Turbo vs Superchargers

[Dave Balfour]

I am new to the list and I am not sure how this fits in with the
fuel injection. A solution is to have a turbo and supercharging on
the same engine Like the Fairbanks OP engines. They are a 2 stroke
oil burners. and use a normal roots blower and then have
turbocharger that feeds the inlet of supercharger.As the turbo
boost builds the superchargers input pressure becomes as high as
the output pressure and it just free wheels. You have low rpm
response from the supercharger and high rpm effiency from the
turbo.
dave balfour
observer

----------
| From: Frederic Breitwieser
<frederic.breitwieser at xephic.dynip.com>
| To: diy_efi at efi332.eng.ohio-state.edu;
diy_efi at efi332.eng.ohio-state.edu
| Subject: Re: Variable Compression, Variable Displacement you
decide
| Date: Wednesday, February 18, 1998 8:58 AM
| 
| >Again same as above.  The auto books I have read say the
biggest problem
| >with a supercharger is how much power the use at high rpms. 
This they
| >say is the only disadvantage of a supercharger over a turbo.
| 
| This has been my perceptino as well.
| 
| Turbos offer much better performance in the mid-high end of the
RPM range,
| simply because they have to spool up based on lower exhaust
pressure at
| lower RPMs.  Superchargers, being belt driven, and most of the
time driven
| by a 1:4 or a 1:8 gear-up system, right off idle are making
boosted power.
| The problem with superchargers, as you said, with a 1:8
planetary drive
| (for example), your engine sitting at 6000 RPM, your blower is
spinning at
| 6000 * 8 = 48000 RPM.
| 
| It comes down to application - for a street car with not so high
RPMs (lets
| say, around 5k or so), a supercharger is great.  Turbos tend to
be better
| for road racing and/or tracks of that sort.  Of course, there
are millions
| of exceptions.
| 
|