I discovered the hard way this week that with the HEI module, the GROUND IS EVERYTHING!!!

I spent the past 8 hours trying to find out if I had a dead coil or module, only to discover that the bracket (similar to Dan's picture, but not exact) wasn't really tightly attached to the Module.

Some longer screws took care of it, but I have to say I was shocked at just how key this was.

Basically, GROUND the hell out of it!

It is also very important to use the paste that comes with the module on the contact surfaces with the heat sink, to ensure good heat transfer.

The GM heat sink is available from, among others, summitracing.com, for $14.95.

Olaf

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Aspenized

Be careful with using heatsink compund (or thermal grease). Heatsink compound is can an insulator; it's just not as insulative as air. It's job is to fill in the imperfections of the metal surfaces, the pits and whatnot that would never make contact between heatsink and module. But on all the peaks of the metal surfaces, you don't want that paste--it'll cut down on heat transfer.

http://en.wikipedia.org/wiki/Thermal_grease
http://www.techpowerup.com/printarticle.php?id=134

I've always told people to wipe it on, then wipe it off--that way it'll still be bare metal to bare metal (on the microscopic peaks)--or to not use it all. [Actually, when I design stuff, I prefer to avoid it altogether--but I'm not design high power anything.] I don't see that recommendation in the above two links, so I won't recommend that here: but I will say that, the odds are, you will want to be sparing on that grease. Unless, of course, there is more to the story (the GM compound is also anti-sieze, and/or it's the better grease with metal in it, etc).

The heatsink paste comes with the module, instructions are included. (at least with the LX-301 module from Standard)

Olaf.

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Aspenized