Hi all previously put post up regarding thermostat and poor mpg, changed the thermostat, sensor and chod. I have filled the tank up and still haven't noticed much better fuel consumption. 160 miles for half a tank. My journey consists of 85% motorway driving. I understand I didn't buy the coupe for fantastic mpg. Just wondering what people's thoughts are, and suggestions. Just to add thermostat working fine

Heavy right foot, flat tyres, in need of a service? Loads of options if there is something wrong, but Tbh 320 from a tank isn't that bad.

You need to work out your mpg to know exactly.

The car has been recently serviced, haven't checked tyre pressures recently. Would running higher boost make any difference. Not sure what its running at??

It could if you always use it and/or the car isn't set up for it.

The quickest thing you can do is get the tyre pressures spot on then have a look at your spark plugs. If you have over fueling, as I think you're suggesting, they would be black on the ends. A nice tan/chocolate colour indicates a good fuel air mix.

Work out your mpg based on a few good tanks of fuel and I suspect you'll come out around the 30 mpg mark.

Cheers szkom will check tyre pressures and plugs ASAP but if your saying 320 is not too bad then as I said didn't buy it for mpg

I can get an easy 400 miles from a tank driving at a decent pace over my twisty A road commute. I am doing 70 miles a day though. If it were motorway miles I'd be disappointed with less than 430 so I think something needs addressing somewhere.

Saying that, although I drive at a quick pace, I am very smooth.

Fill the tank, set the odo, run it down to about a quarter full, fill it up again, check the odo, check the litres required to refill.

miles divided by litres multiplied by 4.536 gives you mpg. Simples (eeek).

On a run I can get 40mpg no problem; around town and stop/start 25. Average is around 32 - not bad for the power and style. Just depends whether you point and squirt, or drive conservatively, using the power when needed...

Can we presume you have a 20vt ? If so you are having fuel consuption problems at 85% motorway driving.
The best thing i did was have a custom Flea map.
It will make your coupe breath better and enable better consumption.

As Tim says - if you're just measuring mileage by where the fuel gauge is you're basically guessing. Brim it, drive normally, brim it again - ideally from well below half - and then do the sums. Best to repeat a couple of times to see if it's constant.

Then see what you get in miles per litre or miles per gallon.

Is there many performance petrol engines currently in production to see over 25mpg reguarly?

Better than 25MPG...

Almost all the Lotus's are over 30mpg,
Porsche Boxter 30mpg,
VW Scirocco 2.0 TSI 265PS DSG 35mpg

Plenty more.. but it's all down to how you drive them.

I've argued for years that any car, irrespective of engine size, which cannot maintain 30mpg or better at constant 70mph cruise is *broken*.

BMW 330Ci M sport 33.7mpg

Well I'm from the other end of the scale - 80% my driving mainly consists of a short 5 mile trip to work & town/urban driving.

(not good I know, but it's my only form of transport at the mo!)

mine has been mapped & is not highly modified, driving it steady, with occasional boost I get round 26 mpg, with an 'average' of 28.12 which for urban/town driving, which I think is very good.

Try the Japanese spec Mitsubishi Evo or Subaru Imperza, massive turbo, super close ratio box, you will struggle to get 25mpg even on the highway!

Don't care if it's designed that way; it's been designed broken. It takes pretty much the same *power* to move a vehicle at a constant speed, within a fairly wide range. Smaller cars a little less; heavy cars a little more; more aerodynamic cars a little less and so on.

The amount of petrol that must be burned to generate that power - a fraction of what the engine is capable of - is broadly comparable in all engines until you get to sizes where the pumping losses become significant. Equally, gearing losses and friction losses through the tyres in particular can be significant.

But those losses occur more with bigger heavier cars with larger engines: I contend therefore that designing a car to that specification is broken.

As an aside: a turbo engine is generally more efficient than a normally aspirated simply because of the lower cylinder pressures; the pumping losses are less. Equally, because the engine generates more torque at lower revs, there is less friction loss both in the moving parts of the engine and in the (higher final drive ratio) gearbox. Which is why a 20vt will cruise at 40mpg and mine is lucky to get 35.

My E39 M5 will do 30 point something at a steady 70 on the motorway (until the trauma of being passed by old grannies in 1.0 Polos gets too much :D).
Sensible normal use on rural A roads sees about 25mpg overall.

Hi all worked out mpg yesterday and getting 30.95. Worked out half my journey to work is up and down the gears through town, just wondering people's thoughts are

Sounds pretty good, bearing in mind a damned quick car from the previous century

My thoughts are that your fuel consumption isn't excessive and sounds ok, so get out, fill it up and enjoy it

Yes, that doesn't sound too much for a 20vt.

The best range that I ever got from my 16v was c. 500 miles on one thank of gas. ONCE, at country road speeds... That averages about 36.6 miles/gallon, I think.

Now, that's a different story. It's running on LPG.

Meh! I have given up on mpg on the alfa.... 30 is pretty good as an avergae for a 20vt from what i recall.