Realistic max MPG for a 1390cc Volkswagen Polo

[AndrzejM]

Here is a diagram of all pulleys of your engine:


Where:
1. Main pulley mounted on the crankshaft
2. Tensioner
3. Alternator
4. A/C
5. Power steering

That's what I've found

[Mustang Dave]

Originally Posted by Goldenstate

Do not be afraid to try synthetic lubricants in the transmission and rear end. These two areas can make a nice dent into better mileage.

Synthetic lube in the engine can also make a noticeable difference in fuel economy. Last November, I switched my Mustang from Motorcraft 5W-30 semi-synthetic blend to Mobil 1 0W-30 full synthetic motor oil. I made it through this past Winter without dropping below 30 MPG. That's never happened before.

[Bataleon]

Originally Posted by AndrzejM

Here is a diagram of all pulleys of your engine:


Where:
1. Main pulley mounted on the crankshaft
2. Tensioner
3. Alternator
4. A/C
5. Power steering

That's what I've found

Thanks for the info. I looked under the hood again this morning and there are definitely only four pulleys. As depicted in your diagram, 1 is definitely the main crankshaft, 2. is the tensioner, 3. is the alternator, 4. is the A/C, while 5. is missing. Perhaps like renault_megane_dci said, the power steering is provided via a electric motor or through the steering column itself. The exact model of my Polo is an 9n3 (mk4), but I haven't managed to find a service/workshop manual for it.

Originally Posted by Mustang Dave

Synthetic lube in the engine can also make a noticeable difference in fuel economy. Last November, I switched my Mustang from Motorcraft 5W-30 semi-synthetic blend to Mobil 1 0W-30 full synthetic motor oil. I made it through this past Winter without dropping below 30 MPG. That's never happened before.

That's seriously impressive. Your average of 31.4 mpg (US) with a 4L Mustang puts my Polo's fuel economy to shame. Do you have a kill switch installed?

[Mustang Dave]

Originally Posted by Bataleon

That's seriously impressive. Your average of 31.4 mpg (US) with a 4L Mustang puts my Polo's fuel economy to shame. Do you have a kill switch installed?

Thanks!
No kill switch - I don't Engine-off coast. Nor do I "Drive With Load" or "pulse and glide". I "Drive Without Brakes" and make extensive use of cruise control and DFCO. I know I'm doing almost everything "wrong" according to many members on this site, but my numbers aren't all that bad.

[Bataleon]

Considering you drive a 4L V6 Mustang, your figures are excellent! What do you use to measure your fuel economy?

[AndrzejM]

Originally Posted by Bataleon

Thanks for the info. I looked under the hood again this morning and there are definitely only four pulleys. As depicted in your diagram, 1 is definitely the main crankshaft, 2. is the tensioner, 3. is the alternator, 4. is the A/C, while 5. is missing. Perhaps like renault_megane_dci said, the power steering is provided via a electric motor or through the steering column itself. The exact model of my Polo is an 9n3 (mk4), but I haven't managed to find a service/workshop manual for it.

I've checked and you have an electric pump running your power steering system. That's why one pulley is "missing"

[Mustang Dave]

Originally Posted by Bataleon

Considering you drive a 4L V6 Mustang, your figures are excellent! What do you use to measure your fuel economy?

Thanks.
I use an Ultra Gauge EM to monitor my instantaneous fuel economy, and the factory "AVERAGE MPG" display to see how I'm doing since the last fill. My calibrated Ultra Gauge is very close, but the factory gauge is optimistic by around 1 MPG. The only numbers that really matter are the (correct) odometer miles and the gallons pumped into the tank.
I have the fuel log numbers to show what I've accomplished.

[Bataleon]

Originally Posted by AndrzejM

I've checked and you have an electric pump running your power steering system. That's why one pulley is "missing"

Nice find, thanks. If I wanted to disconnect the A/C pulley, would it be possible to use a belt which only connects 1 (main pulley) with 3? (the alternator)

Originally Posted by Mustang Dave

Thanks.
I use an Ultra Gauge EM to monitor my instantaneous fuel economy, and the factory "AVERAGE MPG" display to see how I'm doing since the last fill. My calibrated Ultra Gauge is very close, but the factory gauge is optimistic by around 1 MPG. The only numbers that really matter are the (correct) odometer miles and the gallons pumped into the tank.
I have the fuel log numbers to show what I've accomplished.

Awesomely detailed fuel log. I wish I could do the same but I very seldom fill my tank right to the brim.

[AndrzejM]

Originally Posted by Bataleon

Nice find, thanks. If I wanted to disconnect the A/C pulley, would it be possible to use a belt which only connects 1 (main pulley) with 3? (the alternator)

That won't be as easy as changing the belt only. Your alternator is placed in a place, that you can;t run the serpentine belt from the main pulley to alt and use a tensioner. That is required for the proper belt tension.

My Polo has alternator mounted on a spring and it works as a tensioner for the serpentine belt. But I think that can be done...

[Bataleon]

Originally Posted by AndrzejM

That won't be as easy as changing the belt only. Your alternator is placed in a place, that you can;t run the serpentine belt from the main pulley to alt and use a tensioner. That is required for the proper belt tension.

My Polo has alternator mounted on a spring and it works as a tensioner for the serpentine belt. But I think that can be done...

True. That's a pity! What if I removed the serpentine belt completely and replaced the battery with a deep cycle battery?

I jacked up my car during lunch and tried spinning the wheels to see if there was any brake drag. The two front wheels are very stiff and only travel about 1/5 of a turn, even with a good push (the car gear was in neutral).

The back wheels are slightly better, although the back left wheel spins freely and then suddenly slows down, almost as if the brake pad is rubbing at a certain point.

How freely should the front and back wheels spin? Is brake drag easy to adjust?