Before you do anything you need to determine the amount of horsepower being used by your current belt (I assume) drive fan.  It is not a difficult calcualtion but you do need to get the drive ratio (fanrpm/engine rpm).  It may be that your fan is not sucking a lot of HP.
You would need to add a hydro transmission temp gauge also.
JT
	
		
			
		
		
	
				
			You would need to add a hydro transmission temp gauge also.
JT