Miller's Mule Blog

MegaJolt.   Mega.  Jolt.  –That’s a funny name. Where does a name like MegaJolt come from? What is MegaJolt? What can MegaJolt do for me? Well, sit down, have a read, and I’ll tell you.

• First, a bit of history
  In the late 80′s, car manufacturers started to take a serious look into the inefficiencies created by mechanical distributors. Even the best units, when tested, will show +/- 2 degrees of ignition timing. The cause of this error is due to the inherent backlash and wear of mechanical components. This wasn’t the only problem though. Manufacturers noticed poor combustion at idle and started using vacuum diaphragms to further adjust timing. These systems worked well until again, being mechanical, would wear and fail.
  
  Their solution, was an electronic revolution!

• Distributorless Ignition
  An electronic distributorless ignition system (EDIS), is an ignition system without a mechanical distributor. Instead, they have multiple coils connected directly to each spark plug. A computer determines where the engine is in it’s cycle, and when to fire each coil. Is MegaJolt that computer? Well.. kinda.
  
  Though there are many different distributorless ignitions, the Ford EDIS proved to be a tinkerer’s dream. Its advantage is that its electronics were separated into different components, a high power relay to fire coils, and the engine’s computer (ECU) to control advance. One could even unplug the ECU and the ignition system would still run (albeit at a static 10 degrees of advance). This got people thinking.. What if we unplugged the ECU and put something else in its place? That something else became MegaJolt!

• What is MegaJolt?
  MegaJolt is an ignition advance controller. Sounds complicated though it really isn’t. An ignition advance controller is a device to control an engine’s ignition timing. In older cars a controller is as simple as weights and springs in a distributor. As the engine spins, the weights allow the ignition timing to advance in proportion to the engine’s RPM. To tune the advance, one could simply change the springs holding the weights and this would change how much advance the distributor would produce.

• If MegaJolt is just a box of weights and springs, what do I need it for?
  In newer cars, the ECU acts as an advance controller and to tune an ECU you need special tools. To tune MegaJolt, however, all you need is a computer (or even just a smartphone!) To put it simply, MegaJolt allows you to tune the ignition timing of a Ford EDIS without special tools.

• So, that’s it?
  Hardly! That’s only the tip of the iceberg. Since its inception, the MegaJolt project has grown immensely. Many features were added over the years, turning MegaJolt from just an advance controller to much more:
  
  It can be a rev limiter.
  It can correct for air temperature.
  It can be a pressure switch.
  It can be a data logger.
  
  The list goes on. In a way that is almost where MegaJolt goes wrong. Too many features. It is important to remember, feature-rich as it may be, that these features are only extras, and are not required. It can be as basic or as complicated as system as you want. Either way, it is the best standalone ignition advance controller out there.

If you’d like to know more, follow these links to the other posts in our series on MegaJolt:

• Modes of MegaJolt

Oh yeah.. how did it get its name? Originally there was MegaSquirt, another project for DIY fuel injection. MegaJolt was a side project for DIY spark control. If fuel injectors give you a ‘squirt,’ its only natural that ignition gives you a ‘jolt.’