Technical Start&Stop in stop-and-go traffic

[Engineered]

Fiat claim between 5% and 8% savings by using S&S...
See: http://green.autoblog.com/2008/12/1...ch-stop-start-system-in-the-500-for-5-8-fuel/

 

[grimwau]

Fiat claim between 5% and 8% savings by using S&S...
See: http://green.autoblog.com/2008/12/1...ch-stop-start-system-in-the-500-for-5-8-fuel/

:chin: Didn't Fiat also claim 69.8mpg overall average for the TA?

 

[Engineered]

:chin: Didn't Fiat also claim 69.8mpg overall average for the TA?

No, they actually achieved this figure in official tests.
Well done Fiat to have effectively beaten the system - an 'A' rating (=zero road tax & CC) for a car that is so much fun and relatively quick. Look at other cars with this 'A' rating - yawn inducing the lot of them

 

[grimwau]

Fiat claim between 5% and 8% savings by using S&S...
See: http://green.autoblog.com/2008/12/1...ch-stop-start-system-in-the-500-for-5-8-fuel/

:chin: Didn't Fiat also claim 69.8mpg overall average for the TA?

No, they actually achieved this figure in official tests.

What's the difference between the validity of my "claim" and yours?

Does it mean that Fiat didn't achieve 5% to 8% in official tests?

 

[Engineered]

I don’t think the S&S claims (5% to 8% savings) have anything to do with the “official” government tests. I believe these figures are the result of a series of manufacturer’s tests. Consequently, the results need to be considered in this context.

However, the 69.8mph result is officially tested and ratified (not just “claimed by Fiat”) and the result is a Band ‘A’ tax rating, resulting in zero road tax, no congestion charge and (most important for some) low ‘benefit in kind’ tax.

Despite my TA being an absolute hoot to drive, its log book says ‘92’ in the CO2 column - so its lumped in with Prius’s and other boring super-economy yawn-boxes.
Regardless of “real world” fuel consumption, Fiat should be applauded for managing to produce a Band ‘A’ car that people actually enjoy driving and one that drivers would choose to buy, regardless of any economy claims.

 

[Super Uwe]

I don’t think the S&S claims (5% to 8% savings) have anything to do with the “official” government tests. I believe these figures are the result of a series of manufacturer’s tests. Consequently, the results need to be considered in this context.

However, the 69.8mph result is officially tested and ratified (not just “claimed by Fiat”) and the result is a Band ‘A’ tax rating, resulting in zero road tax, no congestion charge and (most important for some) low ‘benefit in kind’ tax.

Despite my TA being an absolute hoot to drive, its log book says ‘92’ in the CO2 column - so its lumped in with Prius’s and other boring super-economy yawn-boxes.
Regardless of “real world” fuel consumption, Fiat should be applauded for managing to produce a Band ‘A’ car that people actually enjoy driving and one that drivers would choose to buy, regardless of any economy claims.

IMO your last point here rather explains why Fiat have managed to save their bacon with the TwinAir - I don't think there's one person on here who has said that it was boring to drive, and so it has papered over the "economy issue".

Personally I still find it weird that people on here haven't managed to get near to 55/60mpg on a regular basis - I think Fiat should sponsor jrkitching to drive one for a month and see what he can get!

 

[FloJo]

My stop start has been behaving oddly - I stop at traffic lights and the stopstart kicks in, but approx 10/15 seconds later the engine starts up again. Foot is very much away from the clutch. At first I wondered whether it's to do with vibrations of other traffic - the first time I remember it happening a lorry had rumbled by in the next lane. I've yet to see whether this is happening on short journeys as I've not done a longer drive for just over a week now. Does anyone else have this sort of problem?

 

[jrkitching]

IMO your last point here rather explains why Fiat have managed to save their bacon with the TwinAir - I don't think there's one person on here who has said that it was boring to drive, and so it has papered over the "economy issue".

Personally I still find it weird that people on here haven't managed to get near to 55/60mpg on a regular basis - I think Fiat should sponsor jrkitching to drive one for a month and see what he can get!

