[Keefy]

Originally Posted by Jason73

https://bimmerlife.com/2020/05/16/re...an-advertised/

https://www.bmwblog.com/2019/09/19/u...und%20381%20HP.

2 articles showing the actual dyno wheel HP of the B58 engine is in the 380-390 range. So the 382 BMW number does appear to be wheel HP not crank. Well over 400HP at the crank, 425-440.

Impressive figures that's for sure.

[g11hoonigan]

Alternatively, look at the baseline of those businesses selling tunes, like Burger motorsports. They're based out of California and using dynojet.

[ASAP]

Originally Posted by Jason73

https://bimmerlife.com/2020/05/16/re...an-advertised/

https://www.bmwblog.com/2019/09/19/u...und%20381%20HP.

2 articles showing the actual dyno wheel HP of the B58 engine is in the 380-390 range. So the 382 BMW number does appear to be wheel HP not crank. Well over 400HP at the crank, 425-440.

Those are both RWD cars... the loss on an AWD vehicle is far greater... my rough guess is that on a Dynojet it would be equivalent to an m340i X drive... so I would guess around 360 WHP is a safe bet which is still very good.

Either way, dynos are about the most irrelevant point of comparison on this planet outside of comparing stock numbers to numbers after mods if you dyno on the exact same dyno before and after.

The most relevant comparison of vehicle performance that takes everything into account - weight, power, power curve is 1/4 mile trap speed. The X3 M40i does 107-108 Mph trap which tells me everything about how fast it is in the real world.

For example that Supra dyno's 380 WHP but traps 117 MPH in the 1/4 which is 10 mph faster than the X3 M40i... so while power levels are similar, due to the weight of the X3, we would never even be able to see the tail lights of the Supra in a race.

[Jason73]

The OP was just asking about actual crank HP of the B58, these articles show that according to their tests. Of course the X3 will be slower and actual wheel HP will be less as well. But as far as crank, they should be the same.

[g11hoonigan]

The OP was asking for dyno and crank in the same sentence. No one does a dyno and then calculates back to the crank hp numbers. Dynamometer is attached to the wheels and in the enthusiasts world, it makes more sense to determine what your car is making at the wheels.

[lex97h]

I may have used the incorrect terminology, but I just wanted to know if the actual hp is 382 at the crank. So if the vehicle was dyno with 350WHP then for sure it is a possibility since there is a 10 to 20 percent of power loss due to drive train. However, there are reports where the vehicle has been dyno with 400+ at WHP which led me to believe 382 is not the actual HP at the crank if that makes sense.

[ASAP]

Originally Posted by g11hoonigan

The OP was asking for dyno and crank in the same sentence. No one does a dyno and then calculates back to the crank hp numbers. Dynamometer is attached to the wheels and in the enthusiasts world, it makes more sense to determine what your car is making at the wheels.

that was kind of my point and this reconversion offers almost no value... it goes back to the n54 days years back

i guess perhaps its just to say my car makes 400 hp crank to another suv owner without any sort of concern of "actual real world" performance

dynos are useful for 1 thing and 1 thing only... getting a baseline dyno and then comparing mods after

crank hp is borderline useless for anything unless ur comparing cars of identical weight... unless u reconvert back to hp/lb

albeit that still tells u far less than 1/4 mile trap speed about the cars performance

its like people that compare 0-60 times of rwd to awd cars... a subaru wrx does 0-60 in the 4s w only 260 or hp... so does a 2016 bmw 340i... go race those 2 cars and see how that goes

[Jason73]

I agree with you 100% ASAP. Just pointing out that published HP numbers by BMW appear to be wheel numbers not crank. Looked as if the OP was wanting to know an approximate idea of what the actual crank HP is. 0-60 times for the X3 are quicker than published as well. I believe BMW rates it at 4.4 seconds, Car and Driver and I believe Motortrend show 4.1 and 4.2 seconds.

[g11hoonigan]

All good fam. I just think it's a moot point to discuss the crank HP in this case, although I'd agree that it's fun to know and to talk about.

Several factors affect the power once the 'rubber meets the road.' The drivetrain loses is one of them and we get to see this topic being discussed across different forums and then some random numbers thrown in anywhere between 10-20%. Since it's expressed in %, it quickly becomes arbitrary esp when applied to different cars. It's vehicle specific. If it's vehicle specific and we know people are just throwing in some arbitrary numbers, what number do we trust then? And the HP rating is always the peak, regardless if crank or whp, and I think the area of the graph across the rpm range is more meaningful to discuss than the peak power. It's a brain exercise, too!

