Let's be honest, all of us Indian car enthusiasts has a crush on some or the other iconic cars, and a lot of it has to do with their really good engines. Some of those engines make great power, some of them sound like music to our ears, some of them are exotic and some of them are a very capable platform for tuning, but such cars hardly ever made their way to the Indian market, leaving a car sized void in all of our hearts, right? However, where on one side we are seeing our favorite engines getting replaced by soul-less batteries, surprisingly there is this one engine which can pretty much make-up for those voids. This engine is very reliable, is a hoot to drive, returns good fuel economy, has tons of tuning potential, is capable of making big horsepower numbers right from the factory, and the best part about it: It is also thankfully available in our country! Here is your introduction to that very B58 engine which not only powers the FASTEST CAR MADE IN INDIA (the M340i) but is also one of the best and most capable engines on the global market today!!!
Getting Introduced To The B58
BMW has the reputation of being the 'KING OF INLINE 6 ENGINES' and have more than a century worth of history of making inline-6 engines, right from making engines for aircrafts back in 1917 when they weren't even an automobile company. Having produced some great modern turbo inline 6 engines like the N54, N55 and the S55, the wizards at BMW finally decided to make their best inline-6 ever, the B58!! It was first introduced in 2015 (in foreign markets) with the LCI version of the F30 340i, and it replaced the N55 engine which was used in the F30 335i and many other BMW cars. And as all good things take time, the B58 too did not make it's way here to the Indian market until 2019, and although it gained recognition from powering the enthusiast's favorite - M340i, it actually first debuted in India in the BMW Z4 (G29). This made the B58 the first 'Non-M' 6 cylinder offering since 2012 in their 3 series lineup for our country.
Different iterations of the B58
Just like many other engines from BMW, the B58 also received timely revisions and technical updates over it's course of time. Here are the details of all the revisions BMW did to their B58 since it's launch:
Gen1 B58: This version of the B58 was launched in 2015 in overseas markets but was altogether skipped for India. It came only with a 2 port cylinder head configuration and had a rather high compression ratio at 11:0:1. The biggest limitations were it's 2 port exhaust which caused a bottle-neck in the higher revs and also the HPFP (high pressure fuel pump).
Gen2 B58: Codenamed as B58TU (technical update) was launched in 2018, and this was the engine that made it's way to the Indian markets with the Z4 in 2019. This engine was made with both 2 and 6 port configurations, former of which pushed out 335hp (for ex: Z440i, X340i, 740Li etc) and the latter made around 386hp (for ex: pre-LCI m340i) The noticeable changes from the gen1 B58 were:
Gen3 B58: In 2022, BMW replaced both the 2 port and 6 port B58TU engine with the B58TU2 based on the 2 port B58TU. The noticeable upgrades over the B58TU are as follows:
Technical specs of the B58 (TU2)
The B58 is a member of BMW's new modular engine family which includes the likes of B58, B48 and the B38 for their petrol engines. The B48 engine is a 4 cylinder unit available in lower variants like the G20 3 series in India and the B38 is a 3 cylinder unit used in some smaller cars abroad. The B58 however is a 3-liter turbocharged inline six-cylinder DOHC engine, with a single 'twin scroll' turbocharger and dual injection fuel system which includes both, fuel injection and port injection and has a compression ratio of 10:2:1 in it's current avatar. The latest iteration of this engine makes around 375hp and 500nm torque, which translates into a power bump of around 40hp as compared to the previous 2 port engine but torque remains same at 500nm. However, this engine does comes with slightly different states of tunes across the BMW lineup. It also has a 48V mild hybrid setup with a 11hp electric motor, translating into even better low end performance and improved fuel efficiency. Interestingly, the bottom end is based off the B57 diesel engine, which gives it a long stroke setup and has a oversquare setup which means it has a shorter bore of 82mm as compared to its longer stroke of 94.6mm. The engine block of the B58 has a closed deck design and is a cast aluminum construction housing 'semi-forged' internals, as in a forged crankshaft and also forged connecting rods, but cast pistons. The low end response is extremely good giving it plenty of torque at low revs, which starts to build right from under 2k RPMs, and the engine revs all the way upto 7000 RPMs, which is pretty high for a modern turbocharged engine.
