I have an old alfa 2L running EDIS4 and would like to upgrade to the later twin spark.
I was wondering if it could be possible to use a EDIS8 system with two coil packs and connect the "wasted" spark to the second plug?
Would I have to fool the ignition control side of the MS into thinking it is driving an 8 cylinder instead of a 4?
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EDIS on twin spark engines
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EDIS on twin spark engines
by bcal on Sun Sep 23, 2007 3:19 am
2L Alfa powered Model A Ford roadster.
MSII 2.88ini
EDIS4
GSXR ITBs
MSII 2.88ini
EDIS4
GSXR ITBs
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bcal - Helpful Squirter
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by Matt Cramer on Mon Sep 24, 2007 7:59 am
You'd be better off running two EDIS-4 modules; I've seen that done on twin plug heads before.
- Matt Cramer
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by bcal on Tue Sep 25, 2007 12:17 am
Matt Cramer wrote:You'd be better off running two EDIS-4 modules; I've seen that done on twin plug heads before.
Thanxs Matt. I have pondering this some more come up with another, crazier, idea.
Maybe I could parallel up two sets of coils from each output.
That is if the driver in the EDIS module can cope.
If using 2 edis4s would you just parallel off the pip and saw voltage signals?
2L Alfa powered Model A Ford roadster.
MSII 2.88ini
EDIS4
GSXR ITBs
MSII 2.88ini
EDIS4
GSXR ITBs
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bcal - Helpful Squirter
- Posts: 123
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- Location: Sydney Oz
by Jim on Tue Sep 25, 2007 11:11 am
The EDIS-8 makes a spark every 90 degrees ,
you need a spark every 180 degrees .
You can only use an EDIS-8 on a 4 cyl. when the 36-1 Trigger Wheel is
mounted to the cam or dizzy , even then , your Ignition Advance numbers
would be twice what they should be , so this is generally a bad idea .
The EDIS modules are current limited to ~6amps ,
that means each channel can only deliver full power into one coil .
You must still split-up the high voltage outputs between cylinders 1&4 and 2&3 .
This is because it takes ~10 times the voltage to jump a spark plug gap
when the cylinder is under compression than it does to jump the
gap on a cylinder that is on the exhaust/overlap part of the cycle .
So , each coil , must be supplying spark to cylinders 1-AND-4 , (or 2-AND-3) ,
you can't run 2 plugs in the same cylinder with one coil .
To run 2 EDIS-4 modules you only need one VR pick-up to supply both ,
pay careful attention to the polarity of the sensor ,
EDIS will will do strange things if the polarity is reversed .
Then you the run the PIP signal from one module to MS ,
and MS will supply a SAW signal to both modules to control timing .
...................Jim
you need a spark every 180 degrees .
You can only use an EDIS-8 on a 4 cyl. when the 36-1 Trigger Wheel is
mounted to the cam or dizzy , even then , your Ignition Advance numbers
would be twice what they should be , so this is generally a bad idea .
The EDIS modules are current limited to ~6amps ,
that means each channel can only deliver full power into one coil .
You must still split-up the high voltage outputs between cylinders 1&4 and 2&3 .
This is because it takes ~10 times the voltage to jump a spark plug gap
when the cylinder is under compression than it does to jump the
gap on a cylinder that is on the exhaust/overlap part of the cycle .
So , each coil , must be supplying spark to cylinders 1-AND-4 , (or 2-AND-3) ,
you can't run 2 plugs in the same cylinder with one coil .
To run 2 EDIS-4 modules you only need one VR pick-up to supply both ,
pay careful attention to the polarity of the sensor ,
EDIS will will do strange things if the polarity is reversed .
Then you the run the PIP signal from one module to MS ,
and MS will supply a SAW signal to both modules to control timing .
...................Jim
'95 GM 4.3 Vortec V-6
Single Plane Intake w/ported GM TBI Injection
Ported Heads , stock roller cam retarded 8 degrees
MS-II , V-3 board , v2.881 Code
EDIS ignition , Innovate WB-02
Single Plane Intake w/ported GM TBI Injection
Ported Heads , stock roller cam retarded 8 degrees
MS-II , V-3 board , v2.881 Code
EDIS ignition , Innovate WB-02
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Jim - MegaSquirt Newbie
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- Location: Crystal River , Fla
by bcal on Tue Sep 25, 2007 11:08 pm
Cheers Jim, that makes sense to me.
Thanks for the tip on maintaining the wasted spark.
The only thing I need to clarify is how to get 2 SAW signals from MS.
Thanks for the tip on maintaining the wasted spark.
The only thing I need to clarify is how to get 2 SAW signals from MS.
2L Alfa powered Model A Ford roadster.
MSII 2.88ini
EDIS4
GSXR ITBs
MSII 2.88ini
EDIS4
GSXR ITBs
-
bcal - Helpful Squirter
- Posts: 123
- Joined: Mon May 03, 2004 3:40 am
- Location: Sydney Oz
by Jim on Wed Sep 26, 2007 5:25 am
There is only one SAW signal from MS ,
but it is connected to 2 modules .
...................Jim
but it is connected to 2 modules .
...................Jim
'95 GM 4.3 Vortec V-6
Single Plane Intake w/ported GM TBI Injection
Ported Heads , stock roller cam retarded 8 degrees
MS-II , V-3 board , v2.881 Code
EDIS ignition , Innovate WB-02
Single Plane Intake w/ported GM TBI Injection
Ported Heads , stock roller cam retarded 8 degrees
MS-II , V-3 board , v2.881 Code
EDIS ignition , Innovate WB-02
-
Jim - MegaSquirt Newbie
- Posts: 0
- Joined: Sun Aug 28, 2005 8:50 am
- Location: Crystal River , Fla
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