Upgraded Ignition Requirements?

[jakub421]

Hi!
Looking at upgrading my ignition as stated in the FAQ:
"
77-79 & 80-83 Hi Performance Ignition

Cap and rotor from 77-79 model
Wire set 110-8025 from Jegs: $66.99
Bosch Red Coil: $37 from Ireland Engineering
AR52 spark plugs: $12 from Jegs.

For the '77-79 models, you will want to convert to electronic ignition first. The points won't like the hotter spark of the red coil. The '77-79 cap is socket style which allows for more wire options, like American V8's. The rotor has a smaller nose so it has less spark scatter at high rpms. The Bosch red coil allows you to run a higher gap, up to .050". To run the red coil, you have to either swap to the 77-79 cap, rotor, and plug wires to have compatible fittings, or you have to swap one end on the coil wire to the socket style fitting rather than the post style used in the 80-83 wires. Also, to run the AR 52 plugs, you have to use the older style plug wires due to the non-removable cap on the plug tip.

For more info, see this thread:
Help with Bosch Red Coil
"

I have a '78, so I already have the required distributor, wires and plugs are no issue.

The only question I have is about the Bosch Red coil.
On the coil, it states: Use only with external resistance 1.8 ohm or electronic ignition. The FAQ doesn't mention anything about the ballast resistor.

I am currently running Pertronix 1847V, ballast wire bypassed and replaced with a 0.9 ohm resistor and Bosch "Black" coil 00010.

Does the Bosch Red Coil require a 1.8 ohm ballast resistor, or can I just run it on straight 12V with the Pertronix ignition?
I haven't really been able to find a direct answer.
Thanks!

[gsumzzz]

I believe that Pertronix needs a 3 ohm or better coil. the blue bosch should fill the bill. the pertronix craves 12v minimum (test the readings at the distributor). my '78's original wire was only reading 11.1v. if you got a 1978 e21 that power "ballasted" wire from the fuse box is probably toast (wire will be dried, brittle and plastic insulation cracks away easily). i just routed in a new length of wire from the fuse box to the distributer. the results were a quicker start, smoother idle and improved acceleration above 3000 rpm. good luck. this electronic ignition upgrade in the pre-facelift cars is the best performance upgrade bar none.

[epmedia]

There is a 1.8 ohm ballast resistor (ceramic style) that is suited for the Bosch Red coil for when using points.

https://www.authenticclassics.com/Bo...uth-004354.htm

More reading I saw here, good info..

https://www.burtonpower.com/hp-coil-...221119031.html

[jakub421]

What if I have Pertronix electronic ignition already equipped? Do I still need a ballast for the coil?
My current setup is:

12V from fusebox -> 12V to pertronix and 0.9 ballast resistor -> voltage through resistor -> ballasted voltage to Bosch 00010 coil

[jakub421]

Thanks for the help guys, I actually think I've found my answer for the pertronix manual:
"
Q. What type of coil do I need?
A. The ignitor is compatible only with a “points type” coil. Eight cylinder enginesrequire a minimum of 1.5 Ohms of resistance in the primary circuit. Four & six cylinderengines require a minimum of 3.0 Ohms of resistance (primary).
"

So for the M10, a 1.8 ohm resistor would be required as stated on the Bosch Red Coil 00013.

It might be useful for anyone attempting the modification to update the FAQ to include ballast resistor also.
THanks

[autox320]

Thanks for the help guys, I actually think I've found my answer for the pertronix manual:
"
Q. What type of coil do I need?
A. The ignitor is compatible only with a “points type” coil. Eight cylinder enginesrequire a minimum of 1.5 Ohms of resistance in the primary circuit. Four & six cylinderengines require a minimum of 3.0 Ohms of resistance (primary).
"

So for the M10, a 1.8 ohm resistor would be required as stated on the Bosch Red Coil 00013.

It might be useful for anyone attempting the modification to update the FAQ to include ballast resistor also.
THanks

Didn't realize my original setup was in the FAQ. That was my old autocross performance ignition setup early 2000's (E21parts) ignition set but used stainless wires

Our rig now we use
Pertronix ignitor II (allows 0.45 ohm primary coil and has adaptive dwell)
0.45 ohm pertronix flamethrower ecore coil (60104)
Magnecor wire set for 1980-1983 BMW 320 (45295)
later style 1980-1983 distributor cap (pin locking style) (always use Bosch brass/copper only)
1977-1979 rotor button with resistor delete (can source ones premade from IE)
And of course a TII mechanical advance distributor (RaceTep or IE) Not really recommended for street use due to super fast advance ie adds +22 degrees by 2000rpm (all in like a light switch)
NGK vpower plugs for your application ie heat range and gap (modified with cut back ground electrode and gapped .035" due to motor setup)

The standard Pertronix ignitor and hotspark units can only run down to a 3 ohm primary coil to keep from burning up. The later II model can handle switching down to 0.45 ohm. Can always use 3 ohm or higher with either.

Edit: guess could throw in that yes the red coil would need ballast since primary is low around 1.2 ohms. I used to run the red coil without the ballast using the original 1983 BMW stock electronic ignition and the setup like the first post. Was many years ago but it did work and worked well. Was hot stuff for the time.