Not What I Expected

[mumof4]

The examples i gave..were for my car.and what i know she can do...other cars may differ..

[jackspud]

i have my galaxy chipped and when i drive it i get about 44MPG my wife gets 50-52 MPG but only when i have my performance chip switched on. when it is off i get about 35 MPG and she gets about 42MPG. i was amazed that not only do i get more power with the chip but more fuel econemy as well :D

[mumof4]

Oohh i love it when you get angry.

 

Hmmm...i was a bit..calm now. ^_^

[Smilge]

mmmmm ..well that was an interesting read .... ^_^ I'm still a little confused on this "burping" method. I prefer the "farting" method myself ..... it tends to annoy people without arguing the fact and when you earn as much as I do, then trip computers are as much use as a trap door in a canoe. ^_^

[raymac]

When i put in

[Scorpiorefugee]

I have to come in and support Mum of 4 on this labouring thingy. I support her view entirely. As I've commented before, My experience covers about 2,000,000 miles and I often drive with the engine running at not much more than 1000rpm. I have to add that the older 110 BHP unit is happier at this than the newer 115 one. I've never blown an engine, never lost a clutch and I always get good MPG. It's just a question of being in the right gear at the right time. You can tell when the engine is labouring and an experienced driver can anticipate and avoid it.

 

As far as fuel economy is concerned, I have to admit to being somewhat embarassed to find that I'd been running my newer Gal with low tyre pressures because I trusted the Ford mechs (Daft or what?) and the tyre fitters. When I restored the correct pressures the economy improved by 5MPG or possibly more.

 

I always check my MPG full to empty and simply calculate Miles per litre. I work on 10 MPL = 45MPG and If Ican get that I'm happy.

 

On the subject of best speed, I've found that about 55MPH returns about 55 MPG but a stady 70 gives a balance between staying awake and getting 1000 mile out of a tankfull (I wish)

[gregers]

read this weeks auto express,makes very interesting reading concerning fuel economy,JUST A SHAME ITS NOT FOR US TDI DRIVERS,they even managed to better the combined results of the manufactures and they worked out you could possible save hundreds of pounds a year on your fuel bill.

[Scorpiorefugee]

I hope they're better informed than those wazzocks associated with the amusing but dangerous Clarkson in the Times Sunday supplement. They seem to be blind to anything that doesn't support or justify their own lifestyle or distorted vision of reality.

 

;)

 

Actually, If I can find a copy I should like to read it. If they can better the manufacturer's figures it has to be good. I can't imagine why it doesn't apply to diesels. Does it involve fuel additive tricks or the like?

Edited May 19, 2007 by Scorpiorefugee

[tiny]

A lot of HGV's (LGV's) have the tacho not only marked numerically for RPM but also showing, yellow , green and red zones. These indicate, not only the RPM of the engine, but also when the engine is running most efficiently. Keep it in the green and you will save a fortune on your fuel bills.

 

Now as I have posted previously, I work for an international tyre company, I am also a director and transport manager of a small/mid size private haulage company (our family business).

 

I dont want to start an argument here (especially with you MO4 ;) ), your engine may not be in your opinion labouring at 40mph in 6th, but it will not be running at its most efficient at such speeds in that gear. Diesel engines have a very narrow spread of power, this is why 6 speed transmissions are used on diesel cars, it is easier to keep the engine in its power band with a 6 speed than it is with a 5 speed. This means it is easier to keep your car on the power whilst driving, not just for performance but for economy.

 

In an old diesel clunker, such as a 70's transit, you put your foot down to increase the speed and there was a direct link between you putting your foot down and how much fuel was delivered to the engine. But a modern Electronically governed diesel takes all sorts of measurements and calculates how much fuel is delivered to the engine dependant on a plethora of other conditions (road speed/air temp/engine temperature/gearing profile etc).

 

The best way to keep an engine economical is to keep it running at its most efficient speed (engine speed NOT road speed). An internal combustion engine is not terribly efficient at the best of times, but when run under optimum speeds (or over for that matter) then they are even less efficient. You may not realise, but often it will require more throttle to run a car at 40mph in 6th than in 5th, or even 4th. On a fly by wire system such as the sharalaxhambra has, it is impossible to measure throttle input against fuel input to the engine as this is all calculated by the computer, having the accelerator 1/2 on in 1st will not be using the same amount of fuel as 1/2 on in 6th.

 

Looking at the facts, a diesel engine has a narrow spread of power across the rev range, typically most power (torque)is delivered between 2500 and 3000 rpm in a car, much lower (1600-2100)rpm in a commercial vehicle.

 

So, keep your(diesel) car between 2500 and 3000 rpm and you should maintain the greatest fuel ecomomy because your engine will be running at its most efficient. Under these RPM and your burning fuel just to try and maintain momentum, above these and you will be burning more fuel than it is possible for your engine to translate to power.

 

If your car has 6 gears and is designed to run in excess of 70mph in top gear with the narrow power band that a diesel engine has then it is impossible for it to be efficient in top gear at 40mph. If it were, VAG/Ford wouldn't be selling a 6 speed diesel, they'd have a 2 speed instead.

