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mysocal911 mysocal911 is online now
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Join Date: Feb 2014
Location: Lomita, CA
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Quote:
Originally Posted by Jonny H View Post
Really? What about motorcycles? "
They pretty much all still use CDI.

What motorcycles other than single/dual cylinder, or two cycle? My GSX1000R doesn't use CDI. It uses COP (coil on plug).

Quote:
Originally Posted by Jonny H View Post
OEMs don't use CDI on mainstream cars because inductive is cheaper.
That's one factor. Another is than CDIs have higher failure rates.

Quote:
Originally Posted by Jonny H View Post
Another factor is that modern engines run lean mixtures which suits the longer burn of inductive. 911s do not
In high revving, rich mixture and high cylinder pressure applications, CDI is favoured.
You are aware that Porsche produced air cooled engines after the 911SC (CDI), that no longer used CDI, e.g. 911 3.2, 964, & 993, right?


Quote:
Originally Posted by Jonny H View Post
If you look at racing, high revving or high cylinder pressure is usually the driver, but in some cases plug fouling is the reason
It's of little relevance to relate the air cooled Porsche cylinder head design to a F1 head design to rationalize use of CDI over an inductive discharge ignition.
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Dave
Old 05-09-2021, 09:15 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #27 (permalink)