# How's your Diesel performing?



## gebbel (15 May 2008)

With the price of fuel rocketing, I have been focusing a lot recently on the fuel economy of my car. Put just over 65L (14.5 Gallons) of Diesel into the almost empty tank today at a cost of €89.26 . I am sure that this will give me 1000km (620 miles) in total, driving 70% of the time to and from work on the M1. So I am getting an average of 42.75 MPG. Is this good or bad comparetively?
By the way the car is an 2005 A4 2.0TDi


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## galwaytt (15 May 2008)

I would have thought the A4 would score better, tbh.........we've just bought an 06 Saab 1.9Tid, and it's getting........38?


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## markowitzman (16 May 2008)

merc E270 Diesel 48-50mpg


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## Dinny (16 May 2008)

Galwaytt,

Can you let me know how are you finding the Saab 93, I am thinking of changing my Commercial Discovery 3 to one as i am now doing over 550miles per week. I was hoping to get more mpg than that though on motorways would you get 45mpg+?. Are you do a lot of driving around the town or a mix with motorway driving? Is your car the 120 or 150bhp model?
The discovery is doing 33.5mpg but this is mostly long drives.


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## aircobra19 (16 May 2008)

I'd say if you used cruise control and sat at the optimal speed you'd get more out of these diesels. Sitting at the speed limit is often harder on fuel. BMW's used to have a economy display. So perhaps look for features like that.


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## tuirse (16 May 2008)

I'm driving a late 2003 (new model) Avensis D4D Portarlington to Sandyford everyu day and average about 60mpg according to trip computer so about 650 between fills  - depends on driving style and how much time spent crawling on M50


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## Mpsox (16 May 2008)

I have an 06 Peugeot 1.6Tdi diesal and according to the onboard computer thingy I am averaging 68.9mpg at the minute. I drive from Carlow to Tallaght daily, which is a mixture of N7/M7 and get stuck in traffic for a while on my way in and especially out on the Belgard Road.


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## Caveat (16 May 2008)

galwaytt said:


> .........we've just bought an 06 Saab 1.9Tid, and it's getting........*38*?


 
Is this correct? To me, for a 1.9 diesel, that sounds pretty poor.


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## rebel16 (16 May 2008)

Mpsox said:


> I have an 06 Peugeot 1.6Tdi diesal and according to the onboard computer thingy I am averaging 68.9mpg at the minute. I drive from Carlow to Tallaght daily, which is a mixture of N7/M7 and get stuck in traffic for a while on my way in and especially out on the Belgard Road.



Is it a 307 or 407?


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## cruchan09 (16 May 2008)

I get 38-40 mpg from a 2.4 volvo s60 d5. If I stay off the back roads and try to stick to main roads I get better results, up to 45mpg.


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## rob30 (16 May 2008)

Dinny said:


> Galwaytt,
> 
> Can you let me know how are you finding the Saab 93, I am thinking of changing my Commercial Discovery 3 to one as i am now doing over 550miles per week. I was hoping to get more mpg than that though on motorways would you get 45mpg+?. Are you do a lot of driving around the town or a mix with motorway driving? Is your car the 120 or 150bhp model?
> The discovery is doing 33.5mpg but this is mostly long drives.


 
I  have a petrol Saab 9-3 150 bhp, and she just loves petrol. Getting too pricey to run now. 7l/100k out of the city, can be 12l/100 k dri ving arond town.


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## gocall01 (16 May 2008)

tuirse said:


> I'm driving a late 2003 (new model) Avensis D4D Portarlington to Sandyford everyu day and average about 60mpg according to trip computer so about 650 between fills - depends on driving style and how much time spent crawling on M50


 
Driving a 04 Avensis D4D, West Cork driving, trips range from 20 miles to 60 miles.
Generally getting between 52mpg and 58mpg depending on my driving style.
At the moment it seems it's always in a hurry!!!


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## john m (16 May 2008)

We have a Kia C'eed 1.6 diesel and its doing about 55-57mpg and a new shape Corolla 1.4 D4D and its doing about 65mpg. All the above mpg are based on a 100mile commute on country roads. The Kia feels like a rocket compared to the Toyota, but thats not saying much!


