dual 450 cfm TBI for 383 ci SBC

[rr]

I don't understand how this would work. How do you get the
newly driven PnH drivers to peak-droop-n-hold? All you
are saying is to use a big mosfet to drive the injectors.

The signal from the '747 is a bit on the strange side also. It
will go into the droop-n-hold without an injector on it. This
makes for a funny waveform to trigger from.

BobR.

don.broadus at exeloncorp.com wrote:

>   I suggested  to use a 100 ohm or so resistor. If you use a 1.2 ohm this
> will simulate 1 injector. The driver FETS for the other injectors will
> follow the on/off times off the 747.  This will fire additional injectors
> without digging into the 747 circuit. If your worried about not having peak
> /hold on the added injectors then you need to redesign the 747 driver, and
> then you wont need this adapter
> in this form.
>
> > -----Original Message-----
> > From: rr [SMTP:RRauscher at nni.com]
> > Sent: Monday, January 29, 2001 3:20 PM
> > To:   gmecm at diy-efi.org
> > Subject:      Re: dual 450 cfm TBI for 383 ci SBC
> >
> >
> > It's not that easy. Remember that these are peak-n-hold injectors. . .
> >
> > BobR.
> >
> >
> > don.broadus at exeloncorp.com wrote:
> >
> > > They would have to be P channel MOS fets since the 747 drivers go to
> > ground.
> > > put a 100 ohm or so load resistor on the the 747 output and the other
> > end to
> > > +12 VDC. the P Channel MOSFET turns on when the 747 driver goes to
> > ground.
> > > since P Channel FETS are hard to come by in high currents , It might be
> > > easier to use a inverter with a pull up and a N- Channel FET.
> > >
> > > Don
> > >
> > > > -----Original Message-----
> > > > From: Bruce Plecan [SMTP:nacelp at bright.net]
> > > > Sent: Monday, January 29, 2001 10:53 AM
> > > > To:   gmecm at diy-efi.org
> > > > Subject:      Re: dual 450 cfm TBI for 383 ci SBC
> > > >
> > > >
> > > > Stay tuned,
> > > > I got a new box here to try with some Honkin Power Mosfets in it.
> > Done
> > > > externally would be a min parts deal, just a good heatsink needed.
> > This
> > > > is
> > > > not intended as a daily driver deal, just a kludge to get the job
> > done,
> > > > and
> > > > for off road purposes......
> > > > It should last with 6 TBI style injectors.
> > > > Just need some TBI injectors to risk.
> > > > My first, *bad deal* has left me with a TBI injector shortage.
> > > > If some one has 6 or so junk TBI injectors that they don't need (but
> > > > function electrically), that would help.  They and the box will run
> > till
> > > > failure so they will be probably totally trashed....
> > > > Bruce
> > > >
> > > > > -> Other than building a driver box to control the 4 injectors, what
> > > > > -> kinks can people forsee?
> > > >
> > > > >  Can't you just use the output from the 747 to trigger a couple of
> > > > > Honkin' Big Transistors(tm)?  Or do you need to add extra stuff?
> > > >
> > > >
> > --------------------------------------------------------------------------

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