Miles per gallon
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- Citroen Sorceror
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- My Cars: 2003- Passe-Partout 1.9 TGD estate
2005 Grolliffe Tizzydee turbo estate and sundry other BXs and Grace, a CX TRD.
2008 to 2023 - all sorts of stuff, some interesting
2024. TxD 1.9D estate. 'Wheelybin' - x 12
The hydraulic pump makes less difference than you'd think, it is only loaded when the wheels are steering or if the accumulator is being recharged. The figures are by no means poor by comparison with other vehicles of similar weight and horsepower although leaner burn engines have come a long way since Simca designed the XU engine. Computer controlled ignition has helped a lot and fuel injection is far more refined. Carburetted engines are thirsty. Worn carburetted engines with worn carburettors very much worse.
The Turbodiesel BX estate is between 10 and 20% more frugal than a current Golf 1.9TD
at a steady 80 MPH!
The Turbodiesel BX estate is between 10 and 20% more frugal than a current Golf 1.9TD
at a steady 80 MPH!
Now thats more like my old 16RS... I've found my strobe , so I'll tackle the thing tomorrow... I have thought about tracking down the bits and bobs and adding monopoint injection on and getting shot of the carb altogether ... I did it to my sisters Pug 205XS years ago....Eric Brough wrote:I'm running a BX16 TXi - the late monopoint injection system. Over the last 20000 miles I've averaged 432 miles-per-filling. That comes out at 37.7 mpg.
E.
Doz
2007 Citroen C1 (it's not a real Citroen)(With a complete set of wheel trims)
2006 C4 1.6VTR+ (Alloys no wheel trims)
1982 Mini HL (No wheel trims, no wheels)
1993 Kawasaki GPZ500
2007 Citroen C1 (it's not a real Citroen)(With a complete set of wheel trims)
2006 C4 1.6VTR+ (Alloys no wheel trims)
1982 Mini HL (No wheel trims, no wheels)
1993 Kawasaki GPZ500
This is a good answer regarding the pump, but why for example when the GTi is injected and controlled by ecu does it not achieve much better than 30mpg even when being driven calmly in a controlled manner?tom wrote:The hydraulic pump makes less difference than you'd think, it is only loaded when the wheels are steering or if the accumulator is being recharged. The figures are by no means poor by comparison with other vehicles of similar weight and horsepower although leaner burn engines have come a long way since Simca designed the XU engine. Computer controlled ignition has helped a lot and fuel injection is far more refined. Carburetted engines are thirsty. Worn carburetted engines with worn carburettors very much worse.
Offhand I don't know what the mpg figures for a 2.0l Ford Mondeo are but I suspect much higher and it's a heavier car.
1991 BX19GTi Auto
- pindimar
- BXpert
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MPG in petrol BX19
well, my BX19 TZi manual wagon gets around 28 mpg or 9.81 litres/ per hundred kilometres on a country/city cycle, but around town it drops down to 24-25 mpg or 11.33 litres / per 100 kms. Total freeway & country running seems to be around 35-38 mpg.
How accurate my checks are is another matter, I guess??
Greg F
How accurate my checks are is another matter, I guess??
Greg F
- sleepy0905
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- DavidRutherford
- BX Digit man!
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Fuel injection varies massively. One electronic injection system can be so different to another that there is no comparison.Way2go wrote:when the GTi is injected and controlled by ecu does it not achieve much better than 30mpg even when being driven calmly in a controlled manner?
For instance.... is the system single point, multi-point-paralell or multi-point-sequential. Airflow sensor... flap-type or hot-wire-type?
etc.etc.etc.
The BX fuel injection system (as I understand) is not massively advanced, as it uses a fair bit of analogue electronics to modify a basic fuel curve from a look-up-table. This is fairly crude, and not much more advanced than a carburettor (although far less likely to wear out)
As processor speeds have increased, modern fuel injection systems have become fully digital, and as such can be far more tightly controlled.
The same is true of ignition timing. Early electronic systems used little more than a MAP sensor and rpm speed sensor, and were analogue. The ignition scatter was large, and hence the engine could never run with optimum advance all the time.
Modern systems are far more advanced than this, with the same ECU controlling ignition and fuelling with fully digital control, and as such the engine can be on the limit of advance and the limit of lean-ness all the time.
