Does anyone run a C5 X7 diesel estate?

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moizeau
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Re: Does anyone run a C5 X7 diesel estate?

Post by moizeau » 24 Aug 2019, 20:00

Does he coast in neutral LOTS? I'm also guessing Peter uses engine braking 1/4 mile before the junction and rarely touches the brakes.

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Re: Does anyone run a C5 X7 diesel estate?

Post by GiveMeABreak » 24 Aug 2019, 20:10

No hope of that round here - you'd be run off the road by a Massey in no time.

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Re: Does anyone run a C5 X7 diesel estate?

Post by Hell Razor5543 » 24 Aug 2019, 20:13

GiveMeABreak wrote:
24 Aug 2019, 20:10
No hope of that round here - you'd be run off the road by a Massey in no time.
That would be messy!

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Re: Does anyone run a C5 X7 diesel estate?

Post by GiveMeABreak » 24 Aug 2019, 20:16

Yes a lot of the local Welsh lads belong to the rally club, so don't hang about regardless of what they're driving!

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Re: Does anyone run a C5 X7 diesel estate?

Post by Peter.N. » 24 Aug 2019, 20:57

Well its probably not quite accurate as it was reading 64.1 when I left home so the traffic did take a bit of toll on it. The fact that the traffic was moving slowly when at all helps as the consumption at 40-50 mph is considerably higher. I am one of those annoying drivers who rarely brakes as I leave a good space between me and the cars in front, and seldom exceed 60 mph.

I spend most of my journeys to Scotland in the slow lane with the lorries - unless it gets to slow, much less tiring than trying to overtake all the time and much less taxing on the vehicle - and the fuel. Managed over 70 mpg going to Scotland in the Merc this year, but the C5 is far preferable to drive and ride in so shan't be doing that again.

I think the way I drive would bore most of you to tears, I know it does my son. 'Why don't you overtake this lorry' he says, 'because its going fast enough for me' I say. :) :roll:

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Re: Does anyone run a C5 X7 diesel estate?

Post by andy5 » 24 Aug 2019, 21:49

admiral51 wrote:
24 Aug 2019, 17:39
Now if we were to have a competition on who gets the best MPG then can i suggest Peter is excluded ...
I wanna enter a category for biggest difference between best and worst on a tankful of the same car

931 vs 310 miles range, run out both times

58.3 vs 19 mpg

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Re: Does anyone run a C5 X7 diesel estate?

Post by Peter.N. » 24 Aug 2019, 22:11

19 mpg would give me palpitations. :shock:

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Re: Does anyone run a C5 X7 diesel estate?

Post by Harlequin » 25 Aug 2019, 08:41

Im getting 19.1 on the petrol C5 V6 ;) granted though its only around town , although it was 33 mpg on the way home (would be over 40 mpg now its been serviced especially gearbox oil).

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Re: Does anyone run a C5 X7 diesel estate?

Post by AJM C5 » 25 Aug 2019, 15:39

Peter.N. wrote:
24 Aug 2019, 22:11
19 mpg would give me palpitations. :shock:

Peter
Blimey, this seems like a million miles away now since the fixes went into my X7 '09. Great car, and although I usually admire it each night while sitting in the courtyard for a few minutes, its just a tool to me ultimately. Oh dear; does that suggest I may be getting past it then… such wonderful creations being mere 'tools'…

Anyhow, glad you`re managing to find your way around issues to bring it up to scratch, Peter, once they`re running well they`re dream cars, excellent in fact. Of course, this means tomorrow morning I may find a puddle of oil under the front wheels and a non-starter and then think otherwise. Or worse, down the nether regions as yet unexplored.

On the economy front I just wouldn`t know, other than coming from a 10MPG V8LR (though most of the time on LPG which is usually not available here) and being mighty pleased when the fuel gauge after top-up on best diesel says in précis….'You have 1350 kms to go before needing a refill'. That`s good enough for me.

So its all going well here with the X7 after the 3-4 weeks work required, I listen to everything, the suspension which over some ground going slow does …I don`t know… `a slight pop and gurgle`, almost inaudible, but other than that nothing. I did flush the oil again, but with no Castrol Edge to pick up locally I replenished with C2 stuff again. 'Old stuff' had only done 200km max.

I noticed someones post earlier about an interior for yours Peter, and you questioning the seat connections which Marc explained. Well, here`s my front interior which I enjoy when opening the door most days (the rear appears like new)…. Almost makes me want to go and get more DIY materials EVERY day just for the pleasure of getting in there, and switch on the AC too of course.

Hope you`ve all enjoyed the mini heatwave there, and that your C5s have coped and behaved themselves.

Enjoy.

Kind Rgds

AJ
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Re: Does anyone run a C5 X7 diesel estate?

Post by bobins » 25 Aug 2019, 22:30

A serious question - is the hypermiling going to make it tricky for the car to carry out successive regens on the DPF ?

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Re: Does anyone run a C5 X7 diesel estate?

Post by GiveMeABreak » 26 Aug 2019, 00:09

It will use assisted regeneration more frequently in that case as it will take the car longer to get to temp I suspect, so will use more additive (the figures I quoted in the additive / mileage table were for worst case scenario driving. Also the reason some owners use less additive when doing cruising miles.

But no coasting in neutral required as the injection shuts down when the foot is off the accelerator of course. Assisted regens when temp is not reached will mean more use of glowplugs too.

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Re: Does anyone run a C5 X7 diesel estate?

Post by Paul-R » 26 Aug 2019, 11:01

Coasting in neutral will keep the injection going so the engine doesn't stop. Modern cars, ever since the introduction of computer controlled injection, only shut off fuel injection when the engine is on the over-run - i.e. you're using the engine as a brake. In fact coasting makes hypermiling less efficient.

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Re: Does anyone run a C5 X7 diesel estate?

Post by GiveMeABreak » 26 Aug 2019, 16:23

That's what I meant^

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Re: Does anyone run a C5 X7 diesel estate?

Post by admiral51 » 26 Aug 2019, 16:47

I still lack a lot of knowledge on the regeneration process, not so much what happens but more to do with how the BSI/ECU's determine when the vehicle is being driven at given parameters to start the process.
If it thinks it can perform a regeneration on a vehicle being driven around town, ie stop start low speed environment, then if i sit at say 60 mph on a motorway with cruise control on how does it decide when the time is right ?

I know nothing on the telly and my mind is wandering :)

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Re: Does anyone run a C5 X7 diesel estate?

Post by GiveMeABreak » 26 Aug 2019, 17:09

It looks at the soot loading in the DPF - it uses a differential pressure sensor to measure the differences in pressure of the exhaust gasses (inlet and outlet) to determine if the filter needs regenerating. But additionally, there are strategies employed by the system to deal with all sorts of driving conditions.

If you are motorway driving, then more 'passive' regeneration can occur naturally as the exhaust temperature is higher - so it may burn off the soot without assisted regeneration.

When the car is stopped and started on shorter journeys, assisted regeneration will be needed - but even then, the process can be interrupted if the car is stopped half way through for example.

The Engine ECU records all this and makes a determination as to when a regen is needed:- if the process is constantly interrupted (short journeys), and it has tried several times to start a regeneration, it will flag up a warning 'risk of particle filter clogging' or similar. This when you need to go for a reasonable journey of at least 15-20 minutes at 40 mph speed to allow a regeneration to happen. This is when the engine ECU may turn on power consuming devices like the heated rear window and activate the glowplugs to get the engine temperature up more quickly and of course the DPF additive lowers the combustion temperature needed for burning off the soot.