I own a Turbocharged Twinkie and aside from additional maintenance with ADs I am happy to have them living in Arizona where density altitude is an issue.  My aircraft does not have intercoolers and I have never had issues regarding overheating.  The turbos have manual wastegates and I utilize them on takeoffs when density altitude is an issue and when flying at altitudes where manifold pressure is reduced below where I would like to cruise.  Otherwise, they are not utilized, which reduces fuel consumption. I do have my aircraft maintained by a shop that is very familiar with the Comanches and RayJay turbochargers. The engines on my aircraft are IO320-C1As.

Jeff Matar

@jeffrey-j Thank you.  If I hear your right, it can an be flown as a non-turbo Twinkie until needed or desired.  I assume one must goose it occasionally to keep parts moving and lubed.  Am I correct in assuming that, if you don’t need the boost, it can be turned off in high work times to allow concentration on more pressing matters (busy airspace, IFR, etc.).  I also assume the potential occasional nature of use helps engine/turbos last longer.

@106460 

You are correct.  The Turbos have manual wastegates.  They turn all of the time however I do operate them frequently to keep them well lubricated.  Depending on how high I choose to fly and how quickly I want to arrive determines my decision to utilize the turbos in flight. The airport elevation and density altitudes play into my decisions to utilize them on takeoff. The only negatives I see, and really only a slight inconvenience, is determining when they will be required for takeoff.  The wastegate controls need to be manipulated on the takeoff roll when they are required and it is a distraction, however there are techniques you will master after a short time.  As previously mentioned, living in Arizona with the heat and high elevation airports, I personally would not own this aircraft if it was not turbo-charged.

Example, when I depart out of a high elevation airport, I utilize the turbos after the  throttles are fully advanced.  I engage the turbo-chargers and I am careful not to over-boost the engines on the takeoff roll.  The turbos are always added after full throttle has already been reached.  On power reduction, the turbo-charging is reduced first, then the throttles are retarded.  

If you have questions, feel free to call me at (480) 227-4361.

Jeff

Extremely important that you fly with someone who can educate you on the performance of a manual wastegate aircraft. The most important aspect might be that you need to ensure that you do not overboost the system. There was a tragic event at KSNA Orange County, CA, in 1972 when an instructor and student took off with the turbos engaged, overboosted the engines and blew one engine, then the other, and crashed. 

It is valuable to visibly see how the turbos work. The air intake to the engine comes through the turbo system and closing the wastegates pressurizes the system. It's great help to actually see how they work so that you don't make mistakes.

The PA30/39 is a magnificent aircraft, and is definitely the best built in this category, but it is a high performance aircraft and operating one with turbos is best done with some help.

Thank you both so much.  I will definitely give you a call, Jeff.  Any particular days and/or times that work better?

Jeff,

I added a general topic here, but interested in your experience with maintenance/overhaul of the Rajay turbochargers?

Ralph