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ignition coil for m20?

Guest Anonymous

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Guest Anonymous


The number is #0 221 118 335. A friend who is the local distributor wizard tested a bunch of coils for us and the blue one was no better than a stock 2002 coil. The red one was better but the MSD Blaster coil was best of all.

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Guest Anonymous

So on my '02 I had bought a Bosch Blue Coil and Crane XR700... now that I am putting in my m20 engine.. and didn't get the stock coil with it.. can I just use the Bosch Blue Coil with no issues?

BTW; if anyone is wondering, the reason I'm posting all my m20 questions here is really for the sake of the archives.. after all, the engine IS going into the '02, and I know others will be doing the same (or ARE doing the same)



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Guest Anonymous

what are you using for a dis? if you are useing the euro sidemount then you need the stock electronic coil. on my next engine i am going to use a full MSD setup. and the euro sidemount distrb. will just act as a trigger, like it does now, but with much more ZAP!!!

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Guest Anonymous

having said that.. the blue will still work 'fine' or no? I really don't wanna spend any more money on this 'phase'.. i already 'have' to order shorty headers today..thats gonna hurt the pocketbook.



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Guest Anonymous

Thanks to that lost genius, XbetenoirX.

Confirmed it about a month or two ago with the Bosch Ign. Parts spec book at a local tech's shop - it's all true.


'76 --------

Posted by XBeteNoirX on October 22, 2000 at 22:58:04:

In Reply to: Theory, please. posted by mikeS on October 20, 2000 at 13:09:53:

(posted from: spider-mtc-td023.proxy.aol.com (

Bosch lists four types of coils for induction type ignition systems. They are:

Type E(Black)6V-12V systems for 4 cylinder engines. No resistor needed. Output 13.5 KV.

This was the type commonly found on small 4 cylinder engines i.e. Volkswagen, etc.

Type K(Blue)6V-12V systems for up to 6 cylinder engines. No resistor needed. Output 17.5KV.

This was the type commonly found on 6 cyl VW and as a performance upgrade for 6V systems and lower power 12V systems. Should never be used on BMWs.

Type KW(Black) 12V-24V systems for up to 6 cylinder engines. Output 22.5KV. For 12V operation use ballast resistor 0.6-1.0 ohms, for 24V operation use ballast resistor 4.5 ohms. This is the coil that came standard on all BMW engines. As you can see going to a Blue coil would be a significant step backwards.

Type KW(Red) 12V systems for up to 8 cylinder engines. Output 26.5KV. Use with 1.4-1.8 ohm ballast resistor. If the ballast resistor is omitted, the points will burn up very quickly. If a transistor trigger is used, then a ballast resistor is not required.

When a resistor is required, it should be placed in series with the igniton hot (12V) lead. It should be mounted with a heat sink since it will get quite hot.

All induction coils actually contain two wire coils, a primary and a secondary.

The primary coil contains a few hundred turns of thick copper wire. Since the wire diameter is large and the wire is short, the ohm reading is very low 0.8-1.4 ohms and the coil will conduct a substantial amount of current to the points.

Current flow to the points is a function of voltage, coil wire resistance and points closed dwell time. More than about 4 amps will usually destroy a set of points.

The secondary coil contains 15000-30000 turns of very thin copper wire. Since the wire is thin and very long, the resistance is high, usually about 12-18KOhms. Thats a thousand times more than the primary side. While the secondary coil does not flow high current, it does produce a very high stepped-up voltage necessary to jump gaps in the cap and spark plug gap.

Hopefully, this will settle the discussion regarding coils. For those who would like to know a great deal more about induction ignition systems, the best text is a training phamplet by Bosch called: "Battery ignition systems" part number VDT-UBE 120/3 En. It covers not only point type ignition but also transistor and CDI type ignitions. After reading the text throughly, you'll agree most information about ignitions is mere marketing hype.

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