Coil on plug

[flybywire]

Does anyone out there use a coil on plug (or "coil near plug") setup? Are you happy with it?

Secondly, anyone have any good leads on where to find coil on plug units? What about how to drive these units? I'm having trouble finding information like signal levels, polarities, pinouts, etc.?

I'm looking at doing a custom ECU and am considering using coil on plug as opposed to a DC-CDI "box" or the like. It's for a single cylinder so coil on plug looks simple and light in this application...

[B Lewis @ PE Engine Management]

flybywire,

Honda F4I coils work great. They are inductive (not CDI) so they can be driven with a darlington, IGBT or something similar with just a 12v feed. Other options are automotive coil-on-plug units. For these, look for the ones with 3 wires. Generally these will have the ignition driver built in to the coil. All you would have to provide is the open collector drive signal. I think we have a couple of Ford units lying around here like that.

Hope this helps. Feel free to give me a call if you would like.

[Matthew]

we're experimenting with the '99 R6 coil-on's with an AEM CDI box.

[BeaverGuy]

Here at Oregon State, we are running a coil on plug set up using the ignition module from haltech and the stock ZX6R coils.

[flybywire]

Thanks for the quick replies everyone. I'm off to look for info on automotive coil on plug units.

PS Brian, the PE Ltd website has some great and hard to find information and it looks like you guys have done a super job on your products. Thanks for your continued support of FSAE!

[B Lewis @ PE Engine Management]

Thanks flybywire,

Let us know what you find to use.

[flybywire]

I like the idea of integral drivers. Mostly because I don't want to bring the reflected noise, etc. from the ingnition coil primary back into an ECU. Most hopeful right now is probably a coil from a 2003 BMW 325i Sedan and the spark plug connector. Available through any of Worldpac's many resellers.

Worldpac Catalog Reference (http://catalog.worldpac.com/worldpac/part.jsp?partner=default&year=2003&make=BM&model=325-I-003&category=F&showChildren=true)

Also hopeful is the 1998 Audi A4 1.8L or the 2003 Audi A6 V6 2.7L Turbo (Engine APB-2.7). Barring those, I'll have to bite the bullet and use those nice compact F4i coils...

[Denny Trimble]

I can sell you some Honda coils for cheap:
http://students.washington.edu/dennyt/fsae/coils.jpg

Our engine guy learned not to mix up the motec TC and Ignition multiplexers, and leave the power on for a few minutes. He also left some burnt flesh on the ignitor module.

[SimonUK]

Anyone successfully used coil on plug coils with only 2 ignition drivers? Ive seen some claims that you can, but i remain sceptical as you need to run them in series and hence only have 6.5-7v at each coil.

[Dan Deussen @ Weber Motor]

Simon,

When you run the coils in series you will have to approximately double the dwell (charge) time for the coil. The Denso coils of the F4 and R6 need about 2.5ms to charge at 14V. So if you run them in series you will need to charge about 5ms to get good spark. You typically should allow the coil at least 1ms to properly discharge. One revolution of the engine takes 6ms at 10k rpm. 5ms charge + 1ms discharge = 6ms --> 10k is the max rpm you can efficiently run the coil.

Unless you can find coils that require less dwell time I would not recommend this setup. But there are many dual coil packs out there that should work fine with just two coil drivers. We have successfully used Accell coils for many years.

[Ben Beacock]

Dan:
Do you know if GSXR coils are effictively the same for dwell time?

[Dan Deussen @ Weber Motor]

Ben,

I don't know for sure, but I think that most of these Denso coils should work well right around 2.5ms. I have actually only measured the dwell time with the stock ECU on a 2002 Yamaha R1, but the CBR600RR, F4(i), and GSX-R coils all look very similar, except for length.

I have personally used Yamaha R1, CBR600RR and F4(i) coils with 2.5ms dwell and they worked fine.

Maybe Brian @ PE has some more details.

[B Lewis @ PE Engine Management]

Hi Guys,

We ran some tests a while back on the F4I coils where we actually measured the time constant. If memory serves me, they were just about 1.5 ms to fully saturate. Anyone can reproduce the same test by using a batterry, sense resistor and a scope.

[Dan Deussen @ Weber Motor]

Brian,

I believe your ECU only has two ignition outputs. How do you drive four coil-on's? Do you put them in series and double the dwell time or do you have large enough drivers that can handle 16A to 20A charging current so you can run them in parallel?

[B Lewis @ PE Engine Management]

We put them in series and run about 3ms dwell. We don't see a difference on the dyno between this and running 4 independent drivers.

[davidmanning]

We put them in series and run about 3ms dwell. We don't see a difference on the dyno between this and running 4 independent drivers.


Sorry to bring up and old thread, but what rpm were you running with the 3ms dwell when you didn't see a difference on the dyno?

dave