however like the idea of two different metering systems
installed simultaneously. Would be very unique.  

Bill Robertson
#5939

>--- In dmcnews@xxxxxxxxxxxxxxx, "mydmc5898" <mydmc5898@...> wrote:
>
> I'm considering doing this. I just changed the frequrency valve in my 
> car, to try and fix a high idle. (No luck) Anyway two of the hoses 
> snaped like twigs. I had put in a new distrubitor, injectors, had 
> almost all the parts replaced since maybe January of 2006. But the odds 
> and ends. 
> 
> But I'm getting tired of the high idle (2000rpm), and fuel problem 
> after problem. Well you guys know the story. I could never stop owning 
> this car, but I just want it to work.
> 
> Is there anyone on this list that has done it? I tired looking at stuff 
> on the internet, reading about it, trying to see what parts I need. But 
> if anyone could send me an email about how they did it, I would greatly 
> appricate it.
> 
> thanks!
> -Darryl
> 5898
>




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