FIAT have got away with it so far because most folks bought the TwinAir for performance, not fuel economy - and it's easily the best performing "A" band car out there.

The real test will be when the normally aspirated TwinAir is launched. That car will be bought for economy, not performance - and if folks end up getting around 30mpg less than FIAT's official combined figures, then I suspect the complaints will come flooding in....

 

[hemmertolesen]

This is not an issue with start stop. EVERY car will role back when the engine is off on a hill. Use the handbrake. :bang:

Does the vacuum-thing in the brakes fail so much while the engine is stopped, that they cant hold the car on a hill?? There's no warning about that in any of the manuals. I thought that was the whole point of having hill-holder installed always if you have stop&go in the car, but if it isn't standard, that's a pretty inconvenient .

Luckily you can't get a 500 in Denmark without hill-holder

 

[306maxi]

Does the vacuum-thing in the brakes fail so much while the engine is stopped, that they cant hold the car on a hill?? There's no warning about that in any of the manuals. I thought that was the whole point of having hill-holder installed always if you have stop&go in the car, but if it isn't standard, that's a pretty inconvenient .

Luckily you can't get a 500 in Denmark without hill-holder

There's a custom made device in the 500 purely for these situations. It's called the handbrake.......

 

[RobW]

Does the vacuum-thing in the brakes fail so much while the engine is stopped, that they cant hold the car on a hill?? There's no warning about that in any of the manuals. I thought that was the whole point of having hill-holder installed always if you have stop&go in the car, but if it isn't standard, that's a pretty inconvenient .

Luckily you can't get a 500 in Denmark without hill-holder

Q

do they translate the owners handbook into Danish?

 

[hemmertolesen]

There's a custom made device in the 500 purely for these situations. It's called the handbrake.......

aye, which is why I labbeled it an inconvenience Coupled with the notorious "instability" of start&stop (you never really know whether the motor will stop or not), you'd have to have a hand on the handbrake every time you where on a hill. And if you aren't fast enough (or it catches you by surprise and stops the car) you risk rolling right into the crossing causing a major crash... Also adds to the time it takes to start the vehicle again. Lets make it a major inconvenience . Maybe there aren't many hills in Italy... oh wait, there is... People should just spend some money on the hill-holder then!

 

[RobW]

aye, which is why I labbeled it an inconvenience Coupled with the notorious "instability" of start&stop (you never really know whether the motor will stop or not), you'd have to have a hand on the handbrake every time you where on a hill. And if you aren't fast enough (or it catches you by surprise and stops the car) you risk rolling right into the crossing causing a major crash... Also adds to the time it takes to start the vehicle again. Lets make it a major inconvenience . Maybe there aren't many hills in Italy... oh wait, there is... People should just spend some money on the hill-holder then!

yes that is how you drive

 

[hemmertolesen]

yes that is how you drive

Lol, no Actually the issue here isn't much about the hill-holder... If your regular brakes can't hold the car on a hill (start&stop or not), that car isn't legal for road use and should be serviced. Driving that car to the garage would probably also be illegal - it should be towed. Brakes in a car are required by law to work, even with a failing vacuum booster and engine off, you'd just have to press a bit harder (and the booster will even work 2-3 times after engine is cut). I suspect that the vacuum booster is faulty on the OP's car which causes the brakes to loose power instantly as the engine is cut. He should check for that by pumping the brakes a few times and keeping pressure on the pedal while turning on the car (pedal should then depress slightly). But this is all basic theory from the driving lessons, so I shouldn't elaborate too much...

I just wouldn't want to be in a car that couldn't brake if the engine broke down on the highway. Ever tried to decelerate from 130 km/h to 0 with the handbrake? My Gran Turismo tells me it isn't safe

 

[306maxi]

Lol, no Actually the issue here isn't much about the hill-holder... If your regular brakes can't hold the car on a hill (start&stop or not), that car isn't legal for road use and should be serviced. Driving that car to the garage would probably also be illegal - it should be towed. Brakes in a car are required by law to work, even with a failing vacuum booster and engine off, you'd just have to press a bit harder (and the booster will even work 2-3 times after engine is cut). I suspect that the vacuum booster is faulty on the OP's car which causes the brakes to loose power instantly as the engine is cut. He should check for that by pumping the brakes a few times and keeping pressure on the pedal while turning on the car (pedal should then depress slightly). But this is all basic theory from the driving lessons, so I shouldn't elaborate too much...

