AH1951 wrote:"Stop start does work in terms of fuel savings."
Of course it does, but by how much?
I've driven cars with an automatic Stop/Start system and I hate them.
It saves about 5% in Zurich, quite a lot more in London, over 10% some times. Special summer tyres save about 2% over special winter tyres. The ECU won't do a stop start cycle if the battery is not fully topped up, and the super expensive battery was replaced with a normal cheap one which has lasted over 3 years so far. Idling the car uses about the same amount of fuel as moving at 15 to 30kph! The has an automated manual transmission (as used in Lamborghini £4K to replace by VW, unreliable, but cheap to DIY fix), and the car will coast in neutral, but won't shut the engine off while coasting, so it uses fuel idling going down a slight incline unless you manually shift or trigger engine braking when it can then fully shut off the fuel. The nice features about the car is the suspension. It is lowered and stiffened, and all the wheels and suspension components are light, handling is much nicer and crisper than a normal car. Switching to massively heavier standard steel wheels, instead of super light Mag ones, is noticeable.