Ivan
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| posted on 25/9/14 at 08:33 AM |
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quote:
Originally posted by David Jenkins
I'm not convinced - my Yaris has this and, apart from being an annoying 'feature', the car has an enormous battery that's
about twice the size of the one fitted to my old Yaris that didn't have this functionality. Think of the difference in battery size between
petrol and diesel cars and you'll understand just how big this battery is.
tl/dr: It may save fuel while sitting in traffic, but I have the extra weight of a huge battery to lug about.
Forgot to mention - if I've got the air conditioning on the engine only stays stopped for 30 seconds or so... so fairly pointless, really.
[Edited on 23/9/14 by David Jenkins]
This is the ideal spot to save massive weight using a system of capacitors like this
https://www.youtube.com/watch?v=8miq6sDy0wA
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simonrh
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| posted on 25/9/14 at 08:41 AM |
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I have had it in my company mondeo (manual gearbox) for 3 years now and I get confused when I drive my Quantum now and it doesn't stop in
traffic.
My only observation is:
-On a manual it only stops when you knock it in to neutral and release the clutch, unlike an automatic you get the the decision on when to stop the
engine. If you are in stop start traffic and sitting in first gear then it wont stop.
-Doesn't stop on cold mornings until the engine is hot.
-Doesn't stop on hot days if AC is running
-Doesn't stop if battery is low
-Sitting in stationary traffic / at a level crossing most people wouldn't switch off normally but after 10 mins of sit idle there must be a bit
of fuel being saved.
-Company car tax bill is definitely lower for it.
-My main concern about longevity is not the beefed up starter etc it is the fact that there is no turbo run-down. If you come tanking down a motorway
and into the services it will still just stop. The little 1600 diesel in mine is a PSA engine that is famous for destroying oil and then, ultimately,
turbos and this can't be healthy. The turbo will still either be spinning or crazy hot at least. Not aware that it has any kind of accusump
system.
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coyoteboy
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| posted on 2/10/14 at 12:45 PM |
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Turbos spin down in seconds and generally there's plenty of oil left in the journals to cope, it's coking on the shaft bearings that that
will cause you a problem with that sort of operation - I'd have hoped they'd have a built in turbo-timer type function where if
you've been at high load it would integrate your boost time to give a delay. Obviously that's not been implemented!
As for the cost - just look at your idle fuel use using an OBDII scanner and you'll see just how much of your fuel goes down the drain sat at
traffic lights.
[Edited on 3/10/14 by coyoteboy]
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David Jenkins
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| posted on 5/10/14 at 12:11 AM |
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One reason they're pushing stop-start is to reduce pollution in the areas near to traffic jams, lights, etc. In some European countries you can
be fined if you keep your engine running while stopped in a traffic jam. Don't know how effective this technology is at dealing with that,
especially as mine turns back on after just 30 seconds.
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coyoteboy
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| posted on 5/10/14 at 01:34 AM |
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http://www.scotland.gov.uk/Publications/2003/04/16936/21249
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ashg
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| posted on 5/10/14 at 09:20 AM |
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seems to work well on my bmw. its a pain when your crawling in motorway traffic with the odd stop but there is a button to disable it.
round town its fine with traffic lights. you pull up its stops. you put the clutch down and its started again before the clutch pedal even gets half
way to the floor to put it in gear. the good thing about it is that if every car has it it will cut down fumes and noise pollution in towns when the
traffic is heavy. yeah it wont be a lot but its something.
as for it wearing out the starter. well bmw put it right on the bottom of the bell housing so its a doodle to swap. 20mins on the ramp max.
as for oil pressure, well on a tight engine the oil pressure takes a few seconds to drop anyway, the system is primed as the car has been running so
i would guess the wear will be marginal. I'm sure manufacturers did plenty of life testing.
Anything With Tits or Wheels Will cost you MONEY!!
Haynes Roadster (Finished)
Exocet (Finished & Sold)
New Project (Started)
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