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914World.com _ 914World Garage _ Hey Brad!!

Posted by: Lawrence914-6 Apr 3 2003, 07:01 PM

I got the coil in two days from Summit... just like you said! Cool service.

Question: the instructions say something about a ballast resistor with a points setup. Do I need this, with my CD box and points?

-Rusty

Posted by: rick 918-S Apr 3 2003, 08:58 PM

I have an MSD 6A and a Blaster Coil on my BMW 2002 with points. I needed to run two ballest resistors in order to drop the voltage to the contact set to around 4 - 6 volts. I tried using the Blaster Coil with the stock resistor and then with the replacement provided with the coil but I was burning points about every ten minutes or so. The directions don't seem to be clear about adding the second resistor. They seem to suggest replacing the stock one with the one provided with the coil. At least that's what I read into it.

Posted by: jkeyzer Apr 3 2003, 09:01 PM

I thought the MSD hardly sent any current at all through the points. How could it be burning them??

BTW I have a 6A and a blaster coil in the 911 and no ballast resistor. But I am using a Pertronix.

Posted by: rick 918-S Apr 3 2003, 09:05 PM

It's the Blaster Coil that does it. Your Petronix isn't effected.

Posted by: Brad Roberts Apr 4 2003, 01:58 AM

LB,

(I have been out of pocket preparing for a race this weekend)

You should not need the ballast.... BUT keep a set of points close by just in case. It been quite a while since I ran points with a MSD. My gut feeling says you wont need it with the CD box.

B

Posted by: jkeyzer Apr 4 2003, 02:05 AM

The coil should not matter. With an MSD you do not connect the coil to the points in any way - it is through the MSD box. The MSD has both a positive and negative wire that are separate from everything else and go straight to the coil - you're not even supposed to ground the negative wire to the engine at the coil.

It is my understanding that the MSD just sends a trickle of current through the points like the stock CD unit on a 911. That small current triggers the coil current separately.

Posted by: Brad Roberts Apr 4 2003, 02:09 AM

Yep. The stock CD box functions just like the MSD 6AL (except the rev limit)

B

Posted by: Lawrence914-6 Apr 4 2003, 05:29 AM

Hey Brad,

Thanks for the quick reply.

I'm not using an MSD CD box. I'm using the Bosch, and maybe a Permatune in the future.

-Rusty

Posted by: si2t3m Apr 4 2003, 10:06 AM

Here is the way i see it (and please tell me if i'm wrong).

The points only send a signal to the CDI box or MSD box.

The CDI box sends the mega spark or signal to the coil.

Coil sends the big spark to the Dizzy cap

Dizzy cap & rotor bring current to the proper sparkplug wire.

Wham, you got spark at the sparkplug and hopefully an explosion in the combustion chamber.

Marc-André

Posted by: Lawrence914-6 Apr 4 2003, 10:26 AM

Yeah, that's pretty close to correct, except you forgot points in the loop (for stock cars like mine).

If you increase the output of the coil, then you put more wear and tear on the points.

-Rusty

Posted by: Lawrence914-6 Apr 4 2003, 12:13 PM

I called MSD. They told me that with the stock Bosch CD box, I shouldn't need the ballast resistor.

Cool.

-Rusty

Posted by: Brad Roberts Apr 4 2003, 12:18 PM

BLOW IT UP Rusty....LOL

B

Posted by: Lawrence914-6 Apr 4 2003, 12:20 PM

Nope... don't need to blow up a third box.

Are you rattling my cage?

-Rusty