BMW S55 vs S58: Performance, Reliability & Tuning

BMW forever left the world of naturally-aspirated performance motors in M-series cars in 2013 with the launch of the S55. Succeeding the NA V8 S65 motor, the S55 was a 3.0L twin-turbocharged inline-6. Despite being the performance version of the N55, the S55 has little in common: a closed deck block, twin turbos, forged pistons, lightweight crankshaft, and dual high-pressure fuel pumps, to name a few.

With the S55 being such a positive inclusion under the hood of the F8X platform, BMW continued to roll with the 3.0 twin-turbo inline-6 formula. While the BMW S58 is still a relatively new engine in comparison to some of their other long-running engine series, the S58 has proven to be a worthy successor to the BMW S55. In fact, the S58 has blown expectations out of the water. Some people are even claiming that the BMW S58 is one of the best engines ever made from a performance and reliability standpoint.

Now that the S58 has been around for a while, the natural question asked by many people is how does the S58 stack up against the S55 in terms of performance, reliability, and tuning potential?

If you would rather consume this content via a video, check out our BMW S55 vs S58 video below:

S55 vs S58 – BMW S55 Engine

BMW S55 Engine Specs

Stock Power: 425hp / 406tq (different versions have anywhere from 405hp-493hp)
World Record HP: 1,150whp (approx. 1,350 crank hp)
Displacement: 2,979cc (2.979L)
Turbocharger: Twin “single-scroll” turbos
Compression: 10.2 to 1
Bore x Stroke: 84.0mm (~3.31”) x 89.6mm (~3.53”)
Internals: forged steel crankshaft, forged aluminum alloy pistons and rings
Block Design: Closed-deck
Redline: 7,500 rpm
Injectors: Bosch solenoid style direct injectors

S55 Engine Performance & Mods

Some people were disappointed that BMW moved away from the V8 platform. However, there certainly is no disappointment in S55 performance capabilities. While the N55 was toned down for reliability, the S55 was cranked up to a whole new level. 

With 425hp out of the gate, this engine is believed to be significantly underrated with stock dyno’s coming in around the same numbers. With basic FBO mods such as a tune, downpipes, intake, intercooler, and E85 gas, the S55 engine can push a cool 600whp. And better yet, this list of FBO mods won’t run you any more than $2,000. Talk about serious power! 

With a horsepower record of 1,150hp to the wheels, the S55 is the highest horsepower BMW engine to exist. With partially forged internals, a closed-deck, and special cylinder wall and piston coating, the S55 engine is the most capable and powerful BMW engine in existence. But, what about the next generation S58?

Read our more detailed tuning guide here: How to Build a 600WHP BMW S55 M3/M4 for $2,000

We also have a dedicated BMW S55 Engine Page that covers specs, common problems, popular modifications, and more.

S55 Engine Reliability

After 6-years of on-the-road data, the S55 appears to be an extremely reliable motor. On pre-2016 engine models, the crank hub was complained to be a high-failure point, resulting in a “spun” crank hub. The crank hub issue turned out to be blown out of proportion by a company called TPG tuning, using a scare tactic to sell more of their aftermarket crank hubs. The S55 crank hub is the same design as used on the N54 and N55, and while it can and has failed on stock S55’s, it is a highly isolated problem that was improved by BMW in 2016. 

Outside of this overblown issue, the S55 appears to be a fairly bulletproof engine. There are a handful of small issues, common across all BMWs, such as HPFP failure, carbon build-up, etc. but overall, nothing that should be a serious red flag for any potential buyers. Check out our guide on S55 engine problems for more info.

The combination of power and reliability on the S55 is astounding and unrivaled by any other BMW engine – except the BMW S58.

