[Di3s3l_Power]

Looking at 45e technical specifications it shows:

ICE 286 hp and 450 Nm torque (331 ft lbs)
Electric 113 hp and 265 Nm torque (195 ft lbs)

sum together and you get 399 hp and 526 ft lbs torque compared to 394 hp & 443 ft lbs torque

Why? peak electric motor doesn’t intersect with peak ICE engine, especially on torque values ???

[TurtleBoy]

All hybrids are like that as far as I know. You can never get the max out of each at the same time is how I saw it explained.

[Di3s3l_Power]

Originally Posted by TurtleBoy

All hybrids are like that as far as I know. You can never get the max out of each at the same time is how I saw it explained.

Got it, the power area under the curve (hp & tq graph) should be higher than an equivalent rated ICE engine

[sigmabody]

Originally Posted by Di3s3l_Power

Why? peak electric motor doesn’t intersect with peak ICE engine, especially on torque values ???

I think it's probably a function of the HP/TQ being an oversimplification of the torque curves for engine operation modes (HP just being peak torque ratio-relative to a specific engine RPM). It can also be messy with EV's because of gearing, I think.

I suspect that if you graphed the aggregate torque curve for the combined output in a specific engine mode, you would get the peak torque and peak HP quoted, or close. The torque curves would show a more complete picture, though.

[sigmabody]

Originally Posted by Di3s3l_Power

Got it, the power area under the curve (hp & tq graph) should be higher than an equivalent rated ICE engine

This is not necessarily true... the curves just look different. EV motors have a flat torque curve from zero, which usually drops off after a specific speed; see https://www.carthrottle.com/post/how...nstant-torque/ for example. If you add in an ICE, it makes the graph more wonky (high torque initially, then maybe slight drop off, then the ICE may catch up). The EV motor part of a PHEV isn't going to move the needle much on HP, though, since that's weighted by engine speed (ie: the same torque value at 6k RPM is much higher HP than at 3k RPM).

That doesn't mean a pure ICE cannot have more area under the curve (especially if it's high revving and/or high torque); the PHEV just "bumps up" the lower torque values in the ICE curve. That doesn't usually translate into significantly higher HP, but instead gives you a more expanded effective power band, which can feel better in the real world.

[eelnoraa]

Originally Posted by Di3s3l_Power

Got it, the power area under the curve (hp & tq graph) should be higher than an equivalent rated ICE engine

My understanding similar to TurtleBoy

ICE motor has an up side down "U" shape torque curve. so peak UP will be at rather high RPM because power = RPM x torque x constant ratio. As long as torque doens't drop significantly, higher RPM, higher power.

EV has the max torque at 0 RPM, as RPM increase torque reduce. So peak power of EV will be at much lower RPM

Since ICE and EV motor is couple before the gear, if they are both active, they will spin at same RPM. Peak power doesn't line up. Same as idea should apply to torque curve as well. I wonder if anyone has a torque/power vs RPM curve for this EV motor, we can line it up with ICE curve to confirm

[nordring]

One thing that I think can be safely said, is the X45e makes more than the stated 394 hp.

The normally conservative Motorweek recorded a 0-60 time of 4.7 seconds.

Saw a calculation somewhere, that I can't find at the moment, that showed its virtually impossible for a 5500-5600# vehicle to accelerate to 60 in 4.7 secs, with only 394 hp

I don't have any experience with these types of calculators, but this one shows you would need closer to 500 HP at the crank to approach a 5 second 0-60 in a 5500# vehicle.

https://www.assassinracing.com/tech/0-60calc.html

[TurtleBoy]

Originally Posted by nordring

One thing that I think can be safely said, is the X45e makes more than the stated 394 hp.

The normally conservative Motorweek recorded a 0-60 time of 4.7 seconds.