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## Whiskey (16 May 2008)

gebbel said:


> With the price of fuel rocketing, I have been focusing a lot recently on the fuel economy of my car. Put just over 65L (14.5 Gallons) of Diesel into the almost empty tank today at a cost of €89.26 . I am sure that this will give me 1000km (620 miles) in total, driving 70% of the time to and from work on the M1. So I am getting an average of 42.75 MPG. Is this good or bad comparetively?
> By the way the car is an 2005 A4 2.0TDi


 

You are not doing very well Gebbel (although as you say yourself, it's an estimate that you'll do 1000km with your 65 litres)

The official Audi figures for your car are an average of 5.5litres/100km which is 51 mpg in old currency.

The official Audi figures reckon that with your car you should do 4.3 litres/100km out of town (65 mpg).

Maybe consider turning off the aircon (cruise control is not to efficient on fuel either).

Also pump you tyres up fairly hard, and "coast" as much as possible.
Also use your brakes as little as possible, if you need to decelerate, take your car out of gear, and let it reduce velocity naturally. (ok you'd fail your driving test if you did this).
Also don't drive with big weight in the boot, or with the windows opened (you want your car to be as aerodynamic as possible).
Finally, drive in the higgest gear possible (without labouring), thats the most fuel efficient way to drive.


Pedantic I know, but it'll save you money and reduce your CO2 emissions


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## Mpsox (16 May 2008)

rebel16 said:


> Is it a 307 or 407?


 
307


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## gebbel (16 May 2008)

Whiskey said:


> You are not doing very well Gebbel (although as you say yourself, it's an estimate that you'll do 1000km with your 65 litres)



Thanks Whiskey,

I am sure I am getting 1000km out of a full tank (65L). I will take some of your suggestions on board to try and improve this. In terms of my driving, I probably work the engine harder than I should. I tend to accelerate rapidly and drive as fast as the law permits and even more in quiet motorway traffic. I have recently begun to use Aircon only when necessary. I'm not sure about the coasting suggestion because it was drilled into me when learning not to do this.


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## Whiskey (16 May 2008)

gebbel said:


> Thanks Whiskey,
> 
> I am sure I am getting 1000km out of a full tank (65L). I will take some of your suggestions on board to try and improve this. In terms of my driving, I probably work the engine harder than I should. I tend to accelerate rapidly and drive as fast as the law permits and even more in quiet motorway traffic. I have recently begun to use Aircon only when necessary. I'm not sure about the coasting suggestion because it was drilled into me when learning not to do this.


 

Yeah, the coasting suggestion is a bit tongue in cheek, it might save you a quarter litre every 1000km, and as you said it's not good practice for safety reasons.

But you should be disappointed if you don't get close on 1200km out of your 65litres, because the folks at Audi reckon thats the *average* return (from a combination of urban and rural driving).

It is an amazing fuel efficiency for a car of your size. Even small deisels like the Aygo or Lupo or a C1 deisel don't get vastly greater fuel efficiency than yours, despite weighing only about half as much, I never could figure out why.


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## patspost (18 May 2008)

Mazda 6 diesel, 136 BHP,
I have recently got into the habit of doing 90 Kph on the communte to work instead of 100 Kph, this has reduced consumption from about 4.7 l /100 km to 4 l/100km according to the trip computer, this works out at 70Mpg. The Rev counter would be showing about 1750 rpm.

 The consumption would be a little higher with the air cond running.
I just set the cruise control to 90 Kph and it is a straight run about 30 km, on dual carriageway with no delays.


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## Whiskey (18 May 2008)

patspost said:


> Mazda 6 diesel, 136 BHP,
> I have recently got into the habit of doing 90 Kph on the communte to work instead of 100 Kph, this has reduced consumption from about 4.7 l /100 km to 4 l/100km according to the trip computer, this works out at 70Mpg. The Rev counter would be showing about 1750 rpm.
> 
> The consumption would be a little higher with the air cond running.
> I just set the cruise control to 90 Kph and it is a straight run about 30 km, on dual carriageway with no delays.


 

http://www.eartheasy.com/live_fuel_efficient_driving.htm

The above link are some easy techniques to reduce your fuel consumption by as much as 40%.

Indded it's true, it seems about 90km/h is the most fuel efficient speed.
Also Jack rabbit starts and hard breaking are very fuel inefficient.