Originally Posted by Jason73

I agree with you 100% ASAP. Just pointing out that published HP numbers by BMW appear to be wheel numbers not crank. Looked as if the OP was wanting to know an approximate idea of what the actual crank HP is. 0-60 times for the X3 are quicker than published as well. I believe BMW rates it at 4.4 seconds, Car and Driver and I believe Motortrend show 4.1 and 4.2 seconds.

C&D, I believe, includes 1-ft roll-out and BMW kind of pads in one or two tenths of a sec on paper, maybe to avoid people b*tching that it was done in a lab or prep'd env, not in a real-world or typical day-to-day setting. I got 4.3 on mine via dragy. So yes, I also think 382 is most likely wheel hp.

Originally Posted by lex97h

I may have used the incorrect terminology, but I just wanted to know if the actual hp is 382 at the crank. So if the vehicle was dyno with 350WHP then for sure it is a possibility since there is a 10 to 20 percent of power loss due to drive train. However, there are reports where the vehicle has been dyno with 400+ at WHP which led me to believe 382 is not the actual HP at the crank if that makes sense.

On the internet, BMW is known to underrate the numbers. But I guess in BMW's terms, they just measure it differently. Thus, 382 is more than likely the actual HP at the wheels. Obviously crank HP is more than that. Just pick a % number between 10 and 20 for the losses, I'd bet my neighbor's GLC43 that no one can prove you wrong - except maybe those engineers at BMW who designed/worked on it.

Dyno result varies on many factors such as fuel quality, location, temp/humidity, drivetrain loss, etc. It's really more of a tuner tool than a comparison chart against another car. Sure there's a correction factor but it's limited to certain parameters only.

Originally Posted by ASAP

that was kind of my point and this reconversion offers almost no value... it goes back to the n54 days years back

i guess perhaps its just to say my car makes 400 hp crank to another suv owner without any sort of concern of "actual real world" performance

dynos are useful for 1 thing and 1 thing only... getting a baseline dyno and then comparing mods after

crank hp is borderline useless for anything unless ur comparing cars of identical weight... unless u reconvert back to hp/lb

albeit that still tells u far less than 1/4 mile trap speed about the cars performance

its like people that compare 0-60 times of rwd to awd cars... a subaru wrx does 0-60 in the 4s w only 260 or hp... so does a 2016 bmw 340i... go race those 2 cars and see how that goes

Yep, exactly.

[Rottweiler]

⬆️ ⬆️ ⬆️

🎤 drop

[g11hoonigan]

Originally Posted by Rottweiler

⬆️ ⬆️ ⬆️

🎤 drop

LoL

[IsleOfMs]

Originally Posted by g11hoonigan

No one does a dyno and then calculates back to the crank hp numbers.

How large was your sample size before you decided no one does it?

Here's the use case:

You tune and dyno which gives you whp.
You then calculate what that would be in bhp so you can compare to other cars as they are advertised from the factory.

By sheer volume of how many cars advertise bhp (literally 100% of them), bhp is a much more useful number to bench race with bc it's a much smaller number of people who tune. Tuners are a subset of all cars and dyno-ers are a subset of tuners.

So if you're in a conversation with another modded car owner who dynos, of course in that case you talk whp. But the vast majority of your time when you're reading an article or looking at an ad, bhp is the number that matters.

[Plimmie]

Originally Posted by Keefy

A few interesting videos, obviously the OEM quoted figures and the dyno figures will always differ due to ambient temp, type of dyno used, fuel load and spec, weight, age of the vehicles used, in fact there are so many variables its hard to compare really, and we don't know how the OEM's are testing their vehicles but interesting videos none the less.

https://youtu.be/NJxVwnMFmq0

https://youtu.be/w8PxX0OE4Sc

Sorry a bit late to the conversation
When you look at the last video where they put the M240 on the Dyno you can see that the wheel hp is in the low 304-308 hp and they calculate the engine hp to be about 371-375HP.

I keep hearing people think the B58 engine must be producing more power.
Are we saying the Dyno is wrong? Is there other data to support HP claims of over 400 HP?

