Rotary engine Rx8

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STURX8
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Rotary engine Rx8

Post by STURX8 »

Looking to see if anyone is interested of writing the code for the rotary engine I have plenty of cars to test it on
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Re: Rotary engine Rx8

Post by AndreyB »

Did not they say that one can a two rotor rotate as a 4 cylinder engine?
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mck1117
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Re: Rotary engine Rx8

Post by mck1117 »

A rotary is just a two stroke (which we already support). It would be pretty simple to modify the firmware to support it properly, but it'll certainly run in 2 stroke mode.
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Re: Rotary engine Rx8

Post by STURX8 »

Okay how can we get started to have it done basically like how it's in the tunerStudio software or the regular megasquirt?
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Re: Rotary engine Rx8

Post by STURX8 »

Also staged injection and injection timing map working properly it is very critical on a NA rotary engine
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kb1gtt
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Re: Rotary engine Rx8

Post by kb1gtt »

I recall timing for both fuel and spark are a bit different then 2 stroke, but totally doable if it's detailed enough for developers to implement. I recall you could get it running with 2 stroke, but to get it to run well, it's expected that some timing changes would be needed. I recall that on prior inquiries, the key issue was getting a developer hardware to develope against.

I recall that we currently inject for a calculated time and we start at a specific crank angle. I recall the timing changes were something like you have to calc the injector pulse length, then calc the start time so that the pulse ends at a specific angle. Very similar to spark, but for injection. The changes were something like that. Doable, but needed to be detailed so developers could develope.
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Re: Rotary engine Rx8

Post by mck1117 »

kb1gtt wrote:
Mon Jun 07, 2021 2:30 am
I recall you could get it running with 2 stroke, but to get it to run well, it's expected that some timing changes would be needed.
Correct. It'll *run* fine without any firmware changes, but needs the leading/trailing spark logic to get the last 10% out of it.
kb1gtt wrote:
Mon Jun 07, 2021 2:30 am
I recall that we currently inject for a calculated time and we start at a specific crank angle. I recall the timing changes were something like you have to calc the injector pulse length, then calc the start time so that the pulse ends at a specific angle. Very similar to spark, but for injection. The changes were something like that. Doable, but needed to be detailed so developers could develope.
We do all this already, with injection ending angle tuned via the "injection phase" table.
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Re: Rotary engine Rx8

Post by STURX8 »

Well I am new to this forms thing not too sure what I'm replying to just need to deal with someone specific to get this going
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Re: Rotary engine Rx8

Post by kb1gtt »

??? What do you need to know? Do you have injectors etc? Are you looking to learn how to wire it? Not sure what you need.
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Re: Rotary engine Rx8

Post by STURX8 »

I have my road race RX-8 ready to go to do any kind of development work on it
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Re: Rotary engine Rx8

Post by STURX8 »

Injector wiring and coil wiring setup will be greatly appreciate it and I could give you feedback of what's going on
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Re: Rotary engine Rx8

Post by AndreyB »

we can help with way more specific questions. i guess your next step is getting comfortable with original vehicle wiring diagram
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Re: Rotary engine Rx8

Post by STURX8 »

That's not a problem already have a megasquirt Evo wired to my RX-8 already the problem is it doesn't do drive-by-wire I have your ECU and the evo working together..... now I want to run only the rusefi by itself just need to know how to run your ECU.. for instance I know there is no stage injection ....so batch firing or full sequential? That's question number one number two ignition output obviously ignitionone is leading front rotor housing 1.... the rest on the ignition need to workout
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Re: Rotary engine Rx8

Post by AndreyB »

STURX8 wrote:
Sun Jun 13, 2021 12:25 am
I have your ECU and the evo working together...
wow, that's a lot of sweet info here! pics please? details please?

we are too short on software devs :( i am extremely excited about the opportunity but cannot promise anything.
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mck1117
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Re: Rotary engine Rx8

Post by mck1117 »

STURX8 wrote:
Sun Jun 13, 2021 12:25 am
That's not a problem already have a megasquirt Evo wired to my RX-8 already the problem is it doesn't do drive-by-wire I have your ECU and the evo working together..... now I want to run only the rusefi by itself just need to know how to run your ECU.. for instance I know there is no stage injection ....so batch firing or full sequential? That's question number one number two ignition output obviously ignitionone is leading front rotor housing 1.... the rest on the ignition need to workout
Get it running as a "2 stroke" on rusefi first. That'll be plenty to at least idle and putter around. Video of a running car would help motivate implementation of staged injection 🙂
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Re: Rotary engine Rx8

Post by STURX8 »

Do I run it as a 2-cylinder 2 stroke or 4 cylinder 2 stroke
Last edited by STURX8 on Fri Jun 18, 2021 1:14 am, edited 1 time in total.
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Re: Rotary engine Rx8

Post by STURX8 »

Check this out
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STURX8
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Re: Rotary engine Rx8

Post by STURX8 »

Well
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STURX8
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Re: Rotary engine Rx8

