>Automotive engines apparently are stout enough to handle
> a certain amount of boost to get a
>horsepower increase without damage.

So are aero engines, a racing Merlin can take maybe 120-140" boost, thats 3
to 4 atmospheres!
Mot many auto engines get near that!
In fact it maybe takes 1000 hp to drive the superchargers!

Clive

----- Original Message -----
From: "John Rodgers" <j_rodgers@CHARTER.NET>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Friday, October 18, 2002 3:20 PM
Subject: Re: Increasing horsepower

> Turbo Charger, Electro Charger, Turbine Compressor......!
>
> The principle is the same. A turbine (turbo) takes in air, and using
> centrifugal force compresses the air which exits the compressor into the
> airflow system of the engine. Thus the charge of air for the fuel is
> more dense, and there fore needs more fuel for proper fuel/air ratio.
> Greater amount of fuel/air into the cylinder means more power for the
> same displacement.
>
> How that turbine is driven is not important except from an efficiency
> standpoint.  Exhaust drive is the most convenient and probably the most
> efficient as it provides some power recovery from the heat and motion
> energy of the exhaust.
>
> The shop where I have been working has a high pressure air compressor
> that is a centrifugal turbine type compressor that uses an electric
> motor to drive it.
>
> Today, automotive application of electric drive turbo compressors may be
> reasonable, given changes in technolgy.
>
> There are two approaches as to the goal of turbo charging or
> supercharging as it were. Ad it applies heavily to piston powered
> airplanes particularly.
>
> One, to turbo charge for the purposes of INCREASING horsepower, and two,
> to turbocharge for the purpose of MAINTAINING horsepower as altitude
> increases. In the case of the latter, automatic flow gates are installed
> so and overboost won't occur with the resulting engine damage such as a
> blown cylinder --- literally - right off the engine. Automotive engines
> apparently are stout enough to handle a certain amount of boost to get a
> horsepower increase without damage.
>
> My 2 cents.
>
> John Rodgers
> 88 GL Driver
>
> John Rodgers
> 88 GL Driver
>
>
> Andrew Grebneff wrote:
> >
> > >Superchargers are normally powered from the main crank (which means
> > >that they add more air in proportion to the engine speed.)
> >
> > In fact most superchargers today are exhaust-driven, and are sloppily
> > called turbos. This has been a thread on the list before. Turbos ARE
> > superchhargers, plain and simple. They came into common use on
> > American aircraft in the war (B17s, B24s, LP38s) and were initially
> > called "turbosupercharger", later contracted to "turbocharger".
> >
> > >However,
> > >with modern electronics, yah, I guess it is possible to add them and
> > >control them via electronics (and electric motors) instead. I can see
> > >certain advantages to that too, like no additional friction added to
> > >the crank...
> >
> > VW had Mitsubishi working on electric turbochargers in the 80s, using
> > torpedo-motor technology. This came to nothing, obviously, or these
> > would have replaced exhaust-driven turbos (allow me a little
> > hypocrisy!).
> >
> > Note that a turbocharger MUST have a turbine, or naturally it's not a
> > turbo. A turbocharger has an exhaust-driven turbine connected by a
> > shaft to a compressor wheel. As an electric unit would have no
> > turbine (replaced by a motor), it would not correctly be a
> > turbocharger. So what should it be properly called? Ideas?
> > Electrocharger? Bah, just electric supercharger.
> > --
> > Andrew Grebneff
> > 165 Evans St, Dunedin 9001, New Zealand
> > <andrew.grebneff@stonebow.otago.ac.nz>
> > Seashell, Macintosh, VW/Toyota van nut