Topic: OK to use 10 watt resistors with green dyna coils?

[Duke McDukiedook]

I think it should be okay but looking at Mark's pictures it looks like he was using 1 Ohm 25 watt resistors with the 3 ohm dyna coils to lessen the load on the system.
Is it OK to use 10 watt before I start soldering it together or should I try and get the 25 watt ones?

[Swoop]

HM told me he used 10's which he found to be overkill and he now uses 7.5's
I bought the 10's for mine to be safe.
FYI

[Bodi]

If the coil is ON, resistor power dissipation is around 10W. (12V on 4 ohms is 36W, 1/4 of that will go to the resistor). But the coil is not always ON... and the other 24W would get that coil steeenking hot in short order if it were. Actual power dissipation while running depends on dwell angle, and the real current with pulsating DC through a coil isn't exactly E**2/R because it's an inductive load. 7.5 watt rated resistors will be fine, if you have room for 10W that's fine too. It would be best to have the resistors coupled to a heat sink, being held against the frame would work.

[Duke McDukiedook]

I mounted them to an aluminum L bracket like in the picture so that should sink off some heat.

[Jerry Rxman Griffin aka MuthaF'er]

Sell your 3ohm and get some 5ohm

[Sellsme]

How do you  know if you have 3 or 5 ohm?

[Swoop]

Usually green is 3 ohm...or just measure the primary with an ohmeter.

[Duke McDukiedook]

Sell your 3ohm and get some 5ohm

I have wasted waaay too much time on making the 3 ohm resistor thingy happen to go back now.

[Duke McDukiedook]

How do you  know if you have 3 or 5 ohm?

3 ohm dyna coils are green and will say so on the coil. Like dowel said the easiest way to find out is measure the primary with an ohmmeter. if it is a stock Honda coil it should be 5 ohms.