<VV> RE: Cooling fan improvement

[Craig Nicol]

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! 

 

In a message dated 8/3/2007 6:01:02 PM Eastern Daylight Time, NicolCS
writes:

Well, since you asked – how about reducing the heat?  Fuel injection, roller
rockers, roller lifters, synthetic oil all reduce heat and improve fuel
economy.  Once that’s done, you can cut back on the fan and fan HP by simply
slowing it down with a larger pulley.  (Ever compare the radiator size
between say a ’70 ¾ ton pickup and a current ¾ both with a 350 and air?  The
newer one is about ½ the volume (though part of that is ‘cause it’s
aluminum).  This reduction is due to roller cams and EFI.)

Craig Nicol

 





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