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## Froggie (18 May 2008)

markowitzman said:


> merc E270 Diesel 48-50mpg


 
I agree with this, my Dad got 58mpg out of my E270cdi on a long trip, I average 47mpg. its manual not auto!!


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## markowitzman (18 May 2008)

mine is auto........use cruise control a lot which helps?


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## Froggie (18 May 2008)

markowitzman said:


> mine is auto........use cruise control a lot which helps?


 You are better off with Auto when it comes to selling, I have had mine up for sale for a couple of months and no one wants a manual Merc....


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## Jack The Lad (18 May 2008)

Whiskey said:


> cruise control is not too efficient on fuel either


 
Surely the opposite is true? Constant speed = better fuel consumption?


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## who ru (18 May 2008)

we all know there's no need to have air conditioning in ireland - it's an added extra on some models but we never need to/get to use it!!!!!!!!!!!!!!!!!!!!!!!!!!!

anyway for fuel efficiency just use normal blow through ventilation - tis plenty good enough haha.


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## Whiskey (18 May 2008)

Jack The Lad said:


> Surely the opposite is true? Constant speed = better fuel consumption?


 

Aparently Cruise control is not as fuel efficient as a driver who can skillfully maintain a desired speed.

For example compare someone cruise controlling at 90km/h, and a driver without cruise control doing around 90km/h

Whenever there is a hill, the cruise control will quickly open the throttle, using more fuel to maintain at 90km/h.
The fuel efficient driver with no cruise control will allow his car to decellerate a fraction until he gets to the top of the hill (to avoid opening the throttle), and then accelerate gently to 90km/h on the next level piece of road or downslope.

However Cruise Control has a lot of advantages, and I was wrong to say it's not fuel efficient. It is fuel efficient in many driving situations (i.e. intercity motorways)


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## Mad_Lad (18 May 2008)

hey who ru. I love my climate control, and I find it had no effect in the fuel consumption. Emissions maybe a little. There is no need for it all the time but it's nice to have it and turn it off when i don't need it! You will use more fuel with the windows down as you create more drag. I get about 700 miles from full mark to last red mark on my Audi A4 1.9tdi 130bhp. And it's the multitronic automatic. They are a very effecent gearbox more so than dsg box but not as much as the 7speed dsg. Which is lighter on fuel and less emissions than a 6 speed manual. I am getting better fuel consumption since I switched to continental premium contact 2's. About 5-7 better and I have them at 34psi. Hi whiskey I find cruise not to be as efficient I think because people only hit the brakes when their car gets too close to the traffic, which wastes fuel. the trick is to judge the distance and keep off the brakes as much as possible. Works for me! and here is a more accurate way to calculate your fuel consumption, Your cars clock is usually always set to about 5mph more. So your mpg is going to be off a little. http://www.torquecars.com/tools/uk-mpg-calculator.php


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## Whiskey (18 May 2008)

Mad_Lad said:


> hey who ru. I love my climate control, and I find it had no effect in the fuel consumption.


 
Your climate control will have no effect on fuel consumption unless the aircon kicks in.  And in Ireland, the aircon will seldom need to kick in unless you set the temp low.

I think climate control is a fantastic thing. I can't understand why its such an expensive extra when buying a car, compared to buying a car with aircon and no climate control.

After all what is climate control apart from thermostatically controlled temperature, or is there more to it than this ?


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## tech3 (18 May 2008)

excuse my ignorance... but how can you work out how much diesel the car uses .when I fill up every week it costs around €75/€80 approx. I do on average 1000km per week. the diesel cost €1.27 a litre..


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## Frank (18 May 2008)

Keep an eye on amount of fuel rather than price. I had to put 62 litres of fuel in my car this weekend to fill up. 570 miles covered including 300 mile round trip to castlebar helped my economy on this tank.


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## alan.caulwel (18 May 2008)

for best economy max revs 2000 and in top gear = economy in spades


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## Whiskey (18 May 2008)

tech3 said:


> excuse my ignorance... but how can you work out how much diesel the car uses .when I fill up every week it costs around €75/€80 approx. I do on average 1000km per week. the diesel cost €1.27 a litre..


