MSD wiring question

[Paul Thomas]

We are using dual MSD units on a twin plug project. Can i run the 10 gauge power wire from the MSDs directly to the post on the starter where the battery wire hooks up?

Paul

[fred cook]

Each MSD unit should pull approximately 7 amps at 7,000 rpm and probably only about 3 amps each on startup. So if you are comfortable pulling an extra 6-8 amps thru the starter circuit while cranking the engine you should be ok. If you are going for a really high performance setup, you might want to run the circuit straight from the battery. I am running a single MSD unit on my SC and have the main power lead coming from the starter. So far I haven't been able to discern any change in the sound or starting capabilities of the starter.

Good luck with your project!

Fred Cook
'80 911SC coupe

[Randy Webb]

Where is the best place to tap into the starter circuit? At the terminal on the starter itself? Or is there a better tie-in point somewhere?

[VaSteve]

When we installed mine we hooked it to one of the fuses on under the plastic cover ahead of the fuse (unfused). It's a long way to the starter assuming you're installing it where the CD box is.

[Paul Thomas]

Since two boxes are little bulky, i relocated them to the rear.



Here is the distributor trial fitted in the motor.

[fred cook]

It actually takes no more than about 3 feet of wire to get to the starter post. There is not a lot to tie the wire down to between the starter hot post and the engine compartment and wires under cars need protection so I put the power wire inside a piece of vacuum line to "armor" it. I also replaced the 3 fuse panel in the engine compartment with a 4 flat fuse unit and wired the power lead thru a 20 amp fuse "just in case". I think you will find that 2-3 feet of 10 gauge wire will have a negligible resistance drop. Just make certain to use the very best connectors that you can find/buy.

Fred Cook
'80 911SC coupe

[Randy Webb]

Here's my question -- Is it better to make that 3 foot run to the starter terminal? Or to make a shorter run to the fuse area?