Help! stock or electric fans?

[MarkH]

Hello all, I dropped in an aftermarket aluminum radiator - extra capacity for the 50 extra HP in my 1978 L82. Question;
should I keep the stock fan and put the stock shroud back in, or remove the stock fan and go with electric fans with a built-in shroud?

I understand GM spent quite a bit of time getting the cooling system optimal for these cars, but that was 35 years ago. Any advantage with cooling efficiency? What about power drag on the engine with the stock fan and clutch?

What has been your experience?

 

[JohnZ]

Hello all, I dropped in an aftermarket aluminum radiator - extra capacity for the 50 extra HP in my 1978 L82. Question;
should I keep the stock fan and put the stock shroud back in, or remove the stock fan and go with electric fans with a built-in shroud?

I understand GM spent quite a bit of time getting the cooling system optimal for these cars, but that was 35 years ago. Any advantage with cooling efficiency? What about power drag on the engine with the stock fan and clutch?

What has been your experience?

Your new aluminum radiator has more cooling (heat rejection) capacity than the old copper/brass one you removed; I'd re-install the stock fan, clutch and shroud and you shouldn't have any issues.

 

[TimAT]

I agree with John here. Remember, back in the days of the C3's racing seriously, electric fans were not a real option. And those guys were running 160+MPH.
Electric fans are good, but they have the potential of opening up a host of electricla issues. I know personally of one that locked up and quit cooling altogether, and another one that puts enough load on the alternator there's a 300 RPM drop when the fans come on. Makes getting the idle adjusted correctly a real pain.
HP loss won't be an issue unless you're in a race only situation

 

[spikebot 81]

Here is some info on electric fan swap I did last winter 2010-11. Picked up a fan from the pick and pull for $28 out of a 95 Ford Tarus. Very popular fan set up because ford used a high cfm. I run a 180 stat. Already had the 100 amp alternator. This fan pulls 30 amps on low speed and up to 45-50 on high speed. I'm only running the low speed circut. I have the crummy adjustable controler with a probe in the radiator. No noticable performance increase after the conversion. Temp gage never goes higher than 195 deg but once the fan comes on it never shuts off. I beleive the controler is the real problem but that is another project for another day. The stock fan clutch system cooled the engine to the same specs, 195 deg and no higher. The engine in this 81 was not stock but still a slug with 882 smog heads and flat top pistons, very mild camshaft, long tube headers and dual exhaust. Winter 2011-12 installed a new engine and 2004r trans. The new power plant has got to be at least 100hp more than I had and the cooling system is unchanged, 195 deg with 180 deg stat.

new engine specs:
350sbc .030 over bore
12cc dished pistons
rhs 180cc 64cc chamber iron heads (pro action series)
60103 Luanti camshaft
600cfm edle carb
edle performer intake
stock crank and rods
9:48 to 1 compression