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Currently Supported Configurations 
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These specifications are temporary due to unimplemented high performance XGATE fuel injection code which could potentially fire all device pins with mediocre performance. Once that is developed this post will be edited to reflect the current state of the play, or a new thread will be created and this one will be here as a part of history.

Currently we have 6 timed channels officially designated as ignition channels, but usable for either ignition or injection duties.

This post will only cover 4 stroke and rotary engines

This limits us to the following configurations early on in the development cycle:

Note: An appropriate set of RPM/position sensors, matching decoder and associated sync level is required for all of these.

12 cylinder engines

  • Semi sequential injection ONLY
  • Wasted spark ignition ONLY
  • Distributor ignition AND Bank/batch injection

10 cylinder engines

  • Semi sequential injection AND Distributor ignition
  • Wasted spark ignition AND Batch injection
  • Distributor ignition AND Bank/batch injection

8 cylinder engines

  • Semi sequential injection AND Distributor ignition
  • Semi sequential injection AND Twin distributor ignition
  • Wasted spark ignition AND Bank/batch injection
  • Distributor ignition AND Bank/batch injection

6 cylinder engines

  • Sequential injection ONLY
  • COP/CNP ignition ONLY
  • Semi sequential injection AND Wasted spark ignition
  • Semi sequential injection AND Distributor ignition
  • Wasted spark ignition AND Bank/batch injection
  • Distributor ignition AND Bank/batch injection

5 cylinder engines

  • Sequential injection AND Distributor ignition
  • COP/CNP ignition AND Batch injection
  • Distributor ignition AND Batch injection

4 cylinder engines

  • Sequential injection AND Wasted spark ignition
  • Sequential injection AND Distributor ignition
  • COP/CNP ignition AND Semi sequential injection
  • COP/CNP ignition AND Bank/batch injection
  • Semi sequential injection AND Wasted spark ignition
  • Semi sequential injection AND Distributor ignition
  • Wasted spark ignition AND Bank/batch injection
  • Distributor ignition AND Bank/batch injection

3, 2, and 1 cylinder engines

  • Sequential injection AND COP/CNP ignition
  • Sequential injection AND Wasted spark ignition
  • Sequential injection AND Distributor ignition
  • COP/CNP ignition AND Semi sequential injection
  • COP/CNP ignition AND Bank/batch injection
  • Semi sequential injection AND Wasted spark ignition
  • Semi sequential injection AND Distributor ignition
  • Wasted spark ignition AND Bank/batch injection
  • Distributor ignition AND Bank/batch injection

Notes:
1) Sequential and COP/CNP etc in a 1 cylinder context just means timed to the event inside the full engine cycle.
2) Distributor does not apply to single cylinder engines.
3) Wasted/semi sequential doesn't apply to 3 cylinder engines.

Rotary engines

Rotary engines have some specific requirements that other engines do not have or do not usually have.

In the ignition area they have both a leading and trailing spark plug. These should be fired a few degrees apart and are relatively unimportant except for emissions. Power level increases from running the trailing plugs as well as the leading plugs, rather than just the leading plugs, are in the order of 1 or 2 percent.

In the fueling department most have staged injection from the factory. Each rotor has two intake runners with a throttle butterfly in each. The throttles are operated in a progressive fashion, with one opening first, and then the other. Because of this the secondary injectors must only be engaged once there is sufficient airflow in the secondary runners.

Available Compromises

The effect of the above is that for full independent control of a rotary, you need 4 channels per rotor. Given that the majority of rotaries are the twin rotor 13b, and that we have only 6 for the time being, we need to make some compromises.

  • Run a single stage of big injectors that can satisfy the engines fuel demands, and remove/plug the other injector bungs - This is a good choice for naturally aspirated engines and a less good, but still valid choice for turbocharged engines. This allows all other functions to be run optimally on a 13b by saving 1 - 2 channels, and saves either 1 or 3 channels on the 20b allowing less compromise elsewhere.
  • Run both primary and staged injection in semi sequential mode - This is a good choice for turbocharged engines or naturally aspirated engines, either 13b or 20b.
  • Don't run trailing plugs at all - This isn't a bad solution for most setups, but can be a bad choice on very high power setups where tight control of the flame front is required.
  • Run leading plugs in wasted spark mode - this is only suitable for the 13b or rare quad rotor engines, it's not possible to do this on the 20b.

