My Green Skoda Fabia (VW Polo) R3 CRTDI - finally smashed the 3L / 80MPG barrier

[GreenTDI]

Originally Posted by California98Civic

You can get tire weights at tirerack.com

Thanks!
It is noticeable that narrow & taller tires are quite expensive. Probably because there is little demand for such sizes and therefore little production. A 165/70 or 175/65 tire is pretty rare for a 15" wheel.
185/60 or even 185/65 seems to be the better choice.

Today unexpectedly achieved a good consumption. As Belgium is slowly coming out of lockdown, it was very busy on the road. Did some city driving, traffic jams everywhere so after that I tried country roads. The result was a satisfying 67.2 MPG! The warm weather will also have to do with it.
I try not to get overconfident but I am very hopeful for this summer.

[GreenTDI]

Yesterday I experienced something strange with the TDI, something that has never happened before.

While driving, somewhere in the middle of the ride - with a warm engine -
I noticed that there was no power at all while accelerating, even though I pushed the pedal to the floor after a while. It took a awful long time before the car realized that I asked for power (aprox. 10 seconds) before the boost came.

I must add that I have never driven so economically before for such a long time, maybe this is normal and recognizable to some of you? Is there is a program that switches off the turbo during long periods of quiet driving to save fuel? Because it seemed like that, consumption was also incredibly low. I'm not sure. There were no fault lights or notifications on the dashboard. It's a turbo with variable geometry.

[Piotrsko]

In mine, with the Cali software, that means you are in a special regeneration cycle because soot levels are too high. Torque or vagdpf would verify. The solution is to take it out on the highway for a high speed periodic full throttle "tune up" of about 100 km.

[ptitviet]

Hello, so new results on my side :

Originally Posted by ptitviet

Looking forward to it!

So first long trip in a long time (due to lock-down). Sion to Bourg en Bresse in France. About 300km each way, downhill and uphill.

3.6l/100km one way and 4.1l/100 back, so 3.8l/100km in average (61-62mpg US). Not bad considering GPS speed was 100km/h in Switzerland, 110 in France (105 and 115 tacho). The wind was globally not helping, most of time against me...

[ptitviet]

Regarding your problem : did you get an EML light? Best thing would be to look then to the fault codes. Otherwise, maybe you turbo is a bit dirty and variable geometry was getting a bit stuck?

My advise would be, when you need to accelerate to do it strongly with middle high revs (2-3k rpm). If you do not have to brake after, it is also very fuel efficient and this will help your turbo to get often enough in the right geometry.

I don't have this problem, but I do have enough of uphills to make my turbo work a lot

[GreenTDI]

Originally Posted by Piotrsko

The solution is to take it out on the highway for a high speed periodic full throttle "tune up" of about 100 km.

Regeneration happened today, noticeable by the higher idle speed and a burning smell. So he definitely needed it.
Full throttle is not recquired for starting this cycle because it wil only happen in 4th and 5th gear between 1800 and 2500 rpm, as stated in the manual.

Originally Posted by ptitviet

Regarding your problem : did you get an EML light? Best thing would be to look then to the fault codes. Otherwise, maybe you turbo is a bit dirty and variable geometry was getting a bit stuck?

I had no lights or anything. It just drove like there was no turbo for a while. It will have a service in two weeks, then we'll see if there are some error codes.

But I put the TDI on work today, revved it up to 4000 rpm a couple of times. In July I will let the engine stretch his legs on the Autobahn It helps for a better MPG afterwards.

[GreenTDI]

Originally Posted by ptitviet

Hello, so new results on my side :

Wow great result! Especially considering the speed. Thanks for sharing. It will get better and better.

I did a 110 mile trip today and got an astonishing 74 MPG. That's including particulate filter regeneration, revving the engine up to 4000 rpm a couple of times and a constant speed of 62 MPH on highways.

Result: 73,9 MPG
Distance: 108 miles
Average speed: 52 MPH
Direction: back and forth
Weather: dry, 20°C, 18 MPH wind NNE
70% highway at 62 MPH, 30% country roads



Fun fact: did 500 miles since last refueling, there is still 1/3 in the tank and still have a range of 220 miles.

[California98Civic]

I'm glad you found a solution to the turbo problem. It does not sound like you need to do 100km/hr from what you wrote. In 5th gear and 1800 RPMs how fast would be be going? At 2000 rpms? Your FE would be higher than at 100km/hr, surely, which is good for your 90 mpg goals, no?

[GreenTDI]

Originally Posted by California98Civic

I'm glad you found a solution to the turbo problem. It does not sound like you need to do 100km/hr from what you wrote. In 5th gear and 1800 RPMs how fast would be be going? At 2000 rpms? Your FE would be higher than at 100km/hr, surely, which is good for your 90 mpg goals, no?

You're trying to get me to raise my goals, aren't you?
Maintaining a slower speed will certainly give me an advantage. 100 km/h, for me it's rather a psychological limit to not get in the way of big trucks ...

Ratios in 5th gear:

2000 rpm = 105 km/h (66 mph)
1900 rpm = 100 km/h
1800 rpm = 95 km/h
1700 rpm = 90 km/h (56 mph)
1600 rpm = 85 km/h
1500 rpm = 80 km/h (50 mph)


From my experience I know that the green zone is the engine's "sweet spot". Higher and consumption increases exponentially. Lower, the load on the engine becomes too great.
If I take into account that the minimum engine speed is 1800 rpm for the regeneration cycle, 95 km/h of 59 mph should be better of course. It's not a huge difference with the speed I'm maintaining now. BUT if I can stay behind a lorry - they're limited between 52 and 59 MPH in Europe - that will increase my MPG even further.

[GreenTDI]

OK, I put it to the test. I had a big ride ahead of me and lowered the speed by ~3 mph - 59 MPH (95 km/h) instead of my usual 62 … From time to time I kept driving behind trucks. It was quite hilly because it mainly went through the Ardennes - known in the US for the toughest battle in the second world war. So I called the trip my Battle of the Bulge - a tribute.

Result: 78.4 MPG = 3.0l/100km, turning my car into a Lupo/A2 3L car
Distance: 144 miles
Average speed: 50 MPH
Direction: back and forth
Weather: dry, 22°C, 10 MPH wind NNE
90% highway at 59 MPH, 10% country roads



That's an instant improvement of 4,5 MPG. I think this is about the lowest consumption possible with my driving behavior. I've got some more mods to do first so we'll see.