Injectors and resistors

[Steve Lamb]

>>My next major project is to get an 808 ecm to drive a Nissan VG30DET
>>engine.  This a 3L Quad Cam 24V single turbo engine.  We believe we
>
>Is that the engine found in the Maxima over here (USA)? (no flame)

Not sure really.....but I think it's very similar to the engine used in
late model US spec 300ZX's, although they had an extra turbo.  The engine
is actually to be installed in a 260Z.  A friend bought it cheap, but with
no ecm, thus the interest in the Delco stuff because it is cheaper than the
aftermarket systems over here.

>>I'm reliably informed that the 808 will not drive 6 low impedance
>>injectors.  One alternative would be to change the injectors, but this
>>would add quite a bit to the cost.  Another possible alternative is to
>try
>>what Nissan did with its early L-Jet based systems......use a resistor
>in
>>series with each injector and thereby increase the total load (?) seen
>by
>>the injector driver.
>
>I haven't tried it but I'd guess that'd work.  Surely it would limit the
>peak current to the proper value.  However - the time for the injector
>to open will be extended.   Don't know if that will be a problems or
>not...
>
>I'd suggest trying the resistor trick and watch for problems at idle
>(when the fuel delivery is low and I'd guess any problems would be
>revealed)...

These were the sorts of things I was worried about.

>If that doesn't work you could use any number of peak-and-hold injector
>driver chips to drive your 2.5 ohm injectors.  Roughly, you would
>connect the injector outputs from the 808 to the drive inputs of the P-H
>driver chips.  Someone recently posed the part number/URL of such a part
>from Cherry and/or Linear Tech...  Looks fairly straightforwards.

I've actually got some LM1949's and getting the Cherry's should be no
problem.  This would be the next step in the event that the extra resistors
or other options didn't work !!

>Let me/us know if you need advice about doing this!

OK, thanks


Steve Lamb
Department of Defence, DSTO
Aeronautical and Maritime Research Laboratory
506 Lorimer Street
Fishermans Bend  VIC 3207 Australia

Tel: +61 3 9626 7525
Fax: +61 3 9626 7089

IZCC #180