Saw a calculation somewhere, that I can't find at the moment, that showed its virtually impossible for a 5500-5600# vehicle to accelerate to 60 in 4.7 secs, with only 394 hp

I don't have any experience with these types of calculators, but this one shows you would need closer to 500 HP at the crank to approach a 5 second 0-60 in a 5500# vehicle.

I am by no means an expert but it seems to me that someone put a lot of time into a calculator that means nothing. Obviously they are related but it is torque that is more important in determining the rate of acceleration and not HP. I could be wrong but always think of it as torque gets you there, HP keeps you there.

[eelnoraa]

Originally Posted by nordring

One thing that I think can be safely said, is the X45e makes more than the stated 394 hp.

The normally conservative Motorweek recorded a 0-60 time of 4.7 seconds.

Saw a calculation somewhere, that I can't find at the moment, that showed its virtually impossible for a 5500-5600# vehicle to accelerate to 60 in 4.7 secs, with only 394 hp

I don't have any experience with these types of calculators, but this one shows you would need closer to 500 HP at the crank to approach a 5 second 0-60 in a 5500# vehicle.

https://www.assassinracing.com/tech/0-60calc.html

I won't read too much into this. There are too many unknown assumption. And if we go by theory, then energy conservation is the only way. Car's kinetic energy at 60MPH, and HP (Watt) integrated over time. I think if we do this, 45e's rated HP will do it comfortably, because no lost is considered anywhere.

Now, if we need to consider reality, things get exponentially complicated which I don't think the simple parameters this site ask is enough. We will need to know tire traction, gear ratio, torque convertor efficiency, shift speed, engine placement, suspension setting .... The fact that this site ask for AWD/FWD/RWD input, it make some assumption on traction.

[eelnoraa]

Originally Posted by TurtleBoy

I am by no means an expert but it seems to me that someone put a lot of time into a calculator that means nothing. Obviously they are related but it is torque that is more important in determining the rate of acceleration and not HP. I could be wrong but always think of it as torque gets you there, HP keeps you there.

I think it is HP that matters. Torque get you offline fast at low RPM. Once RPM reach higher range (at 1st gear), it is HP matters. High HP mean high "torque x RPM".

The extreme example is if two exactly cars, same weight, same gear, same tire ... And their engines have exact same flat torque number, except Car1 has redline at 4K RPM, Car2 has redline at 8K RPM. Both car will launch the same, but car1 need to shift at 4K RPM, torque@wheel wheel is reduced by gear ratio. Car2 can keep the low gear until 8K RPM. Car2 will accelerate faster beyond 4K RPM. The difference between them is NOT torque value, it is HP.

Now, it obvious depend on what speed we are trying to achieve. Most modern auto transmission car reach 60MPH with 3rd gear at redline. Manual or older auto (6 speed) will reach 60MPH with 2nd gear at redline. Since we have to max out 1st to get to 60, it is HP. For speed that we can remain on the same gear, it is torque that matters tho. That lead to everyday usage, here is where torque matter too, because we hardly drive at peak hp rpm.

[TurtleBoy]

Originally Posted by eelnoraa

I think it is HP that matters. Torque get you offline fast at low RPM. Once RPM reach higher range (at 1st gear), it is HP matters. High HP mean high "torque x RPM".
.

After I posted I did some searching and it appears that the "torque v HP debate" is a common one. After reading many articles on it I just came to the conclusion that both are important, a lot easier that way.

[sigmabody]

Originally Posted by eelnoraa

I think it is HP that matters. Torque get you offline fast at low RPM. Once RPM reach higher range (at 1st gear), it is HP matters. High HP mean high "torque x RPM".

Torque is what matters, actually, or more specifically the torque curve (torque per engine speed). HP is just a simplification of the peak torque/RPM combo point (HP at an RPM point is torque multiplied by the ratio of RPM/[fixed], where [fixed] is 5200 iirc). So there's a HP curve also, but it's strictly derived from the torque curve.

I believe HP is/was "commonly" used because the belief was that a higher-revving engine was better, since (a) that meant less shift points, and (b) that meant you could use less gearing to get the same performance. But the torque curve is the definitive measurement of effective performance.

