[Turbanator]

Originally Posted by mobike008

wish you covered more aspects on how they compare with respect to " daily driving".

That's a genuine question, but a lot will depend on the end user. Many folks like to rev harder or don't bother about stiff suspension (age can be one - as I notice how my son drives vs myself?)

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

Originally Posted by karan561

I personally could feel the extra 150 NM hence reported.

Originally Posted by mobike008

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.

Originally Posted by navin

The volume of a cylinder is Pi*r2* h; hence, the mass of the cylinder would be Pi*r2*h*D.

If we refer to these charts (if relevant today- upgrades?), much more torque is available on B58 at very low RPMs- 450Nm @1380 rpm. Perhaps that might explain the difference in daily driving, for sedate drivers. But, the experience can indeed be different depending on who is driving.

I must also add, from my personal experience, the first time I went to check the M340i, I asked myself what all the noise was about this car. I could push the accelerator all the way to the floor; it was simply no match for my ride at that time, an M5, where I could barely push the accelerator beyond a point. Later on, when I went to check a 330i for a known, and then drove the M340 it was much nicer (fast) I haven't had a chance to drive the new M4 yet, so cannot comment but let me try to find one and update here.

[thecarguy]

Originally Posted by navin

Can anyone explain if the bore-to-stroke ratio has any bearing on the power-to-displacement ratio and why?

That’s a very complicated question you are trying to find the answer to. I think there are so many factors that come into play given that there are some constants(rate of combustion, piston speed etc) that apply differently to different bore/stroke ratio that there will be no meaningful correlation to be found.


Maybe someone else more mechanically aligned can correct me and answer this.

[karan561]

Originally Posted by Turbanator

If we refer to these charts (if relevant today- upgrades?)

That B58 chart is of the lower spec B58 (450 NM) & not the B58 technical upgrade (TU) one which is discussed in this thread since the opening post and engine in the M340i (500 NM) gets the B58TU which is also called B58D & full engine code is B58B30O1.

[Turbanator]

Originally Posted by karan561

full engine code is B58B30O1.

Yeah, I thought so. These guys usually keep updating stuff regularly.

Are the changes significant? I can only assume B58 got even better torque at lower RPM's? Were you able to find any such info for the newer engine?

[karan561]

Originally Posted by Turbanator

Yeah, I thought so. These guys usually keep updating stuff regularly.

Are the changes significant? I can only assume B58 got even better torque at lower RPM's? Were you able to find any such info for the newer engine?

Turbanator Saab,

B58B30M0 (340 HP & 450 NM) v/s B58B30O1 (382 HP & 500 NM) will open a new topic now

Lets stay on this topic (B58TU M340i v/s S58 M4) for now, Thanks

[Turbanator]

Originally Posted by karan561

B58B30M0 (340 HP & 450 NM) v/s B58B30O1 (382 HP & 500 NM) will open a new topic now

It's ok. I thought about this due to the observations of fellow members about driveability. The idea was to mention the high torque this engine generates at low RPMs.

Looks like there is another update on this - TU2 - or is it the same that you referred here? (I see similar power ratings).

The B58 was first updated in 2018 for the 2019 model year (B58TU1), which makes this the engine’s second revision.

The new B58TU2 engine uses the Miller cycle for increased efficiency and features redesigned intake ports and combustion chambers, an electronically controlled Vanos variable camshaft timing system, and an ignition system featuring an active coil with integrated electronics. The turbocharging system including the intercooler has been optimized, while the cylinder head and exhaust manifold are now one integrated component, as they were on previous lower-output versions of the B58TU1. This is in contrast to the 382-horsepower B58B30O1, which uses an exhaust manifold with an integrated turbocharger as opposed to a cylinder head with an integrated exhaust manifold.

https://bimmerlife.com/2022/04/22/bm...hnical-update/

[karan561]

Originally Posted by Turbanator

Look's there another update on this - TU2 or is it the same that you referred here?

TU2 is mild hybridised.

Hence, if people are reporting better torque at the low end, it's due to this 48V mild hybrid system.

M340i LCI has a mild hybrid system which would feel more torquey at low RPM & also more fuel economical.

[Reesnat]

I don't know the internal technical details as much to comment, but as someone who's had a lot of seat time in the B58, S55 and now the S58, from a practical standpoint, these are the key differences:

B58 - Fantastic all round engine for everyday use. Great low down torque, extremely smooth and fun to drive. Looses out on the top end.

S58 - Massively upgraded engine that can do tons and tons of power but because its designed for higher horsepower, and uses bigger turbos, the low end isn't as alive as the B58. BUT, get past 3k RPM and this engine will pull like a freight train until redline in a way no other 6cyl engine does today on the market.


Other important aspects to take into account that go beyond the internals is the supported cooling package and the gearbox its paired with. The B58's cooling is not great and will pull power in hot conditions. Furthermore the ZF version of the gearbox paired with the B58 also isn't as strong and will pull torque once it gets hot. So on a track day, dont expect the B58 to survive more than a couple laps at a time, it will get all sweaty and pull power across the board.

The S58 on the other hand has a very impressive cooling package that's designed to survive track use all day long. And a much stronger ZF gearbox that can support much higher torque and has a dedicated cooler to itself. An S58 will happily do a full track day without breaking a sweat, unlike previous M cars or even many Italian supercars.