Turbo question

[Fastinated]

I have been through a bunch of older posts, but I am still confused why newer turbo engines need to be run up every few hours. Until the other day I didn't know the turbo'd engines had a supercharger as well. Is this the reason? I did hear about it not running at an optimal temp. But I was under the impression that the thermostat will keep temps at proper temp. Large trucks idle all day long and still get 1,000,000 miles plus.

Is this something noticable when you do finally give a little extra juice? Hesitation (forgive me old 2 stroke bikes loading up), smoke? If there is no smoke (more than normal) then to me it's getting a complete fuel burn.

I did see about the carbon build up, top ring space, etc. I'm sure some of these engines were put into buses as well and I know they idle for prolonged periods.

Reason I am asking is while we are looking for a boat to live on that is a big deal. I'm a putter, lost the speed bug long ago. Plus turbo's are added expense/complexity. So currently I've been looking at only older models w/o turbos.

While I have you smart fella's here is the fuel consumption better, and if it is enough to over come the downsides.

[Avenger]

I'm not sure how this got missed, but in an attempt to answer your question;

No engine is designed to, nor does well idling all the time. Trucks, buses, generators whatever, they're all designed to work for a living. When they refer to temperature it's cylinder temperature, not coolant temp. Cold cylinders lead to incomplete combustion which leads to sooting. The general consensus appears to be you can run at a moderate speed for a while but periodically you need to "spool 'em up" to burn off the carbon. If we're going to be technical a set of pyrometers will tell you a lot more about engine loading than people's opinions.

Also, there are efficiency issues with running large engines at small engine outputs. Nothing that will make up the price of a repower, but it's not efficient. If you're really concerned about that there's an excellent thread about propping for lower speeds to increase efficiency:

http://www.samsmarine.com/forums/sho...g-Engines-Slow

Turbos and superchargers.... all 2 stroke Detoits have blowers. It's not a performance upgrade.

Hope this helps.

[StratPlan61]

Fastinated,
remember thats a 'blower' on that Detroit. It becomes a supercharger only when added to the induction side of an engine as it forces air into the combustion chamber. On a Detroit, it 'blows' the exhaust gases out of the combustion chamber in place of the exhaust stroke - which of course is missing on the 2 stroker motor.