Megasquirt 2 Tooth Angle

[neilc 1]

I have Megasquirt 2  Board 3.0 running MSextra 3.4.4 I am running XU 9 8v engine with a mi16 flywheel and VR sensor. The Megasquirt manual states 114 degrees for a 60-2 wheel not sure how they come up with this figure.  TDC occurs between tooth 12 & 13 if each tooth is 6 degrees where does 114 come from?  Can someone enlighten me.

 

Ins there any members running megasquirt withXU9 8 v engine out there what are your settings?

  

 

[welshpug 1,652]

Thats just where it is  (or is not in this case of a missing tooth)

 

Same angle used for any aftermarket ecu if you utilise the standard crank sensor location.

Edited February 4, 2023 by welshpug

[andy0075 9 1 Cars]

Because tooth number 19 is under the sensor at TDC. Look at the picture.

 

In real life, you have to check this 114°, when the engine is running.

In my case i have 116° in the Megasquirt settings to get real TDC.

Edited February 4, 2023 by andy0075

[neilc 1]

I see the light.  Thanks Andreas

[neilc 1]

Andreas the picture that you attached leads me to another question.
 The plate with 2 notches represents as follows:

first mark - (tdc one pointing 12/13). The second notch is (tdc +10 )degrees.  If I am correct and I set the timing to fixed in megasquirt at 10 degrees BTDC then if the tooth angle is correct the timing light will show the white line appearing at the 10 degree mark on the plate?

[petert 584]

Some ECU's also have a tooth offset option. The idea being, to get the trigger point as close as possible to the maximum timing advance point, in order to minimise the calculation/response time. For example, under light load you might have 40º BTDC. If you set the trigger point to 48º with a tooth offset of 11, this equates to the original 114º.

 

Otherwise, it's a very long time between 114º and 40º.

 

eg

(6 x 11) + 48 = 114

 

Regardless, lock the timing at 10º BTDC and verify with a timing light using a timing plate.

Edited February 4, 2023 by petert

[neilc 1]

Thanks Peter, to clarify if I have locked the timing at 10 degrees before tdc, when I use my timing light the mark on the flywheel should show up at the 10 degree mark on the metal plate?

 

 

 

 

 

 

[petert 584]

Correct.

[neilc 1]

Thank

[andy0075 9 1 Cars]

if you want to get rid of the ignition distributor you can use this cheap solution instead :

[petert 584]

Four LS1 coils mounted on a strut brace is my go to budget wasted spark solution.

Edited February 5, 2023 by petert

[neilc 1]

I will bear those solutions in mind, I am using the coils used in a Peugeot 205si a car that was sold here in Australia as I had access to car that was being wrecked and it was free.  I will see how my solution goes.

 

 

 

 

 

 

[welshpug 1,652]

that'll work just fine, standard leads work, take the thermostat housing with it,   its what I have on my 1.9 8v.

[neilc 1]

I have it installed seems to be working, taking it to dyno in the next few days