3-rotor engine with the 36-2-2-2 wheel?
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3-rotor engine with the 36-2-2-2 wheel?
I just installed an MS3 on a RX-8 with a 3-rotor engine with a Renesis front plate and Renesis 36-2-2-2 wheel and VR sensor.
Unfortunately I got the message that this combination is not supported.
Digging into the code confirms this:
/* ---------------------- 36-2-2-2 ------------------------ */
- snip-
/* only 2 rotor or 4-cyl or 6-cyl supported */
conf_err = 1;
How hard would it be to add support for 3-rotor engines on the 36-2-2-2 wheel?
Thank you!
Unfortunately I got the message that this combination is not supported.
Digging into the code confirms this:
/* ---------------------- 36-2-2-2 ------------------------ */
- snip-
/* only 2 rotor or 4-cyl or 6-cyl supported */
conf_err = 1;
How hard would it be to add support for 3-rotor engines on the 36-2-2-2 wheel?
Thank you!
The man behind MS Labs
2005 Audi A3 2.0L TFSI DSG AWD - Extreme MS3
2002 Mazda Miata 1.8 6sp - Enhanced MS3 1.4.0, sequential injection, sequential ignition, big turbo, lots of boost
2005 Audi A3 2.0L TFSI DSG AWD - Extreme MS3
2002 Mazda Miata 1.8 6sp - Enhanced MS3 1.4.0, sequential injection, sequential ignition, big turbo, lots of boost
Re: 3-rotor engine with the 36-2-2-2 wheel?
I got this to work by modifying the code in ms3_ign_wheel for the 36-2-2-2 wheel:
trigger_teeth[0] = 6;
trigger_teeth[1] = 17;
trigger_teeth[2] = 26;
trig_angs[0] = -150 + tmp_offset;
trig_angs[1] = -150 + tmp_offset;
trig_angs[2] = -150 + tmp_offset;
However the RPM gauge is somewhat erratic; it's bouncing up and down by 7-26rpm at 1000rpm (stim RPM). When I set the engine configuration back to 2 rotors, the RPM gauge is dead on solid at 1000rpm and literally doesn't move.
Is the RPM calculation based on specific trigger teeth or on ignition events? The tachout teeth on the scope don't seem to coincide with any ignition events.
trigger_teeth[0] = 6;
trigger_teeth[1] = 17;
trigger_teeth[2] = 26;
trig_angs[0] = -150 + tmp_offset;
trig_angs[1] = -150 + tmp_offset;
trig_angs[2] = -150 + tmp_offset;
However the RPM gauge is somewhat erratic; it's bouncing up and down by 7-26rpm at 1000rpm (stim RPM). When I set the engine configuration back to 2 rotors, the RPM gauge is dead on solid at 1000rpm and literally doesn't move.
Is the RPM calculation based on specific trigger teeth or on ignition events? The tachout teeth on the scope don't seem to coincide with any ignition events.
The man behind MS Labs
2005 Audi A3 2.0L TFSI DSG AWD - Extreme MS3
2002 Mazda Miata 1.8 6sp - Enhanced MS3 1.4.0, sequential injection, sequential ignition, big turbo, lots of boost
2005 Audi A3 2.0L TFSI DSG AWD - Extreme MS3
2002 Mazda Miata 1.8 6sp - Enhanced MS3 1.4.0, sequential injection, sequential ignition, big turbo, lots of boost
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Re: 3-rotor engine with the 36-2-2-2 wheel?
It is based on the trigger teeth.Reverant wrote:Is the RPM calculation based on specific trigger teeth or on ignition events?
James
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Re: 3-rotor engine with the 36-2-2-2 wheel?
Well I add an additional trigger (num_triggers = 3) and change the trigger angles, nothing else. The trigger teeth (number of teeth and duration of every tooth) remain unchanged, what could be wrong here?
The man behind MS Labs
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Re: 3-rotor engine with the 36-2-2-2 wheel?
