Audi 100 2.5 TDi (C3)
 

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.

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.

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..

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.

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)

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

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.

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.

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. :D

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.

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 :D


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

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...

Maybe they couldn't catch up to the competition. But in the USA, they didn't have hardly, if any diesel car competition. If you wanted a diesel car you got a Volkswagen, or you paid a small fortune for some luxury brand, or you just didn't get a diesel car.

There were a lot of things I really liked about my ol' VW diesel. I wish there existed a car that offered the same experience nowadays.

@Isaac Zachary
Well, cars that loud, small and noisy you might find still in india.

But if you want to buy an newer decent real economic Diesel car in the US, its not VW its the Chevrolet Cruze 1.6.
Not the best reputation in the US for the gas versions, had some issues with warranty in the first model (Cracking coolant reservoir), but in general reliable and rugged.

A swiss hypermiler was (is?) holding an record with the same engine in a Opel (Buick Regal) 3,46Liter (67mpg) and 2111km with one fillup.

Ya, the Cruze had crossed my mind. It wasn't that ithe Golf was diesel, noisy or made thick black clouds of smoke that made me like the car. It was that the car had some 500,000 miles on it and no signs it was going to ever die. The car felt immortal, even after all those miles. I drove it 14 times down into Mexico and back with it's never failing me, ever. Well, except for one small thing that was kind of my fault and was an easy 15 minute fix.

That, and it was very economical to drive. Once I drove over 600 miles and could only get 10.5 gallons into the fuel tank. And that was without any ecomods or really trying to get good fuel mileage. The car had only cost me $600 to begin with.

Another thing I loved about it was the extreme weight bias. The front was way heavier than the rear making it drive like a tank through snow without the need for AWD. (Although at higher speeds it did understeer quite a bit.)

I guess the manual shifter and low power also made it fun for me (I know, I'm weird.)

The person I sold it to is thinking of getting rid of it and I'm wondering if I should go get it from him. I just don't know of any other cars that get some 50mpg, that feel like they can make 500k miles without needing so much as a sparkplug change and that feels fun to drive for someone who doesn't like to go fast.

its not weird, almost all our european ****box-hatchbacks are handling similar. ^^

I had an Seat Arosa (= VW Lupo) with an 1.7 non Turbo. 230.000 Miles in 4 Years. Cornered also pretty well, but had also its flaws. Parts were pretty expensive, every year a timing belt change, no A/C Available, and needed all the time new doorstraps.

The Non-Turbo engines were low mainteance compared to never ones, thats true. But off course they needed (and need) a little more then glow plugs.
Timing belt, injectors, and after a certain mileage the distributor injection pump needs some work.

I wouldnt go such long distances in these cars today, they were built to keep to price low, but such a lack of comfort wasnt even back in the day necessary. On the other hand the Golf was the sucessor of the bug, so for the typical VW Driver this was already ScienceFiction.

Thanks for putting it into perspective. For long trips the car was rather uncomfortable. Still, the car seemed quite awesome for it's age.

What I liked about the Golf diesel was that it was easy to work on. I had a factory repair manual and could change everything myself. But the Toyota hybrids I have now are different. I want to change the brake fluid on them, but can't without a $600 tool and a $2000/year subscription. I even took the Avalon to the dealer (200 miles away) and asked if they would do it. They took the car, changed the oil instead and "forgot" to change brake fluid.

What I liked about the Golf is that it still didn't even burn oil, even with so many miles on it. I did have to change out a couple seals so it wouldn't leak, but that was about it. The Prius burns oil, about 2 quarts per oil change. And it has only 200,000 miles on it, less than half what the Golf had. And of course that has now fouled the catalytic converter. I'm looking at the possibility of having to change out the rings and pistons. And if the block is scratched, that would be the end of story for the Prius because the block can't be bored. Unlike the Golf, that if I ever did need to rebuild the engine I could bore the block and drop in some oversized pistons.

The Prius also is having hybrid battery problems, I had to change out a module because of a dead cell. I know this is a temporary fix, and will cost me potentially thousands to fix properly. My Golf never had a problem like that in the 7 years I owned it, and it was over 30 years old. The Prius I've only owned for one year, and it's only 15 years old. The Prius is also needing a wheel bearing, and the dash lights aren't working either now.

Long trips? I feel somewhat the other way around, I'd still take the Golf on a hundreds of miles trip, but not the Prius, even though it's much newer. Even if I got everything fixed on the Prius it would be a while before I trusted it.

