What am using is coils within the Saab DI cassette, running in semi sequential coil over plug system, that means two coils spark at the same time, yes it is wasted. But listening to these guys at saabcentral and saablink makes me laugh. Some say DI cassettes go bad and DI cassetes this and that and that they can't take too much wasted spark bla bla bla. They are totaly clueless as how the cassette works. These cassettes do go bad but coils never go bad. What goes bad is the ION sensing sensor but that effects Saab factory Ecus but not MS2. We can use the coils within the cassette and there is nothing going to happen to coils unless you run too much dwell, coils can last forever in wasted mode. In wasted mode spark plugs take a beating because they spark two times instead of one, but who cares, you run performance engine anyway you should change spark plugs often anyway.
Am controling fuel and ignition and using code Extra 2.0.1, using modded EZK crank hall sensor and modded trigger wheel 4-1, using coils within saab DI cassette, 93 9000T lucas 36lb injectors, 93 9000 air temp sensor, AEM wideband UEGO guage controler.
MS2 is so much better than stock management.
Here is the main pulley from 2.1L saab 900, it is just basic trigger, triggers two times per revolution unmodded.
Here is the same trigger wheel but modded, one extra window added the same size as other ones that comes after trigger #1, so this wheel will have 3 triggers at falling edge with 4th trigger missing, A 4-1 crank trigger. Thats all you need to mod to run semi-cop on a saab! pritty easy and cheap haa?
Watch video here:
dissinformation from KeithG's website:
The 'dwell' scheme required to drive a DI cassette is coded into the MS2/E code base. All DI cassette is 4 coils and 3 sensors that have nothing to do with those coils, you got two ion sensors that listen to the coils like osciloscope and you got one engine knock sensor. Then you got 4 coils that use same 12 volt power wire and have each individual negative coil leads output, and those are the leads that MS2 will trigger, so basicly all it is being used is 4 coils. This mith that cassette is something special is your dissinformation. So yes 'dwell' scheme is coded in MS2/E to run 4 coils in wasted spark mode. Do to the fact that these coils are located directly over spark plug it is called Coil Over Plug run in semi sequential or wasted mode. So yes keith you are wrong, MS2 code runs a scheme to run 4 coils and not to run DI cassette myth.2007, Sep 4
New update. I have been running MS2/E for a few months. The 'dwell' scheme required to drive a DI cassette is coded into the MS2/E code base. In the dwell type box, it is called 'time after Spark'. It needs to be set to 1.0ms or more. If you are running Wasted spark, 0.9 to 1.0 should be fine. If you are running COP, run as much as you can. I run 1.6ms. Keep in mind the requirement for the 2.5ms between discharges of the capacitor and the maximum amount of time available between firings. In Wasted Spark mode, it will fire 2x as often as in COP mode. This is usually not a problem until you get to substantial RPMs. You will feel it misfire if you exceed the required charge time.
In the dwell type box, it is called 'time after Spark'. It needs to be set to 1.0ms or more. If you are running Wasted spark, 0.9 to 1.0 should be fine. If you are running COP, run as much as you can. I run 1.6ms. Keep in mind the requirement for the 2.5ms between discharges of the capacitor and the maximum amount of time available between firings. In Wasted Spark mode, it will fire 2x as often as in COP mode. This is usually not a problem until you get to substantial RPMs. You will feel it misfire if you exceed the required charge time. This is totaly wrong information. You don't have to do any of that. All you need to do is select dwell setting "charge at trigger" and thats it, no need to be entering any dwell values. Am running like this all the way to 7000 rpm and 20 psi of boost, no miss, just smooth hard pull.
People this is total dissinformation too, you don't have to do any of this. "to drive the DI cassette, again the cassette myth, all it is used there is 4 coils, thats all.To drive the DI cassette, I increased the current by changing all output transistor s to 2n2222 (substitute these instead of the 2n3904s that are in the kit) and changed the base resistor from 1k to 470 ohm. Then I soldered a wire from the top leg of the LED to the trigger pin on the DI. You do also need to build an extra output circuit exactly like this in the proto area for the 4th spark output.
Today I checked the timing again and timing is spot on, it does not flactuate like the timing that you get out of stock distributor. 4-1 wheel defenetly works great with MS2 and 4 coils over plugs in wasted mode. Nice, clean and reliable install, easy and cheap.
Nice modification !
Concerning your wheel modification, the trigger's lenght must be the same but the position is it important ?
Is it easy to configure the EZK sensor in the MS II ?
- MegaSquirt Newbie
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- Joined: Sun Mar 06, 2005 8:15 am
- Location: Chicago, IL, USA
A couple of points:
- 1) The reason that 'charge at trigger' works with the DI is due to the waveform created. This will work for the 4-1 trigger wheel you are using, but will not with a 36-1 (like I am using) or a 60-2 due to how that particular feature generates its trigger waveform.
2) The DI cassette is absolutely not just 4 coils mounted to a plate. This is documented around the web. For a more detailed read, you may want to refer to the T5/T7 suite documentation in this PDF http://trionic.mobixs.eu/Trionic%205.pdf. What I posted back in '05 agrees pretty much word for word with what is in this documentation.
3) I cannot run 'charge at trigger' with my 36-1 wheel so cannot comment on how well or poorly a DI cassette will run in wasted spark mode with this trigger scheme. From a read of the documentation above, it would seem that it cannot have the same spark energy firing 2 plugs as it does firing sequentially.
4) In my experiments in running the DI cassette here on my car as well as another list member running it on his, it does sink more current to run it in wasted spark mode (look at the trigger trace on a scope and measure how close to 0V it is able to pull down the trigger lead with a 2n2904 versus a 2n2222). FWIW, the engine runs better (less misfire) with a T7 cassette in W/S mode than a T5 cassette, but the engine still does not perform as well as running the DI cassette in sequential mode or even compared with running the OEM stock ignition (single coil, wires and plugs with MS controlling dwell). That is my experience as well as the other list member I am referring to.