[838]

+1

... on paper, that shud b wheel dyno... or might even be a guesstimate to the highest😆

... for the longest time, me myself and i, trust more on... butt dyno , well i mean yes, wheel/crank dyno on paper looks amazing for some and those who can read translate count the figures... yet, that butt-preassure-pulled-back dyno, it satisfy me enough thou

[Leem40i]

Originally Posted by Plimmie

Sorry a bit late to the conversation
When you look at the last video where they put the M240 on the Dyno you can see that the wheel hp is in the low 304-308 hp and they calculate the engine hp to be about 371-375HP.

I keep hearing people think the B58 engine must be producing more power.
Are we saying the Dyno is wrong? Is there other data to support HP claims of over 400 HP?

Relying on one dyno to define what an entire car model produces is impossible. The variables with each car and each dyno can make that number wildly different.
It's generally, over many dynos, accepted knowledge that The M line typically puts to the wheels roughly what BMW claims to be the crank HP.

[strohw]

Originally Posted by Plimmie

I keep hearing people think the B58 engine must be producing more power.
Are we saying the Dyno is wrong? Is there other data to support HP claims of over 400 HP?

Sure, reference the large amount of 2021-current Supra dynos all over the web and then compare them to the single dyno you posted. It's been mentioned a few times already in this post, but BMW rates the Non OPF B58 in its most aggressive factory tune at 382hp, regardless of vehicle or drivetrain. In the Supra with a RWD setup, it will generally dyno at 370-390whp. This engine in an AWD setup will lose another ~5% putting you around 350-370whp.

To answer your first question, is the dyno wrong? If you see them as a tool to view differences, then it doesn't matter what number it states. If you expect it to provide a general base line that's similar to the majority, then it's reading quite low. If this engine was in most other manufacturer's vehicles, they'd rate it at 420-430hp. Since the majority use the SAE BHP standard.

[Plimmie]

Originally Posted by strohw

Sure, reference the large amount of 2021-current Supra dynos all over the web and then compare them to the single dyno you posted. It's been mentioned a few times already in this post, but BMW rates the Non OPF B58 in its most aggressive factory tune at 382hp, regardless of vehicle or drivetrain. In the Supra with a RWD setup, it will generally dyno at 370-390whp. This engine in an AWD setup will lose another ~5% putting you around 350-370whp.

To answer your first question, is the dyno wrong? If you see them as a tool to view differences, then it doesn't matter what number it states. If you expect it to provide a general base line that's similar to the majority, then it's reading quite low. If this engine was in most other manufacturer's vehicles, they'd rate it at 420-430hp. Since the majority use the SAE BHP standard.

Sorry, I posted a screen capture of the YouTube video that was being referenced to earlier in this thread (posted by Keefy). when I look at the numbers they don’t stand out to me as particularly high…especially as they show the wheel hp 305 Hp!! as well as what they calculated at the crank 375.
If you watch the video you see they tested different cars, and the numbers all come relatively close to what the manufacturer stated (VW, Audi, BMW) the car should have. This leads me to believe that their dyno,must be sort of in the correct ball park?!.

The two articles that were referenced later on, talk about the hp numbers, but don’t show any results. So it’s not clear how they got to their claims.

This is not an attack on the B58 ( I have two, and both of my cars certainly feel faster than my Mustang GT which was dynod at 385 at the wheel), but more to understand whether people have actually measured the output at the wheel (not the calculated crank number) and actually see 375-380 at the wheel of a B58 engine car? All the dyno’s I have seen so far were of the calculated crank numbers.

[vrships]

Originally Posted by Plimmie

Sorry, I posted a screen capture of the YouTube video that was being referenced to earlier in this thread (posted by Keefy). when I look at the numbers they don’t stand out to me as particularly high…especially as they show the wheel hp 305 Hp!! as well as what they calculated at the crank 375.
If you watch the video you see they tested different cars, and the numbers all come relatively close to what the manufacturer stated (VW, Audi, BMW) the car should have. This leads me to believe that their dyno,must be sort of in the correct ball park?!.

The two articles that were referenced later on, talk about the hp numbers, but don’t show any results. So it’s not clear how they got to their claims.