In the Avalon, the radio stopped working and I can't figure out how to fix it. And looking in the previous owner's repair notes, this isn't the first time it has gone out. In the Golf I could just swap out the radio for something else if it ever stopped working. I did change the transaxle fluid and the radiator fluid on it though. But I still can't do the brake fluid. (How infuriating!)

I also use two sets of rims for winter and summer tires. Well that makes the TPMS light stay on all winter long. And these cars don't do near as well going slow in the snow.

It's just several little things like these that drive me nuts with newer cars.

The earlier TDIs were unbeatable in terms of real consumption and performance. And as said before: also easy to work on and the pumpe-dose technique was dated, but reliable. A TDI has never been the most refined diesel on the market. (or the cleanest ...) But at the time, they never had to. They had many other assets which made them successful.

I've had to kind of overhaul my Toyotas engine (1ZZ-FED) as well due to excessive oil consumption.
I failed emissions due to the visible cloud coming out of the exaust.
The bores where still in pretty good condition without scratches and an intact cross-hatch pattern, so I just gave them a little hone, new rings and drilled the pistons.
Also:
A big fault was in the oil controll rings and drain holes.
They are both prone to clog up and seize, causing high oil consumption.
Valve stem seals also often go bad, wich increases oul consumption as well.
This results in carbon deposits everywhere.
Had several mm of carbon and ash on my exaust valves, piston crowns and combustion chamber.
Especialy the stuff on the exaust valves is a ***** to clean off, even with a drillpress and wirebrush.

Not sure if the Prius is the same, but I've heared the valve stem issue and oil controll ring issue are typical Toyota problems...

Thanks! I wasn't aware of the valve stem seals bring an issue on the Toyotas, but that would be an easier thing to reach than the rings.

Yes, I do believe oil control rings are the problem. I theorize it's a combination of small drain back oil holes, at the oil control rings, low tension compression rings and the fact nobody changes their oil as often as they really should. Most owner's manuals have two oil change schedules, and most people do the less often schedule even though their driving almost always fits into the more often oil change schedule.

But there point was I could get an old VW diesel that's in ok condition and probably drive it all over with very few problems that will be very cheap to fix. But I just don't feel that way with newer cars with even just half the mileage.

Small? Sure, and I see many of those Maruti Suzuki models with Uruguayan plates in Brazil during summer. Loud and noisy? Not anymore.


Even though nowadays the Cruze is made only in Argentina, and the current generation never got the Diesel there, this very same engine was retained in Korea for the Trax. It does surprise me the Trax never got the Diesel option in the U.S. though.

More like Tata Nano. ;)

For the Diesel, Suzuki uses the Fiat 1.3JTD, also still in Brasil I guess. Real good small(est) engine, had 4 from these.
Suzuki had a lawsuit with VW because the germans demanded the japanese to buy their engines as part of a cooperation contract. The old suzuki guy didnt want to ruin his reputation, because with unreliable engines the Indians wont buy a suzuki for the next 3 generations anymore, and not with my name on the car, so he refused and they cancelled the cooperation at all.

Nope, the Trax/Mokka had a 1.7l. This is a way older engine that derived from the Isuzu 4EE1 from the early 1990s. This was modernised several types by GM/Opel und build in Poland. The common rails versions used in the Corsa C, and Astra G.
But they turned out to be the worst option because Opel were available with the way more advanced 1.3 JTD for the smaller cars, and the 1.9 JTD from the cooperation with Fiat.

The 1.6 is a complete different engine, the first (and probably last) Diesel that got actually developed by Opel, just in 2014/2015 so indeed realy new for a engine.

The Cruze will be the last option in the US for a realy long time to get a smaller, economical and reliable dieselcar. -

We might se a comeback from Stellantis (Chrylser/Fiat/Peugeot) but this will take a decade at least.

Already phased out :D


Brazilian vehicles fitted with that engine, unfortunately, were restricted to export due to regulations not allowing their fitment on regular cars.


Suzuki has even developed a very interesting 1.5L turbodiesel catering to India, yet it had been phased out too early as regulations were not favoring Diesels so much in India too, while CNG is now promoted more often.


The older Isuzu-based engine was used until 2015, when it got replaced by the GM-designed MDE. At that time, IIRC Chevrolet was already pulling the plug on the European market.


There was a Diesel derivative of the Family II fitted to the Opel Ascona C, but prior to this one there were Diesel derivatives of the CIH fitted to the Opel Rekord D or E.