50mpg from 1.4TDI90 on long trip - normal?

That's good, but not doubting, ;-) does it work out the same if you use a calculator, just curious, as I have no DIS and only work it out on full to empty, if you get my drift.

What sort of speed do you drive at on the motorway?

bba
 
The DIS works quite well and things like the remaining range display adjust fairly well and fairly dynamically.
For example I took a 180km trip along decent roads rather than town driving and ended up with more range remaining as I arrived than when I left.
The average l/km shown on the DIS when the car is started is pretty close to my figures calculated in excel.
If you go for a long drive after months of town driving it can be best to reset the DIS before you start to get the average closer to the trip average.
 
My DIS all-time MPG average is showing 62.1MPG vs. my Fuelly running average of 63.3MPG and a lifetime average of 61.7MPG. I'd say that's pretty close! I've been logging fuel-ups on Fuelly for longer than I've had DIS, and in fact the DIS got re-set back in April when the RNS-E went in, so the DIS should be a close match for the Fuelly "running average"...
 
OK, thanks everyone.

Sounds like I need to change the Thermostat and Temp Sender as a trial - I'll get working on that.
Also intrigued by RABs suggestion of checking the VNT mechanism - thanks for that, I'll try to find that lever..

I will report back to the thread with results, but it probably won't be for a couple of weeks before I change the parts AND give it a chance to have a few long runs.

Thanks all.
 
Is there a certain mileage that this needs to be done at, or just when there is a difference in fuel economy etc?
 
... Also intrigued by RABs suggestion of checking the VNT mechanism - thanks for that, I'll try to find that lever.. ...

A good old Italian tune can be helpful if the turbo is not too sooted-up. Wait until the coolant is fully up to temperature, then drop a gear & floor it up a long hill. You want to be getting near to the red line at full throttle. If you see black smoke out of the rear-view mirror then you have dislodged some of the soot. Repeat on the next hill etc until you see no black smoke.

I used to do this every 1000 miles or so on my old Passat (which had a VNT) when I was hypermiling it.

(If the vanes are caked solid with soot and can't move at all any more, then this doesn't help).
 
The level is actually a connecting rod that connects the VNT mechanism to the vacuum cylinder (at the very rear of the turbo). I suspect that manually exercising the connecting rod on a frequent basis will be just as effective as an Italian tune-up, but if it's coked up, there's no alternative to taking it apart and cleaning it. I've just done my wife's Lupo 3L, so will shortly do a 'how to'.

Don't be tempted to use something that you can buy, which you spray into the exhaust side of the turbo, after disconnecting the exhaust. The seals on a turbo don't function when it is stationary; oven cleaner (which is what it is) and bearings are not a good combination! I use oven cleaner after separating the turbo! It's not a job for somebody who likes to keep their hands clean though!

RAB
 
OK, thanks everyone.

Sounds like I need to change the Thermostat and Temp Sender as a trial - I'll get working on that.
Also intrigued by RABs suggestion of checking the VNT mechanism - thanks for that, I'll try to find that lever..

I will report back to the thread with results, but it probably won't be for a couple of weeks before I change the parts AND give it a chance to have a few long runs.

Thanks all.

I've just replaced my thermostat and the car today took 3 miles to get to 90C. Beauty. It used to take around 10 miles, and up to 15 when it was the depths of winter.....

J
 
Hooray for that Jason! How many stats and temp senders have you put in your A2 now?

I've just replaced my thermostat and the car today took 3 miles to get to 90C. Beauty. It used to take around 10 miles, and up to 15 when it was the depths of winter.....

J
 
Turn your a/c off, switch to Econ unless it's unbearably hot. Coast where safe to, and use predictive driving; don't accelerate when you've a queue or bend ahead and you know you'll have to brake etc.

I generally don't go above 2200 rpm, and that's where all the power is anyway.

I'm a speed freak, but now I'm and mpg freak!

I love a/c too. In some big engined cars I've found it makes little difference to MPG, in the 1.4TDi I've found it does indeed make a difference, even at temperature and at speed.

I treat the MPG as a constant challenge, and only build speed when I know I won't waste it, keep it once I have it, so pee off those behind me and then pass them on the bends kind of driving. It's a challenge.

I don't drive over 60mph on the M'way or A roads either.
 
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The level is actually a connecting rod that connects the VNT mechanism to the vacuum cylinder (at the very rear of the turbo). I suspect that manually exercising the connecting rod on a frequent basis will be just as effective as an Italian tune-up, but if it's coked up, there's no alternative to taking it apart and cleaning it. I've just done my wife's Lupo 3L, so will shortly do a 'how to'.

RAB

Any update on the "How to" please RAB?

Andrew
 
Tom, is there already on the forum a "How to ..." on driving a TDI for fuel economy?

Thanks, Andrew

There's a VW article floating about somewhere, I can squeeze 60 mpg out of town driving, and over 60mpg at roughly 70mph on M'ways. More easily if you stick closer to 50mph.

I'll try and find the article
 
MikeMars has it linked into his forum signature I believe

Just below :)


But my personal top tips are these:
* Keep top speed sensible (ideally <=60mph)
* Avoid short journeys because the engine does not have time to heat up ... dropping the sprogs off at school or quickly nipping 1/2 mile to the shop has a ruinous effect on your tank mpg. Make them walk instead, it's good for them
* Make sure your tyre pressures are always at or above the recommended. They should never drop below
* Remove roof racks / bike racks when not in use
* Do not idle to warm up in winter
 
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