 
If you spend 80 euros, and its 1.27 a litre, you use about 63 litres.
(80 divided by 1.27 = 63)


63 litres moves your car 1000km, thats 6.3 litres/100km


It's about 41 mpg in the old system.That's not great fuel efficiency for a diesel. A lot of diesels manage 5.5 litres/100km


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## demoivre (19 May 2008)

Whiskey said:


> If you spend 80 euros, and its 1.27 a litre, you use about 63 litres.
> (80 divided by 1.27 = 63)
> 
> 
> ...



Practice what you preach eh !. roflol.


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## Cabaiste (19 May 2008)

I just switched over to diesel about 2 months ago (just as the prices started to rocket! not taking it personally though!).

I drive a 1.6 Ford Focus TDCI. I am currently getting about 54mpg / 5.2l/100km (both on the trip computer and by manual calculation whenever I fill up).

My driving is approx 90% good N roads and 30 mile twice daily commutes. I use cruise control as much as possible and just turn it off to slow down rather than using the breaks (where safe to do so)!

Was happy enough with this until I saw toyotas and peugeots getting 60+ mpg.

One of the reasons (albeit a low priority one) I choose the focus over the Auris was because the manufacturers fuel economy figures for the focus were better!

I find driving at 90km/hr to be painfull as everyone is just itching to overtake you and will do so even when not safe, pulling infront of you causing you to break more, so probably not as efficient as it should be! Maybe when the roads are quiet!


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## Mad_Lad (19 May 2008)

I really think at this stage. That to save money you should NOT buy a new car. If you think about it. It's nice to have a new car but diesels cost a lot more to buy, are cheaper to fuel I know, But you will have to drive many miles to make up the difference, Chances are you will be trading it in before you even begin to make a saving. Then there is the mad depreciation. If you drive 30 k Miles a year I would say it's worth it to buy a 2nd hand diesel. But after that depreciation will Hit you very hard, and so eliminate any savings you made in buying a diesel in the first place. I bought my A4 Last july the 1st and have done 26k Miles since, Cost me €17,000 with 100k miles on the clock. Perfect service record, only fault was the Air-con Compressor. Which was fixed for €600.00 Euros local mechanic, Audi wanted €1500. I Got the compressor from England myself. I know the engine will go for 300k Miles if I want it to. It’s a very good car to buy 2nd hand. So I'm not too concerned that The A4 is not the most fuel efficient car in the world, But 700 miles from an automatic diesel. 70 Litre tank. Is more than good enough for me! I may change my mind If diesel Hybrids Make an appearance or if the Prius 3 next year has better figures than the current one. But the prices of such technology are insane.


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## PaddyH (19 May 2008)

Mad_Lad makes some very interesting points but i would add that Diesels are getting cheaper because of the VRT reduction. In my case I don't believe in buying new normally but have ordered a new Octavia 1.9TDI for July simply because the retail price is dropping by €2400 and will only be €150 a year to tax and should do 58MPG. I believe bit by bit the retailers will increase the price so now is probably a good time to take advantage of the VRT reduction. I gave some thought to buying second hand but I would be paying €400 a year extra in motor tax. I probably won't buy a new car again. I would also add that Audis/VWs/Volvo etc can be nice but can be pricey - I believe that Skoda's might not be speculator but offer value for money. Alot of Diesels are dropping 3-4K in VRT which will make them as cheap if not cheaper than the petrol models


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## werner (19 May 2008)

gebbel said:


> With the price of fuel rocketing, I have been focusing a lot recently on the fuel economy of my car. Put just over 65L (14.5 Gallons) of Diesel into the almost empty tank today at a cost of €89.26 . I am sure that this will give me 1000km (620 miles) in total, driving 70% of the time to and from work on the M1. So I am getting an average of 42.75 MPG. Is this good or bad comparetively?
> By the way the car is an 2005 A4 2.0TDi


 
That sounds a little on the low side. Perhaps you need to change up a gear a little earlier and use the engine torque for acceleration rather than pushing hard on the accelerator?

I used to have an Audi and I never averaged lower than 45 mpg usually 47-49 on extra urban driving at 70 to 80.

