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End all 36-2 trigger wheel on miata thread

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Old 11-21-2020, 11:58 AM
  #21  
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how much to get it running?

timing was set on oem setup- damper and trigger wheel. Warmed up, locked at 10° fixed, adjusted offset. Do I keep that same offset trying to get it running?

the cam signal is inconsistent on the composite logger, trying to figure out why.

noted on rising/falling

02 chassis 02 motor with vvt.

Initially I tried to use a “good base map” and made 4 holes in the block, hence the greater desire to get someone who knows what they’re doing to get it right.



Originally Posted by Ted75zcar
I recommend you stop ~trying stuff to see what happens~ and look at the raw composite logger data in a spreadsheet program. Tons of people are running FM36-2 wheels on MS3pros (myself included). Randomly changing settings in the tune is just shooting in the dark.

The MS manuals do a good job of explaining how you set a trigger wheel up. If your mechanical cam timing is good, then you can use CAM position at TDC to establish crank TDC and engine phase.

If stuff doesn't look right in terms of the missing tooth location, chances are you have a mechanical timing issue.

Ignore all the stuff people have out there WRT rising vs falling edge. That is a Boolean option that the uniformed love to play with because they think they know what they are doing. The modern MS variants use IC based trigger detection, so the slew rate differences between rising and falling edge has made this selection almost moot. For non-VVT applications, you simply need to select the option that places the cam trigger in a good spot on the crank trigger. You don't want the two triggers to overlap.

These settings do not vary across platforms much at all when using standard hardware. Any tunes that you can find out there that use the 36-2 from FW1.5 should get you in the ball-park. The 1.4 source code describes the implementation of the 36-2 miata triggers as well. If a standard setup doesn't work, confirm mechanical timing.

I don't see what motor you are using, be aware that an NA8 crank trigger sensor is not adequate for a 36-2 wheel. You need to use a BP4W sensor or newer. The BP4W sensor does not mount directly to a NA8 stock oil pump.


Edit:
/* ---------------------- Miata 36-2 99-05 --------------------*/
} else if (spkmode == 55) {
/* 36-2 on the crank with a 2/1 on the cam */
unsigned int i;
cycle_deg = 7200;
flagbyte5 |= FLAGBYTE5_CAM;
no_teeth = 68;
last_tooth = no_teeth;
for (i = 0 ; i < 68 ; i++) {
deg_per_tooth = 100;
}
deg_per_tooth[33] = 300;
deg_per_tooth[67] = 300;

smallest_tooth_crk = 100;
smallest_tooth_cam = 900;

no_triggers = 4;
trigger_teeth[0] = 19;
trigger_teeth[1] = 35;
trigger_teeth[2] = 53;
trigger_teeth[3] = 1;


trig_angs[0] = -300 + tmp_offset;
trig_angs[1] = -300 + tmp_offset;
trig_angs[2] = -300 + tmp_offset;
trig_angs[3] = -300 + tmp_offset;

if (num_cyl != 4) {
conf_err = 1;
}
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Old 11-21-2020, 12:24 PM
  #22  
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The trigger offset is simply an adjustment to the tooth #1 angle, it allows you to compensate for tolerance variations in the system.

The composite logger window provides a graphical representation of what is in the raw data. It produces an error when it sees a trigger where it doesn't think there should be one, or when it doesn't see a trigger and it thinks it should. You have to tell it how the triggers correlate. So, as shown in my previous post, the built in decoder expects to see secondary (cam) triggers on the primary (crank) trigger teeth 19, 35, 53, and 1. So your cam triggers need to occur on those teeth. You tell it where tooth #1 is with the primary trigger angle.

Look at the raw data.
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Old 11-21-2020, 05:20 PM
  #23  
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Why isn’t the cam signal consistently on the composite logger?
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Old 11-28-2020, 07:10 PM
  #24  
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Fwiw pulled fuel pump fuse and plugs
miata 36-2
80°
rising edge
turned off noise filtering
adjust sensor .030” from trigger wheel
ran composite log and trigger teeth log. Trigger log looked weird but had no sync errors

put plugs in and fuel pump fuse and fired right up

read somewhere that increasing the gap adds resistance to the circuit which can clear up noise, most people need to go closer though.
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Old 11-30-2020, 02:54 AM
  #25  
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Have a bit of confusion as I am not seeing this brought up in the thread.

I thought with the 36-2 wheel you had to change to the NB sensor, and that sensors wiring had to be rewired slightly?

Can I continue to use the stock 97 NA sensor with this 36-2 wheel with a megasquirt install?

I had tried to install it a few months ago with all the stuff to change out to the NB sensor and could never get it to work
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Old 11-30-2020, 03:14 AM
  #26  
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It is my understanding that NA crank sensors are raw VR sensors, while NB crank sensors are VR sensors internally conditioned to act like a hall sensor, or open drain that needs a pullup.

All megasquirts should be able to be configured to use a raw VR sensor like the NA uses, but you would need to set it up properly.

I have no idea if the sensor has the fidelity to use a 36-2 wheel, either. It might be too slow to use so many teeth...
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Old 11-30-2020, 04:04 AM
  #27  
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You can revert back to Miata 36-2 mode and switch back to sequential with VVT and knock now.
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Old 11-30-2020, 07:57 AM
  #28  
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im in an 02 chassis with 02 vvt

Originally Posted by Malic
Have a bit of confusion as I am not seeing this brought up in the thread.

I thought with the 36-2 wheel you had to change to the NB sensor, and that sensors wiring had to be rewired slightly?

Can I continue to use the stock 97 NA sensor with this 36-2 wheel with a megasquirt install?

I had tried to install it a few months ago with all the stuff to change out to the NB sensor and could never get it to work
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