Looking for some feedback on the dwell-time I'm controlling with a MegaSquirt3 ecu on a single coil streetdriven 360ci LA engine.
Electronic distributor feeding the MS3X the signal which controls a 7-pin HEI module to trigger the MSD Blaster SS coil.
I've read the Blaster SS can handle 4.2 - 4.5ms of dwell at 14v.
And I found firsthand too much dwell-time will cause the coil to auto-spark.
So erroring on the safe side I kept 4.2ms as the max charge-time of the coil, and ramp down as rpm goes up.
The car's alternator charge and ignition voltage is 14.7v and MegaSquirt's dwell battery compensation should be limiting dwell-time to around max 4.0ms.
I keep dwell at around idle fairly low to prevent heating up the coil for no reason.
Looking input if there's anything that could be improved or something you would do differently perhaps.
Digital dwell control
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- BigBlockMopar
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Digital dwell control
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Re: Digital dwell control
Where is peak torque and peak hp of the engine?
I'd move the pink blob to the right to match the spark output to the demand or just extend it to the right.
How far right is determined by the answer to the question above.
Holley fixed dwell control of an MSD box is 25* dwell so dwell time is constantly calculated relative to RPM.
One can also use adjustable dwell and fill in a KPa vs dwell time table similar to the MS3 table.
Unfortunately, I'm unable to find a good example as Holley sample files only use this option with DIS with dwell time starting at 4.5ms and increasing to 5.8ms at 100KPa.
I'd move the pink blob to the right to match the spark output to the demand or just extend it to the right.
How far right is determined by the answer to the question above.
Holley fixed dwell control of an MSD box is 25* dwell so dwell time is constantly calculated relative to RPM.
One can also use adjustable dwell and fill in a KPa vs dwell time table similar to the MS3 table.
Unfortunately, I'm unable to find a good example as Holley sample files only use this option with DIS with dwell time starting at 4.5ms and increasing to 5.8ms at 100KPa.
- BigBlockMopar
- Momentary Specialist
- Posts: 336
- Joined: Fri Mar 25, 2016 8:53 pm
- Location: Netherlands
- Contact:
Re: Digital dwell control
Peak torque is around 3750rpm and peak hp @ 4650rpm (CompCams XE256h).
For the moment still limited by restrictive iron heads and cam.
For the moment still limited by restrictive iron heads and cam.