InputTrigger/SubaruThirtySixMinusTwoMinusTwoMinusTwo (2010-06-15 20:02:31)

There is a contradiction about crank-pattern inside the Subaru manual (thanx for everyone contributing so we finally sorted it)

Cam info

There is a camsync pulse 45 crank degrees before Cyl 1 TDC, then the second comes 135 crank degrees after TDC

Camsync:

subaru2001-camwheel.jpg

The relative position of the cam (having the camsync pulse coming inside the middle of the long gap) was a reasonable design decision.

Crank:

subaru2001-crankwheel.jpg

crankwheel1modi.jpg

just tell me the direction of rotation !

On both pics with the wheel, it turns anti-clockwise. The engine runs clockwise, but the pic is of the back of the wheel.

The engine and the wheel physically turn clockwise, but the above photo shows the back of the wheel, so looking at the pic, the wheel turns counter clockwise.

That confirms: our implementation assumed the above photographed wheel rotates COUNTERCLOCKWISE so the double long gap is followed by 13 tooth, not 16.


Crank Sensor wheel drawing, as mounted on the engine - rotates clockwise: (Beware: the plotted function is wrong: it shows a group of 13 teeth, instead of 16! This caused a lot of confusion)

subaru2001-crankwheelpic.jpg


just thinking

The choice to have the long gap detected at 30 BTDC and 0 TDC is weird.

We can look at it as 15+3,3+12+3


Subaru 36-2-2-2 implemented with camsync: derived from c024 (12 cranktooth + 1 campulse)

Than burn, and might need to reboot.

Please measure+figure how to set trigger tooth and TDCdelay.

(tooth 0 is after the long gap after the group of 16 normal tooth). So triggertooth=4 + 90 deg TDC-delay or triggertooth=5 + 60 deg TDC-delay SEEMS appropriate. (The strobe will tell)


Test pattern

Here is a [wav file] (with CamSync. Inverted to play properly. 670 RPM ?)


Jason's notes

Here is a [vemscfg file] of the setup described above (trigger settings)

In Jason's engine there is the possibility of using a 4-1 cam signal. It's for the 2004 WRX STi variable cam system (disabled on this engine for now) and those sensors are still there but unused. We should figure out the 2 pulse camsync, but if the 4-1 is easier to handle quickly, I'm ok with that. There is a 4-1 on each cam, but I expect it's sufficient to just read one of the two (just like this 2 pulse cam trigger).