Discussion
I know I know! This probably isn't the best place to discuss such things, but nevertheless….
I've a 53 plate Clio 1.5 dci (which I think means direct common rail injection) so far I've got just under 400 miles from ¾ of the tank – this is combining motorway and local driving. So it should in theory do another 133miles from what it left – a total of 533miles.
Now my maths isn't that great – but this surely is no where near the projected figures put forward by Renault that say is should do a combined 65mpg.
My car's only done some 9,000 miles and the first service is due at 18,0000 – however I'm minded to give it a service in the hope that this helps the fuel economy.
What do fellow Pistoners' think?
I've a 53 plate Clio 1.5 dci (which I think means direct common rail injection) so far I've got just under 400 miles from ¾ of the tank – this is combining motorway and local driving. So it should in theory do another 133miles from what it left – a total of 533miles.
Now my maths isn't that great – but this surely is no where near the projected figures put forward by Renault that say is should do a combined 65mpg.
My car's only done some 9,000 miles and the first service is due at 18,0000 – however I'm minded to give it a service in the hope that this helps the fuel economy.
What do fellow Pistoners' think?
It's done on a rolling road (so I presume no wind resistance), no electrical load, no a/c, etc etc. I read once that they even put thinner oil in? They probably over inflate the tyres too. They don't actually neasure fuel consumption at all, it's calculated from the CO2 emmissions.
You're also not likely to get very accurate figures by looking at the fuel gauge - you need to go brim to brim.
If your gauge is accurate then sounds like your car is doing 55MPG+ which seems pretty good 'real-world' consumption.
You're also not likely to get very accurate figures by looking at the fuel gauge - you need to go brim to brim.
If your gauge is accurate then sounds like your car is doing 55MPG+ which seems pretty good 'real-world' consumption.
A rolling road? Are you sure? I thought all MPG statistics were produced by a central agency and were actually quite accurate?
If the Renault has a 9 gallon tank then the figures mentioned suggest about 60MPG. If that includes town driving then that is excellent.
My diesel gets 45MPG on the motorway but sometimes only 20 around town so the ultimate distance per tank is entirely dependent on where I've been.
If the Renault has a 9 gallon tank then the figures mentioned suggest about 60MPG. If that includes town driving then that is excellent.
My diesel gets 45MPG on the motorway but sometimes only 20 around town so the ultimate distance per tank is entirely dependent on where I've been.
spnracing said:
A rolling road? Are you sure? I thought all MPG statistics were produced by a central agency and were actually quite accurate?
They are, the idea being that every car goes through an identical cycle in exactly the same conditions. They are accurate in that you can compare one car with another, but they are not a guide to real world motoring. They are however much better than the old sytem that was a constant 56mph, 75mph (when the speed limit was 70mph!) and a combined figure.
I bought a brand new Citroen Visa 1.7 diesel in 1986. Now, granted, it weighed as much as a paper hanky but I did get into that "economy" mind set and started measuring the mpg by brimming the tank, driving and then brimming it again which is the best way of determining consumption. Driving it very carefully, it would consistently return 63mpg.
HOWEVER, I soon found that driving it in a more spirited fashion ie rowing it along (this was probably the best diesel in the 80's)yielded more like 45mpg so I had a quandary, do you use the car for economy or thrash it and enjoy a lesser figure. In the end, I bought a Scirocco GTi. Drving that very very carefully, the computer once achieved 60mpg but driven carefully ie still faster than the Visa, it could touch over 40mpg.
Since then, I have found that I prefer to have a car that consumes a proportionate amount of fuel in exchange for vast performance.
Bear in mind for consumption purposes that the accuracy of the tests is based upon using a full sealed gallon or litre of fuel so is going to be less variable than the brimming the tank technique.
HOWEVER, I soon found that driving it in a more spirited fashion ie rowing it along (this was probably the best diesel in the 80's)yielded more like 45mpg so I had a quandary, do you use the car for economy or thrash it and enjoy a lesser figure. In the end, I bought a Scirocco GTi. Drving that very very carefully, the computer once achieved 60mpg but driven carefully ie still faster than the Visa, it could touch over 40mpg.
Since then, I have found that I prefer to have a car that consumes a proportionate amount of fuel in exchange for vast performance.
Bear in mind for consumption purposes that the accuracy of the tests is based upon using a full sealed gallon or litre of fuel so is going to be less variable than the brimming the tank technique.
My brother works for a co that does a lot of engine bed testing and teels me that ECU's "detect" the standard test cycle as it begins and go into ultra lean, ultra clean and economical mode and who cares about how the engine might last, run etc!
Sneaky huh?
PS - This relates to truck engines but no doubt cars are the same!
Sneaky huh?
PS - This relates to truck engines but no doubt cars are the same!
Smartie said:
Sneaky huh?
I can believe it! A bit off topic, but graphics card manufacturers used to do the same. They'd know what the standard tests magazines would throw at them would be and would cheat in order to deliver blistering benchmarks whenever the recognised tests were being run!
Not sure you should be admitting to owning a diesel powered french vehicle here but if you insist you should test it on at least one whole tank brim to brim rather than rely on "3/4 of the fuel gauge". Remember that the mfrs figure quoted is likely to be for a steady 56mph, no wind, inclines and a steady right foot. If you hoof it the figure is bound to fall.
I replaced my T Reg Renault Scenic Dti (Turbo-diesel) eighteen months ago with an 03 Reg Scenic Dci (Common rail) and have been bitterly disappointed ever since. The old model gave 55mpg overall whilst with the new one I struggle to achieve 46mpg.
