7mgte, 12-1 wheel

[badjuju]

My stock CPS is as follows;

two wheels stacked on top of one another.  the bottom wheel is a 24 tooth, the top seems to be a 2 tooth.

I ground off the top wheel altogether, and ground two opposing teeth from the 24 tooth wheel, in my mind effectively making it a 12-1 (cam spins at half speed, blah blah)

My trigger settings are as follows:

Edge  Rising
Type  Multitooth
Filtering  Disabled
Advanced Filtering Disabled
Special N-1 Disabled
Fiat Stilo Disabled
Nissan Special trigger disabled
bit 7 not in use disabled
TDC After Trigger 60
Number of teeth on wheel 11
trigger tooth 1
next trigger tooth 3
crank min period 160
relatives:
37.5
137.5
313
338
angular width of tooth 30
angular width of missing tooth 30
engine phase, when to reset 240

questions:  I'm cranking at ~140 according to vems, then it'll drop down to 90 for a second, then to 140 again.  my l28 from my 280zx would crank at 300, and that was with compression.  I'm wondering if the cranking rpm is actually 140, and it's dropping to 90 because of a lag in communication or something, or if my trigger settings have it messing up and actually reading 90 rpm?

I had a friend crank for 6 seconds, during which time I counted 6.5 turns of the cam, which equates to 13 turns of the crank, which is ~ 130 rpm, as best as I can count.  We figure that if we can count 130, and VEMS is telling us it's ~140, we might be pretty close.

Also, can someone explain to me the way the relative settings work?

Thanks!

[Wayne]

Hy,
I have this trigger version on a 4cyl. engine,
and i have the right setting from here.

http://www.vems.hu/manual/html/ch09.html#fig.configpritrig

When i look on your setting, "next trigger tooth" must be 4 not 3.
the angular width of tooth in my setting is 10, for missing is 20.

And have a look on the value "constant for rpm calc".

[badjuju]

I'm having trouble understanding the engine phase variable.  could you elaborate?

assuming a phase of 240 on my engine (is this correct?):

Angular width of tooth = engine phase / ( imaginary teeth * 2 )
240/(12*2) = 240/24 = 10?

[badjuju]

and i didn't see anything about "constant for RPM calc" on that page?

[Wayne]

"constant for rpm calc" is in
(settings), (constants) menü
the right value on a 6cyl. should be 2000

[badjuju]

Changed it in constants, thanks!


Was my guess about engine phase correct?  Should I be at 240?  If so, my angle per tooth should be 10.

[badjuju]

I'm getting a flag in VemsTune that says "Trigger Error", what does this tell me?  Configured wrong?

[Wayne]

When do you get trigger errors ?
Do you driver the distributor with a drilling machine ore with the starter motor ?

[badjuju]

Thought I'd close this one out.  Sorry.

Basically just screwed with trigger settings for a few hours and got it all worked out.