Anybody installed wasted spark with efi?
Discussion
Hi Steve you have probably seen this picture already. I made brackets to fit to the back of cylinder heads into existing holes. Probably similar in position to yours. My problem is that I forgot about the position of the Lambda sensor which is fouled by the coils on the coil pack that side. I would be interested to see your bracket.
spatz said:
out of curiosity what is wasted spark ?
You only see this in V8 and higher.It is a financial choice. You will see that most ECU's can cope with 6 injectors and 6 coils just fine. To handle more, the affordable ecu get's into trouble.
There for they use the wasted spark method. On a V8, V10 or V12 there are always two pistons in top position, one of them is in compression, the other in exhauststroke.
The coil fires those two cylinders, one effectively in the compression stroke and one wasted in the exhaust stroke.
Wasted spark method also doesn't require cam timing if you use batch injection.
Hence cheaper and easier.
MarkWebb said:
Steve
I guess that they mount to a plate which is fixed to the gearbox mount adapter? Do you have a picture of that?
If you look close at the pics you can see one mounting hole high in the centre. In another pic you can see two holes low on the bracket and wide apart.I guess that they mount to a plate which is fixed to the gearbox mount adapter? Do you have a picture of that?
These three positions match the top three bolts attaching the adaptor plate to the back of the engine block.
Coil on plug or individual coil is obviously the best way to go for the most control and power of spark but this requires cam position sensing and 8 coils and is therefore expensive. A wasted spark system fires two plugs at the same time in cylinders that are 180 degrees different in position to each other. So one is on the firing stroke and one is on the exhaust stroke. The plug firing on the exhaust stroke is the wasted spark. The system therefore only requires a crank position sensor to operate and can generate a more powerful and longer duration spark at high revs when it is needed. The system also does not need a distributor so timing is far more accurate as lash in the distributor drive and errors in timing due to cam walk are done away with. Downside is plugs fire twice as often.
The coil packs shown are Ford coil packs used in Fiestas and Escorts.
Each pack is in effect two coils with two connections to each.
They are connected to an EDIS8 controller.
If the EDIS is not connected to an ECU or has lost signal it reverts to a 'limp home mode' of 10 degrees advance. In normal use it sends a timing signal to the ECU and gets back a modified timing dependant on what the ECU mapping says the timing should be.
Steve
Each pack is in effect two coils with two connections to each.
They are connected to an EDIS8 controller.
If the EDIS is not connected to an ECU or has lost signal it reverts to a 'limp home mode' of 10 degrees advance. In normal use it sends a timing signal to the ECU and gets back a modified timing dependant on what the ECU mapping says the timing should be.
Steve
spatz said:
so simply said if your ECU is supporting wasted spark you do not have to buy the 8 cylinder versions but can go with the 4 cylinder hardware setup and the right coils ?
With the most simple injection constant injection it could work, but with every other injectionmode you still need 8 injector output from the ecu.
Pb3 said:
I one have two injector driver outputs!
I run in batch fire mode with 8 injectors, which may sound bad, but does not make a great deal of difference. Full multipoint really only comes into play with emmissions at or around idle.
Don't even think with our engines that sequential is even possible. You almost need fullcycle injector times to get the required amount of fuel in the cylinder when you floor it, and if you would have injectors large enough to support sequential, it wouldn't be able to supply acurate enough fuel in the low end.I run in batch fire mode with 8 injectors, which may sound bad, but does not make a great deal of difference. Full multipoint really only comes into play with emmissions at or around idle.
Sequential works well for idle and emissions as the injectors only fire once per cycle and at the correct time. In batch or bank to bank they fire twice per cycle( because of no cam signal) this makes mixture and emission control not so good at idle and small throttle opening. At full throttle not so much of a problem. Sequential works fine on our engines but a correctly sized injector is open 80% of the time at full throttle.
Gassing Station | Ultima | Top of Page | What's New | My Stuff