Can anyone help. I'm fitting a Stack unit to my cosworth and i have to fit a 47K ohm resistor to the coil. Can anyone tell me where i can get one from

 

try RS components mate

 

Had a look on their web site and book, but nothing at 12v

 

Look for Wattage rating not Volts.
W= V x A

 

As ROD says you need to know the wattage, the resistor is the easy part, but get one too weak, wattage wise and it will burn out.
When you know the wattage look for CERAMIC resistors, if you get stuck pm me with the details, they're a only a few Ł's, so no biggee.
They may well be rated at 500V or more but this is as said irrelevant.
tabetha

 

i'd look at maplins fella, have loads of items in stock.

 

Thanks for the info guys. The Stack unit has to be connected the negative terminal of the coil for engine speed. I've had a look through the Stack manual and it doesn't tell me any tech as to what the amp is. I thought that the resistor had to be D.C. voltage and not A.C. mains

 

Resistors don't care what the type is ac or dc, obviously with ac they need to be half the resistance as they only have half the live, ie one negative wave and one positive, they only need to resist the positive.
What exactly does the manual say, if it's connected the the LT side of the coil negative why does it need a resistor externally mounted ?
PM me the exact ecu model and I'll check with me wiring man as he's bound to have done looms for these before.
tabetha

 

Hi, the Stack model is ST8130. When connecting to a Ford a 47k ohm resistor is required. It just says ' For system which require series resistor on the engine speed wire the resistor must be connected directly to the negative terminal to limit interference from the high tension leads.