I just wouldn't want to be in a car that couldn't brake if the engine broke down on the highway. Ever tried to decelerate from 130 km/h to 0 with the handbrake? My Gran Turismo tells me it isn't safe

Start&Stop tends not to come into play at 130kph.....

 

[bgunn]

(you never really know whether the motor will stop or not)

Don't you? To use an oft-quoted statement on this forum, maybe you should RTFM. I've never been in the position where I don't know that the engine will stop or not.

 

[hemmertolesen]

Don't you? To use an oft-quoted statement on this forum, maybe you should RTFM. I've never been in the position where I don't know that the engine will stop or not.

I read the manual which is why i concluded that you couldn't always know beforehand if S&S would kick in. I don't know exactly how many watts my GPS, radio, charger and heater is using and in what ratio compared to current battery charge... I also don't know the exact temperature the motor has to reach for the system to function compared to outside temperature (with hot and running engine S&S works down to around 4 degrees C i've been told). Maybe when I've driven the car for some months I'll get the hang of it, but not yet. It's good to know that you can learn it and it's not as eratic as it sounds on the forums.

 

[306maxi]

Don't you? To use an oft-quoted statement on this forum, maybe you should RTFM. I've never been in the position where I don't know that the engine will stop or not.

Put your flameproof suit on!!!!!

 

[306maxi]

I read the manual which is why i concluded that you couldn't always know beforehand if S&S would kick in. I don't know exactly how many watts my GPS, radio, charger and heater is using and in what ratio compared to current battery charge... I also don't know the exact temperature the motor has to reach for the system to function compared to outside temperature (with hot and running engine S&S works down to around 4 degrees C i've been told). Maybe when I've driven the car for some months I'll get the hang of it, but not yet. It's good to know that you can learn it and it's not as eratic as it sounds on the forums.

and I don't know the bite point of an Audi A4 1.9 TDI's clutch but I'm sure that if I drove one for a while I'd get the hang of it.

Why are you complaining about the operation of a car you're obviously not familiar with? Has it perhaps not occured to you that you just need to get to know the car and how the system works? Start&Stop doesn't operate in a random manner, there are a load of predefined parameters that it operates within and you need to get used to this.

Just remember that on the internet people post to complain most of the time, people like bgunn who come along and say "I read the manual, S&S works fine for me and you need to RTFM" are fairly rare. Once people know how S&S works there are VERY few issues with the system other than issues which are caused by having to drive a car in a way which causes the system to flag up an issue such as having to reverse for a distance and slipping the clutch (which of course you should do)

 

[RobW]

Lol, no Actually the issue here isn't much about the hill-holder... If your regular brakes can't hold the car on a hill (start&stop or not), that car isn't legal for road use and should be serviced. Driving that car to the garage would probably also be illegal - it should be towed. Brakes in a car are required by law to work, even with a failing vacuum booster and engine off, you'd just have to press a bit harder (and the booster will even work 2-3 times after engine is cut). I suspect that the vacuum booster is faulty on the OP's car which causes the brakes to loose power instantly as the engine is cut. He should check for that by pumping the brakes a few times and keeping pressure on the pedal while turning on the car (pedal should then depress slightly). But this is all basic theory from the driving lessons, so I shouldn't elaborate too much...

I just wouldn't want to be in a car that couldn't brake if the engine broke down on the highway. Ever tried to decelerate from 130 km/h to 0 with the handbrake? My Gran Turismo tells me it isn't safe

you really dont understand

hill holder is not a parking brake, it is a feature that helps you do hill starts without rolling back
the car has lots of driver aids but you still have to actually drive as normal