EV/hybrid vehicles invalidate some of the conventional wisdom, since they can provide torque during ICE shift points (and/or don't have shift points). This makes RPM somewhat immaterial, and thus HP immaterial, although the torque curve is still relevant (since EV motor torque drops off at higher motor speeds). EV motors also give better real-world performance than HP numbers would suggest, since they don't have the traditional ICE torque curve that the HP derivation is somewhat assumptive of (in terms of usefulness). Thus manufacturers quote more fuzzy "combined" figures, to try to give some comparable context to the oversimplification of the actual torque curve(s).

Bottom line: hybrid is going to be "faster" in the real world than the HP would suggest, because of "filling in" lower-end torque and providing electric motor torque during ICE shifts. That doesn't mean manufacturer numbers are wrong (see: HP and peak torque figures are simplifications of the definitive torque curve), and/or understated, since real-world performance can be better than comparable ICE vehicles with the same HP/TQ numbers. That's my understanding, anyway.

[jad03060]

Also note that the max HP and the torque curve of the ICE in the 45e is different than that in the 40i...the 40i revs higher and has a different gearset than the 45e.

[sigmabody]

Originally Posted by jad03060

Also note that the max HP and the torque curve of the ICE in the 45e is different than that in the 40i...the 40i revs higher and has a different gearset than the 45e.

Indeed: as I understand it, the 45e has an under-tuned version of the same straight-six engine used in a number of BMW models, including ones where it is tuned for much higher performance. This should really help with reliability and endurance of the engine, in concept, as it is both well-tested and not stressed in the 45e configuration.

[eelnoraa]

Originally Posted by sigmabody

Torque is what matters, actually, or more specifically the torque curve (torque per engine speed). HP is just a simplification of the peak torque/RPM combo point (HP at an RPM point is torque multiplied by the ratio of RPM/[fixed], where [fixed] is 5200 iirc). So there's a HP curve also, but it's strictly derived from the torque curve.

I believe HP is/was "commonly" used because the belief was that a higher-revving engine was better, since (a) that meant less shift points, and (b) that meant you could use less gearing to get the same performance. But the torque curve is the definitive measurement of effective performance.

EV/hybrid vehicles invalidate some of the conventional wisdom, since they can provide torque during ICE shift points (and/or don't have shift points). This makes RPM somewhat immaterial, and thus HP immaterial, although the torque curve is still relevant (since EV motor torque drops off at higher motor speeds). EV motors also give better real-world performance than HP numbers would suggest, since they don't have the traditional ICE torque curve that the HP derivation is somewhat assumptive of (in terms of usefulness). Thus manufacturers quote more fuzzy "combined" figures, to try to give some comparable context to the oversimplification of the actual torque curve(s).

Bottom line: hybrid is going to be "faster" in the real world than the HP would suggest, because of "filling in" lower-end torque and providing electric motor torque during ICE shifts. That doesn't mean manufacturer numbers are wrong (see: HP and peak torque figures are simplifications of the definitive torque curve), and/or understated, since real-world performance can be better than comparable ICE vehicles with the same HP/TQ numbers. That's my understanding, anyway.

Oh well said well said. yes, not a single peak toque number, nor peak HP number, but torque curve.

As for high rev car, in reality, high rev car will have relatively lower torque curve, so gear ratio become closer to avoid large drop in RPM. So end to end gear ratio is more or less the same. I am speaking from experience with AP1, so need to shift more often. For proper deisgn car, shifting is a joy tho. But due to low torque high RPM engine, it is not a very good daily use car

[wbeemer]

Probably because peak power don't overlap over RMP range.

[eelnoraa]

Originally Posted by sigmabody

Indeed: as I understand it, the 45e has an under-tuned version of the same straight-six engine used in a number of BMW models, including ones where it is tuned for much higher performance. This should really help with reliability and endurance of the engine, in concept, as it is both well-tested and not stressed in the 45e configuration.

