New car... old member

[ainarssems]

Originally Posted by 89forever

A bit of holiday time during this festive season meant i was able to revisit the Aux Heater install.... whilst it had made a difference and had reduced warm up a time a bit, the more i thought about the more it wasn't making me think WOW, what a difference......
So i Googled, and read.... and read a bit more.... and then for good measure, read it all again. None of the install guides mentioned an additional coding requirement on the Auto HVAC side of things....



Channel 21 on Adaptions, change your 0 to 1, press save....

What does that do, i hear you ask???

well once you have rebooted your MMI it gives you another additional setting to turn on



It now gives me the engine preheat option, rather than just aux heat and aux vent.

Time will tell if it makes a further improvement...

I think the engine preheat option only works if you install additional switchover valve that turns off antifreeze flow to engine and sends all to HVAC. If you do not have that valve antifreeze will always go to both HVAC and engine. It's a big lump of metal/ coolant/oil and can soak up a lot of energy so you don't really get much heat in cabin if coolant circulates around engine as well.

If you look at it in perspective it's only 5.5kW heater when your home bolier is about 30kW. Also when you are driving around you use maybe 15-30kW of engine power at 20% efficiency which means you get about 60-120 kW of waste heat. Some of it goes in exhaust, some in coolant but I don't know the split how much in each.


Edit:
It appears you have about 25% usable power, 5% in friction, 30% in coolant and 40% exhaust.