[Land-speed] Sorta off-sorta on-topic..turbocharging theory

[Jon Wennerberg]

On Nov 12, 2007, at 10:44 PM, Ray Buck wrote:

Before I write anything I'll state my utter lack of experience with
turbochargers.  I've never worked with them at all.  So if this is a
stupid question, please chalk it up to ignorance of the whole
concept...and I'd be grateful if someone who has some real world or
theoretical knowledge can enlighten me.




Ed, I think your idea is not out of the question -- but won't work  
the way you're thinking about doing it.  That is (as others have  
already pointed out), the turbo compresses incoming air using the  
energy in the outgoing exhaust.  There's a little loss of energy,  
too, in bearings and other parasitic loads.  Where would the power  
for the exhaust sucker come from (flywheels don't count -- they need  
to be powered by something, and the pulses of energy from individual  
combustion events are used by the turbo's normal operation -- I doubt  
there'd be enough left over for your machine).

The concept of pulling the exhaust out might work -- but the energy  
would have to be supplied from something -- not the incoming air,  
since it's powered by the exhaust.  But could you power an exhaust  
extractor from a small motor or engine?  Would you be able to gain  
enough to make the extra energy load worthwhile?  That's best left  
for others to explore.  You'd need either a good-size remote  
electrical source to power the sucker (pun intended) -- remote so you  
don't lose more power sucking than you gain from the sucking effect  
-- or a "pony" engine that does nothing but power the exhaust puller- 
outer.  That remote engine would put you into a different class if  
you're talking about a race vehicle, or it would be an additional  
load, noise generator, fuel user, and space taker if you're talking  
about doing it in the family grocery-getter.

So -- would it work?  I suppose so, theoretically.  Is it worth the  
hassle to engineer and design and prototype and build?  Unh, maybe,  
if you have time and a shop and a drawing board handy.  Is it  
preferable to twisting the boost know up a bit (to get more power) --  
probably not.

Nonetheless, a nice concept for thinking about while drinking this  
morning's coffee.

                 Jon Wennerberg
Seldom Seen Slim Land Speed Racing
              Marquette, Michigan
              (that's 'way up north)