[Ducati] exhaust energy, turbos and diesels

[Tim Doucette]

Brad, interesting thoughts about multi staged turbos.  That's what would
be needed for gasoline powered sporting engines to be effective, let
alone efficient.  Spent some years learning about and tuning turbo cars.
The 1.8T being the last effort.  

My conclusions are that in its current technology, turbocharging does
not make at ton of sense unless you had no other way to make power.
Seems to me, unless you are running at a constant rpm (planes,
generators, big rig diesels etc) the physics of turbo inertia works
against the "sporting feel" most of us gear heads want out of an engine.
And to your point, it also beats the hell out of the efficiency and
economy especially given the added maintenance (oil changes, turbo &
waste gate failures, cooling system stress, pressure leaks) and reduced
engine life.  

In the case of the 1.8T, it is hardly a world beater in economy even
though it is turbocharged; even using a power per unit of fuel
measurement.  If it were, we'd be seeing turbos show up in hybrids and
other green vehicles.  It is not a panacea and in fact it's probably the
wrong technology period.

Tim   

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Message: 7
Date: Tue, 27 Nov 2007 22:58:30 +1100
From: "Kerry and Brad Black" <bikeboy at alphalink.com.au>
Subject: [Ducati] exhaust energy, turbos and diesels

.......which brings me on to my point.  if you wanted to make real use
of the energy going out the exhaust you'd have either a wide ranging
variable turbo (not sure if they exist) or a twin / triple / quad turbo
set up.  the smallest turbo would be boosting while you were cruising
around at 60 - 100km/h, because in reality that's where a lot of bikes
spend a lot of time (mine does) and when they're also very inefficient.

most people don't worry about this sort of stuff tho, and no one turbos
a bike to help the part throttle fuel economy.  but when you're running
an interstate truck and spending $100,000 a year on fuel (probably
more), 1% increase in economy is a decent chunk of cash.  10% makes
owners take real notice.

brad