38mpg at 70mph. 2004 C5 estate 110bhp

Post by **Peter.N.** » 25 Sep 2011, 19:57

Did a test this morning on the 406: Charmouth to the M5 28 miles average 62.4, M5 to bristol at 65-70 mph overall consumption for total mileage 60.2. I know the computer is reasonably accurate as we last week did a tour of Yorkshire, well over 1000 miles on a tank - I do drive a bit carefully though.

Peter

THELABMAN · Post by **THELABMAN** » 25 Sep 2011, 20:17

My Driving is remarkably similar to your's Torq..

About 2 miles to the M8 motorway and a 17 mile drive into work and about a mile off the motorway. The Return is a bit longer to I get bak on the M8 and the total return Journey is about 42 miles and I reckon it costs me about £5 in diesel at around 137p a litre.... and that's at as steady a 56mph as I can manage.

Working shifts I'm out before 6am so the motorway's quiet and the same coming home at 7pm, going in for an 11am start it's still quiet and coming home at 10pm it's as quiet as the grave..... I reckon on getting about 8 miles from every £1 of fuel.

Post by **Peter.N.** » 25 Sep 2011, 20:48

Is this a 2.0 litre 8 valve engine?

Citroenmad · Post by **Citroenmad** » 25 Sep 2011, 21:18

THELABMAN wrote:My Driving is remarkably similar to your's Torq..
and that's at as steady a 56mph as I can manage.

You could always fit cruise control

Stepto1 · Post by **Stepto1** » 26 Sep 2011, 20:06

I'm really surprised at some of these figures. I've got a lowly 1.8 16v Xantia and yet on a long run from Nottingham to Plymouth at a little more then 70 mpg, I easily get 36mpg. If I stick to 70 mph I get nearly 40 mpg. Around town and on country roads it's quite poor as it's a heavy car but by no means as bad as some cars.

My car was nearly free as no one seems to want a petrol Xantia but if I were to pay say £500 for a deisel, (I swapped a knackered Fiesta for mine!), it would take years to get my money back. Also I don't see many problems on here regarding petrol engines. Think I'll stick with what I've got. It uses no oil, is easy to service and gives a decent turn of speed.

torq · Post by **torq** » 26 Sep 2011, 21:48

Peter.N. wrote:Is this a 2.0 litre 8 valve engine?

It's a 2Ltr and as far as I can tell it's an 8 valve. Parkers.co.uk led me to believe it'd be a 16v, last time I'll believe them!

T

cachaciero · Post by **cachaciero** » 26 Sep 2011, 22:49

andy5 wrote:
cachaciero wrote: Being---snip-- I wonder what was done and is it retrofittable
The more I look at figures for some cars, the more I think the manufacturers might almost make them up for their own convenience - not only are there are so many cars with CO2 figures ending in 9, like 99, 119, 129, but also a lot of cars have recently improved consumption by 10 or 15% without losing weight or any explanation of improvements to the fuel system or significant aerodynamic mods.

I suspect that much of the improvement is real and is due to improved control software, probably if I had to guess in the area of EGR. Having looked closely at the differences between the 138 Bhp 2.2 and the 173 version of the same engine it would seem that the boost has been improved (twin turbo's) in both range and pressure and the inclusion of a Lambda sensor in the exhaust would permit much finer control of injection /EGR and boost. The numbers? well I suspect that 119 is just the right side of a limit 120 isn't

There's one car which has improved from 56 to 74 mpg combined figure in 3 years. There have been some aero mods, but when they also add a stop start system I don't see how can that improve the extra-urban figures from 74 to 83 mpg. In real life, on a German site where people publish their own figures, only 3 people out of over 100 have bettered 65 mpg overall, only a dozen above 55 mpg, and the median is about 50.

Assuming that we are talking about the same car improvements in one particular part of the regime does not necessarily mean that that will be proportionally represented in over all mileage. On the face of it an improvement of 10mpg by implementing a stop start system seems a bit unlikely BUT I am sure that a stop start regime could be devised that would maximise the benefits even if not achievable in normal conditions.