That's not 120 degrees between each trigger.Reverant wrote:trigger_teeth[0] = 6;
trigger_teeth[1] = 17;
trigger_teeth[2] = 26;
Re: 3-rotor engine with the 36-2-2-2 wheel?
I trimmed each trigger tooth angle afterwards. Then I measured the period between ign A, ign B, ign C on the scope. At 833rpm, the engine cycle is 72ms and the period between each ignition event and the next one is exactly 24ms - verified on the scope. The engine actually runs now.
The man behind MS Labs
2005 Audi A3 2.0L TFSI DSG AWD - Extreme MS3
2002 Mazda Miata 1.8 6sp - Enhanced MS3 1.4.0, sequential injection, sequential ignition, big turbo, lots of boost
2005 Audi A3 2.0L TFSI DSG AWD - Extreme MS3
2002 Mazda Miata 1.8 6sp - Enhanced MS3 1.4.0, sequential injection, sequential ignition, big turbo, lots of boost
Re: 3-rotor engine with the 36-2-2-2 wheel?
Yellow is trigger, green is ign A, blue is ign B, pink is ign C.
Engine period is 72ms:
Ign A to ign B is 24ms:
Ign B to ign C is 24ms:
Ign C to ign A is again 24ms:
The engine starts up faster than the stock RX-8 13B engine and runs well, so I'm a bit confused why the tacho reading is so erratic, even on the bench with a perfect signal.
This is what a 833rpm signal (the yellow signal in the pics above is at 833rpm) looks like in the logs when set to 3 rotors:
The RPM values in the log are 810rpm, 820rpm, 828rpm, 837rpm, 845rpm, 855rpm.
When set to 2 rotors, it's literally a straight line showing a constant 833rpm.
What have I done wrong?
Engine period is 72ms:
Ign A to ign B is 24ms:
Ign B to ign C is 24ms:
Ign C to ign A is again 24ms:
The engine starts up faster than the stock RX-8 13B engine and runs well, so I'm a bit confused why the tacho reading is so erratic, even on the bench with a perfect signal.
This is what a 833rpm signal (the yellow signal in the pics above is at 833rpm) looks like in the logs when set to 3 rotors:
The RPM values in the log are 810rpm, 820rpm, 828rpm, 837rpm, 845rpm, 855rpm.
When set to 2 rotors, it's literally a straight line showing a constant 833rpm.
What have I done wrong?
The man behind MS Labs
2005 Audi A3 2.0L TFSI DSG AWD - Extreme MS3
2002 Mazda Miata 1.8 6sp - Enhanced MS3 1.4.0, sequential injection, sequential ignition, big turbo, lots of boost
2005 Audi A3 2.0L TFSI DSG AWD - Extreme MS3
2002 Mazda Miata 1.8 6sp - Enhanced MS3 1.4.0, sequential injection, sequential ignition, big turbo, lots of boost
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Re: 3-rotor engine with the 36-2-2-2 wheel?
This is one case where the "Trigger logger" is actually useful - wheel decoder development. It shows you the times between each decoded trigger that are then used for the RPM calculation.
James
James
I can repair or upgrade Megasquirts in UK. http://www.jamesmurrayengineering.co.uk
My Success story: http://www.msextra.com/forums/viewtopic ... 04&t=34277
MSEXTRA documentation at: http://www.msextra.com/doc/index.html
New users, please read the "Forum Help Page".
My Success story: http://www.msextra.com/forums/viewtopic ... 04&t=34277
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New users, please read the "Forum Help Page".
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Re: 3-rotor engine with the 36-2-2-2 wheel?
But the teeth are the trigger events that determine RPM. And your trigger teeth are not 120 degrees apart hence the varying RPM. The 2 rotor code has trigger teeth 180 degrees apart which is why the RPM is correct and stable. (Note that the 6 cylinder code also has the trigger teeth 120 degrees apart).Reverant wrote:I trimmed each trigger tooth angle afterwards.
Jean
Re: 3-rotor engine with the 36-2-2-2 wheel?
