MPG Comparison/Observations

Dammit, I know I need a tdi :cool:

The only figures I can offer for comparison are for a 2001 Passat 1.8T and a 1999 Polo 1.4. Using both for commuting, 13 miles each way of mixed roads, Passat 36-37mpg, Polo 48.5. In the snowy weather with some long motorway journeys I got 41mpg from the Passat and a sniff of a decent length trip in the Polo gets it in the 50s. I guess a 1.4 petrol should do similar mpg to the Polo, well I'm assuming that so I'm looking at petrols as well as diesels now :eek:
 
Petrol 1.4 2001 reg.

Hi Nuttinew, i have a basic 1.4 petrol, had it for five years and my 'averages' over this time is/are 42./44 mpg, you can get better results on motorways up to 55mpg,but general mixed driving is as stated previously, still a great little car though, i love it!!, Cheers ALAN.
Ps, yes i do have a chipped motor, and it does move quicker and smoother, but you only get an extra
7BHP, and it will run all day in the 3no scale If required!!.
 
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Will said:
Today was the first proper warm day for me driving the car and what a difference it has made :)

Monday - 150 miles (temp ~5C)
Friday - 160 miles (temp ~15C)

average mpg = 76 :)

If Monday mornings could be a bit warmer I could well hit 80mpg without beginning on mods like 5th gear and a remap.
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Will - At what speed did you achieve the 76?
 
Will said:
Lights and heater on:
@70mph = 60mpg
@60mph (mild temp) = 70mpg
@60mph (cold temp) = 65 mpg
@60mph (mild temp, strong wind) = 65mpg
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Will said:
Monday - 150 miles (temp ~5C)
Friday - 160 miles (temp ~15C)

average mpg = 76 :)
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Pugliese said:
Will - At what speed did you achieve the 76?
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The 76mpg, as the others I quoted was measured full tank to full tank, over a ~300 mile journey, mostly cruising at 60mph.
 
pamanal21 said:
Hi Nuttinew, i have a basic 1.4 petrol, had it for five years and my 'averages' over this time is/are 42./44 mpg, you can get better results on motorways up to 55mpg,but general mixed driving is as stated previously, still a great little car though, i love it!!, Cheers ALAN.
Ps, yes i do have a chipped motor, and it does move quicker and smoother, but you only get an extra
7BHP, and it will run all day in the 3no scale If required!!.
Click to expand...


:cool: A friend has his Passat 1.8t remapped and it was so much smoother to drive the extra bhp was just an added bonus:) I'll always maintain it's how a car feels to drive that is the most important thing and the 1.4s have felt sluggish when using the throttle gently:( Annoying but I guess for emmissions or somesuch in the same way Bluemotions have a lower tickover.
 
Speed, the biggest enemy of fuel consumption!!

As many of you know, one of the biggest influences on fuel consumption is speed.

I thought I would put a brief explaination of why this is the case. I know that for many of you this will be like teaching my grandma to suck eggs, but here it is anyway!!

Aerodynamic drag forces go up with the square of speed. For example if you drive along at 75mph instead of 55mph, the force required to push you through the air goes up by (75^2/55^2) = 1.86 times. Now of course you will cover a given distance more quckly, so in term of mpg, you need to divide this by the linear ratio of the speeds, so the equation goes:

(75^2/55^2) / (75/55) = 1.36 times or 36% more energy reqired to overcome aerodynamic drag per mile at 75mph than 55mph.

There are 2 other sources of friction that increase with speed: Rolling resistance and engine friction. Both of these increase aproximatly linearly with speed (at lease in this fairly small speed range), so in fact for these 2 sources of friction the speed you drive doesn't have much of an effect in terms of MPG, because although the fuel you use increases linearly, so does your speed, so fuel used per mile doesnt change much.

There are things you can do about rolling resistance: energy saving tyres, narrower tyres, higher tyre pressures etc.

There are things you can do about engine friction as well, the higher 5th gear mod is the best example. simply make the engine rev at a slower speed for a given road speed. Personally I would like to change the 5th and final drive ratios for the one's from the polo bluemotion, reducing the engine speed by 20% in 5th.

But when all is said and done, it is aerodynamic drag that makes the most difference, so if you want to save the plannet, drive slower!!

Andrew
 
it's not about saving the planet, it's about saving my wallet! Personally I don't buy into the "man-made car drivers are to blame for everything global warming climate change 'religion'".
 
I'm with you Adrian,

I just want to get MPG up without spending a fortune. I really would like the gearbox mod, but I figure any improvement in MPG, say 5% will save me about £50 a year so thats 3 years, 30k before I've even paid for the mod.

