I'm having trouble navigating all the STS and MegaSquirt websites and forum threads on this. I looks
like things are easier than a couple years ago with the emissions stuff. It seems like the people that
were building these have moved on to other projects.
I have a 1990 Miata I am building for STS.
What's needed to stay withing the rules now? Just a Megasquirt in the ECU case? The way I understand it, you can only use OEM sensors that came on the car, and you are allowed to replace everything in the ECU box.
If this is the solution, what actually needs to be done?
-Buy or build a megasquirt (what is needed? MS1, MS2, Microsquirt?)
-Mount it in empty ECU box
-Create a plug compatible connector to wiring harness
-Determine a base map (how?)
-Take it to a tuner for dyno tuning
Are there other parts of the rules to be concerned with other than 14.10.F? Are people moving away from this? Are there other solutions now?
14.10.F The engine management system parameters and operation may be
modified only via the methods listed below. These allowances also
apply to forced induction cars, except that no changes to standard
boost levels, intercoolers, or boost controls are permitted. Boost
changes indirectly resulting from allowed modifications are permissible
but directly altering or modifying the boost or turbo controls,
either mechanically or electronically, is strictly prohibited. Traction
control parameters may not be altered. Any OE OBD2 or newer communications
port functionality must remain. The Check Engine Light
(CEL) or Malfunction Indicator Light (MIL) may be disabled via software.
Alternate software maps which violate these restrictions may
not be present during competition, regardless of activation. Only OE
sensors may be used for engine management.
1. Reprogrammed ECU/PCM (via hardware and/or software) may be
used in the standard housing.
2. Supplementary (“Piggyback&rdquo ECU may be used subject to the
a. Connects between the standard ECU/PCM and its wiring harness
b. Must be plug-compatible with the standard ECU/PCM (no splices).
3. Electronic components may be installed in-line between an engine’s
sensors and ECU/PCM. These components may alter the
signal coming from the sensor in order to affect the ECU/PCM operation
of engine management system. Example: fuel controllers
that modify the signal coming from an airflow sensor.
4. Fuel pressure regulators may be replaced in lieu of electronic alterations
to the fuel system. It is not permitted to electronically
modify the fuel system AND replace a fuel pressure regulator.
5. Ignition timing may be set at any point on factory adjustable distributor
2015 SCCA® National Solo® Rules — 87
14. Street Touring®
6. VTEC controllers and other devices may be used which alter the
timing of factory standard electronic variable valve timing systems.