When it comes to powerful straight-six motors, few automakers match BMW’s ability to squeeze huge horsepower and torque figures out of one. They’ve been doing it for decades, most notably in their M-powered models such as the M3. BMW’s first powerful straight-six came to us back in 1972, and was installed within the first iteration of the BMW 3.0 CSL.
Recently, BMW saw fit to resurrect the iconic 3.0 CSL nameplate, and with it, bring back the spirit of that original 3.0-liter straight-six motor. In doing so, BMW created their most power-dense engine ever. The 3.0-liter in question is a version of the current B58 straight-six, albeit with some key mods to make it such a powerful unit. CarBuzz decided to pay homage to this motor, as it deserves a place in automotive history. Read on, and let’s see what we can learn.
Base MSRP $750,000
Engine 3.0L Twin-Turbo Inline-6 Gas
Horsepower 552 hp
The following write-up contains information, specs, and history sourced directly from BMW’s M-division website.
BMW’s Powerhouse: S58B30T0 Hot-Six
What Makes It So Special?
A power density of 184 hp. 308.2 hp per ton. Engine featured in BMW’s first CSL model in 20 years. Creates a large amount of power using a relatively small engine. It features loads of high-tech engineering to achieve its power output.
Enter the BMW S58B30T0, a straight-six which is, seemingly, straight out of a race car. However, the specific mill found within the 2023 BMW 3.0 CSL is of a special breed, as it’s the only one that carries a 552-horsepower rating, which means the engine has a power density or specific power output of 184 hp per liter. That’s not quite up there with the best, but one hp per liter shy of the mighty turbocharged three-cylinder in the GR Corolla. The S58B30T0 is part of BMW’s B58 family of straight-six engines, which has been around for nine years now. These motors have seen applications ranging from the brisk BMW 340i to the rough-and-tumble BMW M3 CS. In short, these engines are no strangers to speed and power.
Related Why The BMW B58 Engine Is A Modern 2JZ
Few inline-six motors garner the same adoration as the 2JZ when it comes to tuning potential, but the BMW B58 comes close.
With BMW’s timeless motto being “The Ultimate Driving Machine”, the S58B30T0 needed to be exceptional, especially since it was installed within the newest 3.0 CSL, a namesake that’s almost as iconic as the Bavarian automaker as a whole. As we’ll discuss below, it’s clear BMW knew this, and excelled in creating a mill that met and even exceeded everyone’s expectations of what a CSL should be capable of.
The What, Why, And How Of The S58B30T0
RM Sotheby’s
Engine Specs
Displacement
3.0-Liter Twin-Turbo Straight-Six
Horsepower
552 hp
Torque
406 lb-ft
0-60 MPH (2023 BMW 3.0 CSL)
3.6 Seconds
The motor in question is a far cry from that original 3.0-liter found in the 1972 BMW 3.0 CSL, one of the most iconic Bimmers ever made. Back then, the 3.0 CSL only made 203 horsepower and 211 lb-ft of torque. Now, it would be ignorant to claim this wasn’t enough power for the time, as the ’72 3.0 CSL was a seriously fast racer for its time. However, these days, its grandson has enough power to run circles around it.
The recipe for such power is a long list of ingredients, but they all come together to make quite a special motor. As we mentioned before, the engine carries a production code of S58B30T0, denoting its place among the hotter versions of BMW’s B58 engine family. In keeping with tradition, the modern 3.0 CSL uses a straight-six configuration. However, a couple of mono-scroll turbochargers were added into the mix to help create those 552 horses.
On top of some expertly-tuned forced induction, the S58B30T0 also features upgrades over the usual mill, such as a molybdenum-steel crankshaft, which is excellent for lightweight heat displacement and its high torsion resistance. Other upgrades include forged steel connecting rods and forged aluminum pistons, the latter of which helps keep engine weight low while the former helps further strengthen the motor. The engine’s compression ratio is quite high, as well, measuring 11.0:1, whereas the normal B58 series motors only manage 9.3:1.
All of these upgrades culminate in that 552-horsepower and 402 lb-ft of torque rating. Not to mention, thanks to the S58B30T0’s upgrades listed above, it can rev up to 7,200 rpm, an impressive number for a straight-six. In short, the 2023 BMW 3.0 CSL’s motor wasn’t born to mess around, it’s an incredibly capable piece of equipment.
How The S58B30T0 Came To Be
As previously mentioned, the S58B30T0 started life as a run-of-the-mill B58-series motor. It’s already a potent engine found in the likes of models such as the BMW 340i and the BMW 740i. However, before that, the B58 engine family can trace its roots to the previous N55 straight-six congregation of engines. Some unique uses of an N55-series engine (the S55 in particular) include models such as the 2017–2020 BMW M4 CS and the 2020–2021 BMW M2 CS.
Related How The BMW B58 Became The Most Reliable BMW Engine Ever Made
In just nine years, the B58 has a proven track record for strength, reliability, and power
Bearing that in mind, it’s clear the N55 family was no slouch, either. In 2015, BMW decided to begin development of a new straight-six engine, which would become the B58 and its subsequent versions. The N55 was slowly phased out after the B58’s introduction.
BMW’s penchant for inline-six power spans decades, and they choose to continue honing their affinity for inline motors due to their ease-of-manufacture, supposed better-balanced power, and smooth operation. Judging by their steadfast dedication to this particular cylinder configuration, it’s safe to assume the BMW straight-six isn’t going anywhere any time soon.
How The New 3.0 CSL Dominates A Track
BMW
While its engine is surely an impressive feat of engineering, the ’23 BMW 3.0 CSL’s serious track prowess isn’t just due to what’s going on under its CFRP hood. There are loads of other pieces of precise, honed engineering at play to turn the 2023 3.0 CSL into a force to be reckoned with on any track day.
One of the core tenants of any car that’s quick around a track is lightness, and the engineers at BMW are well aware of this fact. The modern-day BMW 3.0 CSL features a body constructed largely of carbon fiber reinforced plastic (CFRP). On top of the high-tech body panels, the 3.0 CSL ditches basically all sound-deadening material, so it’s not surprising to hear the inside of the hot Bimmer sounds like you’re piloting some sort of supersonic go-kart. BMW even went as far as creating a new rear exhaust diffuser out of titanium, saving about 10 pounds. It sounds useless, losing only a few pounds, but in the pursuit of speed without compromise, anything goes.
Related BMW 3.0 CSL: 5 Best Features
With a price tag close to $800,000, it’s essential to know what sets the 3.0 CSL apart from any other BMW product.
Another special aspect of the BMW 3.0 CSL is its six-speed manual transmission. While BMW does still offer manuals in models like the M2, M3, and M4, it’s safe to assume the days of BMWs with manuals may be coming to an end in the coming years, judging by what the rest of the automotive world is doing. Take Volkswagen, for example, who just announced the iconic Golf GTI will no longer feature a manual transmission.
Sadly, if you’ve read this write-up and become overwhelmed with a desire to own a BMW 3.0 CSL, your time to buy a brand-new one has already come to pass. BMW only produced 50 units, all of which sold out immediately. However, if you’ve got a seriously large pocket book and time to wait, you’ll most likely be able to find one for sale used at some point. One recently sold via RM Sotheby’s auction for about $1.1 million. Otherwise, you’ll be relegated to gazing at pictures and dreaming of clipping apexes in one of BMW’s all-time greats.