Edited May 19, 2007 by tiny

[big_kev]

Looking at the facts, a diesel engine has a narrow spread of power across the rev range, typically most power (torque)is delivered between 2500 and 3000 rpm in a car, much lower (1600-2100)rpm in a commercial vehicle.

 

I think you will find that the torque in a Galaxy Diesel is around 1800rpm.

 

The difference between a car and a commercial vehicle is that the windows are blanked out in a commercial vehicle.

This strangely does not affect the engine torque.

 

 

 

 

Don't get me started on this one......you think MO4 is bad when she's angry ;)

[tiny]

I think you will find that the torque in a Galaxy Diesel is around 1800rpm.

 

The difference between a car and a commercial vehicle is that the windows are blanked out in a commercial vehicle.

This strangely does not affect the engine torque.

 

 

 

 

Don't get me started on this one......you think MO4 is bad when she's angry ;)

 

Missing the point completely, whether a commercial vehicle or a car the gearing is such that it enables the vehicle to be driven in a way that matches road speed to engine power delivery figures, it is therefore no more than common sense that if a vehicle is designed to be driven at 70mph in a gear that keeps the engine in its most efficient state, than that gear will be unable to keep that engine in its most efficient state if that road speed is almost halved.

 

Where exactly in the rev range the VW units power delivery comes in I do not profess to know, but the power band will still be across a narrow range of revs not a single point (such as 1800 rpm).

[big_kev]

 

the torque in a Galaxy Diesel is around 1800rpm.

 

 

Where exactly in the rev range the VW units power delivery comes in I do not profess to know, but the power band will still be across a narrow range of revs not a single point (such as 1800 rpm).

 

 

Hence the use of the word "around" !

[Scorpiorefugee]

I think the facts are getting a little distorted by differences in the way different drivers interpret road conditions and how much power is actually needed to maintain speed.

 

My reasoning is that energy not used to move the vehicle forwards is wasted. Most energy is wasted in a small vehicle by pushing air out of the way. In a larger vehicle the balance goes towards friction. Windage losses follow a square law whereas friction losses are more linear and can actually reduce slightly as speed increases.

 

There are many situations on level or slightly downhill when all that is needed is a little power to maintain speed. Anyone who has been in a traffic queue will know that in first, second or even third gear can be used with engine tickover is enough to maintain a steady speed. Similarly, 6th gear at 40 requires little or no throttle to maintain speed. To use a lower gear simply means wasting energy pumping pistons up and down.

 

The other waste of energy is unnecessary braking. This occurs as a result of reactive driving either by the driver or others behaving inconsiderately. It is interesting to experiment with cruise control on a motorway by setting it at 70 and trying to avoid changing speed by planning well ahead. I find it very relaxing and satisfying on very long runs but it's all a matter of taste.

 

It is apparently accepted that an engine is most efficient at lower revs under maximum throttle but, while I can appreciate the logic of this, I am in no position to argue. I would never use full throttle in any gear at less than 2000 rpm because at lowers engine speeds the oil pressure can be lower and can be squeezed out from between the lubricated surfaces because the pressure is on for longer for each revolution.

 

It is all a matter of feel and many drivers, my wife included, just feel more comfortable with a more lively feel that you get by driving in a lower gear.

 

In all probability, each of us has good points and bad points and it all tends to balance out. If it ever becomes mandatory to drive at the optimum speed to minimise fuel usage I can imagine that we shall all be on full computer control and be passengers for most of the trip.

 

I shall now sit back and wait for the flack.

[big_kev]

'52 115 ghia TDI, Late 98 110(?) GLX TDI & 04 Picasso Exclusive HDI

 

Ron.

 

Holds on a moment............how many car's have you got....looks like 3 to me !

 

I can understand... 1 for you....1 for the wife.....what's the other one ?

 

You got a bit going on the side...... :D

[mumof4]

*A little hand rises from the back tentatively and a sqeaky voice says..."i was really annoyed the other night and i did actually mean to put 5th gear instead of 6th gear...but by the time i realised, the argument was in full swing and i was het up and refused to admit my mistake."..

 

Hand slowly lowers and the owner of the voice mumbles appologies and creeps away into the dark recesses of the corner...but a bit louder mumbles...."i do know about torque and gearing..and i know when my car is labouring".....*

 

Appologies.

[davgree]

I think many people worry about MPG far to much!

 

We buy fuel by the litre not the gallon, the cost of fuel varys so much - 1-7 pence per litre +

 

Work out how much it costs you to run 100 miles, thats the key, forget the fuel computer, it wont tell you how much your car costs to run!

 

Fill your car to the brim, run 100 , 200, or 300 miles, fill it back up to the brim and get your calculator out!

 

Get you fuel from the same filling station at the same price and see how much your Galaxy costs you per mile.

 

The 2 variables are your foot weight and the price you pay at the pump!

 

MPG really means nothing in this day and age!

