BMW S52B28 engine gives the M52 engine a sporty profile. Its high-performance abilities have outdone most of the upgrades made by BMW for the M52. It is excellent for high-power demand applications, smooth driving while engaging in a responsive blow for its performance.
What are BMW S52B28 Engines?
In parallel to the BMW M52 engine, the BMW S52 engine is the high-performance version of the M52. The engine replaced the North Merica spec S50B30 in the E36 M3.
Contrary to the usual M52 components, the S52 does not have the same Nikasil coated cylinder block. However, it shares the majority of customs of the S50 in comparison to the same line of S50 with its M50.
The production of the S52B28 started when the S50B30 engine operations were put on halt. The S50B30 departed in the European market but started in North America, particularly the S52B32.
The American spec S52 engine is the representative of the M52 series of machines, including M52B20, M52B28, M52B25, and currently the main picture of the modified M52B28 engine.
The S52 engine, though the same as the M52 engine, has its unique qualities, such as different bore and stroke dimensions. To add, the BMW S52B28 does not have a symmetrical square engine but has a larger size compared to the M52.
This engine included several changes in the cylinder heads as well as the cylinder block. Other upgrades that S52 benefitted from along with the M52 engine are lighter, increased and lift duration camshafts, exhaust system, and new valve springs.
The S52B28 engine produces 240 HP at 6,000 RPM and 236 lb-ft of torque at 3,800 RPM. The S52 has a redline of 7,000 higher than M52’s 6,500 RPM redline.
Engine Specifications and Design:
- Production Run: 1995 – 2001
- Cylinder Head Material: Aluminum
- Cylinder Block Material: Cast-iron
- Configuration: Straight 6
- Bore: 86.4 mm
- Stroke: 89.6 mm
- Valvetrain: DOHC four valves per cylinder integrated with VVT
- Displacement: 2.8 L (2793 cc)
- Compression Ratio: 10.5
- Weight: 360 lbs.
- Maximum HP: 240 HP at 6,000 RPM
- Maximum Torque: 236 lb-ft at 3,950 RPM
Engine Design
The six-cylinder BMW S52B28 engine is almost the same as the M52B28 engine, but it is specifically designed for high-performance applications. Apart from that, the M52 engine has a different material on its blocks.
However, the S52B28 engine does not feature the same Nikasil coating in the M52 blocks but instead uses the typical cast-iron engine blocks.
The reason might stem due to the issues attached to the Nikasil. The component consistencies of fuel for every country are not the same, especially the sulfur levels. With that, it affected the M52 blocks causing corrosion and premature corrosion.
IN addition to that, the S52 engine cylinder has a great design exposing them on all sides to maximize the flow of coolant in every way. The engine used seven main bearings supporting the counterweighted crankshaft.
The crankshaft rotates in replaceable split-shell main bearings.
The forged steel connecting rods has the same split-shell bearings at the crankshaft’s end and solid bushings at the piston end. Three-ring type pistons with two upper compression rings and a lower one-piece oil scraper ring; circlips hold the full-floating piston pins.
The cylinder heads witnessed several changes from the M52B28 engine. Including on those are lightweight tappets, lightweight camshafts (with increased lift and duration), and springs.
Moreover, It has a new head gasket following some issues regarding head gaskets failure in some M52s. The intake system remains the same as the M52 with one throttle body, while the exhaust system was restyled for more outstanding performance and efficiency.
Expressing the true intention behind the performance-spec engine.
The BMW S52B28 engine also uses chain-derive dual overhead camshafts with a VANOS system and four valves per cylinder. The engine uses Siemens MS41.1 for its electronic control unit, the same as the S52B32.
Applications of the S52B28 Engine:
- 1996 – 1999 E36 M3 (the United States and Canada only)
- 2998 – 2000 E36/E37/E38 Z3M (the United States and Canada only)
Engine Tuning, Updates, and Modifications
The S52 itself is already a high-performance engine, but if there are things you want to modify and make it more personal, we do have some recommendations for you to base on it.
Some Performance Upgrades
The primary thing that’s inching the S52B28 closer to a lesser power input is due to its narrow runner intake manifold, thirty percent thinner than the M50.
With that, as a low and mid revved design engine, you will need to upgrade it to some performance parts: a cold air intake, M50 intake manifold, or a Turner Motorsport Stage 2 kit. These modifications will increase your power gains to 270 HP.