It is not entire accurate. We just had a meet with our usually track group, we were talking about a new revision of B58 (B58TU2) may come out. But here is what we learned

All current B58 is B58TU, a few variations. For current ?40i small cars (140, 240 340, 44, 540, X3 X4 .., they use something called B59B30O1 version. It is optimized for high HP, 380ish range. For larger cars, like X5, X7 ... it is B59B30M1, optmized for better low end torque and sacrifice high RPM HP. There is a stamp on the block with this number.

Main difference not just turn, the main different we can see is exhaust manifold and header. This is visible by simply looking down underhood on passenger side. O1's design has separate header, will flow better. M1's design is much smaller, so will warmup faster for better efficiency, but less ideal for flow. it only has 2 ports. M1's header is part of the engine (hmmm), but turbo is separate piece. So I guess if turbo is done, much cheaper to replace.

Between 40i and 45e, as far as we can see, they are identical, the M1 version. I think making 45e engine to performance like 40i will be just matter of software. The cost is probably lost a bit of low end torque and gain peak HP. Not sure for daily use, this is a good trade.

M1 and O1 is visually different in a few places, not sure a simple software or fuel map update can match them

[RichardE]

A simple way to understand Torque and Power is: Torque is the amount of work that can be done, Power is the rate at which the work is done.
So a tractor with high torque but low power can pull a very heavy weight but slowly. A Motorbike can only pull a small weight but will pull it quickly.
Then the gearbox is designed to take the torque and power of the available engine and make it useful for various scenarios.
A cars performance is a balancing act of Engine (power & torque), gearbox (power and torque adapter), drivetrain (4wd, 2wd etc), vehicle weight and tyres (putting the energy to the ground for movement). Change one of those things and you will change the overall performance.

[eelnoraa]

Originally Posted by RichardE

A simple way to understand Torque and Power is: Torque is the amount of work that can be done, Power is the rate at which the work is done.
So a tractor with high torque but low power can pull a very heavy weight but slowly. A Motorbike can only pull a small weight but will pull it quickly.
Then the gearbox is designed to take the torque and power of the available engine and make it useful for various scenarios.
A cars performance is a balancing act of Engine (power & torque), gearbox (power and torque adapter), drivetrain (4wd, 2wd etc), vehicle weight and tyres (putting the energy to the ground for movement). Change one of those things and you will change the overall performance.

Sorry, I am afraid that is incorrectly. Torque to rotation motion is as force to strange line motion. Torque is "rotation force" if you will.

The unit for work is Joule. The unit for HP is watt. Joule = watt x second. To bring torque into this equation. physical works like this

Watt (unit of power) = Newton*meter (unit of torqu) x radian/s (angular velocity).

so Work = Torque x rotation speed x time. And Power = torque x rotational speed.

[RichardE]

I did say "simple" Maybe I should have said "Torque refers to the capacity to do work, while power is the rate of completing work in a given amount of time".

(Back to the thread) When it comes to a vehicles performance, it is not just the engine/s that's important, the gearbox, drivetrain, body and tyres all play their part. If you modify the engines characteristics like Torque and Power then to get the best out of the modifications you should also at least modify the gearbox, brakes and the tyres. Then you should change the exhaust, differential/s, suspension etc. etc.

With the ability to reprogram or replace the ECU in most modern cars you can get more HP and Torque as well as remap the transmission. I got the Polestar remap for the Volvo XC60 and that gave about 5kw more power and 50Nm more torque, but it also sped up the gear changes and set the shift RPM to match the new torque curve making the car a little nicer to drive. I wouldn't get an aftermarket remap for the X5, but if BMW come up with a factory option then I might be interested.

[Di3s3l_Power]

^I wish Dinan or some kind OEM performance tune to keep the factory warranty would be available
Especially the B58 on 45e is detuned and has so much potential