<VV> Average gas mileage in Turbos vs. 110's

[FrankCB at aol.com]

Stephen U,
    Put away your bib, no crow eating necessary.   (Where did THAT expression 
ever originate?)
    You are quite correct.  The stock turbo  Corvairs are probably the worst 
mileage Corvairs of all.  As explained in  my Turbo chapter in the Corvair 
Basics Manual (frequently erroneously called  Corvair Beginners Manual) the turbo 
Corvairs lack vacuum advance for their  ignition timing.  That means the same 
24 deg. BTC stays CONSTANT all the  way from idle up to about 4000 rpm unless 
boost is developed.  This fact  coupled with the low CR of about 8 to 1 
causes poorer gas mileage than the other  Corvairs that all have vacuum advance 
built into the distributors.  For a  further discussion on what to do about this 
lack, consult the Turbo Chapter  in the Basics Manual.
    Strangely enough, the latest trend in new cars is  to use smaller engines 
(to get better gas mileage) along with turbos to get  power when you need it. 
 An example is the new BMW that achieves better gas  mileage AND better 0 to 
60 acceleration times than its competitors by using a  smaller engine with 
twin turbos.  Of course this is done with sophisticated  EFI and ignition timing 
both controlled by computer which the Corvair sadly  lacked.  However, these 
can be added to the Corvair turbo as long as you  don't insist on keeping it 
stock.<GGGG>
    Frank "stock is a good beginning" Burkhard
     
In a message dated 10/22/2007 1:20:33 AM Eastern Daylight Time,  
contactsmu at sbcglobal.net writes:

Had an  interesting discussion with my nephew.  Which has better gas   
mileage: a turbo or a normally aspirated engine?  Since, I  believe,  
the 110 and the Corsa turbo are very nearly equal as far  as  
displacement and stroke; the major difference being the  aspiration:  
which of those gets better mileage in NORMAL city /  highway driving  
(not trying to do an economy run)?  Does fuel  injected vs  
turbocharged fuel injected change the  equation?

My take was that a non-turbo would get better mileage than a  turbo.   
(I've never heard of a turbo winning an economy run,  but then I'm a  
newbie to CORSA, too.)

Bib ready for my plate  of crow if necessary.


Stephen U







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