[xlover]

Looks like the inside info (as usual) proved true.

In Competition spec, both versions have 503hp, but the G8X has 479lbft @2750+ vs 442lbft @2600+. Nice bump of 37lbft as well as at near the same peak start.

Obviously, based on X3 M owner feedback, the hope is off-idle lag mitigation. Between the obvious different physical configuration and seeing that jump from tuning, I am optimistic.

[SYT_Shadow]

Very interesting indeed. I wonder if the S58 in the M3/4 will receive a different designation like T0 or something

[SeanWRT]

Originally Posted by xlover

Obviously, based on X3 M owner feedback, the hope is off idle lag mitigation.

Where does that come from please?

[Avaley]

Originally Posted by SYT_Shadow

Very interesting indeed. I wonder if the S58 in the M3/4 will receive a different designation like T0 or something

Comp versions have T0 desig per the spec sheet

S58B30T0 vs S58B30O0 for 73 ft lbs of torque more.

[SYT_Shadow]

Originally Posted by SeanWRT

Where does that come from please?

Many X3/4M owners have complained there's lots of lag off the line

[xlover]

Originally Posted by SeanWRT

Where does that come from please?

as you know (because you are often in the vanguard on this site ) there is a group of x3m owners who feel the off idle lag in that version of the S58 is unacceptable, of course there are also those who notice and it doesn't bother and those who don't really feel it but the feedback is consistent enough that there is something there. With a clearly different tune I think expectations should be high that it was addressed (and if so x3m owners should write asking for this tune in their LCI next summer)

[SYT_Shadow]

Originally Posted by Avaley

Comp versions have T0 desig per the spec sheet

S58B30T0 vs S58B30O0 for 73 ft lbs of torque more.

Very interesting... mechanically I thought the two engines (comp and non comp) were identical and just the the tune changed, and then there was an additional difference between the comp M3/4 and comp X3/4M

Confusing, but to sum up if I've understood you correctly:
-Base S58 engine in M3/M4/X3M/X4M is identical
-Comp S58 X3M/X4M engine is called the S58B30T0
-Comp S58 M3/M4 engine is called the S58B30O0

EDIT: where have you seen this spec sheet?

[mkoesel]

Originally Posted by SYT_Shadow

Confusing, but to sum up if I've understood you correctly:
-Base S58 engine in M3/M4/X3M/X4M is identical
-Comp S58 X3M/X4M engine is called the S58B30T0
-Comp S58 M3/M4 engine is called the S58B30O0

Not quite. As mentioned in the specs table from the official release thread:

https://g80.bimmerpost.com/forums/at...5&d=1600779843

The base model M3/M4 uses the O0 while the Competition model uses the T0. As far as I know, the same is true for the X3/X4 M. I mean it's on Wikipedia, so it must be true.

https://en.wikipedia.org/wiki/BMW_B58#S58

But, no, in all seriousness I think they genuinely do use the same engines, it's just that as xlover points out, the ECU tune is different for the M3/M4 (higher peak torque).

[SYT_Shadow]

Originally Posted by mkoesel

Not quite. As mentioned in the specs table from the official release thread:

https://g80.bimmerpost.com/forums/at...5&d=1600779843

The base model M3/M4 uses the O0 while the Competition model uses the T0. As far as I know, this is the same case for the X3/X4 M. I mean it's on Wikipedia, so it must be true. But no in all seriousness I think they use the same motors, but as xlover points out, the ECU tune is different for the M3/M4.

I would think the engine itself is identical.

The S55 was available in several states of tune but I think it was always a S55

[Avaley]

Originally Posted by SYT_Shadow

Very interesting... mechanically I thought the two engines (comp and non comp) were identical and just the the tune changed, and then there was an additional difference between the comp M3/4 and comp X3/4M

Confusing, but to sum up if I've understood you correctly:
-Base S58 engine in M3/M4/X3M/X4M is identical
-Comp S58 X3M/X4M engine is called the S58B30T0
-Comp S58 M3/M4 engine is called the S58B30O0

Base is 0O0 in the non comp G8x models, while the comp will be the 0t0. Unsure on the XM series, but the T designations (atleast for the B series) have had different compression (11:1 vs 10.2:1 in B48 going from F3x to G3x engines) and slight improvements mechanically, as well as closer to the limit in terms of boost (uptuned more from factory).

Still trying to wrap my head around the exact mechanical differences but despite the S58 engine being brand new, BMW even over 1 model year will make slight adjustments to the engine.

The power from the factory going from first series Bx8 in F3x engines in (2016-19 MY) to second in G2x (19-present) resulted in about 10-20 more hp / tq.

[solstice]

Originally Posted by mkoesel

But, no, in all seriousness I think they genuinely do use the same engines, it's just that as xlover points out, the ECU tune is different for the M3/M4 (higher peak torque).

X3M and M3/M4 has different engines across the board as pointed out by lemetier. The X3M has a different intake system. It can clearly be seen under the hood.

[mkoesel]

Originally Posted by solstice

X3M and M3/M4 has different engines across the board as pointed out by lemetier. The X3M has a different intake system. It can clearly be seen under the hood.

Sure. I was addressing the discussion regarding the engine designations. Both vehicles use the S58B30O0 for the base model and S58B30T0 for the Competition model. Along with the intake/exhaust plumbing, I'm sure there are plenty of other small differences due to unique packaging requirements of the respective vehicles.

[OF Hero]

Any concern that the torque curve starts a bit higher (2750) than the F8X (1800)?

[solstice]

Originally Posted by mkoesel

Sure. I was addressing the discussion regarding the engine designations. Both vehicles use the S58B30O0 for the base model and S58B30T0 for the Competition model. Along with the intake/exhaust plumbing, I'm sure there are plenty of other small differences due to unique packaging requirements of the respective vehicles.