S55 vs S58 – BMW S58 Engine

BMW S58 Engine Specs

Stock Power: 473hp / 503hp and 442tq (503hp is for Competition models)
World Record HP: 1,049 horsepower
Displacement: 2,993cc (2.993L)
Turbocharger: Twin “single-scroll” turbos
Compression: 9.3 to 1
Bore x Stroke: 84.0mm (~3.31”) x 90.0mm (~3.54”)
Internals: forged steel crankshaft, forged pistons and rods
Block Design: Closed-deck
Redline: 7,500 rpm
Injectors: Bosch solenoid style direct injectors

S58 Engine Performance & Mods

With 4 years under the S58’s belt at this point, the modding community has been hard at work developing products to bring the most out of the 3.0L twin-turbo inline-6. As with nearly every turbocharged BMW engine, the tuning community has been doing great work with the S58. If you are interested in learning more about popular BMW S58 engine modifications, check out our BMW S58 Bolt-On Engine Upgrade Guide here.

At this point, there are both piggyback and flash tunes available for the S58 including some of our favorites like the Burger Motorsports JB4 and bootmod3. An S58 tune alone can offer power gains in the 70-100whp and 80-100wtq. Mix in some better fuels like E85 and power gains can exceed 125whp and 150wtq. More on this later when we discuss E85, race gas, and methanol injection.

There are also quite a few popular bolt-on modifications available for the S58 at this point as well. Most of the most popular S58 bolt-on mods are the same ones popular on the BMW S55, which makes sense due to their similarities. Some other popular S58 mods include upgraded dual-cone intakes, catless downpipes, and fueling modifications. Some G80 owners have been able to put down 700+ horsepower with stock internals from bolt-ons alone.

S58 Engine Reliability

There’s little chance that the BMW S58 won’t be a reliable engine in the long term. With fully forged internals, a low compression ratio, and a closed block design, the BMW S58 is shaping up to be an extremely dependable engine. The S55 significantly enhanced its reliability over just about every previous M-series engine. And the B58 has been a very reliable and capable engine to date.

Starting with the BMW N55 and S55, BMW reliability began to hit an upswing, luckily that reliability carried into both the BMW B58 and S58. After the first 4 years in operation under the hood of the G8X, there aren’t any notable or common problems to note, especially in stock form. However, as power increases and additional technology is added, the risk for more common problems increases. As always, you can likely expect a few issues with the common BMW problem children including the HPFP, oil filter housing, valve cover gasket, water pumps, etc.

In a straight reliability battle between the S55 vs S58, the S58 likely has the edge. That is due to the fact that BMW has had time to learn from the S55 engine which was essentially the blueprint for the engine that succeeded it.

BMW S55 vs S58 Performance

What is clear as of right now, is that S58 is more powerful and offers better performance, from the factory. But that doesn’t answer the question, which platform has the greatest potential?

The bottom line is that the S55 vs S58 have vastly different performance characteristics and that they both suit different driving styles better. One of the major considerations is how both engines deliver boost. The BMW S58 has both a higher boost threshold and more turbo lag than the S55 due to the fact that the S58 has larger turbos and a lower compression ratio. This makes the S55 feel more immediate and responsive when you step on the gas. However, the S58’s power delivery feels more akin to a naturally aspirated engine, with power rolling on gradually as the turbos spool.

The S58’s larger turbos and lower compression ratio are also a big part of the reason that it has more power potential than the BMW S55 with factory hardware. There is essentially added headroom for aftermarket antics built into the BMW S58. Now that the aftermarket community is beginning to get caught up with S58 modifications, we are beginning to see absolutely wild horsepower numbers from the S58 that wouldn’t be possible with the S55 without extensive engine building.

The bottom line is that the BMW S58 is still a relatively new engine that still has room to grow. We have high hopes and expectations for the S58, and believe it will be as rock solid as the S55 given they are using virtually the same engine internals. But, at this point, in a straight S55 vs S58 fight, our money’s on the S58 in terms of performance potential.

BMW S55 vs S58 Reliability

The S55 is a masterpiece when it comes to reliability for an M-series vehicle. The S58 is still somewhat new to have developed a bunch of “common problems”, but from what we can tell so far, the B58 is a highly reliable motor. Using that as a proxy for the S58, we hope this engine will live up to and potentially even surpass the reliability found in the S55 engine.