Unpacking The BMW M4’s Potent Engine

BMW and the straight-six engine have been inextricably linked, thanks largely to the success of its high-performance M3 lineup. It’s a lineup that dates to the Nineteen Eighties and has since gone on to incorporate the M4 collection.

BMW M4

Mannequin

M4

Base MSRP

$79,100

Right this moment, CarBuzz is trying on the BMW M4 engine, what makes it tick, and why it’s such a extremely regarded powertrain. There’s rather a lot to like about this straight-six mill and some reliability points to concentrate on, all of that are coated under.

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BMW M’s Love Affair With The Straight-Six

BMW’s M division has been hooked on straight-six energy for the higher a part of 32 years. Although the unique E30-generation M3 featured a four-cylinder engine, the second-gen E36 M3 got here with a 3.0L inline-six and confirmed fans how particular these engines will be.

For the next M3 collection – the E46 that was produced from 2000 to 2006 – the output jumped from 240 to 333 horsepower. Then got here the E90 M3 and its 4.0L V8. It will change into the one time BMW fitted an eight-cylinder mill to this fabled M automotive, a mill that made 414 hp and screamed all the best way as much as 8,400 rpm.

Returning to its roots – type of – in 2014, the fifth-gen F80 M3 landed with a 3.0L straight-six strapped with a pair of turbos. Together with the dramatic change from pure aspiration to compelled induction, the German automaker launched the M4. Up thus far, the M3 was provided in coupe, sedan, and convertible configurations. However as of 2014, the coupe and convertible fall beneath the M4 nameplate, whereas the sedan stays an M3.

The newest straight-six fitted to the M4 is the three.0L twin-turbo S58. An evolution of the S55 from the prior technology, it’s extra highly effective than ever and has reaffirmed BMW’s love affair with its famed inline-six powertrain.

First-Technology M4: Twin-Turbo S55 Launched

When the BMW M4 and S55 engine debuted in 2014, fans went wild – with displeasure. Though the straight-six was again, it was coupled with a pair of turbochargers. After greater than 25 years of naturally aspirated M automobiles, this was seen as a dilution of the model. Merely including turbos to extend efficiency was thought of blasphemy by the diehard loyalists, who noticed this transfer as besmirching the M3’s purity.

Not solely that, when the M4 confirmed up, it successfully cut up the M3 model in two. Just like the addition of compelled induction, this was one thing completely different and, like in so many elements of life, change will be laborious. Seeming to salt the wound, BMW introduced using augmented engine noise of their new scorching rods, a system that used a microphone to reinforce the engine sound and pipe it via the stereo system. Perceived as a gimmick, it left the fanbase flustered.

Nevertheless, these followers seemingly got here round – ultimately – after getting behind the wheel. That is as a result of this new S55-powered automotive made extra energy than the outgoing M automobiles, featured a flatter torque curve, and weighed much less. In different phrases, BMW took the M model heritage significantly and turned out a automotive worthy of the badge.

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S55 Technical Specs

In base type, the three.0L twin-turbo S55 inline-six discovered within the 2014 M4 made 425 hp from 5,500-7,300 rpm and 406 lb-ft of torque from 1,850-5,500 rpm. It was primarily based on the automaker’s N55 engine, sharing the identical block and displacement, however the N55 solely had a single turbocharger. To make it match for M obligation, the engineering crew went again to the drafting board, and the S55 was born.

Notable N55 Purposes

Adjustments made to the S55 included a closed-deck engine block, a light-weight crankshaft, strengthened pistons and connecting rods, a revised cooling and intercooler system, a cross-bank exhaust manifold, and, in fact, a further turbo. All informed, the S55 was extra highly effective, lighter, and extra gas environment friendly than the outgoing mannequin’s V8, whereas nonetheless boasting a 7,600-rpm redline.

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S55: What Was The Most Potent Model?

S55 Variants

All through its manufacturing run, the S55 inline-six noticed obligation in a number of higher-performance fashions with the requisite improve in output. Including the Competitors bundle to the usual M4 pushed horsepower up from 425 to 444, whereas torque remained the identical. The M4 CS dropped 35 kilos of weight versus the bottom M4, whereas including 10 hp and 36 lb-ft of torque over and above the Competitors mannequin.

Nevertheless, essentially the most highly effective BMW M4 engine from this F80 technology was the setup used within the M4 GTS. Boasting 493 hp and 443 lb-ft of torque, this street-legal race automotive was provided in 2015 and 2016. To hit these figures, BMW added a water injection system to chill the consumption cost, which helped with pushing increase strain from 17.2 psi to 21.6 psi.

S55 Widespread Issues

Although typically thought of a dependable engine, BMW’s S55 inline-six does have a couple of frequent issues to concentrate on. Maybe essentially the most regarding is a matter with the crankshaft hub malfunctioning. This could result in crankshaft spin, skipped timing, and doubtlessly catastrophic injury. It’s a steadily reported concern on the Bimmerpost discussion board and by way of NHTSA complaints.

Second-Technology M4: Twin-Turbo S58 Launched

In 2020, BMW launched the second-generation G80-series and with it the S58 engine. Sharing the S55’s structure, this revised 3.0L twin-turbo straight-six was nonetheless closely revised. A extra subtle turbo system was joined by a extra inflexible crankcase and cylinder head.

The compression ratio was lowered from 10.2:1 to 9.3:1, bigger turbos had been fitted, cooling effectivity was dialed up, and the engine might circulate larger volumes of gas. Between these updates and a lighter crankshaft, the twin-turbo S58 was concurrently extra highly effective and extra robustly constructed.

S58 Technical Specs

M4 Engine Comparability: S55 Versus S58

Out of the gate, the S58 engine made 473 hp at 6,250 rpm and 406 lb-ft of torque from 2,650-6,130 rpm with a 7,200-rpm redline. This was a 48-hp improve over the outgoing M4, although torque was unchanged.

In Competitors guise, the efficiency needle was turned up additional to 503 hp and 479 lb-ft of torque. With BMW’s AWD system, referred to as xDrive, that debuted as an possibility on the M4 in 2022, these Competitors fashions might do the 0-60 dash in simply 3.4 seconds.

S58: What Was The Most Potent Model?

2023 BMW M4 CSL Highlights

• 543 horsepower and 479 lb-ft of torque
• 0-60 mph in 3.6 seconds
• 1.02 g’s of lateral acceleration
• $139,900 base worth

Up thus far, essentially the most highly effective BMW M4 that includes the S58 engine is the CSL variant. A light-weight-focused mannequin, it comes with a hood, trunk, roof, and seats constituted of carbon fiber that assist scale back weight by 240 kilos. However essentially the most thrilling information is beneath the hood the place the increase will get turned up from 24.7 to 30.5 psi for scores of 543 hp and 479 lb-ft of torque. Nevertheless, with RWD solely, it is not truly as fast as an M4 Competitors AWD.

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S58 Widespread Issues

To date, there aren’t any main points reported with BMW’s S58 inline-six engine, which is basically because of the truth that it’s a comparatively new powertrain. It is also primarily based on the B58 inline-six from BMW, which is quick gaining a popularity for dependability – particularly by fashionable BMW requirements. The NHTSA studies no recollects or engine-related complaints with these G80 fashions and the boards are quiet. That mentioned, that is an especially high-performance engine that must be fastidiously maintained within the identify of avoiding any future issues.

Sources:
BMW
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Motor Pattern
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Bimmerpost
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BMW Weblog