Are you unfortunatly stcuk in non-moving traffic? It would hit your over all mpg big time


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## Mad_Lad (19 May 2008)

Hi PaddyH. I was looking for an octavia, but couldn't get a dsg in the 2.0 TDI. Nor the spec I wanted. It seems people here only order the basic spec car. But the octavia is a great car. But you will have big depreciation all because of the skoda badge, and it is a crying shame. The tax for me is €590 per year. It's a shame they didn't give the environmentally conscious driver that bought the more fuel efficient car  the reduction in tax before july. But If I was going to buy a new car I would buy a golf. For the ONLY reason is that it will hold its value much better than most cars on the road. But I wouldn't buy a new golf they are far too boring and have no character. I would buy the new bravo they are really much nicer than the golf. Or buy a passat 2nd hand and get a better spec more comfy car than the golf! Another cheaper way of motoring would be to buy a 2nd hand diesel and convert it to ppo (pure plant oil). Anyway this new tax system is useless because the big suv’s  are not expensive enough for the people that can afford to buy and run them. And we will see a lot more tolls in the future. Then there is carbon tax which will be introduced in the not too distant future. And then there is the commercial driver who can buy a big pickup or suv without back seats and pay €50-00 vrt, not to mention the tax they will get back on fuel if you are vat registered! The only sensible way to do it is pay per kilometre, It would work out more expensive for the long distance driver but it is the best way from an environmental point of view! But I will go back to my previous point that for the cheapest way of motoring would be to buy a well maintained 2nd hand car and benefit from someone else paying the vrt and getting the big depreciation hit.  Buy 1.6 diesel from Peugeot or citroen get the 110hp and you have a very economical car, and if you drive using the engine torque as Werner rightly points out you should easily see 75mpg as I did in a van version, although afaik it was only the 80hp 1.6 c4 van. Sorry for the long posts


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## tosullivan (19 May 2008)

Caveat said:


> Is this correct? To me, for a 1.9 diesel, that sounds pretty poor.


I have the same engine in my Alfa and it gets 38mpg on round trips to/from work, up & down through the gears.

That can go up to high 50's mpg on long runs at 120kmh


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## Mad_Lad (19 May 2008)

most cars will not be efficent in towns or slow stop start traffic. That's where the prius comes in.


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## peelaaa (19 May 2008)

I have a  rover 75 diesel. It has the bmw engine, similar to 320d and 520d  and gives about 45-50 average. Very cheap to buy too.


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## Frank (19 May 2008)

if we were all that worried about mpg maybe we should buy the like of the polo tdi. 

70mpg perfectly adequate car.

Not my cup of tea though. Will be happy with middling mpg and decent push in the back with a bit of elbow room.


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## Investing (20 May 2008)

Whiskey said:


> Also pump you tyres up fairly hard, and "coast" as much as possible.


 
Coasting is illegal and not advisable. Your car brakes do not preform to full efficent when coasting due to the less vacuum in the brakes servo!!


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## Pique318 (20 May 2008)

Investing said:


> Coasting is illegal


 I'd love to see proof of this...


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## gebbel (20 May 2008)

Investing said:


> Coasting is illegal and not advisable. Your car brakes do not preform to full efficent when coasting due to the less vacuum in the brakes servo!!



Who says coasting is illegal? I know you will fail your driving test because of it but if it saves fuel, why not? I am also dubious about your statement of the reduced effectiveness of brakes when coasting...I have tried it recently and the brakes work just the same as when in gear.


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## kfk (20 May 2008)

There will be less grip on the road when coasting so keep it in gear. Coasting is not safe.


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## Caveat (20 May 2008)

Coasting is inadvisable, yes (as you don't have full control of the car) but I doubt very much that it's illegal.


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## Mad_Lad (20 May 2008)

afaik modern engines don't use any fuel or almost nothing when you slow down without using the brakes. Coasting isn't illegal but I agree with caveat, you don't have control of your car, and if you need to take off again quick, chances are you will be fumbling around for gears before you find the right one, if you are concentrating enough on the traffic. I wouldn't bother, just slowing down without using the brakes as much or not accelerating hard will do better for consumption.


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## Pique318 (20 May 2008)

kfk said:


> There will be less grip on the road when coasting so keep it in gear.


 I'd love to see proof of this too...cos then the laws of physics would have changed !


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## kfk (20 May 2008)

Pique318 said:


> I'd love to see proof of this too...cos then the laws of physics would have changed !


 
Does an all wheel drive car such as an audi a4 quattro have better grip than a front wheel drive a4 when driven at reasonable speeds? Yes. Think about it. A four wheel drive has better grip than a two wheel drive and a two wheel drive has better grip than no wheel drive which is what the car is when coasting. If you are trying to say that the grip is the same when the car is coasting as to when it is being pulled by the two front wheels then, in that case, the laws of physics would have changed.


