Audi 100 2.5 TDi (C3)

[Autobahnschleicher]

Found something interesting recently:

In 1989 Audi wanted to see how efficient they could get a car.
For this purpose they piched a not exactly small Audi 100 and the (then) new 2.5 TDi 5-cylinder engine. (1T, 265 Nm, 120 PS)
Now the combination of large engine and large car isn't exactly what we would call a good starting point for great fuel efficiency, yet they managed to get 1,76 L/100 km or about 134 mpg /US) with a guy from the TÜV sitting on the passenger seat.
They modified it a bit and drove very efficiently for 4818,4 km and 80,05 hours.
The gearbox has 20% longer than stock, the low rolling resistance tires where pumped up to 4 bar, and the car mostly cruised at 60 km/h and 1100 rpm.
A CD od 0.30 might not be great these days, but in 1982 it was great.

We rarely see efficency like that even today and here.

[LingLongRaceTeam]

You sure want to share the youtube link and the MDR-Interview some years ago of the retired engineer, saying that in that statement enough bogus was included.

We rarely see efficency like that even today and here.

Like the Mercedes W124, also Audi was setting standards in Aerodynamics in the 1980s, which are not so easy to surpass even today in the SUV-Age.
But.. if you would have an similar sized car with an up to date Inline 4, you would get a pretty similar performance under an comparable setting.
Mercedes W212, Mazda 6, Peugeot 508, Insigna B... 2.0 HDI/skyactiv, 1.6 HDI and if you want to get "as low as possible" do the same like audi did, remove the AC, everything non necessary in weight, Pirelli P1 Verde, Michelin Energy Saver in a thin dimension with maximum pressure.

And... no particle filter, and fuel not diluted with biodiesel. We just need a long clean road without traffic, legal to use at 37 mph..

[cRiPpLe_rOoStEr]

Quite interesting how that generation of the Audi 100 suited itself as a testbed for highly-efficient engines with an odd amount of cylinders, including the ill-fated 3-cyl 1.4L Elko Multifuel which resorted to a small oil cooler instead of an actual radiator.

[Autobahnschleicher]

Don't forget the Audi Duo with it's 2.3L 5-cylinder gasoiline engine and electric rear wheel drivetrain.
It was also an Audi 100 (C3)

[cRiPpLe_rOoStEr]

Originally Posted by Autobahnschleicher

Don't forget the Audi Duo

Of course this setup wouldn't be forgotten, even though it took a while for some e-AWD systems to become mainstream.

[me and my metro]

I was very happy with my 1982 Audi 5000 TD. It was an automatic car and got 25 mpg, my wife’s car. I put turbo gas 4 wheel disc brakes and the 5 hole wheels on it and ran the car for 200,000 plus thousand miles. The stick shift versions of this car got 40-45 mpg.

[Isaac Zachary]

I miss my 1984 VW Golf diesel (non-turbo) The odometer didn't work (it was it's third odometer that had stopped working too) and other than CV joints and door handles the car just wouldn't die. I remember on one trip that by Google Maps was over 600 miles I started with a full tank and filled up at the destination and couldn't get more than about 10.5 gallons into the tank. I've done the same trip in my Toyota hybrids and can't make it the whole way without filing up somewhere in between.

[LingLongRaceTeam]

Idk

VAG were good in Marketing, Audi´s Slogan in Germany is "the lead trough technology".
Well the lead in technology always seemed to have others, but with Audi took often the pole position in the race to the scrapyard.

This C3 was for one year available with that engine, but the consumption in reality just was about 6 liters. Not bad, but not realy different then other engines.

And the first passenger car with direct injection Diesel came years before from Fiat, an 2.0 inline 4 in the Croma which was used till they switched to common rail in 1997, while VW/Audi continued to produce their pump-nozzle injection for ages, and refused to do necessary updates. While the french cars all had particle filters for years, VW just started experimenting in their customers cars in about 2005.. while talking about it since end of the 1980s.

In the end this were the reasons for their Diesel Emission theater, they just couldnt catch up with the competition anymore.

[cRiPpLe_rOoStEr]

Originally Posted by LingLongRaceTeam

Audi´s Slogan in Germany is "the lead trough technology".

I remember when "vorsprung durch technik" was used as a slogan by Audi, even in countries where German is not an official language such as Brazil

And the first passenger car with direct injection Diesel came years before from Fiat, an 2.0 inline 4 in the Croma which was used till they switched to common rail in 1997, while VW/Audi continued to produce their pump-nozzle injection for ages, and refused to do necessary updates. While the french cars all had particle filters for years, VW just started experimenting in their customers cars in about 2005.. while talking about it since end of the 1980s.

Took me a while to figure out the Germans who told me Peugeot Diesel engines were better than Volkswagen ones weren't joking.

[Autobahnschleicher]

Pumpe-Düse did have an edge on common rail in therms of injection pressure back then.
However these days common-rail allows for even higher injection pressures.
The interesting part is that IFA of all companies pioneered electronicly controlled common rail injection in a commercial truck in the 1980s.
On the other hand, they also pioneered using explosives to make rear axles out of steel beams...