[SommeR]

Anyone. Is it normal to have way less hp than torque? Did a dyno on my 2020 X4 M40i and results shows 360 hp and 424 lb ft torque.

[BobFriend]

Is it tuned? Those are some big torque numbers.

[SommeR]

No tuning, just a air intake kit.

[SommeR]

The gages on the dash shows more than 360 hp when I’m driving so I’m confused.

[kini62]

Originally Posted by SommeR

The gages on the dash shows more than 360 hp when I’m driving so I’m confused.

The gauge on your dash is not a dyno. Just a software approximation AFAIK.

360 at the wheels with that torque seems really good for stock.

What intake?

[AshtonPJT]

Yes that is normal

[suby01]

Normal. B58 is a torquey summbish. Hellcats know this.

[SommeR]

That’s still a lot compared to the hp. I installed a MAD cold air intake. Same as all the other brands, nothing too different.

[dmicah]

Dynos only measure torque at each RPM and then compute HP at each RPM using the formula HP = Torque x RPM / 5,252. This means that HP and Torque lines will always cross at 5,252 RPM.

Your dyno results make sense. Though others have measured just under 400 HP at the wheels that's due to the variation of each dyno. You can do the computation yourself for each RPM to see if it computes out. In your diagram, you're not getting to multiply big torque numbers by big RPM to create numbers higher than 360 HP.

What you're reacting to is that the B58 is notoriously good with torque down low and throughout the midrange, which makes it more fun to drive around town. You'll notice that the torque starts declining around 4500 RPM. BMW rates the maximum torque for the B58B30O1 as a flat 369 LB/FT between 1500-4500 rpm, which your dyno reflects nicely (although it seems to show a bit more than 400 LB/FT down low). BMW notoriously under-rates its engines, and the B58 is a fairly extreme example. Dynos measure torque at the rear wheels while manufacturers measure and rate at the engine. A reasonable estimate for drivetrain loss between the engine and the wheels is somewhere between 15% and 20%. Conservatively, this means your car is generating over 420 HP and 500 ft/lbs of torque. Feel good about this!

[vrships]

torque is a different quantity than horsepower. You can't compare two different thing. Just like it makes no sense to say why you weight 160 lbs is so much more than your height at 5.7 ft.

Torque however is related to horsepower at the crank so that hp=torque(Nm)×0.0001404×RPM.

But on a dyno, the torque measurement must be corrected knowing the accurate gear ratio because wheel torque is easily magnified up to 15 times by the drive train. For zf8HP50 the 6 gear gives an exact 1:1 ratio (excluding the final gear) so that's usually how people do it. So if you are using 5th or 4th, your torque can be much higher but hp is almost unchanged.

But after all , 420 lb ft is not some crazy number because factory rated 369 lb ft is actually way underrated.

[SommeR]

The shop said they can tune to give me 95 more hp and 54 lb-ft at the wheels with a software and a EPA approved down pipe.

[ASAP]

360 hp seems about right but 424 torque seems real high... the factory rating is torque under hp... so i'd be willling to bet this was dyno'd in the wrong gear

[SommeR]

I thought it was a bit high too.

[Leem40i]

Originally Posted by SommeR

The shop said they can tune to give me 95 more hp and 54 lb-ft at the wheels with a software and a EPA approved down pipe.

Typically you will need bolt-ons that increase intake air flow and exhaust flow in order to achieve significantly higher horsepower numbers. Horsepower is relevant on the top end and when you're at higher RPM you need more flow to exceed what the factory spec is. That's why many Auto Parts manufacturers will state that their air filter or their exhaust system will give you 10 or 20 extra horsepower just by itself. That's partially true but it makes that gain all the way on the very top end, which for most cases is unusable. It takes a tune to bring that power back down into the middle and utilize the added air flow.
I would also like to know what gear this pull was done in. For that matter, what gear is considered the one-to-one gear in this vehicle?

[SommeR]

I’m not sure what gear he did the pull in. Should I be concerned about the numbers on the torque vs the hp?

[ContactPatch]

Whenever I see the "B58" name this always come to mind, another machine that had great power and capable of very quick speeds.


The Convair B-58 Hustler:

[kini62]

Originally Posted by SommeR

That’s still a lot compared to the hp. I installed a MAD cold air intake. Same as all the other brands, nothing too different.

That's the one I was planning on getting. Just put a K&N in the stock box instead. Maybe one day. I'd rather due a high flow catted downpipe first.

[SommeR]

How much HP and torque you running now?

[bouchy]

Is it normal to have way less hp than torque?

Power is not really related to torque. Imagine 2 stroke engine with the same power output compared to 4 stroke. In extreme, low power engine can produce huge torque and vice versa - disadvantages: mileage, lifespan, price.

[BMWbiker]

Originally Posted by bouchy

Power is not really related to torque. Imagine 2 stroke engine with the same power output compared to 4 stroke. In extreme, low power engine can produce huge torque and vice versa - disadvantages: mileage, lifespan, price.

Here’s another way to think about it.

Torque is how hard you twist. Horsepower is how hard you twist related to how fast you are twisting.

So, if you’re using a breaker bar to try to loosen a bolt, but it is not budging, you may be applying a lot of torque, but generating zero horsepower.

Or, if you have an EV, and you apply throttle but the wheels haven’t turned and you haven’t moved yet, the electric motor is applying torque but is not yet generating horsepower. (ICE engines never experience this, since they will stall without a clutch.)

[bouchy]

Today, I came across interesting numbers of the new Ferrari 12 Cylinder (which has twelve cylinder engine - ha.ha.ha):
https://en.wikipedia.org/wiki/Ferrar...%20of%20torque
819 BHP vs ("only") 678 Nm. That's 83% torque to power ratio. My poor old I4 VW engine had 84 BHP and this ratio was 156%... both naturally aspirated

[BMWbiker]

Originally Posted by bouchy

Today, I came across interesting numbers of the new Ferrari 12 Cylinder (which has twelve cylinder engine - ha.ha.ha):
https://en.wikipedia.org/wiki/Ferrar...%20of%20torque
819 BHP vs ("only") 678 Nm. That's 83% torque to power ratio. My poor old I4 VW engine had 84 BHP and this ratio was 156%... both naturally aspirated

Yup. It makes its maximum horsepower at high revs.