Tyres, I have to change anyway, so I thought increasing the diameter, might give the same 5% benefit, by increasing the gearing? I would try and get narrower ones too...Remember the ones fitted to 2CV's, they looked like space savers!

I even wondered if the engine could be re-mapped for economy rather than power?
 
I cover 20,000 miles a year so payback times are different. As for a remap for economy, get it remapped on a rolling road set up for maximisng low down torque rather than galloping horses. You will be able to use higher gears much more and so save on fuel. I would still seriously consider the revised 5th gear for all the other benefits.
 
I agree with the above and just wanted to add that a remap with also a large flat maximum is better than one with just a narrow peak. Also if using 5th gear at VERY low rpm then accelerating may use more fuel than using 4th to make the same acceleration. Lower rpm isn't always the most efficient.

I've just started my Millers diesel additive trial, so I'll be able to report back after a month or two
 
On my sisters golf, 56 plate, it has a recommended gear change number on the DIS. As you say it's suprising sometimes how much you should be revving before you change gear.

On a similar note, Garmin have an eco drive thingy coming out soon. It monitors your driving style, displays mpg etc..., and not only finds the fastest route to your destination, but also the most economical route.

I don't know if it will work in the A2, it plugs into a port like the garages use to diagnose problems.
 
1.2 Tdi (3 litre)

I have the 1.2Tdi and my consumption figures have changed dramatically during this recent cold spell. Last year I was averaging over 90mpg but this dropped into the 70s during this winter, although I have changed my routine now to include much more town driving. My last fillup showed an encouraging return to 88.7mpg thankfully. I was beginning to think the car was getting past it with its 105,000 miles!
I track my fuel accurately now on www.fuelly.com - take a look at -
http://www.fuelly.com/driver/andyfisher/a2
 
Recent economy check runs

Last week I did just over a 100 miles at 60mph 2 adults 2 kids
Today I did 117 miles at 70mph (20 miles at 50 M1 average speed section)

at 60mph I got 65.91mpg (Dryroads, sunny about 12c)
at 70mph I got 66.71mpg (wet roads, about 11c)

Car is standard 1.4 tdi 75bhp with 17" 205 40 17's budget tyres.

Next I want to do it at 50mph if I can stand the boredom.
 
Black Pearl said:
Recent economy check runs

Last week I did just over a 100 miles at 60mph 2 adults 2 kids
Today I did 117 miles at 70mph (20 miles at 50 M1 average speed section)

at 60mph I got 65.91mpg (Dryroads, sunny about 12c)
at 70mph I got 66.71mpg (wet roads, about 11c)

Car is standard 1.4 tdi 75bhp with 17" 205 40 17's budget tyres.

Next I want to do it at 50mph if I can stand the boredom.
Click to expand...

Do you work this out or are the figures from the DIS? Those mpg figures are really impressive!
 
Will said:
The higher mpg at 70mph might be due to a smoother driving style that day, or fewer hills?
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I can't say that there is any difference in driving style, as basically I just held steady at 60 or 70mph each day.

The only differences I can think of is maybe the prevailing wind, but on both days there was little wind. And, that the roads were wet at 70mph, does this decrease rolling resistance? I would have thought if anything it would increase resistance as the tyre fights its way through the water.

I calculate it brim to brim, from the same pump if possible, if not at least the brand of derv. In this case Shell Standard Diesel.

I use either my own spreadsheet or

http://www.torquecars.com/tools/uk-mpg-calculator.php

My car doesn't have DIS.
 
Well ive measured last weeks mileage :-

55.8 mpg

I think i'll give the millers a miss as per the other post, damn tyres and wheels ;)

I guess you cant have your cake and eat then?
 
hotdog1 said:
Well ive measured last weeks mileage :-

55.8 mpg

I think i'll give the millers a miss as per the other post, damn tyres and wheels ;)

I guess you cant have your cake and eat then?
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I wouldn't immediately dismiss Millers. There seem to be more favourable reports than not. For the price of a few pounds it's worth a try anyway, plus the cleaning benefits too.
 
On a tank of regualr shell petrol I've just managed to achieve an mpg of 51 in my 2001 1.4 petrol (34L tank) - 315 miles on 28 litres. This summer's challenge is to get 400 miles out of a single tank! Possible?
 
VonB said:
On a tank of regualr shell petrol I've just managed to achieve an mpg of 51 in my 2001 1.4 petrol (34L tank) - 315 miles on 28 litres. This summer's challenge is to get 400 miles out of a single tank! Possible?
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I guess it's possible if you can find a 400 mile long hill!

I too have the 34l tank, but tdi. I rarely get 400 miles, but in theory could get nearly 500. I suspect it's unlikely, unless you drive it until empty! and even then you would have to get 54mpg.
 
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