Yes, it’s a bit strange that the designation remain the same when ancillaries and ECU software is obviously different. You can’t order them from the model designation alone and expect them to fit.

[SYT_Shadow]

Originally Posted by OF Hero

Any concern that the torque curve starts a bit higher (2750) than the F8X (1800)?

probably larger turbos. The extra 50hp is coming out of somewhere for sure.

When you see the stage 1 tune power curves for the X3/4M you can tell the turbos are larger for sure. It can hold 600whp until redline.
The S55 can't hold even base power until redline

EDIT: The S55, even with aftermarket turbos, won't hold power to redline

[solstice]

Originally Posted by SYT_Shadow

probably larger turbos. The extra 50hp is coming out of somewhere for sure.

When you see the stage 1 tune power curves for the X3/4M you can tell the turbos are larger for sure. It can hold 600whp until redline.
The S55 can't hold even base power until redline

It’s a bit of a mystery. I hope lemetier can shed some light on this. Larger turbos causing a right shifted TQ curve would indicate more Turbo lag than the X3M not less. Similarly if the added TQ is from a more efficient intake system with the same blowers the TQ peak should not be delayed. If its mainly ECU tuning, why the delay the TQ?. It’s intriguing.

[xlover]

Originally Posted by mkoesel

Sure. I was addressing the discussion regarding the engine designations. Both vehicles use the S58B30O0 for the base model and S58B30T0 for the Competition model. Along with the intake/exhaust plumbing, I'm sure there are plenty of other small differences due to unique packaging requirements of the respective vehicles.

Right, we don't actually know where the line is for bmw engineers to change a designation, they might have huge leeway in tune and intake design but no leeway in valvetrain design....

I will add, in my opinion this adds support to the theory that the x3m was intentionally detuned off idle to give it driving characteristics more "SUV like" I suppose we won't know till later this fall when driving impressions are released.

[Avaley]

Originally Posted by xlover

Right, we don't actually know where the line is for bmw engineers to change a designation, they might have huge leeway in tune and intake design but no leeway in valvetrain design....

I will add, in my opinion this adds support to the theory that the x3m was intentionally detuned off idle to give it driving characteristics more "SUV like" I suppose we won't know till later this fall when driving impressions are released.

I’m willing to bet most of the lag is due to ECU undertuning combined with emissions filters.

Once the ECU is cracked and people are bolting on parts, I presume much of the lag will be gone.

Still, hardware wise, BMW engines can be wildly different within even the same designation and they even have changed valvetrain dimensions, compression rates, intake design, turbo design and even aluminum quality. Within the x4/58 engines I’ve seen some T designations having stronger crankshafts and more robust pistons still being the same designation ie both B58xxxx.

[solstice]

Originally Posted by xlover

Right, we don't actually know where the line is for bmw engineers to change a designation, they might have huge leeway in tune and intake design but no leeway in valvetrain design....

I will add, in my opinion this adds support to the theory that the x3m was intentionally detuned off idle to give it driving characteristics more "SUV like" I suppose we won't know till later this fall when driving impressions are released.

Agreed, it seems that way on all points made.

However, BMW’s “SUV like” is the direct opposite of my experience. SUVs are usually driven purely on low end TQ and rarely see mid and top revs or top speed.. Sport cars on the other hand are the other way. Turbo lag is worse for the usual SUV than a sports car IMO. So that explanation from BMW leaves question marks as to its authenticity.

To be clear the technical specs do point to that the SUVs get supporting TQ earlier than the cars but as I understand the comment of SUV like tuning was made to explain why the X3M has a large dead spot at low revs so that doesn’t match at all.

[mkoesel]

Originally Posted by solstice

Yes, it’s a bit strange that the designation remain the same when ancillaries and ECU software is obviously different. You can’t order them from the model designation alone and expect them to fit.

Indeed, but I don't think that this is particularly different from any other BMW engine, or really any other engine from any manufacturer. You'd typically have everything in the long-block assemblies shared between all vehicles, while fuel system, intake and exhaust manifolds, and electrical components might vary depending on application.

[super51fan]

I don't think it is fair to say this car has more lag than the X3 M's S58 until we see dynos to see when and where it makes power since these numbers only tell us peak numbers.

Although the M3 makes 479 @ 2750, there is nothing to say it makes more or less than 443 @ 2600 like the X3 M.

[xlover]

Originally Posted by solstice

Agreed, it seems that way on all points made.

However, BMW's "SUV like" is the direct opposite of my experience. SUVs are usually driven purely on low end TQ and rarely see mid and top revs or top speed.. Sport cars on the other hand are the other way. Turbo lag is worse for the usual SUV than a sports car IMO. So that explanation from BMW leaves question marks as to its authenticity.

To be clear the technical specs do point to that the SUVs get supporting TQ earlier than the cars but as I understand the comment of SUV like tuning was made to explain why the X3M has a large dead spot at low revs so that doesn't match at all.

Right in general the character of a traditional suv motor is more low end torque low rpm. but we need to think in absolute terms, the amount of power the s58 generates is substantially above a normal motor. I would imagine the business case for the x3m assumed a large amount of practical duty AND and continued expansion outside the historical M consumer base. The concept being "make it super easy to handle in the grocery lot" If you think about the violent low end power curve like the s55 has with awd traction it would shock the uninitiated as well as send all your Costco/Lowe's trip stuff in back flying on a quick launch.

Sure there are a ton of "well bmw could have done this or that to deal with it" ultimately it's just a theory but putting myself in the seat of a product owner about to launch an all new car with broadest appeal possible to the target segment I can see it making sense.