View Single Post
Lorenfb Lorenfb is offline
Registered User
Lorenfb's Avatar
Join Date: May 2003
Location: Manhattan Beach, CA
Posts: 2,352
"Could this be the answer as to why so many of the CDS boxes have burned out."

No, that's not true. Again, to get a better understanding of how a CDI
system functions and what its' coil really does, read here: under Ignition Systems.

Porsche has correctly stated that the 911 coil functions as a transformer
versus a energy storage element as in a conventional ignition system.
Therefore, as a transformer, the Porsche CDI doesn't require the inductance
of a conventional coil and can be much smaller. The conventional coil
with its greater inductance causes no problem for the Porsche CDI.

The only problem for a CDI when using a conventional coil is a coil
with a turns ratio much greater than 100 which causes too high
of a spark voltage. Porsche coils' data are here:
Have Fun
Systems Consulting
Automotive Electronics

'88 911 3.2
'04 GSXR1000
'01 Ducati 996
'03 BMW BCR - Gone

Last edited by Lorenfb; 10-13-2005 at 09:42 AM..
Old 10-13-2005, 07:58 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #19 (permalink)