[WingzM]

I took delivery of my M240I about three weeks ago and have kept my speed and RPMs to a "reasonable" level during the break in period.

The B58 engine is rated at 384 HP and 369 Torque, but has anyone actually dynoed their car to verify the actual numbers?

[Coconut]

G20 M340i's have been dynoing around 410/400 hp/tq so I'd imagine M240i's would be around the same.

[WingzM]

Thank You!!

[Hapbob]

Originally Posted by WingzM

I took delivery of my M240I about three weeks ago and have kept my speed and RPMs to a "reasonable" level during the break in period.

The B58 engine is rated at 384 HP and 369 Torque, but has anyone actually dynoed their car to verify the actual numbers?

What’s your seat of pants dyno think ?
Hap

[old_man_feet]

Does anyone know the 230 HP/Torque numbers.

[MPR]

Originally Posted by Coconut

G20 M340i's have been dynoing around 410/400 hp/tq so I'd imagine M240i's would be around the same.

410 hp at the wheels? Do you have any sources?

I realize that BMW underestimates power in specifications. My thought was maybe they used the wheel hp of 382 as the specification hp (crank hp) on paper, meaning it's really a 410-420 hp motor at the crank. It definitely feels faster than 382 crank/~340 wheel.

[marcsg42]

Autoid has a video on YouTube of there car making 406hp at the wheels on a Dyno and they have opf filters in the uk to where us models don’t, so us models should be a couple hp more,but take in consideration every Dyno is different but it’s safe to say we have about 400hp to the wheels which makes it roughly 450-460 at the crank

[akim89]

Originally Posted by marcsg42

Autoid has a video on YouTube of there car making 406hp at the wheels on a Dyno and they have opf filters in the uk to where us models don’t, so us models should be a couple hp more,but take in consideration every Dyno is different but it’s safe to say we have about 400hp to the wheels which makes it roughly 450-460 at the crank

450-460hp at the crank is a bit of a stretch. A lot of videos of the supra (which is significantly lighter), m440i, m340i, and the m240i on racechip's channel dyno'ed in stock form averages about 400-415hp at the crank, which is still a large difference from the underrated BMW numbers.

[inc235]

Originally Posted by MPR

410 hp at the wheels? Do you have any sources?

I realize that BMW underestimates power in specifications. My thought was maybe they used the wheel hp of 382 as the specification hp (crank hp) on paper, meaning it's really a 410-420 hp motor at the crank. It definitely feels faster than 382 crank/~340 wheel.

I have seen Dinan published dyno data saying G20 m340 made 411hp/418ft-lb at crank, 362hp/388ft-lb at wheel. (likely with x-drive, I presume?)

[RockCrusher]

Originally Posted by old_man_feet

Does anyone know the 230 HP/Torque numbers.

Just what the factory publishes: 255hp and 295 torque. RWD numbers would require a chassis dyno.

Trouble is chassis dynos vary quite a bit.

[danallxt]

All official carmaker engine power determinations are measured at the engine output shaft - on an engine dyno. Not on a chassis dyno. There have been dozens of different engineering standards for doing this.
BRAKE HORSEPOWER. Back in muscle car days, people talked about BHP - or brake horsepower. That was the SAE standard for gross power at the time. Basically it tested the engine without the ancillaries - like the alternator, radiator fan and water pump. Sometimes they used headers instead of the stock exhaust manifolds.

BHP went away in the early 1970s and was replaced by SAE standard J1349 - which measured net power by including all of the power-consuming accessories like the water pump, etc., and also the emissions controls, exhaust system and air cleaner.

In 2005 they tightened up the measurement standard again, with a thing called ‘SAE Certified Power’ which basically meant if a carmaker wanted to claim SAE Certification that they had to do it in an accredited lab, witnessed by an accredited third party.

There’s a GERMAN STANDARD for power as well - it’s called DIN (D-I-N for German Institute for Standardisation) - basically very similar to the SAE net power standard. Again, it’s measured at the crank. All the ancillaries are connected. Power is expressed in PS. There are other European standards as well, in short So, in short, carmakers measurement of power all involve measuring at the crankshaft. None of them involve determining engine power by measuring it at the wheels.

