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-   -   BMW B58TU (M340i) vs S58 (M4) Engine : Technical Comparison (https://www.team-bhp.com/forum/technical-stuff/273702-bmw-b58tu-m340i-vs-s58-m4-engine-technical-comparison.html)

The S58 engine in the BMW M4 is based on the B58TU engine from the M340i, it’s been possible to carry over a number of engine components from the B58TU standard production engine.

https://youtu.be/1bQZNUux3ak

^ Above video highlights the same & charts out the similarities, differences & part sharing between these two engines featuring the BMW G20 M340i which is the M Performance model & G82 BMW M4 from the BMWM stable.

For those who prefer text may read on as under;

Introduction;

The BMW B58 engine is found in many cars like the M340i, X3M40i, X4 M40i, Toyota Supra etc. & the BMW S58 engine is found in cars like the M3, M4, X3M, X4M etc. However today's discussion is going to focus on 2 cars with specs. as under;

G20 M340i is a M Performance BMW with the B58TU (Engine Code: B58B30O1) producing 382 HP.

&

G82 M4 is a M Power BMW from the M stable with the BMW S58 (Engine Code: S58B30T0) producing 510 HP (Competition Spec.)

Though the S58 is based on the B58TU but only 10% of the components are same & 90% are different or new or present in some sort of an upgrade.

Let's discuss the Similarities first;

- Chain Drive is the same for both these engines;



^ Timing Chain and the Guide Rail have been adapted to the S58.

- Intake Valves are the same just some material changes to adapt to the S58.

- VANOS concept is the same & carried over with some adaptations;



- Injectors are Same;



- DME is same for both the cars;



^ Has its own software (8.6.S) though for the higher tune.

Differences;

- S58 has 2 Turbo Chargers where as the B58 is a single turbo engine.

^ This is where the S58 makes the bulk of its power over the engines it's based on i.e. B58TU.

- S58 gets 2 Air Intake Ducts v/s 1 in the B58TU;



^ above are the 2 major differences distinguishing the 2 engines but lets also discuss the other part changes, adaptations which the S58 does over the engine its based on.

- S58 gets a New Cylinder Head Gasket;



^ Cylinder head gasket design was revised due to higher combustion pressure of S58 engine.

- New CrankCase;



^ Adapted for Bi-Turbo setup.

- Forged Crankshaft (LightWeight);



- Forged Pistons;



^ Made out of M142P alloy.

A New Exhaust system;



Note above is the standard M Sport Exhaust, M Performance would be different.

- New Cooling System;



^ More Power requires more cooling.

In addition to above changes & adaptations the S58 gets some changes in the Oil supply (Additional Oil Sump lid) & a new (Single Stage) Vacuum Pump :thumbs up

Video posted above in Post #1 has a segment where in I take the S58 engine (M4) for a drive;



So the core narrative around the G82 M4 or the G80 M3 has been about its styling and how controversial its front nose is, but in the middle of all this we should not forget how fantastic it is to drive.
So I have driven the M4 on a couple of occasions previously, once on a drive organised by my dealership and the 2nd time was at a track day event. Both times I have had the opportunity to go all out and experience the power of the S58. But this drive was about how it drives in regular local city conditions at moderately brisk speeds.
Immediate impressions about B58 v/s S58 topic is that the B58 feels more refined & relaxed in the city, whereas the S58 feels more raw & eager.
The torque down under & mid range feels more abundant v/s the B58.
B58 redlines @ 7000 rpm where as the S58 has a 7500 rpm redline.
Quick talk about the exhaust, so my M340i with the M Performance exhaust sounds better than the stock M4 S58, it's true. Both engines sound similarly good but in this car the OPF really restricts the drama. May be an OPF delete should be considered for the M4 owners.
Overall the S58 in the M4 feels like a typical M Car engine where the performance is mega, Limits are approachable & most importantly it's easy to drive fast.

Final Thoughts;

If these cars were into bodybuilding then the B58 is only on protein shake and a natural where as the S58 is the one on steroids. To conclude things it would be fair to say that the B58 is the leader in 6 cyl technology for non M Cars, where as the S58 is bigger on power having a proper Motorsport inclination opening up the possibilities for the tuning world and aftermarket modifications. So the right way to say is that the S58 engine is the more heavy duty B58 engine & the B58 has heavy duty potential.

Excellent comparison Karan, always been a subscriber of your videos due to the pure and unbiased content you produce with high technical tidbits and this video is no different. I felt the production value has gone up considerably as well :thumbs up. Coming back to the car, BMW has made an excellent everyday car in M340i and I feel for our conditions it's a much better car to live with (my personal opinion and not being biased at all).

