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Using PDM to control ignition cut for flat shift

PostPosted: Sun Oct 21, 2018 2:40 pm
by llew
Hi folks,

I will be shortly setting up a motorsport systems strain gauge knob and shift cut control unit on my soon to be delivered holinger.
Due to rules I cannot run an ECU, it's single coil distributor based ignition only for me. The motorsport systems control module's output trigger is a digital switch to ground for the specified cut duration (30-90miliseconds?). They sell an ignition interface module to cut power to a coil but was hoping I could use the PDM instead to simplify things.

Has anyone tried using the PDM to control a shift cut? My only concern was that if I set the trigger time for the input to 0 or close enough to it to still have a meaningfull response time for the shift cut that there might be some transient conditions that may cause switch bounce or just not be fast enough anyway to perform a reliable repetitious action in such a short timeframe.

Was looking for some reassurance before I try something that could potentially be an expensive experiment.

Cheers

Re: Using PDM to control ignition cut for flat shift

PostPosted: Mon Oct 22, 2018 7:45 am
by greenamex2
Why not fuel cut?

Re: Using PDM to control ignition cut for flat shift

PostPosted: Mon Oct 22, 2018 8:39 am
by Stephen Dean
Hi,

I have setup a PDM to do shift cut, I would not recommend it as the PDM is not designed to do this sort of control.

The shift cut module would be a better option.

Re: Using PDM to control ignition cut for flat shift

PostPosted: Tue Oct 23, 2018 10:30 am
by llew
Thanks Stephen, Just the sort of confirmation I was after.

Greenamex... no EFI under the rules.