The following "Units" are not technically essential for any Megasquirt installation, but each has its place, and can make a huge difference and make life easy. I like "Easy", so do others, as such I have decided these are a good idea to have on my web shop.
PWM Kit
To frighten you to death – it stands for "Pulse Width Modulating Valve" – And in English – An Electric Autochoke, and a "Tick over" stabiliser.
To explain further – Comp Safari Racers often don’t have these – they often just use a carefully broken calibrated stick found on the ground and kept - then shoved on start up under the accelerator until its warmed up, but that’s not good, cheap yes, but not good !
A PWM kit has just 2 wires, (and wires for this are included in the loom kit), once fitted for starting you turn the key, and the PWM adds extra air to "Lift" the tick over, which then drops towards the normal tick over RPM as the engine warms up, the limits are tunable, but all my built ECUs come with the software for these loaded which 99% of customers seem happy with!
For helping tick over, when things like electric fans kick in the revs drop – a PWM unit helps stabilise the tick over whatever else is going on, makes for a very very smooth engine. Kit comes with full instructions, a Bung for the removal of the old stepper motor, 2 x new hoses and a second hand 2 wire PWM Bosh Unit – fitting is probably less than 10 mins !
Stim Kit
This is a seriously clever device, and one that many people overlook. I have used one ever since I very first Megasquirted my Land Rover.
It "Mimics" an engine, the ECU behaves as if it is being driven and thinks it connected to an engine ! This gives you a selection of useful things you can do.
The main one I use it for is tuning. I may have a huge data log, rather than work on it in the workshop, I can go indoors, connect the stim, the ECU and the laptop, sit in a comfy chair with a beer (or 2) and run the logging software, change settings and burn to the ECU. You can see all the settings, change them, and get a far better understanding of how Megasquirt works. On the Stim itself there are 5 Knobs that can be turned, to mimic what can change in an engine - these are RPM, 02, TPS (Throttle Position) Air Temperature and Coolant Temperature, and you can save, upload, and download to the ECU whilst running, all you need to add is a PC or Laptop.
This can help hugely, and its normally a very "delicate" unit that the ECUs plugs directly into, and falls out of, and needs a power source, and building - and hence so many don't have one.
So, to make things easy I have put together the "New Stim Kit"- This Complete Fully Built Kit comes with :Its own 13 AMP Power supply - just plugs into the Stim (the Black Lead in the Picture) the other end to a Mains Socket. The Stim itself, fully built, and tested, also included is both a Connector lead to go between the ECU and the Stim (2 Metres long), AND a ECU lead to go from the ECU to the Computer Serial Port (1.5 Metres Long). This allows you to arrrange the stim ECU and your Computer to suit you and have a decent working layout
A Complete Plug and Play unit and easy to use, Just plug it in open Megatune and its alive (and no.... you do NOT get the Laptop in the Picture ! )
USB to Serial Adapter Unit
I would always recommend that for logging and connection of any computer to your MS ECU you use a serial port.
Unfortunately these ports are now seen by PC Manufactures as "Old Technology" or at best left out to save a few quid. Shame, but, if you do not have a Serial Port, then you will have to have a USB to Serial Adapter, and these are at best "Hopeless" and move to "Arrgh...for pitys sake no please no.. " as they fail when you really really need them to work.
Having said that these are the best of the best units I can find, no, they are not cheap but they do work better than any others I have tried. If you have to go USB to serial then this is as good as you can get, personally I'd save your money and buy an old cheap laptop from E-Bay and go serial lead, but, if not I have sold over 20 of these so far and all have said they work, and thats quite something for these adapters.
Megasquirt Wiring Relay Board (Fully Built)
A New Fully Built & Genuine B&G Relay Board for "Megasquirt", or even Megajolt Applications
As you can see from the Picture, around 6" Long, and 3" wide and 2.5" High (inc the Relays themselves) Although Technically not needed when you wire up your new Megasquirt, having used a couple now on installs I have been involved with - BOY - are they a useful thing to have, and this helps with a quick, neat and faster wire up.
Along the front is a Connector block, which has a description for each of the sockets that the wires are placed in, showing which go where, the fuses are similarly marked as to what they relate to, as are the other inputs and exits
The convenience makes this what it is - and there is less chance of getting a mis-wire on installation, all the relays you need on Megasquirt (That is relays for the Main ECU Power, Fuel Pump, and Fiddle circuit (PWM) - which are included - the 3 in the picture). If you are fuel injecting a previously Carb'd engine you'll need to install relays for the main ECU power, Fuel Pump, and Fiddle circuit. You can do this manually, or you can use this Relay Board to simplify this process.
You will also get 4 x fuses – 1 x 20 Amp main fuse, 1 x 10 Amp fuel pump fuse, and 2 x 7.5 Amps fuses for 'INJ1' and 'INJ2' (not Shown in the picture - 'cos I forgot !) . and also comes with a new DB-37 Connector (in the bag) to be used to build your relay cable, and the "half-case" shown in the picture, there is no top of case available, ...my advice is always to place these in a safe and easy to access position, and for any form of serious off road use - this and the ECU should in my opinion be in a waterproof box... just to be safe