I was under the impression that the code decoded every tooth on the trigger wheel and calculated the RPM from each tooth as it passed by. Now I see where the problem is.
The man behind MS Labs
2005 Audi A3 2.0L TFSI DSG AWD - Extreme MS3
2002 Mazda Miata 1.8 6sp - Enhanced MS3 1.4.0, sequential injection, sequential ignition, big turbo, lots of boost
2005 Audi A3 2.0L TFSI DSG AWD - Extreme MS3
2002 Mazda Miata 1.8 6sp - Enhanced MS3 1.4.0, sequential injection, sequential ignition, big turbo, lots of boost
Re: 3-rotor engine with the 36-2-2-2 wheel?
Fixed with the proper tooth selection. Thank you Jean for the explanation!
The man behind MS Labs
2005 Audi A3 2.0L TFSI DSG AWD - Extreme MS3
2002 Mazda Miata 1.8 6sp - Enhanced MS3 1.4.0, sequential injection, sequential ignition, big turbo, lots of boost
2005 Audi A3 2.0L TFSI DSG AWD - Extreme MS3
2002 Mazda Miata 1.8 6sp - Enhanced MS3 1.4.0, sequential injection, sequential ignition, big turbo, lots of boost
Re: 3-rotor engine with the 36-2-2-2 wheel?
Jean, am I getting this right?! The decoder in the code uses all the teeth to determine the crank angle, but only one tooth per cycle (or how you call them 'trigger' teeth) to determine RPM?racingmini_mtl wrote:But the teeth are the trigger events that determine RPM. And your trigger teeth are not 120 degrees apart hence the varying RPM. The 2 rotor code has trigger teeth 180 degrees apart which is why the RPM is correct and stable. (Note that the 6 cylinder code also has the trigger teeth 120 degrees apart).Reverant wrote:I trimmed each trigger tooth angle afterwards.
Jean
Re: 3-rotor engine with the 36-2-2-2 wheel?
It only uses the same number of teeth as is the number of ignition events. In this particular case, it uses 3 teeth of the 36-2-2-2 wheel, not the whole 30 teeth. This makes sense - the engine RPM won't change substantially between these events - at least not for generic RPM usage (ie fuel/ign table lookup, etc). If this was an 8 cylinder on 60-2 wheel, it would "only" use 8 teeth of the wheel for RPM calculation.
The man behind MS Labs
2005 Audi A3 2.0L TFSI DSG AWD - Extreme MS3
2002 Mazda Miata 1.8 6sp - Enhanced MS3 1.4.0, sequential injection, sequential ignition, big turbo, lots of boost
2005 Audi A3 2.0L TFSI DSG AWD - Extreme MS3
2002 Mazda Miata 1.8 6sp - Enhanced MS3 1.4.0, sequential injection, sequential ignition, big turbo, lots of boost
Re: 3-rotor engine with the 36-2-2-2 wheel?
Well, although I totally agree with your statement, I'd like to remind that successful start of an engine is about 2 ignition events. First kicks the crank from 200-300 to ~800 rpm, and the 2nd - to 1400-1500 rpm. At the same time, fastest tach output is each ignition event in most if not all oem setups.Reverant wrote:It only uses the same number of teeth as is the number of ignition events. In this particular case, it uses 3 teeth of the 36-2-2-2 wheel, not the whole 30 teeth. This makes sense - the engine RPM won't change substantially between these events - at least not for generic RPM usage (ie fuel/ign table lookup, etc). If this was an 8 cylinder on 60-2 wheel, it would "only" use 8 teeth of the wheel for RPM calculation.
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Re: 3-rotor engine with the 36-2-2-2 wheel?
And that's what you get here too as I and Reverant said. There is one trigger tooth per ignition event. That's what the trigger is: it triggers an ignition event (not quite but close enough for this discussion).ekam99 wrote:... At the same time, fastest tach output is each ignition event in most if not all oem setups.
Jean
Re: 3-rotor engine with the 36-2-2-2 wheel?
Yep, thanks for clarification