Further, add Schrick 264/256 camshafts, the power will go up to 280 HP. Performance exhaust system and setting headers, the BMW S52B28 engine will show about 300 HP closer to Euro S50B32 ITB.
The above-mentioned is the easiest and cheapest way to improve the BMW S52B28 engine. You can also purchase connecting rods, compression pistons, more aggressive camshafts, head porting, and install ITB.
Turbocharging
Though it is sometimes elusive and hard to achieve, it is real to get 350 HP on the S52B28 engine; enough to buy a supercharger kit. Most of these upgrades usually develop a max boost up to 6 psi, allowing an extra 110 HP.
The stock internals of the BMW S52B28 is enough to withstand 400 HP and temporarily up to 500 HP if you are lucky, but definitely, you don’t want to risk this.
If the engine reaches the 350 HP mark, it seems that you want to elevate the game more. For this, you need to omit the supercharger, if any, and but H-Beam rods, MLS head gasket, ARP studs, low compression pistons.
This kit will reduce the compression ratio preparing your engine for more immense power output. Next thing, you need to purchase a Precision 6266 turbocharger or anything of the same; turbo manifold, wastegate, intercooler, blow-off, fuel pump, and fuel pressure regulator.
You will also need a 3.5-inch performance exhaust system and any aftermarket ECU. After all the modifications and adjustments, you can gain up to 600 HP.
Problems Surrounding the BMW S52B28 Engine:
BMW S52B28 engine is far from the perfect engine, and no engine has the characteristics to become an ideal engine.
Though some machines are advertised that they don’t have issues, well, that could remain true for the early years, but as the years and mileage pile up, the engine will eventually fall into the long arms of issues and troubles.
Radiator and Expansion Tank Leaks
The cooling system of the S52B28, relating to its M52B28 alter-ego, might be the weakest point of this family. Many radiator supporting components are plastic-made.
Meaning, they quickly break if not correctly made due to fluctuating temperature and unstable behaviors leading to cracking and leaking. Radiator leaks commonly stem from the top radiator pipe and the thermostat housing.
So, if you experience regular overheating, you either have a leak in the cooling system or a failed radiator.
Water Pump Failure
Another issue that the engine might suffer is the water pump failure. Though water pumps are typical as standard wear and tear items, BMW vehicles, not only the M52 and S52, suffer from their frail characteristics.
The BMW S52B28 engine, as same as the M52, uses a plastic impeller, an integral part of the engine that sends the coolant through the machine.
The plastic impeller commonly breaks from standard wear and tear, causing the water pump to stop functioning. The water pump usually lasts around 80,000 – 100,00 miles.
Valve Cover Cracks and Oil Leaks
If you’re new to BMW vehicles, most of the pointed concerns of owners are the valve covers. However, if you’ve owned a BMW before, this issue might be no surprise anymore. Well, these valve covers tend to crack over time due to sustained heat inside.
Because they are made of plastic, these valve covers do not have much resistance in such conditions. Even the smallest cracks can result in an oil leak. In addition, valve cover gaskets often cause oil leaks from the standard wear and tear because they are made from rubber.
To know if you have a cracked cover or just a plain old gasket, check if you have a leak. If there is a leak, pull off the cover and assess it for any cracks or irregularities. If all looks good, start by replacing the gasket. Make sure to check the spark plugs too.
VANOS Failure
The M52 family has a dual-Vanos system; the S52B28 Is VANOS integrated. So, it’s not far that, at some point, the engine would likely suffer from this kind of issue.
Unfortunately, VANOS, BMW’s variable valve timing system, has the tendency to fail even in modern and advanced BMW engines. But it is far more rampant in the early BMW engines, which were the first to use the system.
If you experience rough idling, cold start issues, loss of drivability, the appearance of P1520, P1523, and P1397 engine codes.
Summary
The BMW S52B28 engine bearing the higher performance engine of the M52B28 engine has a lot of power to offer to those who desire to own one. Its potential is sure to win some hearts from enthusiasts and hobbyists alike.
But even with that attached badge of the technologically advanced engine, the S52 remained sidelined due to the issues it suffered along with the M52s.
It is a better choice for those seeking a city driving experience but wants to experience an adrenaline rush for once in a while and enjoy the scenic views countryside. It is one of those engines that surely will live up to its expectations.
Just make sure to check the issues mentioned above regularly and religiously.
No one wants to spend thousands of bucks for such a mess and can ruin your weekend and rain on your parade.