fuel saving tips

[zakkaz]

Further to my gas guzzling a4 2.0tdi avant 170 '57 94k. New- oil/filter, fuel filter, air filter, Maf sensor, very light foot, 65/70mph and only doing 36mpg motorway driving only. Are there any other things I could try to get better fuel consumption. Has anyone tried the k&n air filter? would it be worth the £50 cost? I have been told about magnets on the fuel pipes and a high performance fuel filter or is this all hot air?

[rojdag]

magnets are absolute rubbish and dont work, generally with stuff like that if it sounds too good to be true it is. High performance filter or not will not give you better MPG. Your figures sound very low though my petrol does that on the motorway

Try emptying your boot of stuff if there is any and make sure your tyres are fully inflated.

[keemaklan]

I like to run well above the recommended tyre pressures stated by Audi, but only slightly below the maximum TYRE recommended pressure. For example, Audi state 42 PSI i think at the front and rear. My tyres state a maximum of 50-something psi in the tyres, so i put in around 46-48 PSI from cold. The tyres maximum is still well under how much the tyre could really put up with, due to health and safety nonsense so nothing to worry about in all honesty.

Please dont slate me for this, i know the dangers of running high pressures!

Change gear before 2,500 rpm, accelerate not too slow but not fast either. Engine break as much as possible by just easing off the 'go fast' pedal. NEVER LABOUR THE ENGINE!

36 mpg is disgraceful! No 170 should get anything like that on a eco run. Have you ran any injector cleaner through it etc? Dont bother with the K&N filter, barely any difference, especially not in MPG anyway!

[darich]

do you have a roof rack?
checked your brakes for binding?
checked hand brake for full release?
(admittedly, brakes issues would cause heat and burning smell but worth checking)
had all tracking and alignment checked?

Tyre pressures are obviously too high but wouldn't cause low fuel consumption. don't you wear the tyres very quickly in the centre of the tread?

[zakkaz]

I had the x2 new front tyres fitted at kwik fit a couple of weeks ago so you would presume they know the correct pressure, I have just checked them and they are on 30psi. The manual says 235/40/18 should be on 35psi so I will see if that helps.

[James05]

I had the x2 new front tyres fitted at kwik fit a couple of weeks ago so you would presume they know the correct pressure, I have just checked them and they are on 30psi. The manual says 235/40/18 should be on 35psi so I will see if that helps.

You might find your steering feels better as well once you get them up to 35psi....
Never presume anything with KwikFit...did they use a torque wrench to do your wheel bolts up or did they just rattle them up with the air gun ?

Don't bother with the K&N filter, total waste of time and money if my experience with my previous car was anything to go by.

Something else to consider - what brand of diesel do you use ? Now I *know* it all comes from the same tap at the refinery..etc etc, but in my experience with my previous car ( a diesel focus) it would run fine on most diesel, but was terrible on Tesco diesel. It would smoke heavily and sounded like someone was rattling a bag of spanners under the bonnet and the tank by tank mpg dropped.
Obviously there will be people out there with differing views to me, but maybe thats something to consider ? run a couple of tanks from one brand and see how it goes ?

James

[allanmb]

NEVER LABOUR THE ENGINE! !

Why? (In the context of fuel economy)?

[zakkaz]

Thanks James, the next time I fill up I will try BP, I have been using sainsburys but I suspect that is no different from Tesco. As for kwikfit your right, when I went to collect the car one of the bolt caps was missing, when I pointed this out I was told "it was not there when I brought the car in". No way of proving it. it probably fell down a grid and he could not be bothered picking it up. I have also had the car remapped and it also has a new turbo, whats annoying is its doing 30/32mpg combined but 36mpg motorway only, I just hope the correct pressures bump it up.

[mkc]

Ive been getting 48mpg out of a 2.0 Petrol B6. Sat doing 60 drafting behind HGVs on the M4. I started off this morning with 280miles left in the tank, drove for 40 miles and now the Computer says 310 miles left! Of course it cuold be faulty but I reset before each trip. Im very happy as its twice as good as my B8 1.8T 160......

[keemaklan]

Why? (In the context of fuel economy)?

Tell me if im wrong, but as far as labouring the engine in relation to mpg is concerned, if you labour the engine you put major stress on the engine flywheel to keep the engine ''alive''. Whilst the flywheel keeps the crankshaft turning, it will gradually loose power and rpm unless on a normal straight road but even so, the driver will just put their foot down rather than downshift. Putting your foot down in a labouring car rather than downshifting tells the EDCU to inject a lot more fuel than downshifting and using higher RPMS would usually use. This is why a labouring car (diesel) usually smokes a LOT, because of the unburnt fuel coming out the exhaust. It is cheaper to downshift, rev the nuts of it than to labour the engine.

So basically, your on your bike, cycling up a slight incline in 5th gear. Your legs are starting to burn and your feeling the pain in your legs. Rather than change gear on your cycle and then just peddle a little faster, you decide to use your hands to push down on your legs to get up the hill. Using your hands is like flooding the combustion chamber with lots and lots more fuel to keep your bicycle wheels moving. Hope i explained this well enough.

This is not to mention the damage labouring does to bearings, clutch/flywheel and bottom end bearings etc with very low oil pressures due to low rpm. This is particularly important with PD engines.

I believe this to be correct!