Edelbrock TBI Conversion

[Shannen Durphey]

Jason Weir wrote:

> 
> TBI
> 
> 1 injector fires for every cylinder firing.
> 8 cylinders firing means 8 injector events, alternating 4 per injector
> 
> Edelbrock 7747 TPI Setup
> 
> 1 injector fires for every 4 cylinders firing

Huh???

> 8 cylinders firing means 2 injector events. 2 groups of 4 alternating

4 injectors fire for every ignition pulse

> 
> So my question did Edelbrock just put a divide by 2 after each original
> TBI driver and use that to trigger a secondary driver that fed the
> injector groups?  This is the only way that I can see how they might
> have made it work?  Any other ideas..
> 
> This brings up my application question.  When we are dealing with a V8
> things are easy its a divide by 2.. But what if I wanted to do the same
> thing on a 6 cylinder?  Now I have 6 injector events that I need to turn
> into 2.  Its not as easy to make a divide by 3.  Has anyone heard of a
> chip that could do this.. Customizable to do a divide by x, with just
> jumping pins or resistance to pins or whatever.

You're getting some strange numbers here.  Alternating batch systems
fire 1/2 of the injectors per ignition event, when in synchronous
mode.  The fuel pressure, injector size, and fuel map work together to
prevent creating a rich condition.  To prevent large amounts of
remappingin your case, the 3 port injectors together should flow as
close to the same amount of fuel as one TBI injector as possible.   
> 
> Any ideas???
Start looking up injector flow rates.
Shannen
> 
> BTW I am running a TBI right now but I've got the Multi-Port manifold
> just waiting till I can get the electronics figured out..  I know I
> could just swap the ECM to a V6 TPI computer but thats the easy way and
> them I have to learn a new ECM all over again, just when I almost have
> my 7747 setup running great.
> 
> Jason