[DeTomaso] Oil temperature

[Asa Jay Laughton]

Jeff, nice explanation.  I'm not certain though from your science  
perspective if you would advocate the air or water cooling method over  
the other.  Also, at what air speeds does the air cooling of fins on  
the radiator begin to breakdown?  Would it be at speeds seen in  
typical race cars?  (Less than 200mph)

Asa  Jay
Learning something new every day.

Quoting Jeff Cobb <jeffcobb1 at me.com>:

> Interesting thread.
> It has been documented many decades back in the aircraft industry  
> that heat exchangers
> were more efficient if the exchangers airflow speed was much lower  
> than the vehicles speed.
> Cooling air needs time to conduct air from the cooling fins/coils  
> surfaces otherwise the fins
> boundary air allows the laminar air rushing through to not touch the  
> hot metal fins.
> So the ducts entry area needs to be less than the coolers surface  
> area, maybe by 1/4th.
>
> Oil temps should always be warmer than the coolant up to about  
> coolants 210 F, though the oil
> heat rejection reserve capacity must be greater than that of the  
> coolants so that at extreme temps
> the oils temp does not rise quicker nor higher than the coolant.
> After 230F + -, oil temps under load will rise much quicker than  
> coolant temps so a larger reserve
> heat rejection option relative to coolants reserve design must be  
> present so to not allow dangerous
> oil temps, ie; 280F.
> The oil is primary in cooling all the interior heated parts directly  
> whereas coolant takes heat from
> surfaces that are secondary heat conductors, are a slave to radiated  
> heat or metals that capture/hold
> heat from friction.
> Large oil coolers with a thermostatic controlled variable duct  
> nozzle entry and thermostatically controlled
> oil flow may work the best in heat rejection to air.
> Whereas a Laminova tubular coolers work the best in a cooling liquid  
> because of the high surface area
> and has a better ability to keep both temp closer together.
>
> Keep cool,
> Jeff Cobb
>

-- 
Asa Jay Laughton - sent from somewhere other than home
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