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## Pique318 (20 May 2008)

Nobody is attempting to approve the use of coasting around bends unless they've had a brain bypass.

OK, 'grip' in a straight line while slowing down from 50-20 is not going to be different while coasting to that offered while in gear, regardless of 4wd or 2wd.

Your comparison of 4wd vs 2wd is OK but you overlooked one important issue...the 'Drive'.
4wd cars have more grip while the wheels are being driven than a 2wd car has while its wheels are being driven. Around corners, the 4wd is safer because it is using the push-pull effect rather than just the push (for rwd) or just the pull (for fwd).


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## kfk (20 May 2008)

What if I need to swerve while coasting? Surely it is safer to be in gear if this situation arises.

There will be more grip while driving in a straight line if in gear. When in gear and slowing down without brakes, the wheels will control the engine speed thus creating a slight braking force, which causes traction. More traction, more grip.


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## Slim (22 May 2008)

If I get my 115bhp turbodiesel chipped up to 150bhp - will it increase fuel consumption much?


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## Frank (22 May 2008)

Don't think so, the higher torque should make it easier to get up through the gears.

The problem is the stamping on the go pedal giving that push in the back. Go easy on that you should work out about the same on MPG. With way more fun and driveability to boot.


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## Mad_Lad (22 May 2008)

there is no need to coast with modern engines. they use almost no fuel when your foot is off the accelerator, and it a fact that removing drive from the wheels while the car is in motion is dangerous, mostly because you don't have any engine breaking. Hi Slim I agree with frank, if you drive as normal you won't see any increase in consumption. You will get much better responce from the engine with better torque. I don't think you will see 150bhp though, unless some other mod has to be done! What car is it? I would advise you to take it to someone who knows what they are doing, not someone who will re flash your very expensive ecu with new maps that were created for another car. No two engines are exactly the same. And don't use a tuning box, I had two of these on different vehicles and though I did get more power, I also got clouds of smoke!


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## Luckycharm (22 May 2008)

Just switched a month ago to diesel it is a Saab 9.3 1.9 TID - it is 90% used for city driving well a couple of exits southbound where they are doing the work on the M50 - getting around 6.6l to the 100km is that good/bad? Definetly getting alot more mileage then out of the 1.6 petrol car I had.


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## Frank (22 May 2008)

short hop low speed driving is a killer on any car.

I know it makes about 200 miles of a difference on my tdi passat.

Worst case is short hops 450 miles to 60 or so liters best case is mostly motorway 650.

Could do a bit better if I went easier on the right foot but that aint gonna happen.

I still prefer the low end diesel torque to any petrol car I have driven. Bar a supercharged Ford F150 V8 bruiser I got a spin in.


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## gebbel (22 May 2008)

Luckycharm said:


> - getting around 6.6l to the 100km is that good/bad? .


 
As I posted originally, you are getting exactly the same as my 2005 Audi A4 2.0TDi 140bhp. It's not bad, but as was said in this post, driving conditions and driving style will affect this significantly.


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## Kellypk (22 May 2008)

gebbel said:


> As I posted originally, you are getting exactly the same as my 2005 Audi A4 2.0TDi 140bhp. It's not bad, but as was said in this post, driving conditions and driving style will affect this significantly.


 
Luckycharm does a lot better than Gebbel because Luckycharm does 90% of her driving in the city.  City driving is all stop-start, 3rd gear/ 40km/hour.

Gebbel does very poorly with his Audi, driving mostly on the M1.
He should be getting over 1150km with his 65 litres, and not 1000km as he is getting currently.

Then again, maybe the M1 is a constant traffic jam these days ?


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## Luckycharm (22 May 2008)

Kellypk said:


> Luckycharm does a lot better than Gebbel because Luckycharm does 90% of *her driving* in the city. City driving is all stop-start, 3rd gear/ 40km/hour.
> 
> Gebbel does very poorly with his Audi, driving mostly on the M1.
> He should be getting over 1150km with his 65 litres, and not 1000km as he is getting currently.
> ...


 
Luckycharm is a him but is the missus who does 90% of the driving and you are right it is mainly stop start driving


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## gebbel (22 May 2008)

Does the extra bhp/ weight of the Audi (if that is the case) over the Saab not result in the lesser fuel economy?


