TECH QUICKIE – Uses of Twin Spark
Twin spark doesn’t have to be just used for engines with two spark plug holes per cylinder. Oh no.
If you have an S60 or above and want to run unamplified coil-on-plug units but don’t have a cam sensor or just prefer wasted spark to sequential, you can achieve it with Twin Spark mode. All you need to do is wire up the COPs as you would for sequential ignition and turn Twin Spark on in general engine settings. Done, you now have wasted spark COPs.
How does this work?
By default, our ECUs run in wasted spark mode for use with a wasted spark coil pack. If we take a 4 cylinder engine with a wasted spark coil pack, for example, coil driver #1 fires cylinder 1 & 4 and coil driver #2 fires cylinder 2 & 3. Turning on Twin Spark activates coil driver #3 & #4. Coil driver #3 will fire with #1, #4 with #2 so all you need to do is wire the COPs to the right coil outputs and boom, wasted spark COPs.
One example of why is the Suzuki Hayabusa engine. Cam sensors on these have a habit of random failure. Twin Spark mode will stop a bad sensor ruining your day.
Couldn’t I just…?
Couldn’t you just wire two COPs to coil driver #1, another two to coil driver #2 etc. etc.? With amplified coils, yes (although a pullup resistor may be required). Doing that with unamplified coils, however, may allow smoke to escape from your ECU.