The engine also features BMW's Valvetronic system which provides infinitely variable intake valve lift which works directly proportional to your throttle input giving instantaneous response, hence functionally replacing the role of the butterfly valve in a throttle body. It also has a Double Vanos system which continuously varies the timing of the intake and exhaust valves with respect to engine speed and throttle input. However the Valvetronic and Vanos systems are not exclusive to the B58, but present across all BMW engines. BMW also introduced a set of new 6 low pressure fuel injectors to allow port injection in addition to the already existing high pressure direct injection, making it a dual injected system. This is just half the picture as this engine also has a lot of impressive bits built into it, like coated bore liners, cracked connecting rods, honed cylinders, oil squirters, advanced cooling systems and a whole bunch of other things which greatly contribute in making the B58 a lot more reliable, efficient and robust. We already have one of the most in-depth blog on the internet where we not only site but also explain all of these technologies in great detail, and we guarantee that you will definitely find it very informative. You can find the link to it at the end of this blog, until then please continue reading 🙂
Getting Introduced To The S58
Any BMW engine which doesn't start with the letter 'S' isn't the best what they can do, so in 2019 BMW released the S58 based on the B58TU engine.
The S58 is basically like a race engine for the streets and is more capable and robust than the B58, and once the boost kicks-in, it pulls away like it's nobody's business and it's 100-200kmph times are only comparable to supercars. However, it is almost twice as expensive than the same B58 which it is based upon, especially here in India as it is a 'M' specific engine. The B58 on the other hand is comparatively much more accessible and delivers better low end performance and fuel economy, and is a much more usable engine in daily life.
B58 as a Daily Driver
BMW which was once infamous for making unreliable engines, has this time built or rather OVER-BUILT this engine with very strong internals and robust engineering, earning it the 'Ward's World's 10 Best Engines Award' four times. The biggest testimony to the quality and reliability for this engine is that it is the very same engine which Toyota has used in their Mk5 (A90) Supra. Toyota did actually do extensive stress testing of this engine for their Supra, and if this engine is good enough for Toyota then it is definitely trustworthy. Although, just like any other engine on the market it has had a few niggles, but none of them are catastrophic failures and most of them have been sorted out to a large extent. This same engine in the new LCI lineup of BMW cars gives around 6-7 kmpl in city and 11-12 kmpl on highway drives, which honestly isn't too far away from most of the turbocharged petrol cars, especially considering it is a powerful 6 cylinder engine. The long stroke setup assisted by the mild hybrid technology translates into a very peppy low end performance. The ZF8HP transmission which comes paired with almost all BMW's with the B58 engine is a 'match made in heaven' as it is the probably the best torque converter gearbox on the planet, and provides with very quick and precise shifts while also making sure the engine stays in it's powerband at all times, which accentuates the driving pleasure.
B58 as a Tuning Platform
Since the basics are already sorted, let's jump on to the most exciting part. The B58 engine is capable of killing supercars and tuners all over the globe have already started to go all-in on this platform! Since the ECUs on the gen3 cars are still locked, let's have a look at 2 pre-LCI (gen2) tuned m340is to understand how much power can be pushed out by the B58 with just simple bolt on mods and a tune.
The stage 2 car only has a few basic mods like an upgraded heat exchanger, an aftermarket air intake and a decat downpipe and the stage 3 m340i has only a couple of extra mods like an upgraded intake manifold and an aftermarket hybrid turbo, but look at the power gains compared to the stock car, impressive right? And even at those levels, the B58 doesn't break a sweat and can make 800+hp without opening up the engine and it's bigger sibling, the S58 is even crazier and can push out 1000hp on just the stock internals.
Making such high power figures have hardly been so reliable and easy, especially in the Indian market where we hardly got any tuner cars, and the sole flag bearers of tuner cars for the masses have mostly been VWs and Skodas. One of the best tuning platforms prior to the B58 was considered to be the EA888 2.0 TSI engines in the Skoda Octavia VRS, and a lot of VRS owners have already upgraded to the m340i solely for it's B58 engine. And the interesting part is the stage 3 m340i with basic bolt on mods pushes out as much if not more power than the fastest VRS in the country which has a built engine! The Audi S5 with it's great V6 TFSI engine and the Mercedes A45s AMG with the most powerful 4 cylinder engine on earth are some really good options as well, and definitely deserve a lot of appreciation. The A45s is infact makes slightly more power and is much more committed than the m340i, however the B58 takes the cake when it comes to producing and handling higher power figures and at being a much better tuning platform.
We hope that you got a lot of technical insights on this gem of an engine, but actually this was 'just the tip of the iceberg'. We actually have a dedicated blog on what makes the B58 engine so reliable and capable for tuning and modifications, where we take a deep dive into all the technical details to understand what all technologies are built into the engine, why Toyota chose the B58 for their Mk5 Supra, how much power can the B58 and S58 engines make after tuning and we have also compared it to the most famed engines of all time, the 2JZ!! Make sure you give it a read and we guarantee that you will be in for a treat! You can read it by clicking on the link given HERE . There are a lot of such high quality automotive blogs waiting for you on our website, where you can also get paid consultancy with Munish Ji for any car related inquiries and expert advice and browse through some genuine used car deals. Please consider to subscribe our YouTube channel as well, and thank you for your time!!