I haven't changed my driving style and the cars are to all intents and purposes identical. Renault, who claim 56mpg for the Dci, don't want to know. They offer suggestions like roof racks, tyre pressures, heavy passengers etc. but these applied equally to the old model. My only consolation was meeting a fellow Scenic owner who said I was lucky to get 46mpg!
Any suggestions for better economy are welcome but already I'm a very placid driver and rarely exceed 75-80mph.
I haven't changed my driving style and the cars are to all intents and purposes identical. Renault, who claim 56mpg for the Dci, don't want to know. They offer suggestions like roof racks, tyre pressures, heavy passengers etc. but these applied equally to the old model. My only consolation was meeting a fellow Scenic owner who said I was lucky to get 46mpg!
Any suggestions for better economy are welcome but already I'm a very placid driver and rarely exceed 75-80mph.
johnsam said:
I replaced my T Reg Renault Scenic Dti (Turbo-diesel) eighteen months ago with an 03 Reg Scenic Dci (Common rail) and have been bitterly disappointed ever since. The old model gave 55mpg overall whilst with the new one I struggle to achieve 46mpg.
I haven't changed my driving style and the cars are to all intents and purposes identical. Renault, who claim 56mpg for the Dci, don't want to know. They offer suggestions like roof racks, tyre pressures, heavy passengers etc. but these applied equally to the old model. My only consolation was meeting a fellow Scenic owner who said I was lucky to get 46mpg!
Any suggestions for better economy are welcome but already I'm a very placid driver and rarely exceed 75-80mph.
Does the fuel consumption in any way form part of the specification of the vehicle, or is it regarded as just a guide? It could be that the latest emmissions standards (is yours Euro IV?), while reducing certain emissions, also affect the performance and fuel economy.
May be worth talking to someone like AA or RAC if you're a member - there must be a standard 'real-world' test for checking these things.
Fuel economy never lives up to the manufacturers expectations...personally I use a Broquet to improve my fuel economy, the manufacturer guarantees a minimum of 7% although I think I get much better than that, I have also noticed an improvement in the drive quality and lower emissions. I hear that Subaru use Broquet in the Impreza's to improve performance.
I'm addmittedly running a Tdi 405, L reg, 178,000 miles... I've altered the turbo boost (mechanical) and tweaked the fuel pump (mechanical too), and got a healthy dose more power, but even that "old tech" engine, with that many miles on it can still get me 45-50 mpg on a tank, better than what all the car guides say.
So, I either get 530 miles on a tank going 65 on the motorway slip streaming trucks, and generally not changing speed much, or I get 400 miles out of the tank driving a lot harder and getting 38 ish mpg.
I think new cars *can* help out alot on fuel economy, but it's clear from my experience that it's how you drive still, and these small engined eco boxes are designed for slow cruising speeds, so going 70mph+ on the motorway ends up using lots of fuel!!!
Maybe better with a bigger engine and longer gearing that might actually end up being as efficient as a small engine and short gearing, which your using for the wrong purpose?
Dave
So, I either get 530 miles on a tank going 65 on the motorway slip streaming trucks, and generally not changing speed much, or I get 400 miles out of the tank driving a lot harder and getting 38 ish mpg.
I think new cars *can* help out alot on fuel economy, but it's clear from my experience that it's how you drive still, and these small engined eco boxes are designed for slow cruising speeds, so going 70mph+ on the motorway ends up using lots of fuel!!!
Maybe better with a bigger engine and longer gearing that might actually end up being as efficient as a small engine and short gearing, which your using for the wrong purpose?
Dave
Smartie said:
My brother works for a co that does a lot of engine bed testing and teels me that ECU's "detect" the standard test cycle as it begins and go into ultra lean, ultra clean and economical mode and who cares about how the engine might last, run etc!
Sneaky huh?
PS - This relates to truck engines but no doubt cars are the same!
to some extent that's right- you tune the vehicle to meet the legislation
yep brim fill and record mileage, brim fill again and calcluate mpg from what you had to put back in
manufacturers do map the car to meet emmission for certain tests, this can also produce nasty flat spots best thing is to get it obd re-mapped, particularly good on turbo diesels, undetectable by dealers, insurance companies too
the only figure to look at is the xtra urban, in my experience quite a good guide
if you are running a petrol car use optimax, more expensive per lite but better economy and performance
manufacturers do map the car to meet emmission for certain tests, this can also produce nasty flat spots best thing is to get it obd re-mapped, particularly good on turbo diesels, undetectable by dealers, insurance companies too
the only figure to look at is the xtra urban, in my experience quite a good guide
if you are running a petrol car use optimax, more expensive per lite but better economy and performance
my TDCI focus isn't that great on economy either.
i'm getting around 42-44mpg. and thats driving in a less than spirited fashion. i was hoping to have got closer to 50mpg but it seems like i ain't ever going to get that! if i drive it normally i get 38-40mpg.
i don't see the point especially when normal petrol engine cars are starting to return high 30mpg.
sitting at 80-85mph on the motorway tends to return around 38-40ish mpg, up the pace alittle it starts to drop alot.
it seems like i'm not the only one who thinks new diesels are not as economical as the non common rail engines.
i'm getting around 42-44mpg. and thats driving in a less than spirited fashion. i was hoping to have got closer to 50mpg but it seems like i ain't ever going to get that! if i drive it normally i get 38-40mpg.
i don't see the point especially when normal petrol engine cars are starting to return high 30mpg.
sitting at 80-85mph on the motorway tends to return around 38-40ish mpg, up the pace alittle it starts to drop alot.
it seems like i'm not the only one who thinks new diesels are not as economical as the non common rail engines.
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