There are several inherent/recuring problems with AeroVW engines that I believe need to be addressed to keep this cool little engine relevant into the future. I would like to start a thread that focuses on these issues and the solutions that have been found.
I’m working on an EFII system that I believe will solve, or at least mitigate, some of these issues. Here is a list.
- Secondary Ignition module/trigger failures.
- Secondary Ignition coil failures.
- Poor fuel distribution.
There are others, for example low oil pressure and oil pressure sender failures. I would like folks that have solved any problem with these engines to join in and post their solutions, or links to their solutions, here.
Technical writing is not the most enjoyable part of product development. So, I have to keep my eye on the prize to keep motivated. I know my engine is capable of much better performance than it is presently delivering, and I want that performance. Here is the introduction to the EFII manual I am currently working on. The formatting didn’t copy and paste well, but you get the idea.
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Introduction:
The VeeCU, and associated components, implements an Electronic Fuel Injection and Ignition system. The system was designed specifically for Volkswagen air cooled engines that have been converted for aircraft use. To be precise, the VeeCU implements a Speed Density, Semi-sequential, Port fuel Injection system. The VeeCU is designed to take maximum advantage of your existing ignition and induction components.
The VeeCU may be installed on any VW powered aircraft having an engine with the following characteristics:
1. Displacement in the range of 1600 cc to 2400 cc.
2. A fixed pitch propeller.
3. Either Dyna S or Sonex wasted spark electronic secondary ignition system.
4. All four EGTs and RPM instrumented.
5. A well-tuned slide carb with mixture control that is capable of full idle cut off.
The VeeCU provides the following advantages over typical carbureted induction systems.
1. Precise fuel control. The VeeCU allows the operator to balance fuel delivery between each cylinder, over the entire RPM range of the engine resulting in a very low EGT spread. Matched EGTs, along with quick and easy mixture control, makes it easy to keep all EGTs and CHTs in the green. Additional benefits of balanced fuel delivery include increased fuel economy and smooth engine operation.
2. The VeeCU provides a simulated “Impulse Mag”. The VeeCU’s ignition, which replaces your existing secondary ignition, fires at 5 Deg. After Top Dead Center until the engine reaches 400 RPM. This, combined with the precision for EFI, results in quick and easy engine starts.
3. The VeeCU provides precise secondary ignition Dwell Control. Dwell control reduces the secondary ignition power consumption by up to a factor of 10. This massive reduction in power means that ignition coils heat very little. Ignition coil failures should be greatly reduced.
4. The VeeCU uses the existing secondary ignition module as a crank position sensor. In this capacity the ignition module drives a 2 K-Ohm load rather than a 3 Ohm load. Under these conditions there is very little stress on the secondary ignition module which should all but eliminate secondary ignition module failures.
5. The VeeCU uses your existing slide carb, with mixture control at idle cutoff, for a throttle body. With your existing fuel system in place, untouched, it provides the ultimate, non-electrically dependent, backup should the VeeCU or electrical system fail. It’s like having your cake and eating it too.
6. The VeeCU provides a simulated “Red Cube” fuel flow output eliminating the need for a fuel flow transducer.
7. The VeeCU is unique in that it doesn’t require a digital display. Adjustments to fuel delivery are made, and then verified, by referencing the EGT and RPM indications of a suitable engine monitor. The installation requires very little panel space.
8. Finally, with fuel injection, fuel mixture does not vary based on fuel level or G loading. This will be appreciated by those who enjoy aerobatic flight.:—————————————————————————————————————————–
So, I’m doing what I can to give the engine a leg up. I hope others will do the same.
Thanks,
Wes
