The amount of fuel saved is only that which is consumed during idling ... very little. 
You have to have the front wheels pointed straight ahead, gearbox in neutral, and clutch out ... if the A/C (climate control) is on after a while depending on the cabin temperature the engine will restart as it see's fit. As fast as I can get the clutch in and select 1st gear the engine is started and running ... certainly doesn't hinder a quick getaway from the lights.
That 20-25min saved each way I quoted was pretty much ALL after we entered Sydney's outer urban areas and started encountering traffic lights ... not uncommon to sit at lights for 2-3min when it's busy ... do that 5 times and there's 15min!! .... easy to do 5 times (and more) from Sydney's outer edges into the city centre ... especially in peak hour.
The function, if disengaged, remains off until you stop the car and remove the keys ... automatically re-engages every fresh start.
For where we live the fuel saving is neither here nor there but the extra wear & tear on the starter battery and starter motor are the concern.
What's worse ... extra emmissions from extra idling time, or the extra emmissions from re-manufacturing starter batteries and starter motors more frequently ??
				
			 
			
		 
			
				
			
				
			
			
				Kev..
 
Going ... going ...  almost gone ... GONE !! ... 2004 D2a Td5 Auto "Classic Country" Vienna Green
2014 MUX LST with fruit
2015 Kimberley Kamper "Classic"
			
			
		 
	
Bookmarks