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OK, this is how it's going to go!

Write down your mileage on a full tank! I'm just interested in the figures, since i'm not getting much mileage on mine. It's important to include your Gearing type, since this affects the mileage. OK, now SHOOT!

Model:- 1.4S (Y-reg)
Mileage:- APPROX 320
Gearing:- Auto

Model - 1.4 (8v) Match (X Reg)
Mileage - APPROX 380 - 400
Gearing - Manual

Model - 1.6 (16v) GTi (W Reg)
Mileage - APPROX 240-260*
Gearing - Manual

*Thing is I always fill from around about the point when the fuel indicator sits just under ¼ of a tank of fuel so theres a good 20-30 miles more there... probs around 300 then?

Model - 1.4 (8v) Match (X Reg)
Mileage - APPROX 380 - 400
Gearing - Manual


that does more than the 16valver!

DAMN! And i thought that the more valves, the more economical and porky!

Or is it cuz i've got an auto!

I'm pretty sure 8 valves are more economical then 16valves, and I don't think an auto'll help

Model - 1.6 (16v) GTi (W Reg)
Mileage - APPROX 240-260* (have done 300 miles to a tank once or twice)
Gearing - Manual

exactly same as Si_GTi

Well I brim it then reset odo and then brim it again to work it out exactly, done two tests so far. Based on my Shell Garage Receipts...

Here goes:

Measured l, Trip, mpg Computed, Gallons, Remarks
41.07, 402.9, 44.7, 9.01, A/C On
40.46, 436.9, 49.2, 8.88, A/C Off

So best is 437 miles

Am just about to compute another without A/C so I could average them

I'm a bit mean, I don't usually boot it, and I do a mixture of trips to work and friends during the week followed by a trip to my parents at weekend which is about 100miles round trip, so its quite a good combined test. I think that in winter the car will do much worse with the manifold heater working overtime and a stiffer cold engine, headlights etc. (Driving with the heat on full from cold affects the warm up time a great deal and so uses much more fuel)

My Car is a 1.4 16V 75BHP - manual - which according to the book can do 59 MPG at 60MPH (My Arse). The 75BHP model seems most effecient at this speed more so than the 60BHP. The A/C is suprisingly effecient, I don't think you notice it as much when you are around town, but more so when your driving any distance.

Its clearly far better than the GTI on fuel. Maybe I'll drive a GTI sometime and see what I can get.

i hate to be a kill-joy but doesnt it also bear on the fact of how you drive the car?? A) like a t**t, revving through gears (cough) or B) poodling around like an oap on a sunday afternoon drive
just a thought
-Ben-

sometimes i get loads of miles sometimes its less. depends on 1- the way you drive, 2- the engine mods etc 3- the aero dynamic ie with all windos down huge spoler etc will reduce it, 4- the number of people in your car etc! 4- the type of driving motorway, rural, 5- the pressusre of your tyres.
all affects fuel consumpyion lol.
jon

Yeah, he's right.

For best fuel economy its not necesarry to doodle like an OAP, here's why.

Tyres, you want a hard compound and you want high pressure. They also need to be as narrow and as larger diameter as possible to minimise rolling resistance. Think train wheels, very very low rolling resistance. Modern tyres are much better than they used to be, manufacturers realised that the tread pattern eats energy, long pads that don't squash are much better than the older small pads. You can get specially designed tyres designed to reduce emissions and use less fuel, they do make a significant difference, although grip is compramised. Make sure your tracking is straight to, otherwise you are just rubbing tyres away.

Other crap, you don't want any excess weight, the subwoofer, the wife etc, all takes energy to accelerate.

Spoilers, anything that affects the airflow [spoil] will create drag, and this includes wings on planes or cars. There is a boundary layer of about 1" around your car at speed that doesn't move much, if you interrupt this it will dramatically increase drag, so you do not want to open windows or sunroof, these can add 10% to your drag.

Accelerating and braking, you don't want to be doing these, all your brakes do is turn all the kinetic energy you just paid for into heat, you can't get it back again. However, energy conservation is paramount, so you want to increase your speed when you are in a slipstream or going down hill and avoid fighting the loss of speed when you go up a hill.

Gears, 5th gear is best, but only above about 40MPH, in the Mk5, you'll find you need a larger throttle angle in 5th at 35 than you do in 4th so this buggers it up to.

Accessories, anything that uses electricity loads up your engine, unless your alternator is buggered. Headlights, Wipers, Fogs, Demisters, and fans all use significant power. Your radio however doesn't use much when used at low volumes in relation to the other guzzelers.

Air Conditioing, this uses a great deal of power to drive, up to 15HP, it also requires two fans to be running too. You won't notice this round town but you will on the motorway where it will eat fuel. That said, its probably marginally less than having the windows or sunroof open, although this is up for debate. I'd say its worse, because its using 15hp even when your stationary, but the windows become more significant only with speed.

Corners, scrub tyres, which is unavoidable, but having them hard reduces the loss, try to drive smoothly, blend all the corners you take, if you have two lanes and there is no traffic you can blend your corners across the apex, this will actually reduce distance travelled.

Stopping and starting, avoid stoping, if you see a red light you can often reduce your speed enough to keep moving. even a small amount of momentum is significant.

Stopping and Starting the Engine, when the engine is cold it is not very effecient, its in open loop control, and isn't running super lean. It takes about 10 minutes for the engine to warm up, during which time, there is various manifold heaters switched on etc to warm it up as soon as possible. But these are electric and use huge amounts of power. If you get 50mpg on a run, you can expect the economy in the 1st ten minutes to be about 15mpg! So short journeys are about the worst thing you can do. Think twice about where your going, you can be smart and keeping the engine warm do a bunch of stuff whilst its hot. This also dramitically reduces wear. Also - avoid using the heater when the car is cold, it takes about twice as long to warm up, and in fact, some engines in some temperatures can't actually warm up with the heater on!

Don't get stuck in traffic. I had an argument many years ago with a physics teacher. I was pointing out that you get 0mpg when your stuck. I still believe this is true. I go to work at 7:45 and get home at about 4:20, its worth moving your day if your boss allows, to avoid rush hour.

Don't you think its ironic that they call it rush hour? 1) its more than an hour 2) no one is able to rush anywhere, they should call it Stuck Time.

the max i ever got was 564 miles on 1 tank. tdi 75bhp. manual

average 520. my run to work is quite clear and i dont get stuck at lights in traffic etc.

as a general rule i normally fill up 100 miles after the red light comes on. gives me about 6 litres left in the tank. which should be enough for another 80+miles but never dared try it