Quote:
Originally Posted by AndrewCologne
@John
Could be Risky.
I guess the electronics in the DME use a dwell time of 2ms for saturation of the coil. As 3ms @ 6500 is the whole time between each spark and 2ms are at least needed for saturating the coil.
So with 12.5 volts at the Coil ....
Original BOSCH IDI Coil comes with 0.7 ohms and 3.6 mH and with 2ms dwell --> this results in 5.77ampere and 60 mj at the spark
MSD 8222 Comes with 0.7 ohms but with 8.0 mH and with 2ms dwell --> this results in 2.87 a and only 33 mj at the spark
So it depends on how or even if the DME varies the time of dwell. And even if it would seem like it works without problems, it "could" result in a non optimal ignition of the mixture. As IIRC at least 40 to 60 mj are needed to fully ignite the mixture in an optimal way. And here also the compression ratio counts (i.E. up to 10.3:1 with an Euro 3.2 engine and 231hp).
---> BUT if 33 mj are enough (I guess not), then ... trust on luck and even less amperes/heat are needed to be handled by the DME.
See also discussion here:
https://forums.pelicanparts.com/porsche-911-technical-forum/1151696-ignition-question-71t-s.html
And here:
https://nineelevenheaven.wordpress.com/the-ignition-of-the-911-3-0-and-3-2/ |
1. Yes, the DME ECM used for the 911 3.2 varies the coil dwell time.
2. The 8222 coil and the OEM 911 3.2 coils are basically identical. The website referenced below has had Bosch coil parameters included for over 25 yrs,
and referenced before here on this forum.
Check here for coil parameters under Typical Ignition Coil Values
https://www.systemsc.com/diagnostic.htm
Therefore, the spark parameters should be identical when using the 8222 vs the OEM Bosch coil!