toyota injectors

[swagaero]

David Chambers wrote:
> 
> swagaero wrote:
> >
> > David Chambers wrote:
> > >
> > > Hi, I am building a computer to run a friends 20 valve 4AGE toyota motor
> > > in a race car. The question i have is does any one know the driving
> > > requirements for the injectors on this motor. All i know at this stage
> > > is that they measure 34 ohms coil resistance. I am hoping that these are
> > > high impedance injectors and can be all wired in parallel and fired by
> > > one FET to ground. Also does any one know anything about how the
> > > variable valve timing works on this motor.
> > > Thanks
> > > David Chambers
> >
> > Yes they will fire in parallel but it better be a big heat sunk fet.
> >
> > Steve
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> > www.flash.net/~swagaero
> I don't think the fet will get that hot. My calculations show.
>         14 volts/34 ohms * 4 injectors = 1.65 amps.
>         1.65 amps ^ 2  * FET Rds of 0.077 ohms = 0.21 watts
>         junction to ambient temp rise is 80 deg C/ watt
>         therefore Trise = 16.8 deg C or total T of max 61.8 degC at 45C
> ambient.
> Am i missing something here?
> David


Latch up at startup is *2 and you have the average only at low rpm 
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