BMW M30B35LE engine

The BMW M30 series is a lineup of the most popular engines that BMW has produced. With over 9 different modifications, fan love and praise from the world’s most popular publications. This powertrain has been on the lips for practically 26 years. The powerplant has six cylinders, with 2 valves on each cylinder. And it stares at BMW cars from 1967 through 1992. The main indicator of quality is that you can see BMW cars with this engine today, which can give a head start to some modern sedans.

It is loved for being easy to maintain, and the secrets to repairing it are passed from fan to fan by word of mouth. It seems to us that at every car service station, the craftsmen tacitly pass on the secrets of fixing this powertrain.

M30B35LE engine specifications

Advantages

Let’s talk about the benefits. This is real German quality. Even though this powerplant is morally and technically obsolete, it still powers hundreds of thousands of cars. The unit is made of gray cast iron, which simultaneously makes the engine stronger, tougher and less resistant to high temperatures. The 12-valve cylinder head has no deadline. Neither do the timing chains.

Disadvantages

As for operational problems, the entire line of engines is quite resourceful and reliable. The piston system runs about 400-450 thousand kilometers, depending on maintenance and the level of daily load of the internal combustion engine. But the cylinder block together with the head is seriously afraid of overheating. Since the protagonist of our review – the car is quite dynamic, but the resource and power of the engine is more suitable for a measured ride, it is confirmed by the resource of more than 400 000 – 500 000 km.

Therefore, it is necessary to look at the engine temperature sensor every 7-10 thousand kilometers. Another peculiarity of the power unit is that it has a serious appetite for engine oil. In the technical passport, the manufacturer indicates that for each 1,000 km of mileage, the power unit is able to consume up to 1 liter of lubricant. But in practice there are cases when the consumption increases many times. All the fault is the piston rings, which need to be repaired. In this case, the owner of the car expects a major overhaul or replacement with a contract engine. The power plant was equipped with an injector system of fuel supply. Note that the entire line of engines of the M30 series is not equipped with hydrocompensators.

This is why we recommend that you visit the workshop at least every 7,000 to 10,000 km. This is due to the adjustment of the thermal gaps.

Continuing the problems, all future owners of cars with M30B35LE engines. need to stock up on new pipes, which are necessary for the normal operation of the cooling system, it is also necessary to look at the condition of the pump and the cap with a valve for the expansion tank. The list of recommendations ends with a new thermostat.  High temperature of the power unit seriously kills it and significantly reduces its resource.

Modifications

As for modifications, the protagonist of our review received some refinements that allowed to develop power up to 220 horsepower, and torque up to 350 Newtons per meter, at only 4000 rpm. This powertrain we will consider the example of the restyled BMW E32. On the younger models of this legendary car, Bavaria Motors installed a gasoline inline six-cylinder engine M30, which for 1986 was beyond comprehension. Among the nice features, this engine was one of the first to be equipped with a catalytic converter.

This car was also equipped with a three-liter engine, to which we dedicated an article on our portal, and had 188 horsepower. And even its power was enough to accelerate almost 2 tons of iron in 9. 3 seconds. The engine could accelerate the BMW M32 to 100 km/h in 8.3 seconds. The top speed was limited at 240 km/h. In those times, this powertrain is able to give an unforgettable experience of acceleration dynamics. As indicated above, the engine was atmospheric, and was able to accelerate the first 100 km per hour in a little more than 9 seconds. But regardless of the volume, all engines with the index M30 had distributed injection, distribution system with a single camshaft and located longitudinally to the car body.

Fuel consumption is a sore subject for the M30 engine. Despite the fact that the technical passport indicated the lower threshold of consumption in mixed mode of 11.5 liters, but in practice it turned out to be a little more than 13.

Characteristics

The powertrain is a 3.4-liter gasoline inline six-cylinder. Peak power, which is able to reach this unit is set at 211-220 horsepower in the stock. It was installed on cars 5 and 7 series from the concern Bavaria Motors. Let’s start with the technical characteristics. The volume of the engine is 3430 cubic centimeters. Maximum power, which is able to achieve this power plant is equal to 220 horsepower. Torque, which is able to develop this engine is 375 Newtons per meter.

In order to reach this value, the driver needs to accelerate the internal combustion engine to 4,000 rpm. The engine uses high-quality gasoline, with an octane number of 92. The average fuel consumption, which is able to give this engine to the owner, starts at 11.4 for every 100 kilometers driven.

If you squeeze maximum power and torque out of the engine, the fuel consumption indicator can go far beyond 15 liters. As for the engine type, it is an in-line six-cylinder engine with 2 valves on each cylinder. The diameter of the cylinder is 92 mm. As we indicated above, the horsepower ranges from 211 to 220 horsepower. It depends on the rpm of the engine. So, 211 horsepower, and 115 kW on the engine can develop at 5000 rpm. At the same time, 218 horsepower and 160 kW would take the unit is able to develop at 5200 rpm. The maximum, 220 horsepower the internal combustion engine can develop at 5,700 rpm.

The red mark is at 6000 rpm. The engines are not equipped with a supercharger. The compression ratio varies from 9.1 to 9.5, depending on the modification of the power unit. The piston stroke is 86 mm.

Chip Tuning

There are many different parts available for the BMW M30. If you have a desire to make a powerful M30B35, you should start by getting the motor back to normal. After that, there are two ways: buy a “stroker play” kit or aggressive cams.

To make a 4 liter M30B35 you need to buy a 98mm stroke crankshaft, short connecting rods, increase the cylinder bore to 93.5mm and forged pistons. If you increase the cylinder bore to 95mm, you get 4.2 liters, but that kills the engine like hell. The price of a stroker kit is higher than the cost of the whole car.

The second way is you need to work on the cylinder head to increase the compression ratio to 11. After that, you need to buy an expensive turbo kit, buy a cold air intake, a Schrick 284/280 deg. camshaft (or something similar) with springs, a reinforced camshaft, and cams, and you’ll need to work on your performance specs. (or something similar) with springs, reinforced camshaft, and cams, and a performance 3 inch exhaust (or straight-through).  The ECU is also something to pay attention to. If it is carefully tuned, it can give about 240-250 horsepower. You’ll get additional power by purchasing forged pistons, lightweight connecting rods, and a set of separate S38 throttle bodies. The result is an interesting engine, but it’s cheaper to buy a BMW E34 M5 with a powerful S38 M30B35 Turbo

Standard BMW M30 engines have very low compression, so you can install a turbocharger without using forged pistons. Buy on the cheap a Chinese turbo kit for BMW M30 and install it on stock internals.

You can assemble the kit yourself. Just buy a Chinese Garrett GT35, turbo manifold, three inch pipes, intercooler, bypass valve, purge, 630cc fuel injectors and Megasquirt ECU. Don’t forget the ARP head studs and MLS head gasket. After that, you can increase the boost pressure to 11-14 psi (0.8-1 bar), this will produce about 400 horsepower. A Chinese turbocharger won’t last too long, you’ll probably have to buy a new one after a few thousand miles. Instead of Chinese performance parts, you can buy an original Garrett GT35, it will be more expensive but much more efficient. In addition to a single turbo you can make a double turbo M30B35. But already at your own risk.

This engine is installed on the following models:

BMW 5-Series (E12) BMW 7-Series (E32)