This hits home for me, being fan favorite - the mod support for B58 is tremendous and it's possible to reach stock S58 numbers with just a couple of things without sacrificing daily driving or comfort. Honestly the do it all engine for me for sure!

Hi Karan. Thanks for the information. Very interesting. I just bought the X3 M40i and loving it so far. Curious to know if the B58 unit is the same as M340i? The power is down by 15 Hp to 360 in X3 M40i though. Will post my review very soon.

You hit a home run with this paragraph. A lot of us (myself included) have struggled to get past the way this car looks. I bet that if I drive one, I'll start to appreciate the fine engineering that BMW have put into this mad machine.

Thanks for sharing the spec differences between the two engine series. Its always interesting to read this.

Nice comparison and pretty detailed.

While I personally know these differences from the last 3 years that I owned the B58, wish you covered more aspects on how they compare with respect to " daily driving".

I'm on multiple BMW forums and this comparison (B58 vs. S58) is a pretty common discussion and discussed multiple times.

Have always noted that the final favor is always in terms of the B58 purely for the reason that it's a superior engine for "Daily Driving" as not everyone who buys the car goes to a track. In fact, many buyers who buy the S58 also never go to a track in their lifetime. They then realize that it's better to get the B58 instead and use it daily as how it should be.

Just one clarification- All other global reviews says that B58 has more torque below the rpm than the S58 but, your review says otherwise.

Tons of folks have switched from S58 to B58 purely for aforementioned reasons.

One personal experience :

You may know the glorious and only V10 engine from BMW in the old M5 that produces 525 HP .

I did have a friendly drag with it and left it for dust even though the comparison is not apples to apples (N.A vs. Turbo Charged). :)

Hell, yeah. B58 is the most popular BMW engine for mods (basic as well as advanced) and it's proven that its horsepower can be bumped up without any engine modifications to almost 750 WHP.

Congrats on your X3 M40i. Welcome to the X3 family.

Yes. It's the exact same engine from M340i but, tuned slightly differently.

This is news to me that Indian X3 M40i is a detuned version. Mine is a 382 HP version.

Finally, this is one of the finest articles ever written on "B58" engine. It's simple, easy to understand and describes perfectly how this glorious engine behaves.

https://www.bmwblog.com/2021/12/20/b58-best-bmw-engine/

I have this article memorized since it came out. rl:

Thanks for the compliments :thumbs up
Truly.
Congratulations.
Yes, but I believe its the B58B30M2 in the X3 M40i, not exactly sure.
Thanks Sandeep for your appreciation towards my content :thumbs up
Thanks mobike.
Thanks for sharing your thoughts, I personally could feel the extra 150 NM hence reported.
This was just more of an engine v/s engine parts, changes & adaptations breakdown video/thread. The driving bit was just bonus. This content was crafted to let people understand the differences between the two engines which have a same name based on each other but many parts being different and not same. Globally the difference (pricing) between the M340i & M3/4 would not be much but in India the M340i is 1/2 the price.
This content was also dedicated to users to understand the part changes, adaptations, material selection etc. which go into engines to produce that extra HP / Tq. numbers. Hence performing wild tunes on stock engines without hardware upgrades is a bad idea longevity wise.

Interesting thread Karan, with good information. Will make people understand what all the M division does to the S58 to make it different from the B58. In fact I am surprised to see most of the internals are different. I guess you get what you pay for!

Not too sure what an engine has to do with daily driving? While some may say the proper M cars are bit too stiff, etc for daily driving. This is the first time I'm hearing about an engine for daily driving. The S58 is a purpose built engine, and I don't understand why we are getting into this S58 vs B58 debate?

You mean tons of folks have changed from the S58 to the B58? For what reasons? This is just bewildering. I mean unless the car itself was too impractical, there is absolutely no reason I would change my M3 (yes it has the S55 engine) for an 340i or anything equivalent.

The S85 BMW V10 produces 507 horsepower, and that too full power is available only if it is in one of the M modes. Anecdotal evidence from one drag race serves no purpose. Your vehicle is about 12 years newer, with a much faster shifting gearbox with launch control, and all wheel drive.

The article you have listed doesn't provide any real information either. Its just general information on the engine with no technical information to prove its point.

The B58 is a great engine, no doubt. But at a lower budget than the S58. And all those saying its the best, etc are just justifying it to themselves because they don't have the S58.

Nice one Karan. I guess we know what you are upgrading to next. lol.

The M4 is the perfect upgrade from your M340i unless you want the M2.

I see M340i owners have their eyes set on the M2 which is the S58 as well and an upgrade over the B58 vs the M4 which is steeper price jump.

With the M340i, X3 M40i and M2 priced close to each other, only a person who wants a practical option would even look at the M340i or X3M40i over an M2.

