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

[GreenTDI]

I'm going to start my modest eco-modding adventure here. My intention is not to go extreme right away. I've got a little family and the victim is our family car. The interior remains untouched. I'm also health care worker and have to make house calls from time to time, or trips between hospitals. The exterior must remain 'presentable'.
So, I'm going to make small, but efficient adjustments. But craziness comes with age so who knows what the future holds!

The car: a Czech estate version of a VW Polo equipped with the common rail 3-cilinder 1.2 TDI, producing 75 kicking horses and a street shredding 140 ft lb of torque. It feels like there is more to it but TDI's are known to have more power than specified. However, a small diesel engine requires a special way of driving ...

What have I done so far:

1. Short distances = bicycle
Already cycling 3000 miles/year, especially short distances. Those are dreadful for a hypermiler, and it's just not done for a diesel!

2. The base is already pretty good.
Hitting regularly 59 MPG in summer and a total average of 55 MPG is not bad. That's with normal, but gentle driving. The car has some stock aero features like a closed undertray and rear diffuser.

3. Grill block
Or winter cover. I only closed the biggest opening. The upper grill is still open, but already half closed from the inside. The bottom opening above the spoiler is the inlet of the intercooler, as seen in the picture.

For those interested, there are stock covers for most EU cars/vans on this website https://e-heko.com/en_GB/c/Winter-covers/1323.

4. Wiper delete
The wipers are not hidden under the hood and probably create some drag. The wiper seems to be even higher on the passenger side, so I removed that wiper arm completely. Look at page 3 for this mod.

5. Reducing weight
Removed all unnecessary weight from the car: such as child seats, rear seats, spare wheel, tools, all kind of family clutter. In total a reduction of 165 lbs. See and read more at page 4 & 12.

6. Lightweight LLR rim/tire combination
I scored some old forged aluminum Audi rims, weighing just 12 lbs a piece. The new tires are Dunlop Sport Fastresponse, a LLR tire with great handling capabilities in wet conditions. Tire size is now 175/65/15, being 11% narrower, 3% taller and 20% lighter than my previous wheels. Lowering unsprung weight is critical in improving car handling and fuel economy. Page 7 for more information and pic's.

7. Camper conversion
I came up with the idea to turn the car into a small RV for short trips. Did this by recycling and using some leftover materials to keep costs down. The result is a simple, but comfortable sleeping place for 2 people. See page 11 for this 'mod'.

8. Lowering springs
The car has been lowered by 4 cm or ~1.5 inch with H&R lowering springs. It improves handling and lowers drag - less air going under the car, better filling of the wheels wells and less frontal area of the tires. See page 13.

9. ECU 'chiptuning'
Or maximizing engine efficiency. I wasn't looking for maximum power, or a spiky curve, but higher torque and smoother power delivery - a flat curve. The software was specially written for my car and according to my wishes. The result is more than 230 Nm (170 lb-ft) between 2100 and 2800 rpm and 100 hp at just 3100 rpm. More details on page 15.


GOALS
It would be nice to achieve an average of 70 MPG in normal driving conditions, with the possibility of 90 MPG on long (highway) distances. It should be possible knowing that my very best mileage ever - before this adventure - was 71 MPG with the standard car at reasonable highway speeds (~60 mph)
In addition, I would also like to reach a top speed of 200 km/h or 125 mph with this small three-cylinder. That extra horsepower and the aerodynamic adjustments, should make it possible.

The following fact makes me optimistic ...

How the 'famous' hypermiler Gerhard Plattner set a record of 107 MPG during 1246 miles in a stock Skoda Fabia Greenline 1.2 TDI: https://www.carscoops.com/2011/05/ge...-again-drives/

I will certainly not achieve such numbers ... Or shall I get close? I'll keep you ecomodders up to date. Please give suggestions oh wonderful community!

[oil pan 4]

Bigger turbo if you drive long distance on a motorway or autobahn, cold air intake for when air temperature is above about -5C, use bigger intake pipes with smooth bends, install an intercooler if you don't have one, use a block heater.

[GreenTDI]

Originally Posted by oil pan 4

Bigger turbo if you drive long distance on a motorway or autobahn, cold air intake for when air temperature is above about -5C, use bigger intake pipes with smooth bends, install an intercooler if you don't have one, use a block heater.

Bigger turbo: is it really that effective? I'm afraid it may increase consumption. The standard turbo has a variable geometry so the blades are adjusted depending on the engine load to deliver the best flow at every engine speed.

Intercooler is also standard and has it's own inlet, as seen on the picture of the front.

[oil pan 4]

If it's got a variable geometry turbo stay with that.
How about that turbo piping, cold air or rammed air intake?

[GreenTDI]

Originally Posted by oil pan 4

How about that turbo piping, cold air or rammed air intake?

Those are things to look at, indeed. Let's see how the car is doing with minor changes first. A sportfilter could have more effect after chip tuning, when more air is required.
The air intake is already in front of the engine compartment, so it's getting cool air directly from the upper grill.

[GreenTDI]

I set the new standard today to monitor progress before and after some of the improvements.
So finally refueled after 43 days in lockdown ... and got an average of 55,7 MPG. That's totally standard. With inefficient winter tires and some additional weight in the car like the spare wheel and material, 2 child seats and other family clutter. Quietly driven but not slow.

[California98Civic]

If you do the rim/tire mods, try for improvements in as many of these categories as possible simultaneously: overall tire/rim weight reduction, aero cover or vent blocking, narrower and taller tire/rim combination, and Low Rolling Resistance tires. It can be done. Takes a lot of research. Checkout our wheel discs showcase thread for ideas: https://ecomodder.com/forum/showthre...scs-37690.html

[COcyclist]

I do not know what the laws are where you are but the side mirrors are one area to address. It reduces frontal area and removes an obstacle from a very messy region of airflow.

Some Ecomodders have replaced the mirrors with cameras and screens. I have removed the passenger side mirror completely and I fold in the driver’s mirror on the highway. It can be quickly unfolded for city traffic. I have tuft tested it and the airflow is better with the mirror folded. I use small convex mirrors in their place. The passenger side one is inside the car. The driver side mirror is glued to the glass of the folded mirror at the correct angle with a small aluminum bracket.

[GreenTDI]

Originally Posted by California98Civic

If you do the rim/tire mods, try for improvements in as many of these categories as possible simultaneously: overall tire/rim weight reduction, aero cover or vent blocking, narrower and taller tire/rim combination, and Low Rolling Resistance tires. It can be done. Takes a lot of research. Checkout our wheel discs showcase thread for ideas: https://ecomodder.com/forum/showthre...scs-37690.html

That's a good idea! Nice wheel thread btw, very inspiring.

Originally Posted by COcyclist

I do not know what the laws are where you are but the side mirrors are one area to address. It reduces frontal area and removes an obstacle from a very messy region of airflow.

Yes, it is mandatory if the car was supplied with them. But I can replace them by smaller ones or fold them in on longer journeys.

I'm thinking about removing the passenger windshield wiper. Looking at the regulations, I see that it's allowed. Hurray!

[GreenTDI]

I found an astonishing article about Gerhard Plattner who drove a stock Fabia Greenline to nearly 107 MPG on a 1246 mile trip. Assuming this is real, what could be achieved with aerodynamic and weight-reductive changes to this car, AKA ecomodding And how does that man drive? That's perhaps the biggest question.

https://www.carscoops.com/2011/05/ge...-again-drives/