At 08:03 AM 4/1/2003, you wrote: > >The fans were added to modern cars because the newers >vehicles were more > >tightly cowled and that restricted airflow. Additionally, >the newer > >aluminum engines are more susceptible to heat damage that >the old cast > >iron block engines. Thus the automatic fans. > >Yeah, but the fact that rear engine and front transverse mount engine cars >can't have an engine driven fan is probably a big reason too! > >Bill Electrics also have an efficiency advantage. A mechanical (engine driven) fan has to be sized large enough to move an adequate quantity of air at idle and low RPM (sitting in traffic). That means that at high RPM they usually move way more air (and eat up way more HP) than required. Even at 70 mph when there id plenty of air flow across the radiator without any fan. Mechanical fans can suck up a LOT of HP at high RPM. Flex fans and fan clutches help some, but not all that much. An electric on the other hand runs at a constant speed and doesn't increase it's HP requirement as engine RPM goes up. Plus, the electric is turned *off *most of the time when the vehicle is in motion and only eats power when the cooling system requests it... Less HP required for cooling = better fuel economy. Steve |
Please note - During the past 17 years of operation, several gigabytes of
Vanagon mail messages have been archived. Searching the entire collection
will take up to five minutes to complete. Please be patient!
Return to the archives @ gerry.vanagon.com
The vanagon mailing list archives are copyright (c) 1994-2011, and may not be reproduced without the express written permission of the list administrators. Posting messages to this mailing list grants a license to the mailing list administrators to reproduce the message in a compilation, either printed or electronic. All compilations will be not-for-profit, with any excess proceeds going to the Vanagon mailing list.
Any profits from list compilations go exclusively towards the management and operation of the Vanagon mailing list and vanagon mailing list web site.