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## Luckycharm (22 May 2008)

gebbel said:


> Does the extra bhp/ weight of the Audi (if that is the case) over the Saab not result in the lesser fuel economy?


 
The Saab is a big heavy car it is bigger then my old Audi A4 would say there would not be much in the weight difference.


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## gebbel (22 May 2008)

And what is the BHP of the Saab?


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## Luckycharm (23 May 2008)

gebbel said:


> And what is the BHP of the Saab?


 
120 bhp


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## Whiskey (23 May 2008)

What is the relationship between BHP and fuel consumption ?

Is it a case that for any given engine capacity i.e. a VW 2.0litre turbo diesel, the higher the BHP, the worse the fuel consumption ?


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## gebbel (23 May 2008)

Whiskey said:


> the higher the BHP, the worse the fuel consumption ?


 
I can only imagine that is the case.....higher power must require more fuel to deliver it???


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## Caveat (23 May 2008)

Broadly speaking, I think that is the case.


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## Pique318 (23 May 2008)

All things being equal, then mpre bhp = less mpg but that is rarely the case

A 200bhp car may give you 35mpg if driven smoothly/sensibly whereas a 100bhp car might only return 25 bhp if you drive it like you stole it.

Also, a 200bhp car in a small bodyshell is gonna be better than a 100 bhp car in a big bodyshell.
(ie, a 520 will give less mpg than a 320 if driven the same, because it has more weight to pull around, even though it's the same engine.)


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## aircobra19 (24 May 2008)

A 1.6 (130bhp) Honda I had returned better MPG than a 1.1 Ford and 1.0 Nissan. I assume thats because you needed to rev the smaller engines harder (depending on the journey) thus negating any fuel economy benefits. Overall running costs with far higher insurance of the Honda made the better fuel economy meaningless though. ditto servicing and repairs. You need to look at the total cost of running/ownership.


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## Trustmeh (25 May 2008)

I started using some of the various fuel saving tips out there for my 2.2 ltr diesel 4WD. I must say I have seen a huge improvement on mileage. I do the same commute daily mostly on a bypass with little traffic. I use coasting, but only on 1 or two hills in a straight line - in the slow lane. I would agree it probably doesnt make a huge difference, but it isnt causing any harm. The main thing ive tried is to not use the speedometer and drive mostly with the tachometer. I keep the engine under 2500 revs at all times, even going up through the gears. When I can I keep it around 2k and sometimes 1500 when theres traffic. Last tank got me 37 miles/gallon. I know that isnt anything compared to a decent fuel efficient car - but I think its a huge improvement on what i was getting.


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## Mad_Lad (25 May 2008)

aircobra19 said:


> A 1.6 (130bhp) Honda I had returned better MPG than a 1.1 Ford and 1.0 Nissan. I assume thats because you needed to rev the smaller engines harder (depending on the journey) thus negating any fuel economy benefits. Overall running costs with far higher insurance of the Honda made the better fuel economy meaningless though. ditto servicing and repairs. You need to look at the total cost of running/ownership.



I totally agree. But driving a car with 130ps rather than say 60hp is much less work and safer. Driving a car with very low hp is only good for town runs. If you are happy with it then fine, but I think a car with 100-150 hp is fine,any more and it's just a waste! A1.0 car will be more economical in town than a 2.0tdI for sure.


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## aircobra19 (25 May 2008)

Mad_Lad said:


> I totally agree. But driving a car with 130ps rather than say 60hp is much less work and safer. Driving a car with very low hp is only good for town runs. If you are happy with it then fine, but I think a car with 100-150 hp is fine,any more and it's just a waste! A1.0 car will be more economical in town than a 2.0tdI for sure.


 
Not always Driving a Honda with peaky power delivery is a pain in traffic. Often a small 1 lt is far easier with a lighter clutch etc. Less effort and its cruises over speed bumps that you can't with a sports suspension. Most city driving is at slow speeds too.


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## Mad_Lad (25 May 2008)

aircobra19 said:


> Not always Driving a Honda with peaky power delivery is a pain in traffic. Often a small 1 lt is far easier with a lighter clutch etc. Less effort and its cruises over speed bumps that you can't with a sports suspension. Most city driving is at slow speeds too.




