<VV> Re: Cooling fan improvement

[JVHRoberts at aol.com]

Being a turbo guy, I think the cooling system on a Corvair has a HUGE  
deficit. 
Extra fuel actually loses heat, since there isn't enough extra air to  really 
burn it. That's how 2 stroke air cooled motorcycle engines keep from  
overheating. 
When the 50% increase in fuel economy comes from lower aerodynamic drag,  
less weight, and all the other things that reduce HP load, then you're right. 
However, Porsches, the closest other example I can think of, actually had  to 
INCREASE cooling over the years, since the HP was constantly going UP, and  
the burden from catalytic converters, standard air conditioning, heavier cars,  
etc., took its toll.
 
In a message dated 8/3/2007 11:01:50 PM Eastern Daylight Time, NicolCS  
writes:

Huge deficit?  I  wasn’t aware that stock engines had a huge deficit ;-)  Now 
the recently  tested electric fan, that’s another story…   
A fair amount of  engine heat is caused by engine friction.  When we ran 
engines on the  Honda dyno, we only had to motor the (non-running) engine on the 
dyno for  about 20 minutes to reach full operating temperature; that heat is 
almost  entirely caused by engine friction. (Compressing air accounts for some 
of the  heat, but much of that goes out the exhaust pipe.) The #1 source of 
engine  friction in a broken-in engine is the cam/lifter/valve train so switching 
 those components to rollers makes a big dent in engine heat.  Taller  gears 
help too ‘cause engine friction is proportional to rpm.  EFI has a  huge 
effect on engine heat too.  When you have a 50% increase in fuel  economy, all the 
heat from that extra fuel is no longer being rejected into  the cooling system 
and exhaust and heat loads on the cooling system go  down.  All these things 
add up to much smaller radiators (or in our case,  fans) 
Craig 
 
  
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Agreed, but it seems  that all of these are marginal improvements (certainly 
worth doing!) but won't  close the huge deficit in cooling capacity.  
 

 
BTW, there's one  heck of a lot more difference between the '70 PU truck and 
the new one besides  the 350 SBC and the LS series engines! 




 



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