MS2 exploded at the track
 

You can see that damage best in the 2nd photo. From what I can tell it's not reparable as the circuit is burned. Can anyone smarter than me confirm?
https://www.miataturbo.net/attachmen...ine=1379954292
https://www.miataturbo.net/attachmen...ine=1379954292

replace both those caps and move along.

Board looks pretty toasty there as well, Brain...

replace both those caps, fix any broken traces, and move along.

Exploding C16 is something that happens more than it should. Replace with a higher voltage.

Yeah, that.
Kinda makes me nervous.

Can someone point me to which part it is in the schematic?

c16. part of the 5v circuit.

C16 in this schematic

https://www.miataturbo.net/attachmen...ine=1379968572

It's a part of the power supply circuit

Megasquirt 3 - V3.0 board schematics

Where does "12V for MSII stepper" go? (above C16)

Does someone have the manuf. part number of C16?

The official V3.0 BOM says use Digikey 399-3584-ND.

12V for stepper is an optional 12V source for the stepper chip on the MS2 daughterboard.

*This post contains ignorant, yet well meaning questions*

A track environment is understandably tough on mechanical components.
But, is the failure of an ECM on the track a mere coincidence, or does the failure have something to do with sustained high rpm and the very rapid "cycling" of the capacitors to keep up with the injector and coil drivers?

More likely than not, just a bad part (ie lower voltage spec than specified). The time it fails is irrelevant. Another two failures happened at idle.

Thanks, that's what I had thought - with my limited understanding of electronics.

Is this used to power a boost or idle solenoid?

You think like an engineer! Yes cyclic currents in a capacitor ("ripple current") can cause overheating and failure. However C16 doesn't see injector / coil currents. It's not clear how much ripple it sees.

Tantalum capacitor applications need careful evaluation because the temperature, voltage, and ripple current stresses can cause failures. In this application it might be on the order of 0.1 - 1 % per 1000 hours.

Polymer aluminum electrolytic capacitors are less "delicate". I suggest using these:
Digikey 493-6661-1-ND

Invalid Request

The only time I've seen these blow personally is:

1. ran a flyback to s12c instead of s12.
2. installed the MS in a NB and they blew instantly; this happened twice.

otherwise, I've never had one blew from sustained use.

Car had done maybe 30-35 laps over 4 hours. Pull out for the last 3 minutes of track time and :15 later all power cut.

jeff man, email us at websales@diyautotune.com with your info, and we'll mail you replacement caps.