Have in mind that…
The BMW E30 had a large engine option list, and most of them were petrol powered units, that with the help of the sharp handling made the E30 a driver’s car, and a cult favorite, that remains even nowadays a very appreciated car by many classic car fans and tuning specialists. But, we cannot ignore the other two engines that BMW offered for the E30.
The diesel powered saloon cars trend was set by Mercedes in the late 70s, and their fuel economy and reliability made them powerful weapons in the war between the car manufacturers. BMW had their own diesel models on the market, but their commercial success was nowhere near what Mercedes achieved with its models. But take into consideration that BMW was focusing on performance, speed acceleration and handling rather than good fuel economy or reliability. Also, their petrol powered cars had no reliability issues, and their simple but robust construction made them last for ages, without any major intervention. Even nowadays you can find many old BMWs with sealed engines.
Try not to compare it with the petrol engines
As I have told you, in the past things were very different than how they are now, when almost half of the cars produced by BMW use diesel powered engines. That was possible because of the constant improvement of the diesel engine during the years, that allowed the engineers to take it to similar performance figures as a petrol unit, taking into consideration that diesel was for many years significantly cheaper than petrol. But let’s see how the diesel engine merged with the popular E30 from the 80s. Have in mind that this car was a hit, a cult favorite because of its beautifully engineered petrol engines that made it win many touring car championships, rallies and a place in the heart of motoring enthusiasts. It won’t be fair to compare in any way the production figures, and say that the diesel versions were more popular than, let’s say, the M models, that would be almost a sacrilege.
The M21D24 diesel engine
The diesel engine available for the E30 is called M21D24, and it is a 2.4 liter straight six engine. It was launched in 1983 and two years later appeared on the first E30. It was based on the popular M20, and it was also available with a turbocharger. This particular engine was the last diesel unit sold in North America until 2009. As an explanation for this, think that in those times, the price of petrol began to drop down, so people became less interested in fuel efficiency. Also, the bad build quality of American diesel engines, contributed to the decline of diesel powered cars sales over there. However, in Europe this situation happened the other way around. The manufacturers invested a lot of money and resources in the development of better diesel engines, and eventually their popularity increased.
The M21D24 straight six put out 84 hp at 4600 rpm, and the turbo charged version developed 114 hp at 4800 rpm. The most impressive figure of the engine is the torque, that was up to 210 Nm in the turbo charged car. This numbers suggest that the car didn’t accelerate like a bus, but was no racing car either. The impressive torque value made the car deal easily with heavy loads or on uphill roads, but a large diesel means a lot of weight added to the front, and that affected the handling of the car, that wasn’t as nimble and sharp like in the lighter and more powerful petrol versions. This engine equipped other cars apart from the E30 and the E28 BMWs. It was also fitted to the 80s Lincoln Continental, and compared to the USA made diesel engines it was a masterpiece. Another proof of its power and capability of dealing with heavy loads, was made when motorhome manufacturer Vixen decided to put in one of its models.
How users describe it
Being an E30 BMW, you won’t hear any complains about its build quality, rust, or any other thing like this, that would be quite normal for a car that old. The engine uses a decent amount of fuel, 7-7.5 liters for 100 kilometers and proved to be a very tough one, starting no matter of season, temperature or altitude. It doesn’t make the car feel very sporty, but if you know how to drive a diesel, and fully understand how that turbo works when it kicks in, then you will be satisfied with its performance. More recent comments, say that the E30 is perfect as a first car, and when asked, all of them say that they would buy another one in good shape.
However, many people, including me, consider the E30 diesel as an attempt from BMW to make a fast diesel, that didn’t came out as expected. But we can’t blame BMW for this, as the diesels of that era didn’t had the advantage of intelligent fuel injectors, and all the electronic enhancements that eventually made the diesel engines what they are today. It was a simple response to the competition, that started the rise of the diesel engine. An advantage of the 2.4 liter straight six is its simple construction, that allows it to be fueled with used cooking oil, instead of normal diesel, and make it a cost free machine that will take you wherever you need.
I don’t want to end this article on a pessimistic note, so I will show you some diesel fueled E30s that are as fast and powerful as their petrol powered relatives.
This is a E30 with a M57D30 engine. Just look at the acceleration indicator, and say you are not impressed:
Another good example of oil burning diesel power, this time with an engine picked from a 525td
Just ignore the smoke and look how fast this mad E30 disappears. In a cloud of black smoke, of course.