Post by STURX8 »

mck1117 wrote:
Sun Jun 13, 2021 1:51 am
STURX8 wrote:
Sun Jun 13, 2021 12:25 am
That's not a problem already have a megasquirt Evo wired to my RX-8 already the problem is it doesn't do drive-by-wire I have your ECU and the evo working together..... now I want to run only the rusefi by itself just need to know how to run your ECU.. for instance I know there is no stage injection ....so batch firing or full sequential? That's question number one number two ignition output obviously ignitionone is leading front rotor housing 1.... the rest on the ignition need to workout
Get it running as a "2 stroke" on rusefi first. That'll be plenty to at least idle and putter around. Video of a running car would help motivate implementation of staged injection 🙂
Do I run it as a 2-cylinder 2 stroke or 4 cylinder 2 stroke
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Re: Rotary engine Rx8

Post by YuMe3D »

Here's the setup as used for "other" ecus.

the Mazda 13B rotary looks just like a 4 cylinder engine, except for having a 2nd set of plugs delayed by a few degrees. Each rotor has 3 chambers and executes an Otto cycle (intake-compression-power-exhaust) in 1080° of eccentric shaft rotation.
Therefore, setting up a rotary as a 4 stroke cycle, 4-cylinder (since it gives 4 tach pulses per 720°), and 2600cc (displacement x 2), works out fine. The number of squirts per cycle may need some experimentation for your specific installation

see' the rotary in terms of injection cycles.

In 720° of crank rotation, a four-stroke cycle piston engine (two revolutions = 4 strokes) ingests its rated displacement (ignoring volumetric efficiency issues and the like) of air. In the same 720°, the rotary swallows twice its rated displacement (somewhat like a 2 stroke cycle engine).

To understand this, recall that a Wankel rotary engine has three faces on each rotor, evenly spaced at 120° apart. The rotors rotate at 1/3 the eccentric shaft speed, so we see an ignition event every 120°Ã—3 = 360 degrees, and all three faces require 3×360° = 1080° of eccentric shaft rotation.

(Note that all of these factors are determined by the geometry of the case, housing, and gears, and are the same for all Wankel rotary engines.)

In the 13B, there are two rotors, however, and they are phased 180° apart, giving an ignition event every 180°, alternating between the rotors.

Crank Degrees Piston Firing. Wankel Rotor Firing
0° 1 1. (face 1)
180° 3 2. (face 1)
360° 4 1 (face 2)
540° 2 2 (face 2)
720° 1 - restart 1 (face 3)
900° 3 2 (face 3)
1080° 4 1 (face 1) - restart

Obviously this is a starting point and needs to be developed fully for correct Rotary support. Split trailing and up to 3 stage injection.

And to remember there are more than just 2 rotor setups out there.. in some wild cases going up to a ridiculous 12 rotor count. But the largest drag application we've seen is 6 rotor setups. Which should eventually be capable of as we have enough outputs..

Hope this help?

Our "washing machine" powerplant should be arriving in thr next couple of weeks. So then we can start playing as well..
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Re: Rotary engine Rx8

Post by STURX8 »

Thanks really appreciate that I do have the car running on the ecu right now... leading coils only and primary injectors only need some more tweaking not quite right yet but I'll give you a update a bit later this is an RX8 renesis engine there is one weird thing also the RPM is showing higher then normal on the computer about 1,200 RPM more
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Re: Rotary engine Rx8

Post by STURX8 »

Also why can't we take the information from the tunerstudio for the rotary stuff and applied it to this ecu since everything is open source it's a thought I'm not too sure if it works that easy so don't mind crazy idea
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Re: Rotary engine Rx8

Post by mck1117 »

STURX8 wrote:
Sat Jun 26, 2021 1:11 am
Also why can't we take the information from the tunerstudio for the rotary stuff and applied it to this ecu since everything is open source it's a thought I'm not too sure if it works that easy so don't mind crazy idea
what you see in TunerStudio is just the configuration - no actual logic there that runs the engine
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Re: Rotary engine Rx8

Post by STURX8 »

Well I have the engine running but the RPM is showing way too high on the gauge console about 1,500 RPM more than what the engine is actually idling at
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Re: Rotary engine Rx8

Post by mck1117 »

please post your tune and a log of startup/idle at https://rusefi.com/online
Last edited by mck1117 on Sun Jun 27, 2021 12:43 am, edited 2 times in total.
STURX8
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Re: Rotary engine Rx8

Post by STURX8 »

Well have the engine running but the RPM gauge on the gauge console is showing about 1,500 more RPM than what the actual engine is spinning at is there a fix for that it's running the 36 - 2 - 2 - 2 Factory crank trigger wheel so that makes two motor doesn't sound properly when it's accelerating slight Miss to it
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Re: Rotary engine Rx8

Post by AndreyB »

Please post your tune and a log of startup/idle at http://rusefi.com/online - more about this at https://github.com/rusefi/rusefi/wiki/HOWTO-upload-tune and https://github.com/rusefi/rusefi/wiki/HOWTO-upload-log


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Re: Rotary engine Rx8

Post by mck1117 »

STURX8 wrote:
Fri Jun 18, 2021 1:13 am
Do I run it as a 2-cylinder 2 stroke or 4 cylinder 2 stroke
It should run properly as a 1.3 liter, 2-cyl, 2 stroke.
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Re: Rotary engine Rx8

Post by STURX8 »

How would I fire the trailing coils?
Last edited by STURX8 on Tue Jun 29, 2021 1:01 pm, edited 1 time in total.
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Re: Rotary engine Rx8

Post by STURX8 »

I am going to send you my log car songs car sounds great just running on the two leading coils alone thanks for the information let me know what else you want me to send you and we could work on this
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