MG David
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| posted on 26/2/07 at 12:24 PM |
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MegaSquirt II for ignition
I would like to use MegaSquirt to control ignition only as I want to retain the distributor and coil but not the points. The mechanical and vacuum
advance retard of the distributor will be locked.
In the early days of MS you used to be able to convert it to MegaSpark. That does not seen to be what people do these days. Perhaps this is because
they go for MegaJolt instead. So I am now considering using the current MegaSquirt II, but only its ignition features
The main megasquirt site, http://www.bgsoflex.com/megasquirt.html , says the following:-
“MegaSquirt-II, in conjunction with a V3 main board, can control a single coil directly (it still needs a distributor, unless you have a 1 cylinder
engine). The high current circuit uses the VB921 dedicated coil driver IC, which limits coil current to about 7 Amps.”
The questions:-
1) Is there any reason why MegaSquirt II can’t be used for ignition only?
2) While their web site says the V3 board, can the V2.2 board be used with MegaSquirt II in the same way? If so des that mean that miniMegaSquirt,
which I understand is V2.2 based can be used with MegaSquirt II in the same way?
3) Is the 7 amp limit a problem for 4 cylinder engine using a traditional coil?
4) While I would not be using it to control fuelling, I assume I could still use its connection to a lambda sensor to observe the air fuel ratio?
5) I see reference to different types of ignition sensor. My current, rather old, electronic ignition uses a 2 wire sensor in the distributor where
the points would be with a plastic collar over the cam. The plastic collar has 4 vertical metal bars equally spaced around it. Does any one know what
the correct description of that type of sensor is? Will MegaSquirt II take that type of signal or will I have to change to 36-1?
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martyn_16v
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| posted on 26/2/07 at 06:11 PM |
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1. No, you can use it for ignition only if you want, just don't connect up any injectors. It won't care.
2. You can use the V2.2, but you'd need to construct the ignition driver components on a separate daughterboard, the V3 board makes it easier by
having it all on board (ignition control wasn't an option back when the v2.2 board came out).
3. No.
4. Yes.
5. Sounds like a hall sensor, which should be fine with MS2.
To be honest I wouldn't bother with MS2, for your application the only advantage it has over MS1 with the -extra firmware loaded is timing
accuracy (0.1 deg as opposed to 1 deg), but if you're keeping the dizzy you'll lose that accuracy in timing scatter anyway. I'd save
myself a few quid and stick with MS1, it'll still do everything you want 
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