Hi all,
I recently got a 2002 mondeo TDCI 130 LX 5 speed. I have seen on line that people can normally do 50+ mpg, but I am struggling to get 40 mpg. I am mainly driving on motorway and do about 80mph all the time.
The car just had a service done in the main dealer and I also used a wynn injector cleaner, but none of them helps.
Is there anything wrong with it? Shall I take it back to dealer where is going to cost £85 just for a look?
Many thanks in advance,
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By the way, a guy said he can reach 70mph with engine at 1950 rev, but I have to push the engine to 2300 for the same speed?
Also, the rev won?t back to normal (800) when I start cruising in neutral? It will fluctuate between 1000 to 1100 for a while before it settles down.
Is that mean something wrong with the gear box?
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2300rpm at 70 is about right for a 5 speed, in my opinion the top gear is too high on the 6 speed meaning a change down is requied much below 60 where the 5 speed will pull hard in top at 50 or less.
The idle speed will only settle to 800 when the car is at standstill, even if it is rolling very slowly and out of gear the idle will rise a little, the ECU expects that power / revs will be demanded etc.
Nothing wrong with the gear box.
If you are driving it hard then 40MPG is not too bad though you should be able to average around 47mpg in mixed driving and 50+ on 70 to 80mph m/way runs.
How are you measuring the economy?
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Thanks a lot for your answer
I am calculating it out myself after each refill.
I have seen so many fuel cleaning things, wynn, STP, millers? which one is the best, shall I give some other brand a try?
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What is the economy like without the snake oil?
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Its the speed, theres a lot more air resistance at 80mph. Perhaps someone can come up with the formula to show the proportional increase in air resistance and power needed to overcome it as speed rises.
Had a look on the web and could not find it , but theres a graph on this on dave bakers puma racing site. Cant post link as permission and copyright is mentioned.
Regards
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I have found that the rule of thumb seems to be, that for every 1mph above 70, costs you 1mpg in fuel (roughly)
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TourVanMan TM < Ex RF >
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>>Perhaps someone can come up with the formula
In terms of tractive effort at the wheel
Tractive effort = gradient + aerodynamic + tyre rolling resistance
Tractive Effort = mg sin(theta) + 0.5*rho*A*Cd*V^2 + mg(A+BV)
m - vehicle mass
g - acceleration due to gravity
theta - gradient of road
rho - air density
A - frontal area of car
Cd - drag co-efficient
V - car velocity
A - constant tyre rolling resistance term
B - tyre rolling resistance term to describe increase in rolling resistance with speed
This formula can be easily converted to an equivalent one for power (as in this case, power is just Force * velocity)
Road Load Power= mgVsin(theta) + 0.5*rho*A*Cd*V^3 + mgV(A+BV)
Typically, the mass flow rate of fuel with respect to time is proportional to the power the engine is producing.
Number_Cruncher
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Good Evening, I have just been reading through all the threads and had to giggle to myself. I have a BEng in Electronics and Mechanical engineering with years of experience in the Motor Sports industry. I now run my own business in this field and I have to add..... there is no accurate way of measuring fuel economy and that's a fact. I wrote my final year project on the subject which got published in a highly regarded motor magazine ( I can't give the name for obvious reasons ). I looked at the formula which someone has put on here and found two main problems with it...Number 1, you can't really relate the mass flow rate of fuel in the formula to modern injection systems because of its very tight yet variable control of fuel. Number 2, vehicle mass, does this take into account the weight of the fuel in the tank and the rate of the fuel being used by the engine over a period of time......ie, the weight is decreasing as the fuel is being used. Basically, you could sit and try to work fuel economy out using various formulas and calculations but the fact of the matter is....fuel prices is the main factor of our economy!
Kind Regards,
Enginostics.
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What is the economy like without the snake oil?
I have found that cleaning additives hamper my MPG in my diesel Audi A4 also.
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You are doing well to get over 40 mpg. All these people getting over 50 mpg are either very slow drivers, dreamers or useless at maths.
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>>>useless at maths.
Looks like I was right then!