This is not an attack on the B58 ( I have two, and both of my cars certainly feel faster than my Mustang GT which was dynod at 385 at the wheel), but more to understand whether people have actually measured the output at the wheel (not the calculated crank number) and actually see 375-380 at the wheel of a B58 engine car? All the dyno’s I have seen so far were of the calculated crank numbers.

305 WHP makes no sense for this engine. Even for a 335hp gen 1 B58, it's a bit too low. BMW always underate their inline 6 engines, for decades. This is not anecdotal.

There has been a lot of 'Accurate' real dyno measurements with screenshot or even video to show you the whole process. Check out all results from M340i, M40i, Supra 21+, etc. It's pretty obvious that WHP are from 350 to 390, depending on models RWD/4WD. But I have never seen one as low as 305hp.

If you don't believe such, how about the test from Car and Driver:https://www.caranddriver.com/reviews...a-dyno-tested/

388 WHP dyno'ed.

Crank HP means nothing when people can actually dyno the car for WHP, which is what really matters. Tune vendors have been using Crank HP to promote their products, by using an unreasonably high loss factor, they can boast about so more hp gain from nothing. Just imagine how much more "Crank HP" you can get by using a 20% (which is by no means accurate) than a 12% drivetrain loss if your dyno WHP s 350hp?

[Plimmie]

Thanks for posting that article from Car and Driver!
What is going on then with the video that Keefy posted (the test by UK based CarWow where they tested the M240). I thought that the M240i has the same B58 engine. Isn’t that the case? I get that the car they tested is 4wd. Is the drivetrain loss that much in an M240?

[vrships]

Originally Posted by Plimmie

Thanks for posting that article from Car and Driver!
What is going on then with the video that Keefy posted (the test by UK based CarWow where they tested the M240). I thought that the M240i has the same B58 engine. Isn’t that the case? I get that the car they tested is 4wd. Is the drivetrain loss that much in an M240?

I watch CarWow all the time. Their contents are entertaining for sure. But I feel their measurements are questionable or unclear in this set.

The Part 1 has 4 high power models, RS7, C63s, M5 and Panamera (TurboS?), if you look carefully, their whp/Bhp efficiency is increadibly high for the 1st 3 models, around 89.7~91%. But the Panamera was use 84%. I am very curious how they acquired these numbers and 90% for a 4WD model is really high.

The part 2 has 4 mid power models, but only Golf R and M240i showed their wheel power, which both only have efficiency ~82%. That was so much lower than the models in part 1. The RS3 and A45s don't even have WHP displayed. Of course if they had used higher effciency for M240i, it's calculated engine power would be much lower. But I don't believe the Xdrive and 8AT on M5 is 91% while the Xdrive on MX40i is only 82%.

Anyway, other majority of test videos dynoing 382hp m240i,m340i, m40i and Supra I have seen are all in the 350 to 390WHP range.

[vrships]

Originally Posted by Plimmie

Thanks for posting that article from Car and Driver!
What is going on then with the video that Keefy posted (the test by UK based CarWow where they tested the M240). I thought that the M240i has the same B58 engine. Isn’t that the case? I get that the car they tested is 4wd. Is the drivetrain loss that much in an M240?

Originally Posted by Plimmie

Thanks for posting that article from Car and Driver!
What is going on then with the video that Keefy posted (the test by UK based CarWow where they tested the M240). I thought that the M240i has the same B58 engine. Isn’t that the case? I get that the car they tested is 4wd. Is the drivetrain loss that much in an M240?

I watch CarWow all the time. Their contents are entertaining for sure. But I feel their measurements are questionable or unclear in this set.

The Part 1 has 4 high power models, RS7, C63s, M5 and Panamera (TurboS?), if you look carefully, their whp/Bhp efficiency is increadibly high for the 1st 3 models, around 89.7~91%. But the Panamera was use 84%. I am very curious how they acquired these numbers and 90% for a 4WD model is really high.

The part 2 has 4 mid power models, but only Golf R and M240i showed their wheel power, which both only have efficiency ~82%. That was so much lower than the models in part 1. The RS3 and A45s don't even have WHP displayed. Of course if they had used higher effciency for M240i, it's calculated engine power would be much lower. But I don't believe the Xdrive and 8AT on M5 is 91% while the Xdrive on MX40i is only 82%.

Anyway, other majority of test videos dynoing 382hp m240i,m340i, m40i and Supra I have seen are all in the 350 to 390WHP range.