BMW S65: Everything You Need To Know

Being the winner of the international engine of the year award for five consecutive years in 2008-2012 for their 3.0 to 4.0 L category S65 engines, without a doubt has that underdog potential and once rallied against the best engines such as Audi’s 5.2 Liter free-breathing V10, Ferrari’s 4.5 Liter V8, and naturally-aspirated V10 Lexus LFA handing them some serious business on the road. 

As far as love for the engine, BMW enthusiasts share the same sentiments, especially the E92 model of the same line of model, M3, as it is the last M3 to wear V8s and the final M3 that all-wheel drive, electric power steering, and turbochargers are lacking. These days, most cars have turbos, superchargers, improved steering, and racing modifications.

What is the S65?

The iconic S65 engine is a 4.0 Liter naturally-aspirated V8 petrol is a praised loudmouth that can breeze past 8000RPM as they are built through the concept of performance. S65s appear in BMW E90, E92, E93 M3 series, and MF4-S. Following its production from 2007 until 2013, the S65s replaced the S54 straight-six engines where previous generations of BMW M3s are equipped. Since there was no direct replacement for S65 engines, succeeding M3 models were switched from S65 to turbocharged straight-six engines. Also, together with S85 engines, unlike other BMW M engines, are not related to a BMW regular production. 

S65 Engine Specifications and Design

  • Production Run: 2007 – 2013
  • Cylinder Head Material: Aluminum
  • Cylinder Block Material: Aluminum
  • Configuration: V8
  • Bore: 92mm
  • Stroke: 75.2mm
  • Valvetrain: DOHC with VVT Dual VANOS
  • Displacement : 3.0 to 4.0 L
  • Compression Ratio : 12.0:1
  • Weight: 445 lbs
  • Max HP : 420hp
  • Max Torque : 295 lb-ft

Though there are no direct links between S85s and S65s, they share a lot of things. The idea behind S65 engines was inspired by S85s, with their standard features such as throttle bodies, ionic current knock sensing, double-VANOS (Variable Valve Timing for BMWs),12:1 compression ratio. The basic architecture, aluminum construction, and cylinder dimensions are also identical on both engines. 

Rated as a 420hp, 295 lb-ft, this 445-pound lightweight engine will not disappoint you with its ability, even with its mid-level torque, to develop power through high RPMs. The S65’s Engine is 33 pounds lighter than the previous S54s. Modeled from S85’s Siemens MSS65, S65’s Engine Control Unit (ECU), Siemens MSS60, is one reason S65s reduced weight. BMW also replaced the three-pump wet sump system used on the S85 to replace the S65’s wet sump lubrication system with two electrically operated scavenging pumps.

BMW also has this so-called Brake Energy Regeneration. BMW is cunning in terms of their engine’s power consumption and maybe one of the best to ever do it, or much more, integrate it. However, this technology is not an energy-gathering mechanism from brakes or fast recovery on your system, and its primary role is to help the brakes a little by drawing the majority of its electrical power during deceleration and engine braking from its alternator, supplying energy only during braking. The charging rate is reduced in the alternator during acceleration to allow maximum capacity. Therefore, it aids the braking by adding more to engine braking. BMW’s batteries are different as they used an absorbent glass mat with fiberglass sheets between the lead to hold the acid.

 S65s has a Low-pressure Dual VANOS (term used by BMW for VVT) system that uses a double chain to connect the cam sprocket and crankshaft. Via step motor, not helical gears, connects the camshaft to the cam sprocket, which omits the high-pressure system with a standard engine oil pressure on the step motor. 

Two Versions:

First is the S65B40, which appeared in Wiesmann MF4-S from 2009 -2014, BMW E90 (sedan models), E92 (coupe models), E93 (convertible) M3s from 2008 – 2013, it is the M3 engine. The other is S65B44, which appeared in BMW E92 (coupe) in 2010-2011, M3 GTS in 

2011-2012, BMW E90, and M3 CRT sedan. It is the enlarged version of the S65; it uses lightweight titanium exhaust with a longer stroke of 82mm.

Modifications and Performance Upgrades

If you want your M3s to become more of a screamer that gives about a 450 hp boost, you may opt to buy some performance exhaust, replace some filters, or install a new ECU software. This modification has been the most popular way to do it. However, if you don’t mind spending some bucks for enhanced performance, you can decrease the compression ratio that can reach up to 700+ hp or buy the ESS Supercharger Kit. This kit can be installed on stock internals but do not forget to buy ESS connecting rods to increase its dependability.

Problems Surrounding BMW S65

Whether you are planning to have or already own a BMW M3, chances are, your concern revolves around some issues, including cost, definitely, and it’s only a matter of time before those issues occur. Sad to say, it is inevitable but preventable with the correct knowledge and to make your M3 last by being ready and prolonging its valuable years. Here are some common issues that haunt some M3s:

First is the Rod Bearing Failure. Along with the S85 V10 engine, though it has a small percentage of affected owners, S65’s rod bearing wears out sooner than expected, which can be fatal for the engine that can result in failure. However, some owners recommend bearing replacement every 50,000 – 80,000 miles. There are available aftermarket bearings available that can be bought to replace them. But still, this problem can give you some jitters.

Second, the Valve Cover and Gasket. We tackled this issue many times now, and it has always been a concern for many BMW engines. The problem is that there are a small number of leaks on the gasket. Some reason might be the conditions these gaskets undergo, such as extreme temperatures and cooling cycles. So, if you noticed any cracks, or apparent smoke coming from the engine, there’s a possibility that there is a leakage.

Last but not the list is a defective Idle Control Valve that can escalate to throttle actuator failure if not immediately fixed. Having a hard time starting your engine might be one of the signs to look for, as well as irregular and fluctuating idle RPMs.

Summary

BMW’s S65 engine encompasses its performance and reliability beyond our expectations and will continue to impress next-generation enthusiasts. Nevertheless, it is a performance engine, and anything to do with maximizing performance requires time, money, and effort to extend and reveal its maximum potential. It does have some minor issues that might bother you, as an owner or soon-to-be owner, but those problems are not deciding factors to skip BMW S65 on the queue of your car bucket list. This engine holds a special place in our hearts, definitely. 

We hope that we cleared out some clouds in your head regarding BMW S65 engines.

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