You may mix and match the above compromises in order to achieve sufficient control of your rotary engine. Recommended configurations are below:

The last item previously said run trailing plugs wasted, this was in error and is not possible.

2 rotor engines

Turbo charged and mild NA: Run wasted spark on the leading plugs (this is not possible on trailing plugs) and semi sequential injection on the secondary injectors. This leaves four outputs for sequential and cop on the trailing plugs and primary injectors.

Wild NA: Don't run trailing plugs, run primary and secondary injectors sequentially and run cop on the main plugs. Wild NA engines will benefit significantly from proper outboard injection at higher RPM. You my prefer the other option over this one, or some other custom combination. Another option would be to run both leading and trailing in wasted spark rather than dropping the trailing support.

3 rotor engines

Triple rotors are not properly supported at this time. The compromises involved are fairly large by rotary user standards, though would result in smooth running powerful engines none-the-less. Here are the options:

  • Ignition only control: cop on both leading and trailing plugs.
  • Fuel only control: sequential on both primary and secondary injectors
  • Both option 1: cop on leading, no trailing, sequential on primary, no secondary
  • Both option 2: cop on leading, no trailing, Multi-shot batch on primary and secondary, one wasted output.
  • Run two FreeEMS units, one for fuel, one for ignition.

Clearly there are some downsides to running a 20b on FreeEMS right now, however given how uncommon they are, it's not a big deal. If you have a 13b, you will be very satisfied with the results you get from one of the above combinations.

Errors, omissions and corrections welcome!

Fred.

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Sat Mar 12, 2011 3:38 pm
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What is the limiting factor preventing "sequential injection AND COP/CNP ignition" on 4 cylinder (or greater) engines?

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Tue May 24, 2011 4:09 pm
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BenFenner wrote:
What is the limiting factor preventing "sequential injection AND COP/CNP ignition" on 4 cylinder (or greater) engines?

Fred wrote:
These specifications are temporary due to unimplemented high performance XGATE fuel injection code. Once that is developed this post will be edited to reflect the current state of the play, or a new thread will be created and this one will be here as a part of history.

Currently we have 6 timed channels officially designated as ignition channels, but usable for either ignition or injection duties.

RTFM! Particularly, where T = This, not The. :-)

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n00bs, do NOT PM or email tech questions! Use the forum!
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Tue May 24, 2011 9:27 pm
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Doh!

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Wed May 25, 2011 4:29 pm
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I've updated the first post with rotary engine advice. Criticism of this section is especially welcome.

Fred.

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FreeEMS dev diary and its comments thread and my turbo truck!
n00bs, do NOT PM or email tech questions! Use the forum!
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Thu May 26, 2011 11:34 am
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Fred wrote:
Rotary engines

...

Some have one set of injectors are before the throttle plates and the other after them. This means that the secondary injectors should only be engaged while the throttle is at least partly open, if not fully.


Source? I have never heard of this before!

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Thu Jan 19, 2012 7:20 am
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Could easily be wrong. I remember the source being some adamant individual, but don't remember who. I'm up for corrections and additions. Feel free to tell me how it should be.

Fred.

PS, I just about did a back flip when I saw the nick! And I'm still under the duvet, that would have been quite a feat! It's been ages! :-)

PPS, 9:50pm NZ time but wife stole internet, possibly by accident, and I can't post without finding a library or similar. OK, finally online, 7:50am NZ time the following day LOL...

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n00bs, do NOT PM or email tech questions! Use the forum!
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Thu Jan 19, 2012 7:50 pm
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Does this make more sense?

All injectors in rotaries are after the throttle plates however the secondary throttles open progressively, and since the intake runners behind them are sealed off from the primary intake runners the secondary injectors need to be staged.

(it has been ages! :))

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Tue Jan 24, 2012 2:46 am
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Ahh, yes, I'll make that change later today, thanks for your input! :-)

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FreeEMS dev diary and its comments thread and my turbo truck!
n00bs, do NOT PM or email tech questions! Use the forum!
The ever growing list of FreeEMS success stories!


Tue Jan 24, 2012 9:13 am
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I rewrote it, please check my work :-)

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FreeEMS dev diary and its comments thread and my turbo truck!
n00bs, do NOT PM or email tech questions! Use the forum!
The ever growing list of FreeEMS success stories!


Tue Jan 24, 2012 5:00 pm
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