Passat TDi 130 sport estate - disappointing mpg

[randall977]

I know what the official figures are but what should my average mpg be? I'm getting about 42mpg when I drive carefully and 38mpg the rest of the time. I can't remember the engine code but it's a late 01 130 TDi with 55K (well looked after). I had a 99 115 PD TDi Sport saloon which normally did 50mpg and more - why is this newer one so bad - is it drag? Thanks

[Huweth]

I have the same car. My average is in the lower 40's. I can get mid-50's on the motorway at 70mph.
I don't drive fast or slow, but I am always learning new tricks to improve the MPG.
The reason you are getting lower MPG than expected could be many things.
1. The PD engine that you have uses a little more fuel than the VE engine in your old car. MPG shouldn't be that much lower though, so...
2. You are driving a little harder?
3. You have a MAF that is starting to fail?
4. The intake manifold is getting clogged?
5. You are driving on different roads/with more traffic?
6. The tyres are at the wrong pressure (underinflated)?
7. The Trip computer is reading low (they're not known for accuracy!)
8. Several other reasons.

The first thing to do would be to watch the instant MPG readout as you drive and learn to adapt your driving to the car and the situations. I've been able to improve MPG by up to 10 by learning to drive the car better.
If that dones't make a bigish change, then you should start to explore the other possibilities. Try calculating your actual MPG with each fill-up so that you can see how accurate the computer is.

Good luck, and welcome to the forums!

[randall977]

There are some good suggestions there, thankyou. I will work through them and see if I can improve things. I just fitted a K&N filter - was that a waste of time? Saves having to chnage it though.

[Sam]

In answer to your question "Is it drag?" it could well be.

The Passat Saloon has one of the lowest coefficients of drag

Styling-wise, the Passat introduced a new design language, first seen on the Concept 1 concept car, for the latest generation of Volkswagens and this was evident with the Mark IV Golf, Bora and Mark IV Polo. The curvy lines, heavily raked windscreens, and smooth underpinnings helped give the B5 Passat an incredibly low coefficient of drag, rated at 0.27 (sedan model). The drag coefficient is lower than many sports cars, and even bests the latest design of the C6 Chevrolet Corvette, rated at 0.29. The Passat also influenced the styling of many yet-to-be-launched rivals, including modern releases from Ford, such as the 500, and Fusion.

One would presume the Estate version has a higher Cd.

[Lex Luthor]

There are some good suggestions there, thankyou. I will work through them and see if I can improve things. I just fitted a K&N filter - was that a waste of time? Saves having to chnage it though.

Reports are that oil from the K&N can damage the MAF, and they are poor filters anyway, and a diesel will not benefit from this kind of "upgrade" anyway.

[randall977]

So as regards the K&N filter - a bad move - should I take it out?

[Lex Luthor]

So as regards the K&N filter - a bad move - should I take it out?

The concensus of opinion on the various forums is that they are a liability and unnecessary. The regular paper one costs £6 or so and lasts two years.