But on the open road the honda would be much better power wise. Of course the 1.0l car will sometimes feel better in town. and the lack of power won't usually matter anyway. Oh boy if we didn't have cars to talk about! lol


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## aircobra19 (25 May 2008)

Mad_Lad said:


> But on the open road the honda would be much better power wise. Of course the 1.0l car will sometimes feel better in town. and the lack of power won't usually matter anyway. Oh boy if we didn't have cars to talk about! lol


 
Exactly.


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## gebbel (26 May 2008)

Thanks to all the tips in this thread, I have managed to increase the fuel efficiency of my 2005 Audi 2.0TDi 140BHP from just under 43MPG (forgive the imperial!) to 47MPG in one week. Changes I made have included:
1. Checked tyre pressures and found them to be too low (all less than 30PSI) so am now running with 34PSI on each tyre.
2. Listened to all the negative advice re "coasting", but have started to carefully use it...with noticeable benefits to fuel consumption.
3. Quicker gear changes i.e not letting the revs go past 2100RPM before changing up.
4. Most importantly....keeping to the legal motorway speed limit more than before. Less speed = less wind resistance and more fuel saved.

Thanks all


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## aircobra19 (26 May 2008)

I find 100 is much more economical than 120 on the motorway.


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## Caveat (26 May 2008)

I think I read somewhere that generally speaking, once you go over 100kph, fuel consumption increases fairly dramatically in most cars regardless.


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## Cabaiste (26 May 2008)

Caveat said:


> I think I read somewhere that generally speaking, once you go over 100kph, fuel consumption increases fairly dramatically in most cars regardless.


 
Sorry I can't give the source but I read somewhere recently that 10 mph over the speed limit ( I assmume that means the 100kph limit) uses 10% more fuel!!! (mostly due to the increased wind resistance)


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## quinno (26 May 2008)

Wind resistance / drag increases exponentially as speed rises, so a small increase in speed means even more resistance, which means you engine's got to work harder. This converts to poorer mpg at small increases in speed..


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## galwaytt (27 May 2008)

aircobra19 said:


> A 1.6 (130bhp) Honda I had returned better MPG than a 1.1 Ford and 1.0 Nissan. I assume thats because you needed to rev the smaller engines harder (depending on the journey) thus negating any fuel economy benefits. Overall running costs with far higher insurance of the Honda made the better fuel economy meaningless though. ditto servicing and repairs. You need to look at the total cost of running/ownership.


 

And, like a pendulum, it can go the other way, too. my current 14-yr old 3.0 petrol, is getting about 25mpg - but it's depreciated almost completely already, I had enough from selling our 07 Galaxy 1.8Tdci to buy it for cash - so no repayments, and no interest, so it currently represents astonishing value for money. Oh, and cheap to insure, too. (old dinosaur, I guess !!). A new econobox would have to be as cheap as chips, and do a squillion miles to the gallon to match the total cost. Sometimes more is indeed, less...........!!


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## aircobra19 (27 May 2008)

Thats a different point entirely. A old car vs a new one.


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## galwaytt (27 May 2008)

No it's not  - age doesn't tell you anyting about condition or quality.  Neither does mileage.  I bought one in Sept 07 with 111k miles on it.   Worked out so well I'm buying another - with 140k miles on it.   Both reek of quality in ways an econobox can only dream of.

The issue is value for money, full stop.   Long after the stickerprice has faded, the older, prestige car, is still a quality machine........


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## gebbel (27 May 2008)

galwaytt said:


> The issue is value for money, full stop. Long after the stickerprice has faded, the older, prestige car, is still a quality machine........


 
Not if you're driving a lot in it with the MPG you are getting!


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## aircobra19 (27 May 2008)

galwaytt said:


> No it's not - age doesn't tell you anyting about condition or quality. Neither does mileage. I bought one in Sept 07 with 111k miles on it. Worked out so well I'm buying another - with 140k miles on it. Both reek of quality in ways an econobox can only dream of.
> 
> The issue is value for money, full stop. Long after the stickerprice has faded, the older, prestige car, is still a quality machine........


 
Considering the higher tax, MPG and any repairs are likely to be expensive. Its hardly going to work out cheaper than a smaller car bought at the same price, with lower mileage and a smaller engine.  

I thought the thread was about saving money, not quality.


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