This entry is created as a Build of Material list for wanna be W124 Megasquirters in Singapore.
[ Do be reminded that this entry is still a Works in Progress and may have new items added along the way ]
1) MS ECU [ Microsquirt ]
2) External GM 3 Bar MAP sensor [ easy to replace when needed without having to solder ]
3) EV1 Injectors and connectors[ to be calculated depending on engine capacity and number of cylinders and BHP ]
4) 36-1 Trigger wheel [ to be mounted on crank pulley ]
5) Trigger wheel sensor with bracket [ this is same as an ABS or wheel speed sensor in modern cars]
6) EDIS ignition coil [ using EDIS for controlling ignition makes it easier for installation ]
7) Custom fuel rail with fitting for common fuel pressure regulator
8) Fuel pressure regulator with vacuum input [ commonly used for 16v W124 ]
9) Fuel hoses from new fuel rail existing fittings
10) Coolant Temperature sensor and connectors[ using inexpensive model that is commonly used for megasquirt is easier that reprogramming for using existing sensor ]
11) Intake Air Temperature sensor and connectors [ inexpensive model commonly used for megasquirt ]
12) Innovate LC1 O2 wideband controller with sensor [ wideband o2 sensor for full time fuelling feedback ]
13) O2 bung extender [ to locate o2 sensor slightly away from the main exhaust flow, for prolonging lifespan of sensor ]
14) Miscellanous common 4/5 pin relays for powering up the system only upon ignition and also for fuel pump overrun control
15) Colour-coded wires for troubleshooting/maintenance
The above will get you started on replacing the fuelling and ignition system of your ride.
Note 1
Idling will still be controlled by the old system of your car. Though it requires a lot of fine-tuning to get the idling steady, it is not impossible to achieve stable idling.
To control idling fully by Megasquirt, a new throttle body with TPS sensor and the idling control valve will have to be replaced. The hardware redesign will affect the physical Bowden linkages controlling the gearshifts [ for auto transmissions ].
Though it is possible to relocate the Bowden cables to work with the new throttle body linkages, it will take up too much time and additional resources[costs].
Note 2
The O2 sensor bung will be welded on part of the exhaust. And this is a permanent fixture for full time fuelling feedback. [ This fixture will be visible when looking from below the undercarriage of the vehicle ]
Having a full time O2 feedback means that the ECU will automatically adjust the fuelling on the fly to compensate for varying conditions of air temperature, degraded injectors, air pressure differences, etc. The air fuel ratio will constantly be adjusted to what is pre-defined in an AFR table [ set by you ].
This is absolutely necessary to ensure correct AFR delivery at all times even with degraded components/sensors over time. A correct AFR will ensure the engine lifespan.
Note 3
Ride undergoing Megasquirt installation should have a relatively healthy engine and idle control system. A healthy engine and idle control system will ensure stable intake vacuum so that the ECU can read it correctly and provide the fuelling and spark in accordance to the vacuum[manifold absolute pressure ] detected. Engines with inconsistent compression across its various cylinders with have fluctuating vacuum and that might cause erratic idling. [ That being said, it is not impossible to have Megasquirt on such an engine if the owner is planning on fixing it later on].
Labour Works and machining required
1) Mounting of ECU
2) Mounting of 36-1 Trigger wheel on crank pulley
3) Mounting of Trigger wheel sensor and bracket
4) Removal of Fuel Distributor and Spark Distributor and Air Flap Plunger in Air Flow Metering unit
5) Removal of existing Ignition Trigger Board
6) Mounting of EDIS unit + modification to existing spark cables to fit onto EDIS
7) O2 sensor bung welding onto exhaust + wiring to ECU
8) Machining of injector fitting at intake manifold [ widen for EV1 injectors ]
9) Installation of fuel rail/fuel pressure regulators and injectors and connectors
10) Fuel hoses fittings to fuel rail and existing inlets/outlets
11) Relays installation for powering up ECU and fuel pump control
12) Removal and installation of new temperature sensors with connectors
13) Wiring from ECU to various sensors and EDIS.
Tuning is required!
The megasquirt not designed just for a single type of engine.
It can be used from motorboat engines to motorbikes engines to lawnmower engines.
It comes without any usable tuning maps for fuelling [aka VE] or ignition[spark] or injector parameters.
All the configurable parameters will have to be manually configured.
But for the W124 8v, there are already some in Singapore whom have quite usable configurations and new owners of Megasquirt can start from there.
Last but not least, there is never a tune mapping [VE and Spark map] that can be applied for all cars of the same engine. Each and every car is different [ even if engine is the same ]
Because of age, the vacuum at certain range may be different. And for older engines, the pinging may happen at certain ignition advance depending on the fuel octane used. The tuning of each and every car will be affected by such conditions.
And once the driver is comfortable with tuning, he/she may want to have more "umph" at the initial rev range of under 2k rpm and configure it to have more ignition advance in those range. But with additional advance, more fuelling is required to prevent it from pinging.
On another hand, another driver may want to reserve the higher ignition advance on the higher RPMs so that the additional fuelling won't be affected by the low RPM's start/stop conditions which will exhaust more fuel.
So some might ask, is the Megasquirt "plug and play"?
Yes, but the keyword is the "play" part, if the owner is not open to learning how to "play", the system's potential will never be fully utilized.
