John202020 said:

Is there anyone, who can give a definitive answer as to how much fuel they've actually saved vs keeping it switched off, not a guess a proper comparison?

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I doubt anyone can.

I don't get consistent fuel consumption figures at all, so I doubt I could compare S/S on versus S/S off.

Fuel consumption isn't the point though.

S/S is there, so engines aren't running when stopped, so they don't pump pollution into the car behind or into the people around. It makes junctions peaceful instead of the continual drumming and rattling. All this is very VERY important when it comes to diesel engines.

Nowt to do with fuel consumption. It's pollution.

Regards,
Mick.

Mick F said:

S/S is there, so engines aren't running when stopped, so they don't pump pollution into the car behind or into the people around.

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Absolutely, the stop start technology has been aground for years, I remember an episode of BBC's tomorrow's world in the 1980's with what I think was probably a mk2/3 golf with this amazing technology, but it was only when emissions started to significantly tighten up with euro5 that stop start became common place on new cars, before 2009 very few cars have it, euro5 standards came into force in September 2009.

People are kidding themselves to think it saves them lots of fuel because it really doesn't.

portland_bill said:

On the Fiesta 1.0 Ecoboost, it is possible to stop at the end of a fast run, and the S/S system will stop the engine immediately. No time for turbo to spool down. And with water-cooled turbo, it then boils the coolant within it. Doubtful we're saving enough fuel to buy a new turbo. S/S engineers not talking to the turbo engineers?

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gazz_bee said:

Does the Fiesta not keep the water pump on after the engine has stopped like most other modern turbo charged engines?

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It does not appear to. A few moments after a stop from a fast run, the coolant will boil in the turbo, bubbling into the expansion tank quite violently. This will continue for several minutes. There is no noise of a pump running.

As far as I am aware, the water pump is a normal mechanical, engine-driven one, not electric. Despite Ford's claims that the engine will fit onto a piece of A4 paper, the rest of the add-ons, manifolds, alternator, air cleaner, etc., make it much bigger. The space under the bonnet is full and as it is not mine, and will be replaced annually, or if it breaks, I do the necessary routine checks and have not tried to peer into the nooks and crannies under the bonnet.

portland_bill said:

It does not appear to. A few moments after a stop from a fast run, the coolant will boil in the turbo, bubbling into the expansion tank quite violently. This will continue for several minutes. There is no noise of a pump running.

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I found this video, the narrative below which explains the bubbling coolant.

Sound like a great use for waterless coolent which boils at a higher temp ?

This is impressive even for the fiat 500 section! A thread about installing stop start on a fiat 500 has turned into a conversation about boiling turbo coolant on a Ford ecoboost, didn't even stick with the theme of fiat !

That has to be a record