ALternative to VB921?

[McAdam]

I stumbled upon these little gems in the junkyard. they came off of 1989 to 1994 nissan maximas with a vg30e engine in them. they appear to have teh exact same function as a VB921.

would I go about wiring them in in the same way as a vb921? could I run one of these off of FIDLE setup instead of an HEI 4 pin, with dwell control turned on?

its the transistor in the bottom right portion of the jpg.

[jakobsladderz]

If, as the diagram seems to indicate, this is just a transistor then you may need a high current driver to the input. I've used MJ10012 darlingtons for my setup and they use a 100 ohm resistor to 12V to turn the transistor on, that's like 120mA. I wouldn't ask more than about 10mA from a processor pin at most. If the transistor is not a darlington you'll need more like 300mA or more (to drive 7A into the coil).

Also, these transistors will have no current limiting built-in so they'll happily cook the coil if something goes awry..

Could definately be made to work but with the VB921's at $5.50 each, why would you bother?

[McAdam]

I found some infor about the power transistor......

the ignition signal from the ecu is amplified by the power transistor, which turns the ignition coil primary circuit on and off, inducing the necessary high voltage in the secondary circuit to fire the spark plugs. Ignition timing is controlled according to engine operating conditions, with the optimum timing advance for each driving condition preprogrammed into the ecu memory.

help clear things up?

I only ask this because I can go to a junkyard and pocket 6 of these things today, where as I have to wait on shipping for tghe vb921s. and shipping over th 4th? HA!

[McAdam]

so, can this be fired directly off of the ECU a la vb921?n or wire it up like a 4 pin hei through fidle?

sorry, still kind of a noob here...

oh yeah, here is a drawing of what it looks like.... its bolted to the front cylinder head, rught under the dist on a 1989 to 1993 maxima with a vg30e.