Replacing the Type 3 EFI

With the new engine for the Razoredge now procured, I've been looking towards what I need to do to it to get it up and running in the razor. The engine itself is a standard Type 3 fuel injected unit that is currently still in the '71 fastback in my garage. It leaks a little oil, but runs okay, and shows 80k on the odometer. this could possibly be 180k or maybe even higher, but this doesn't bother me as it runs fine, and I will eventually rebuild it anyway.

The choice of a fuel injected unit as opposed to a naturally aspirated unit is, to me, a no brainer. EFI is far superior in terms of low range power, fuel economy and drivability. Not to mention that they are more efficient than a carburetted engine - this is the reason that pretty much all modern cars are EFI'd - stricter emmissions regulations mean that higher efficiency is needed.

But anyway - I digress. I say that a fuel injected engine is better - but this is not regarded as the case for the Type 3. Over the years the L and K jetronic systems have come into a lot of bad press, especially amongst those who maintain thier own cars. The system is hard to diagnose issues on, as there is no diagnostics funtions available to assist in determining what's wrong. Fixing a faulty system is really a case of eliminating all possibilities, one by one, until the fault has been found. There is no laptop port to plug in your laptop, and get an instant readout of what is going on, and to many, this means that the system is considered complex and unreliable.

As I blogged about previously. the other main issue with the stock fuel injection systems is that they are not tunable. There is no way to modify the injector 'maps' to account for even simply modifications, such as fitting an extractor system. Change something on the system and it cannot compensate. Modern systems can overcome this. Either by closed loop feedback, from a lambda sensor, or by simply having the ability to be reprogrammed. This is the main reason that I want to utilise an aftermarket system, plus it is more suited for adding a turbo to later down the track.

I plan on using a distributorless system. this means adding a crank or distributor trigger, and utilising a coilpack instead of a distributor to take care of the ignition side of things. Distributorless systems have a couple of advantages over normal distributor controlled systems. Firstly, there is no electrical 'switch' in the HT (high tension) circuit, it has a direct lead from the coil to the spark plug. This means a stronger spark, and no degredation over time (wear). The other advantage is that the systems generally work in what is called a 'wasted spark' mode. This means that for a four cylinder engine, there are only two coils. This means that they fire twice each cycle, once on the ignition, and once on the exhaust stroke. The firing on the exhaust stroke brings a massive advantage, it helps scavenge the cylinder by ignighting any unburned gasses. All of this together generally means, more efficiency, and in turn, better performance.

Continue reading
  3877 Hits