minute timer setup after power removed

Sorry if this is a repeat, but I looked for a while and couldn't find what I was looking for. A lot of the timing circuits here are just for a matter of a few seconds, and for when power is applied. I am looking for a configeration that will supply power for a certain ammount of time, after the source power has been lost. What I am auctually trying to do is wire a timing circuit up to my radiator fans, so when the ignition is turned off, a relay will kick on and power my fans for about a minute or two, to help with engine cooling after the motor has been shut off. Kind of like a Turbo Timer, but only to run the fans. Any help with this would be greatly appreciated. Thanks

- Steve C

Type this into google

http://www.thesaabsite.com/900old/900&79to94faqs.htm#Cooling+Fan+Runs+Continuously+%28make+both+fans+run%29

http://www.thesaabsite.com/images/radfandelrel89.gif

http://www.buymopar.com/store/restro.html

2889565 Time delay relay

http://www.buymopar.com/store/restro/timer.jpg