Sorry, my bad. I type fast and many times without thinking. Let me clarify.

Along with other aspects (which I will get into in a moment), engine plays an important aspect also in daily driving primarily for reasons of low-end torque availability which is most important aspect for daily driving.

I have a global and local view of what’s happening in this space. Like I said before, I can give tons of examples of folks moving from S58 to B58 as its :

1. More Fuel Efficient (M cars sucks gas like nobody’s business)
2. Harsh Riding which isn’t conducive for daily driving
3. Higher Revving engine perfectly suited for tracks

Thankfully, for us living in US the difference between a B58 and S58 isn’t much.

Just a 10 grand difference. Anybody spending $70K on a B58 can easily fork in another $10 grand for an S58. Yup, such a meagre difference. If I get into pre-owned, it's even more affordable.

During the purchase process, above factors come into the picture and volume buyers choose B58 as they want to use it daily to go to office, grocery shopping, weekend outings and still get the zing that this engine provides.

S58 is no doubt an amazing engine and more powerful than the B58 and is truly special for the purpose it’s built- Racing on track.

Heck, if I had the money, I too would buy an S58 (but, just for weekend spins and track usage).

Did you read the title of this thread and content or just replying to my post? :D

The premise of this thread is comparison of a B58 with an S58.

Hope your bewilderment is sorted after my explanation above.

I don’t know that you own an M3 (since it’s not documented on forum, or is it???).

I am curious to know how do you use your car?

I mean where do you drive it and have you explored the full potential of it? I am sure you don’t do that on Mumbai roads and have to go to a track to enjoy it throughly.

My ownership is documented here on the forum. I have driven my B58 in every possible conditions that a man can drive in and after clocking nearly 50,000kms I have a fairly good understanding of this gorgeous engine.

Hence, I said it was not an apples to apples comparison but, just a fun fact.

B58 will keep beating the V10 in any drag race as by the time it comes into power band the race is over.

Not every buyer is technical. This article is for “real” BMW buyers who have the money to buy it and not get into the technical aspects of it to make a decision.

They buy after a test drive (not reading technical details of the engine) and how they feel about the overall car. Most of the times every B58 test drive results into a purchase as per what I see on the forums. LOL!!

This article is for the layman- simple, clearly lays out the strengths, weaknesses and most importantly it’s diversity.

This is like the Apple vs. Android war.

It’s fun and in lighter vein and nothing serious about it. :thumbs up

There is no definitive winner here as every buyer has their own priorities.

While looks are subjective we should cherish the fact that BMW still makes the 3.0L, 6 Cylinder engines in M cars unlike Mercedes with their 2.0L 4 pot branded as an AMG!

Nice comparison, Karan561. Thanks for sharing.

I too, was surprised by how different the engines are. I thought the S58 was a better version of the B58 until a friendly enthusiast mechanic pointed out to me last year that the B58 and S58 have completely different internals. The Bore x Stroke for the B58 is 82 mm x 94.6 mm (=2,998 cc) whereas the same for the S58 is 84 mm x 90 mm (=2,993 cc).

Having driven the S58 & B58 powered cars (M3C, M340i, M440i) and the '08 V10 M5, I can say that they are clearly engines of a different era.

The I6s are amazing engines with a great mid-range and they love to rev, but the V10 is insane with its 8,250 RPM redline and E-N-D-L-E-S-S power reserves :)

Sorry if I'm being a bit nit-picky.

1) Yes I see that now that you mention it.

2) Exactly, as I said. The S58 comes in the full blown M cars. The cars themselves are purpose built (though the newer ones are getting softer and more useable). So anyone who is switching probably found the vehicle itself a bit more impractical, and moved to a vehicle which provides more comfort, practicality with some of the feel of the full blown M.

3) Well there is a difference between a comparison and a debate.

4) Its not documented on the forum yet. I bought a full blown M knowing it will be my night and weekend car, since I have other vehicles for regular use. I bought it for the pure feel which it provides, and I don't need to being driving like crazy to enjoy it. I have enough fun driving it on Mumbai roads too, and I take it to the track once in a while to explore its potential (since exploring its potential on public roads would have me behind bars, surely you know that).

5) Depends where the race gets over

6) So you mean the automotive enthusiasts buying BMWs (or any other car) don't care about technicalities? Well that's news for me. The M3 was our 7th BMW in the family, and I am on the lookout for another one in the near future. But I certainly did look at the technicalities and the spec sheet and did my due diligence before taking a test drive.

7) Actually its like an Iphone vs Iphone pro max war.

But your last line what I have highlighted in bold is what is true. For you the B58 serves your purpose, for some the S58 serves their purpose. There is no better or worse.