<VV> Re: Cooling fan improvement

[JVHRoberts at aol.com]

Of course, an optimally tuned engine will run the coolest. If you're also  
managing ignition timing, then you can do even better. Is ignition also under  
computer control? Is there a knock sensor? I'd be willing to bet this is  
probably the bigger determinant here. 
 
Lean vs rich is always controversial, but generally speaking, you need to  be 
running quite a bit leaner than ideal to overheat. On target is best,  and if 
you're overly rich, you'll also overheat because efficiency drops, more  
throttle is required, and that leads to more heat AND more fuel consumption. But  
this also assumes the A/F ratio is way out of whack. Not hard to be off with  
carbs, to be sure...
 
In a message dated 8/4/2007 10:56:39 AM Eastern Daylight Time, NicolCS  
writes:

I’ve converted about  20 cars (one Corvair) to EFI. I have a second Corvair 
140 converted to EFI by  Milt Binion.  Generally there has been about a 50% 
gain in fuel economy  (my ’66, for example, gets almost 30 mpg on the highway).  
Several of my  conversions, mostly Tri-five Chevys, went from overheating pigs 
to cool  runners with the change to EFI.  On the cars that had aluminum 
radiators,  overcooling has been an issue and on two, I’ve had to cover a portion 
of the  radiator with lexan to block airflow.  My ’65 and ‘66 EFI 140s run 
about  275 to 325 max in hot weather highway conditions.  I’m open to other  
conclusions, but comparing apples to apples, I’ve concluded that reducing  wasted 
fuel results in reduced heat in the cooling system.  I understand  that this 
subject is controversial; prior to my ’66 Corvair 140 EFI  conversion, I had 
several people tell me that “running it lean” would cause it  to overheat, but 
the opposite seems to be the case.  Thoughts,  comments? 
Craig  Nicol 
 
  
____________________________________
 
From:  JVHRoberts at aol.com [mailto:JVHRoberts at aol.com] 
Sent: Saturday, August 04, 2007 5:04  AM
To: NicolCS at aol.com;  virtualvairs at corvair.org
Subject: Re: Cooling fan  improvement
 
 
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.




 



************************************** Get a sneak peek of the all-new AOL at 
http://discover.aol.com/memed/aolcom30tour