On the other hand measuring turbo cars with standard chassis dynos is usually very unreliable and quite often results in inflated HP figures, that happens if the dyno operators use the commonly applied "correction" factors for temp, elevation etc. Those will throw dyno figures for turbos cars way off.

Me, i'll trust what BMW publishes. Chassis dynos are great for tuning and setting a baseline for tuning changes, then monitoring.checking results of changes.

Seat of the pants dyno? fergit it.

[Nicolas05]

I dyno’d mine before tuning.
I have euro model official rated at 374hp - 500nm torque
On the dyno we measured (stock with catted downpipe and eventuri intake) 395hp - 560nm torque (Crank)

After custom piggyback tune we got 465hp - 715nm torque (crank)

[danallxt]

Originally Posted by Nicolas05

I dyno’d mine before tuning.
I have euro model official rated at 374hp - 500nm torque
On the dyno we measured (stock with catted downpipe and eventuri intake) 395hp - 560nm torque (Crank)

After custom piggyback tune we got 465hp - 715nm torque (crank)

WOW, a 70 hp and 155 nm torque gain after a tune!!! Of course that is taking advantage of the downpipe and intake changes but still, that is awesome. Stock injectors and turbo i assume. What is the max turbo boost to get those numbers? Didn't know the injectors could pump enough fuel for those gains.

[Sizarro]

I had 400 HP stock and now after tuning it's 488 HP (DP+chiptuning).

Stock turbo and injectors.

[danallxt]

Originally Posted by Sizarro

I had 400 HP stock and now after tuning it's 488 HP (DP+chiptuning).

Stock turbo and injectors.

it would be interesting to see what duty cycle those injectors are at to achieve those numbers, gotta be close to maxing out?

[marcsg42]

Originally Posted by akim89

450-460hp at the crank is a bit of a stretch. A lot of videos of the supra (which is significantly lighter), m440i, m340i, and the m240i on racechip's channel dyno'ed in stock form averages about 400-415hp at the crank, which is still a large difference from the underrated BMW numbers.

U say the Supra is lighter ,I believe that has nothing to do with Dyno numbers if you take 2 brand new cars same exact motor and drivetrain and one car weighs 3000 lbs and the other weighs 4000lbs they should in theory put up roughly same numbers up on the dyno give or take a couple hp

[akim89]

Originally Posted by marcsg42

U say the Supra is lighter ,I believe that has nothing to do with Dyno numbers if you take 2 brand new cars same exact motor and drivetrain and one car weighs 3000 lbs and the other weighs 4000lbs they should in theory put up roughly same numbers up on the dyno give or take a couple hp

That's correct. I parenthesized "lighter" because the weight of the vehicle plays a huge role in performance, unsprung weight or sprung. But yes, you're correct that weight does not effect dyno numbers, I just wanted to point out that dyno numbers is not the end all be all. AWD on dynos is super inconsistent, also as you mentioned the drivetrain loss on AWD vehicles does not help as well. A friend of mine has the 2022 supra (a slightly different b58), and from a roll on the fwy he always walks me. On paper, we have the same numbers but his car was faster from a roll. Of course having my 100lb wife in the car didn't help as well haha. But from a dig, which we didn't reach a full 1/4 mile due to the location, I was way ahead every time. I just wish our cars were a bit lighter. Almost 3900lbs on a 2 series is absurd!

[MPR]

It's heavy, but it's hidden well the majority of the time.

[XC3LLR8]

Originally Posted by marcsg42

Autoid has a video on YouTube of there car making 406hp at the wheels on a Dyno and they have opf filters in the uk to where us models don’t, so us models should be a couple hp more,but take in consideration every Dyno is different but it’s safe to say we have about 400hp to the wheels which makes it roughly 450-460 at the crank

Let's just round up and call it 500 hp.