I do know that my car will not achieve the extra urban figures at 70mph but it will at no more than 56mph.

cachaciero

Citroenmad · Post by **Citroenmad** » 26 Sep 2011, 22:51

torq wrote:
Peter.N. wrote:Is this a 2.0 litre 8 valve engine?
It's a 2Ltr and as far as I can tell it's an 8 valve. Parkers.co.uk led me to believe it'd be a 16v, last time I'll believe them!

T

What year is it?

If its from 2001 until late 2004 then its a 8v. If its a facelifted C5 then its a 16v and you really should be getting excellent MPG if its the 16v version.

torq · Post by **torq** » 26 Sep 2011, 23:11

Citroenmad wrote:
torq wrote:
Peter.N. wrote:Is this a 2.0 litre 8 valve engine?
It's a 2Ltr and as far as I can tell it's an 8 valve. Parkers.co.uk led me to believe it'd be a 16v, last time I'll believe them!

T
What year is it?

If its from 2001 until late 2004 then its a 8v. If its a facelifted C5 then its a 16v and you really should be getting excellent MPG if its the 16v version.

July 2004 and prefacelift so unfortunately she must be an 8v.

Even so the owners handbook gives the following figures.
Urban 37.2mpg, combined 49.6mpg and extra urban 61.4mpg

I'd be happy with over 50 for my extra urban commute, I'd hate to have to get another BMW E46 320d touring with its 150bhp, 6 speed gearbox, 53mpg at 70mph M47n engine but with a boot you wouldn't fit a fart in!

Post by **Peter.N.** » 27 Sep 2011, 13:21

I briefly had a 5 series estate, it had about half the room of the XM and used more fuel - not impressed.

Peter

Citroenmad · Post by **Citroenmad** » 27 Sep 2011, 19:12

torq wrote:
Citroenmad wrote:
torq wrote:
It's a 2Ltr and as far as I can tell it's an 8 valve. Parkers.co.uk led me to believe it'd be a 16v, last time I'll believe them!

T
What year is it?

If its from 2001 until late 2004 then its a 8v. If its a facelifted C5 then its a 16v and you really should be getting excellent MPG if its the 16v version.
July 2004 and prefacelift so unfortunately she must be an 8v.

Even so the owners handbook gives the following figures.
Urban 37.2mpg, combined 49.6mpg and extra urban 61.4mpg

I'd be happy with over 50 for my extra urban commute, I'd hate to have to get another BMW E46 320d touring with its 150bhp, 6 speed gearbox, 53mpg at 70mph M47n engine but with a boot you wouldn't fit a fart in!

You should be getting more MPG than you have been, something is not quite right. Might be an idea to get in touch with a local Lexia owner and see if it has stored any fault codes.

torq · Post by **torq** » 28 Sep 2011, 13:47

Well. I fitted a type "B" multifunction display last night and it's working a treat. But on this mornings 20mile run it reported 39.8mpg which is not far off my initial thoughts on mpg. Watching the realtime mpg I get 59mpg at 40mph but it falls off rapidly once I increase speed. it can't all be down to wind resistance. Any ideas, i'm still scratching my head!

Torq

Post by **Peter.N.** » 28 Sep 2011, 17:02

Can't be right, by driving carefully you can often exceed the manufacturers figures, or at least you could the old ones. Have you had the fault codes read? This isn't an auto is it?

Peter

torq · Post by **torq** » 28 Sep 2011, 17:19

Manual. Hope to get my lexia up and running over the weekend and I'd be delighted if it throws up a relevant error!

Citroenmad · Post by **Citroenmad** » 28 Sep 2011, 21:21

torq wrote:Well. I fitted a type "B" multifunction display last night and it's working a treat. But on this mornings 20mile run it reported 39.8mpg which is not far off my initial thoughts on mpg. Watching the realtime mpg I get 59mpg at 40mph but it falls off rapidly once I increase speed. it can't all be down to wind resistance. Any ideas, i'm still scratching my head!

Torq

Our 2.0HDi 110 C5 SX has a 80 mile a day commute most days, mixed driving of motorways, towns and into a large city at rush hour - crawling. Its averaging 46mpg and its not driven slowly.

I have the same commute as the above and my C5 HDi 16v is doing 49/50MPG.

Something is not quite right with yours.