As always "your results may vary" As most of you know the Ellison vapor lock issue is what brought me down in May of 2019. After the rebuild I swore off TBI's and actually tried the MA3SPA carb as recommended by WW and could not get the Corvair to run correctly. It was always too rich. It also hung way below the engine creating headaches for the cowling. So after many months of frustration I went back to a TBI and now WW is not recommending the MA3 carb although he says it works ok. (there's a whole back story to that too) Anywho, I have talked to others that had the same experience that I did so goodbye MA3 carb.
This is my experience with the Corvair engine and using a TBI. I have to assume it would be the same for VW. It is my understaning that the EFS2 for VW's was discontinued. Ellison EFS3A: 1. Can vapor lock if TBI regulator gets too hot. (Ellison would not acknowledge this fact. Multiple users have experience with this fault) 2. No method for braking a vapor lock. 3. I could never get the engine to shutdown using mixture without increasing the throttle. (minor annoyance) 4. RAM air worked fine. See recommendations below. 5. No support that I am aware of. Rotec 34-2 1. regulator bypass button provides engine priming (works great, save weight too) 2. regulator bypass button will break a vapor lock. 3. Engine shuts down fine with mixture only to full lean. 4. RAM air worked fine. I see an increase of a minimum .5 inHg manifold pressure. I open ram air right after takeoff. AFR does not change. See recommendations below. 5. Support available (Rotec sells overhaul kits) My Recommendations. 1. If using Ram Air add an airflow straightner to the intake flange right before the TBI. (sold on ebay $20) 2. Filter, filter, filter. Don't ignore the importance of having the cleanest fuel you can get. The holes in the spray bar are smaller than small. 3. Run a AFR system. Dual AFR is better as it will show you which side of the engine is leaning first. 4. Intakes shorter than 6" after the TBI will decrease uniform mixing and will likely cause one side of the engine to lean first. Rotec manual: https://www.rotecaerosport.com/_files/ugd/ef523b_b5817e340a9e4a8bbb1d0ebd894974fd.pdf -- KRnet mailing list KRnet@list.krnet.org https://list.krnet.org/mailman/listinfo/krnet