[mumof4]

Ahhh..but its a good debate though....im joining the petrol heads now!. :D

[tiny]

Going off on a tangent here, how much is the cheapest and most expensive fuel near you?

 

For me petrol(unleaded) is 96.9 (Morrisons) and 99.9 at a private BP.

[gio]

I think the facts are getting a little distorted by differences in the way different drivers interpret road conditions and how much power is actually needed to maintain speed.

 

My reasoning is that energy not used to move the vehicle forwards is wasted. Most energy is wasted in a small vehicle by pushing air out of the way. In a larger vehicle the balance goes towards friction. Windage losses follow a square law whereas friction losses are more linear and can actually reduce slightly as speed increases.

 

There are many situations on level or slightly downhill when all that is needed is a little power to maintain speed. Anyone who has been in a traffic queue will know that in first, second or even third gear can be used with engine tickover is enough to maintain a steady speed. Similarly, 6th gear at 40 requires little or no throttle to maintain speed. To use a lower gear simply means wasting energy pumping pistons up and down.

 

The other waste of energy is unnecessary braking. This occurs as a result of reactive driving either by the driver or others behaving inconsiderately. It is interesting to experiment with cruise control on a motorway by setting it at 70 and trying to avoid changing speed by planning well ahead. I find it very relaxing and satisfying on very long runs but it's all a matter of taste.

 

It is apparently accepted that an engine is most efficient at lower revs under maximum throttle but, while I can appreciate the logic of this, I am in no position to argue. I would never use full throttle in any gear at less than 2000 rpm because at lowers engine speeds the oil pressure can be lower and can be squeezed out from between the lubricated surfaces because the pressure is on for longer for each revolution.

 

It is all a matter of feel and many drivers, my wife included, just feel more comfortable with a more lively feel that you get by driving in a lower gear.

 

In all probability, each of us has good points and bad points and it all tends to balance out. If it ever becomes mandatory to drive at the optimum speed to minimise fuel usage I can imagine that we shall all be on full computer control and be passengers for most of the trip.

 

I shall now sit back and wait for the flack.

 

You are indeed entitled to your own opinion, even though i disagree with alot of what you have wrote.

BUT "oil pressure below 2000rpm" it is indeed critical that oil pressure is at max before the engines reaches max torque,so fear not

you will have max oil pressure by 1500 rpm.

 

as for your 40 mph in 6th, being better or more effiecent than 40mph in 5th, sorry no, unless you are going down a hill

and we are talking about proper running not 100 or 200 yards, in favourable conditions but in proper

everyday driving.

[mumof4]

.

 

as for your 40 mph in 6th, being better or more effiecent than 40mph in 5th, sorry no, unless you are going down a hill

and we are talking about proper running not 100 or 200 yards, in favourable conditions but in proper

everyday driving.

 

 

I refer you to post 40....again appologies..i was upset that day, think that was the day i found out about the Gal, all the days just blended into one.

[El Dingo]

Going off on a tangent here, how much is the cheapest and most expensive fuel near you?

 

For me petrol(unleaded) is 96.9 (Morrisons) and 99.9 at a private BP.

 

All I know is that in a corridor along the A4 between Reading and Slough it's up to 5p per litre more than Shell at the A33 near the M4... This is rip-offs ville around here!

 

There's also a good and cheap Shell station just off the M25 near St. Albans.

[seatkid]

Hi everybody! Glad to see everyone is pontificating profoundly about their theories.... :16:

 

Anyway, I can cheerfully state that my average fuel consumption has been over 52 mpg for the last 8000 miles. I can extract up to 63 mpg on a long run, but this depends on road, traffic and weather conditions.

 

One day, I may enlighten you all about driving ECOnomically, but not today... :D

[davgree]

Going off on a tangent here, how much is the cheapest and most expensive fuel near you?

 

For me petrol(unleaded) is 96.9 (Morrisons) and 99.9 at a private BP.

 

 

In Gloucester we have:

 

Tesco Derv at 95.9, then other garages charging 99.9

 

Why do they charge so much more? Buy 60 liters and thats

[jkspoff]

They charge it because people pay it ! Company car/van owners mainly, they really don't care where they buy their fuel from or how much it costs. It's unfortunate that we live in a country of lazy people who can't be bothered to shop around for better value, therefore demanding better prices elsewhere.

[tim-spam]

It is apparently accepted that an engine is most efficient at lower revs under maximum throttle but, while I can appreciate the logic of this, I am in no position to argue.

This is only true for spark ignition engines, which includes those fuelled by petrol. The reason is that the pumping losses associated with operating at part throttle on a petrol engine reduce engine efficiency. These pumping losses are caused by the throttle butterfly in the intake restricting the amount of air being drawn into the cylinders.

On a compression ignition engine, there is no throttle butterfly, and the consequent lower pumping losses is one of the things that contributes to the better efficiency of a diesel engine over a petrol engine. In other words a diesel runs permanently with a wide open throttle. This is also one of the reasons why turbochargers work so well with diesels.