Sport Display Max HP

[Thor2j]

I've had my '15 M5 for about 2 months. Playing with the sport display my max HP is 540. I've seen others state that there's show way over the stated 560hp. I realize it's a little gimmicky and probably not very accurate but why is mine so much lower then others. I turned everything to sport plus , mdm on and hammered 1st,2nd,and 3rd.

[SteveC]

Originally Posted by Thor2j

I've had my '15 M5 for about 2 months. Playing with the sport display my max HP is 540. I've seen others state that their's show way over the stated 560hp. I realize it's a little gimmicky and probably not very accurate but why is mine so much lower then others. I turned everything to sport plus , mdm on and hammered 1st,2nd,and 3rd.

It depends what it actually measures, because its not measuring actual horsepower; it just displays the result of a calculation based on some other values

[Speed808Ix]

depends on what gear too!

[Thor2j]

Originally Posted by SteveC

It depends what it actually measures, because its not measuring actual horsepower; it just displays the result of a calculation based on some other values

I'm just wondering what it actually measures. Why would mine be lower??

[SteveC]

Originally Posted by Thor2j

I'm just wondering what it actually measures. Why would mine be lower??

If you think about it, all it really needs to measure is rpm and air temperature.....then have a look up table which drives the display

All the look up table does is provide the HP rating by RPM and a temperature correction factor and the job's a good 'un (as they say in these parts).

There's no easy way to measure actual HP and Torque. Could be as simple as the fact you measured it in Florida on a hot day and the others were in Canada, freezing their patooties.

[Boss330]

Originally Posted by SteveC

If you think about it, all it really needs to measure is rpm and air temperature.....then have a look up table which drives the display

All the look up table does is provide the HP rating by RPM and a temperature correction factor and the job's a good 'un (as they say in these parts).

There's no easy way to measure actual HP and Torque. Could be as simple as the fact you measured it in Florida on a hot day and the others were in Canada, freezing their patooties.

You need a bit more than RPM and temp... Throttle position determines if the car is just cruising along, coasting or accelerating...

My understanding is that it works roughly the same as a aftermarket OBD reader that calculates hp and torque based on some of these values:

-RPM
-Air Temp
-Mass Air Flow
-Fuel Flow
-BSFC (this value is a "unknown" on a aftermarket OBD tool, but BMW engineers know this value at every rpm and load on the engine)
-Throttle position
-Ignition timing
-Boost Level

If you have these values you can calculate the engines HP and Torque very accurately.

You can also do a very rough estimate just based on the engines mass air flow sensor. If the mass air flow to the engine is 200g/s that roughly equals 200kW (272hp)

[SteveC]

Originally Posted by Boss330

You need a bit more than RPM and temp... Throttle position determines if the car is just cruising along, coasting or accelerating...

My understanding is that it works roughly the same as a aftermarket OBD reader that calculates hp and torque based on some of these values:

-RPM
-Air Temp
-Mass Air Flow
-Fuel Flow
-BSFC (this value is a "unknown" on a aftermarket OBD tool, but BMW engineers know this value at every rpm and load on the engine)
-Throttle position
-Ignition timing
-Boost Level

If you have these values you can calculate the engines HP and Torque very accurately.

You can also do a very rough estimate just based on the engines mass air flow sensor. If the mass air flow to the engine is 200g/s that roughly equals 200kW (272hp)

Yes, that makes perfect sense...so getting back to the OP's question, which values could cause the car to register lower peak HP?

[Boss330]

Originally Posted by SteveC

Yes, that makes perfect sense...so getting back to the OP's question, which values could cause the car to register lower peak HP?

Good question...

Would like to see a picture of the display readings to verify that it indeed says 540hp

Assuming it does, it could actually be a sensor that reads low. Say the MAF sensor is slightly off, that would cause a wrong result when calculating HP. Worse, it would also affect the DME's calculations for fuel and timing etc. Affecting engine HP.

The theory about warm or cold weather should not influence the HP since these engines have the capability to adjust boost to accomodate for different climatic conditions and altitudes.

[Thor2j]

Originally Posted by Boss330

Good question...

Would like to see a picture of the display readings to verify that it indeed says 540hp

Assuming it does, it could actually be a sensor that reads low. Say the MAF sensor is slightly off, that would cause a wrong result when calculating HP. Worse, it would also affect the DME's calculations for fuel and timing etc. Affecting engine HP.

The theory about warm or cold weather should not influence the HP since these engines have the capability to adjust boost to accomodate for different climatic conditions and altitudes.

That's what concerned me. I realize I am in florida but would think the boost would compensate. Each tic mark is 40 hp. The red marker stopped between 520 and 560. Tried to take a picture but it was hard one handed coming off red line in 3rd gear before the max mark reset.

Can other people with 15s post their numbers.

One reason I'm wondering is I had a '13 c63 amg coupe with a rentech tune and the M5 doesn't feel as fast even though it should be every bit if not more. Maybe the wonderful noise the amg made made it feel faster then it was. When I look down at speedo on m5 I'm impressed but not as much seat of the pants.

[SteveC]

Originally Posted by Thor2j

Tried to take a picture but it was hard one handed coming off red line in 3rd gear

[Northern X5M]

Originally Posted by Thor2j

That's what concerned me. I realize I am in florida but would think the boost would compensate. Each tic mark is 40 hp. The red marker stopped between 520 and 560. Tried to take a picture but it was hard one handed coming off red line in 3rd gear before the max mark reset.

Can other people with 15s post their numbers.

One reason I'm wondering is I had a '13 c63 amg coupe with a rentech tune and the M5 doesn't feel as fast even though it should be every bit if not more. Maybe the wonderful noise the amg made made it feel faster then it was. When I look down at speedo on m5 I'm impressed but not as much seat of the pants.

Boost would compensate to a point. If you have hight IATs which is probably your case, then your car will be dumping timing.

[E90potentialbuyer]

OP - good question. I have not looked closely but I think my car (with CP) has shown a Mac of about 540 as well. I have never managed to get close to 575 that it should have.

For reference, it's a 2015 with CP. curious!

[CSL335i]

I have an F13 M6 CP with 575HP. I also have Awron display, which displays the same HP and NM as the Sport display on Navi.

The car has factory software and has the following modifications:
- factory turbos with some machining to provider better exhaust flow
- ceramic coated turbine side of turbos
- ceramic coated exhaust manifolds
- ceramic coated OEM downpipe
- Okada coils

Before modifications i had 575HP/685-690NM, after modifications the max values i had: 717NM and 589HP (whatever does it mean).