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What is the economy like without the snake oil?
It's kind the same.
I am wondering shall I give STP a try as they have beed doing this for quite a while.
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I am wondering shall I give STP a try as they have beed doing this for quite a while.
No - try driving at 70mph for a month and come back and tell us what the MPG is like.
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TourVanMan TM < Ex RF >
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Mine used to give about 43mpg while the computer tried to tell me it was 47mpg. That was a TDCi130 on a 53 plate. Lots of people I spoke to when I had mine, got worse figures than that.
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Hi,
I've got a 52 plate Mondeo TDCi 130 and I can get 510 miles on a full tank - thats doing naughtily fast on the A1 and minimal urban driving. However, I can't find how many litres my tank holds which isn't much good really, is it? Well at least I tried to help!
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Surely the 510 miles isn't using the full tank as some diesel will still be in the tank.
How much fuel do you put in? That will tell you how many MPG you are getting.
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On any car a couple of litres will always be left in the tank when you run out of fuel and there will always be airspace in the tank even if you brim it-that is on any tank used since the 80's.On any common rail the fuel feed pump will shut down before it runs dry-to protect the pump and the rest of the system.
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Hi I've got a 52 plate Mondeo TDCi 130 and I can get 510 miles on a full tank - thats doing naughtily fast on the A1 and minimal urban driving. However I can't find how many litres my tank holds which isn't much good really is it? Well at least I tried to help!
Hi, I always put 50 liters in the tank and it will last for around 500 miles until the lights is on which calculates out something like 39mpg.
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I had a 2002 TDI 130 for 4 years . I always used to get more than 500 miles to the tank and sometimes around 600 . I just used to fill to the brim and drive it until the warning light came on . I suppose I drove it reasonably carefully with the odd blast here and there. There was never much point in using more than 3000rpm. The trip computer was a little optimistic .. I think it claimed a little over 50mpg but I worked it out once and I think it was more like 47 or 48.
Definately reduce your cruising speed and see what happens.
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Definately reduce your cruising speed and see what happens.
And keep the tyre pressures up, raise them for prolonged high speed as instructed in the handbook (and on the fuel flap), it's amazing what difference an extra few psi makes.
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Hi I always put 50 liters in the tank and it will last for around 500 miles until the lights is on which calculates out something like 39mpg.
There's about 4.545 litres to the gallon, so if you're getting 500 miles to 50 litres that's 45.5 MPG - not bad really. Roughly the same as I used to get from the Mondeo TDCi I had as a company car.
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There's about 4.545 litres to the gallon so if you're getting 500 miles to 50 litres that's 45.5 MPG - not bad really. Roughly the same as I used to get from the Mondeo TDCi I had as a company car.
I am a little bit confused here. when we say mpg here, are we using us gallon or uk Imperial gallon? I used google calculator which seems using us gallon.
Excuse my lack of knowledge.
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MPG quoted in the UK will generally be in Imperial Gallons. I did wonder when you mentioned 39 MPG, as 39 MPG in US Gal is about 45 MPG in Imperial :-)
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MPG quoted in the UK will generally be in Imperial Gallons. I did wonder when you mentioned 39 MPG as 39 MPG in US Gal is about 45 MPG in Imperial :-)
So mine is not too bad then. Thank you all who gave me advice anyway.
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So mine is not too bad then.
I'm soooo glad I stayed out of this thread :-)
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I have recently bought a 2009 Mondeo Estate TDCI (140) withn the quoted MPG (combined) at over 53mpg. I don't drive with a heavy right foot so was surprised to see the MPG computer saying that I was averaging about 43 mpg. So I resorted to the old fashioned method of topping up, using a tank full and then refilling, and in reality my overall MPG is about 39!!!!
What a con! I would not have bought the car if I had known! I traded in a Toyota Avensis Estate, 2 litre 55 plate which returned without fail 47mpg no matter what sort of motoring Iw a doing and that is the quoted mpg. I couldn't work out how a heavier car with about 25 more bhp could return a better mpg and now I know the truth - it can't!!
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