Trigger wheels

[Goo'Roo]

Hello I can't figure out how  properly draw a 24-1 or -2 teeths, that I have to use with maxxecu and ignitech ECU.





I've measured that the center of the spline on the crankshaft is offset by 102.5° before the 1-4 cylinders TDC.

Now I have a couple of questions..

-Where do I have to locate the missing teeth? Just before teeth n.1? 

-Does usually the ecu consider the midpoint of the teeth crest while reading or the first edge that encounters?

-How many degrees before 1/4 cylinder TDC shall I place the first tooth, considering the second question?

Thank you all 

 

[Arttu]

Tooth #1 is usually the first one after missing one(s). Most of the ECUs are quite flexible for location of the #1 tooth / missing tooth. But for reliable decoding during cranking it would be best to place it at point where the crank speed is highest during cranking. Apparently this is around 100° BTDC on inline 4 engines.

Reading point of a tooth should be in the middle of the tooth. When using VR type sensors. This is the point where polarity of signal reverts and crosses 0V level. With hall type sensors the point would be either edge of the tooth. For reference see: http://www.useasydocs.com/theory/pickups.htm

Just in case if you get fed up making the trigger wheel, I can deliver a 24-2 wheel for oil cooled engines. Should fit on some water boilers too.

[Goo'Roo]

Nice reading for tonight, Thanks Arttu.

So for example in a 24-1 like an Hayabusa gen2, with the missing lobe at 100°, considering a tooth every 15°  would you use tooth 30 to start advance cylinder one with 10° of base advance? Or would you choose the 29 with 25° of base advance?  With base advance I mean the distance between the tooth of the cylinder you're considering and his TDC

[Arttu]

What? I guess that's some ECU specific stuff?

With most of the ECUs that I have played with you just enter angle of #1 tooth and angles between the cylinders. Then the ECU will handle the rest to get desired ignition timing. Old Megasquirt 1 was an exception where you had to fill in reference trigger tooth numbers for each cylinder within certain window from ignition event.

[Goo'Roo]

10 minutes ago, Arttu said:

What? I guess that's some ECU specific stuff?

With most of the ECUs that I have played with you just enter angle of #1 tooth and angles between the cylinders. Then the ECU will handle the rest to get desired ignition timing. Old Megasquirt 1 was an exception where you had to fill in reference trigger tooth numbers for each cylinder within certain window from ignition event.

Ok, ignitech is still like ms1 then. 

I understand now why I was so confused. 

[Arttu]

I don't know how it works with Ignitech but with MS1 the reference teeth had to be before your highest ignition timing. Meaning if you want to use maximum 40° ignition advance then the reference tooth must be at 45° BTDC or earlier. But preferably not too much earlier since that would increase timing error.

[Goo'Roo]

1 hour ago, Arttu said:

I don't know how it works with Ignitech but with MS1 the reference teeth had to be before your highest ignition timing. Meaning if you want to use maximum 40° ignition advance then the reference tooth must be at 45° BTDC or earlier. But preferably not too much earlier since that would increase timing error.

I have to send them an email to ignitech, tonight I'm going to start studying maxxecu software.

Thanks Arttu

[Fredrik_Steen]

You can use the stock wheel with Maxxecu. But you need a VR sensor.

Why use ignitech ecu instead of only Maxx?

[Goo'Roo]

6 hours ago, Fredrik_Steen said:

You can use the stock wheel with Maxxecu. But you need a VR sensor.

Why use ignitech ecu instead of only Maxx?

I have both ECUs, and I have to do two different bikes.