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Re: [T3] upgrades to stock-FI motor?


On 20 Sep 2006 at 20:19, Dave Hall wrote:

> > I've got an exercise circuit on a breadboard, but I need to resurrect it and
> > make a permanent version. It's adjustable in pulse frequency and pulse width.
> > Once done, I need to mount it to the same framework and set it up to get power
> > from the same 12 V source as the pump.

> Are the main injectors 12V, Jim?
> I thought I read they are less, but the cold-start one is 12V.  Maybe that's
> urban myth though.

Yes, the D-Jet injectors are 12 V. You can tell that if you take apart one of 
the Bosch testers; they just send 12 V to the injectors for testing. In the D-
Jet brains, there is a power transistor acting as a switch for each pair of 
injectors, so in normal operation the pulse sent to an injector is just the 
system voltage minus the saturated voltage drop across that transistor, which 
is probably around 0.5 V.

The L-Jet injectors are different. They use a series resistor for each injector 
to drop the voltage and eliminate inductive ringing. I'm not sure how the 12 V 
ends up getting divided between the injector and the resistor.

-- 
Jim Adney
jadney@vwtype3.org
Madison, WI 53711-3054
USA

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