Eggenfellner Subaru STI for sale

29 May 2008 Eggenfellner Subaru STI for sale

Update: 20210918 I ended up removing the Eggenfellner Subaru engine and replacing it with a Lycoming. Any post that references the Eggenfellner or the Subaru should be there only as an example of what not to do. Listen to the designer, and install the engine that that designer recommends – which for the RV-8 is a Lycoming IO-360.


I’ve decided to sell my Eggenfellner Subaru STI engine. It is a FWF package including an electric 3-blade MT prop with prop controller, RV8 engine mount, supercharger, intercooler, engine computer, dual fuel pumps, exhaust system, mufflers, and all accessories.

The reason I am selling it is because the package is not yet complete, and I would like to get my aircraft flying.

There are some people still doing development of the engine. The systems that will need work to make this FWF kit complete are:

  1. New Gen III PSRU. The current Gen II supercharger that was shipped with the engine has been grounded due to several in-flight failures. I might be able to source one of these from another builder that has decided not to use his. A new Gen III is about USD 6000 from the Eggenfellner Aircraft.
  2. Change out the supercharger for a turbocharger. The Gen III PSRU has a lower gear ratio, which allows the engine to rev higher, producing more power. A side effect is that the supercharger will spin faster than it was designed to. This can be resolved with a new supercharger pully, but I believe the best solution is to install a turbocharger.
  3. Replace the Engine Computer. The ECU that is installed should be reliable, and many have found it works well. Some have had problems, and are switching to an SDS engine computer. I would recommend this change.

I really regret having to change this engine out for a traditional aircraft engine. I feel that the Subaru engine is an outstanding fit for aircraft, but I just don’t have the time and resources to finish the development work on this package. The original supplier, Eggenfellner Aircraft, is no longer developing this package, having moved on to a 6 cylinder engine.

There is a yahoo list of about 25 other owners of the STI engine that are working together to finish the development of this engine, so I’m confident at some time in the future it will become a very viable powerplant for aircraft use. This list is called EggenfellnerSubaruSTI and is open to all STI owners. This is a good place to discuss this engine, and the development work being done from Australia to the US to Lithuania.

Please contact me if you have interest in this package (mick at rv8.ch, please include “eggenfellner” in the subject). If I don’t sell it, I will pickle it, put it in the corner of the workshop, and when the development work is complete, I’ll either put it on this RV8 or my next one! šŸ™‚

1Comment
  • Doug Lomheim
    Posted at 20:59h, 21 March

    So sorry you ended up going to the Eggenfelner “road”…he still owes my buddy about $10K for parts never delivered.