Why would BMW ever under rate their horse power on an engine especially an M3/4

M 4 FUN · 02-16-2020, 03:38 AM

Isn't correction factors used in all countries? At least in Sweden we use it to compensate for temperature and elevation. Just to eliminate those factors we measure Power we have this standardised measurement.
Maybe BMW are rated slightly lower than what they produce in Power because if they are compared against other brands in tests they perform slightly better than expected against cars with the same estimated poweroutput. That would give them good credit for great engineering and not lying about performance, just like Porsches normally do. They always seems to perform better than what the factory numbers are.

zenohua · 02-16-2020, 04:06 AM

I don't believe those wheel dyno numbers unless someone actually take out the engine to get the crank HP.

wayman519 · 09-28-2020, 05:41 PM

One other consideration is racing.

If BMW states the engines performance within industry norms. Then the car can be classified to race in a lower power bracket than what the car is capable off. This also gives BMW incentive to engineer a car with lower displacement yet provide incredible power figures. This is how M cars began.

02-16-2020, 03:38 AM	#67
M 4 FUN Captain 605 Rep 641 Posts Drives: 320 Si, M4 comp. M3 E46 Join Date: Aug 2016 Location: Sweden iTrader: (0)	Isn't correction factors used in all countries? At least in Sweden we use it to compensate for temperature and elevation. Just to eliminate those factors we measure Power we have this standardised measurement. Maybe BMW are rated slightly lower than what they produce in Power because if they are compared against other brands in tests they perform slightly better than expected against cars with the same estimated poweroutput. That would give them good credit for great engineering and not lying about performance, just like Porsches normally do. They always seems to perform better than what the factory numbers are.
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02-16-2020, 04:06 AM	#68
zenohua Private 112 Rep 51 Posts Drives: 09 E90 M3, 21 G80 M3 Join Date: Sep 2015 Location: Melbourne iTrader: (0)	I don't believe those wheel dyno numbers unless someone actually take out the engine to get the crank HP.
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09-28-2020, 05:41 PM	#69
wayman519 Second Lieutenant 79 Rep 250 Posts Drives: E82 N52 6MT A51 Join Date: Apr 2012 Location: Canada iTrader: (0) Garage List 2018 BMW X2 [0.00] 2009 128i [0.00]	One other consideration is racing. If BMW states the engines performance within industry norms. Then the car can be classified to race in a lower power bracket than what the car is capable off. This also gives BMW incentive to engineer a car with lower displacement yet provide incredible power figures. This is how M cars began.
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