Given that Electronic control has now advanced to the point that the processor is faster than the engine speed, I doubt that we will see the same advances in engine efficiency over the next 20 years that we have seen over the last.
this might be a signature
- docchevron
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Excellent answer David!
Mine is the Motronic multipoint parallel. But of course injection is pre inlet valves so additional benefits on later engines will also probably advance through 2 stages 1) increasing from 2 to 4 valves per cylinder and 2) direct metered injection.
Presumably it's 'cos Doc's car has 16 valves he was able to reach his staggering 42mpg on that occasion. I think that will never be attainable in my 8v auto.
Mine is the Motronic multipoint parallel. But of course injection is pre inlet valves so additional benefits on later engines will also probably advance through 2 stages 1) increasing from 2 to 4 valves per cylinder and 2) direct metered injection.
Presumably it's 'cos Doc's car has 16 valves he was able to reach his staggering 42mpg on that occasion. I think that will never be attainable in my 8v auto.
1991 BX19GTi Auto
If yo work out how much modern cars weight compared to a car from the 80s its amazing.
This is down to ompuers and most fo all sfaety features Useing a mid range Golf as a reference, a 1.9TDI has approx 105bhp but weights 1400kgs where a BX 1.7TD has 90bhp but weights approx 1000kgs. So the BX has 15bhp per tonne more. So will be faster and more economical.
This is down to ompuers and most fo all sfaety features Useing a mid range Golf as a reference, a 1.9TDI has approx 105bhp but weights 1400kgs where a BX 1.7TD has 90bhp but weights approx 1000kgs. So the BX has 15bhp per tonne more. So will be faster and more economical.
- Philip Chidlow
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- Citroen Sorceror
- Posts: 1266
- Joined: Fri May 20, 2005 8:51 pm
- Location: straddling the channel
- My Cars: 2003- Passe-Partout 1.9 TGD estate
2005 Grolliffe Tizzydee turbo estate and sundry other BXs and Grace, a CX TRD.
2008 to 2023 - all sorts of stuff, some interesting
2024. TxD 1.9D estate. 'Wheelybin' - x 12
As David points out, much is due to the way the injection system is metred. K-jetronic was once considered very efficient but it ran on the principle of four injectors spraying fuel constantly. Multipoint is better as a rule but the Motronic system is controlled by an air mass meter which is very sensitive to leaky pipes of which there can be many on a GTI/TZI.
To get a real world figure, look at Doc's 16V which is well rebuilt. 42 is very good but it will drop a long way used hard. The average GTI is strangled by its cat and usually has a worn distributor plus big carbon buildups on the inlet valves, all of which causes its efficiency to plummet.
A good decoke can work wonders on them.
To get a real world figure, look at Doc's 16V which is well rebuilt. 42 is very good but it will drop a long way used hard. The average GTI is strangled by its cat and usually has a worn distributor plus big carbon buildups on the inlet valves, all of which causes its efficiency to plummet.
A good decoke can work wonders on them.
- docchevron
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The best way to de-coke a valver is give it a Billy special tune up.
Warm it up fully, then lots of high revs and over-run from high revs, clears an amazing amount of rubbish out.
Taking the head off aint too hard to do, but, use the engine as it was intended now and again and it'll keep itself in pretty good nick.
Of course, decent fuel helps too..
Cheers
Chris G
Warm it up fully, then lots of high revs and over-run from high revs, clears an amazing amount of rubbish out.
Taking the head off aint too hard to do, but, use the engine as it was intended now and again and it'll keep itself in pretty good nick.
Of course, decent fuel helps too..
Cheers
Chris G
Smokes lots, because enough's enough already!
Far too many BX's, a bus, an ambulance a few trucks, not enough time and never enough cash...
Far too many BX's, a bus, an ambulance a few trucks, not enough time and never enough cash...
- ken newbold
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Best I could get out of a n/a 19D Estate was about 55. I found my TZD estate would do quite a bit better.Philip chidlow wrote:I'm getting low to mid forties around town with the TXD and I would have expected better - I'm not driving it hard but there is a fair amount of stop/start and sub 5 mile trips.
Best on a trip was 52 mpg. Doesn't sound right to me - with all these stories of people getting 58 to 60 mpg out of theirs