I, as well as Steve (as he stated) would enjoy hearing more about the positives on turbo charging too.
That said, I want to say that I did not want to come off sounding negative, I just wanted to point out my concerns about turbo charging from my experience's in high performance turbo charging. There are so many benefits to turbo charging an engine from performance in power and fuel economy. Yes I said fuel economy and what I meant by that was you can run a normally smaller displacement engine to gain economy while getting the benefits of additional power by force feeding air/fuel via the turbo. My problem was I never could keep my foot out of it to really see the fuel economies but they are there. Also, my experience was performance related and not of the altitude normalizing that would be associated with aircraft turbo applications. However, some of the same issues apply. I pointed out, and Steve and others pointed them out as well. The main concerns I would have are oil and engine temps due to the very high temps a turbo can achieve. As I recall 1600 degrees F. As Steve pointed out, I would never consider a turbo without a intercooler. An intercooler is used to cool the turbo charged air fuel after it goes through the turbo and before it enters the combustion chamber. Do not mistake the idea that an intercooler is for cooling the turbo charger. Its not. That will be the job of your over sized oil cooler. When the engine in a turbo charged motor is shut down, that 1600 degree turbo (which is oil cooled) will act as a furnace to cook the remaining oil in the turbo. This will effectively coke the oil. This is why normal shut down of a turbo charged motor is not recommended. Its why turbo timers are used to circulate that oil after engine shut down. I know the Dragonfly guys and Tri Q guys did a lot of turbo charging of the Subaru motors and some of the Corvair guys had been looking into it or have done it. But I believe weight and engine life issues may have slowed down or halted the use and development of those turbo applications. One more thing. It was my understanding when I did turbos on performance applications that you did not just slap a turbo on any engine. Don't put ten pounds of boost on a 9 to 1 or 10 to 1 compression motor and expect it to hold together very long. You will effectively have a 19 or 20 to 1 compression motor. These are diesels. That kind of compression will blow up a motor. Also, make sure you have the right exhaust valves to handle a turbo or you will be burning them up. Not fun pulling off to the side of the road at 10,000 feet when you eat a valve cook a piston or blow a head gasket. It was a lot of fun doing turbo apps in automotive applications. Computer controlled air fuel metering, precise BOV/ Waste gate control, air/fuel mixture control and other systems allowed reliable power gains. I am not sure I have seen anything better than old unreliable mechanical systems available to do this on a VW motor. But what the William Winns and MJ's and ML's are doing with the systems they have available on Corvair motors would to me seem to be the better platform in which to start a turbo project. I love my GPAS VW and all that Steve Bennett has done. But the fastest way for me to mess up all that reliability is to slap a turbo on my VW motor without finding out if and how it can be done reliably. OK, I have ranted enough. I too want to hear from those that have done it so as to get the positive and learn how. Thats what this is all about. Sorry for running on but, I hope I was informative in some way as to the how what to look out for and what not to do. I would love to get 70, 80 or more horsepower out of my VW motor and if I could add a turbo to it and get reliable life out of it, I would do it. But, in my opinion, it might make more sense to look at a Corvair that can get 100 hp or one of these 23xx VW motors. But, lets hear from the ones who know how and have, instead of us (me) who know how not to. By the way, I worked on some turbo spam cans that came into the aviation shop I used to work in. But they were very rare. I have to wonder why they were so rare. Jeff York KR-2 N839BG Lexington/ Georgetown, Kentucky ----- Original Message ---- From: "Teate, Stephen" <[email protected]> To: KRnet <[email protected]> Sent: Mon, January 3, 2011 10:22:28 AM Subject: RE: KR> To Turbo or not to Turbo that is the Question "I've already heard some of the negatives from others, but does anyone have a list of positives?" Both Jeff Scott and Jeff York have responded to this and made excellent comments to be considered. I admit I am biased to the positive side of turbo's so I will add my opinion.
