Thoughts on how the power is limited

curtdragon · 10-29-2022, 03:24 PM

For the M3/4 I found this

From Car and Driver

"As a refresher, the standard $70,895 M3 comes only with a six-speed stick and produces 473 horsepower and 406 pound-feet of torque from a wonderfully smooth twin-turbo 3.0-liter inline-six. Opting for the $2900 Competition upgrade, however, necessitates the fitment of an eight-speed automatic, yet brings more turbo boost (24.7 psi versus 18.9) and an additional 30 ponies and 73 pound-feet."

Do you think they just further reduced the boost?
Or do you think they remapped the ecu

GrannyShiftG80 · 10-29-2022, 03:36 PM

Remapping the ecu = reducing the boost

curtdragon · 10-29-2022, 03:50 PM

Yeah no.
So getting a boost controller is remmaping the ECU?

Yes I get that the turbo wastegate is electronically controlled by the ECU. But obviously I’m not talking about that.

I’m asking if they’ve done exactly the same thing which was to limit the boost and no other changes.

boostspoon · 10-29-2022, 04:45 PM

Quote:

Originally Posted by curtdragon

Yeah no.
So getting a boost controller is remmaping the ECU?

Yes I get that the turbo wastegate is electronically controlled by the ECU. But obviously I’m not talking about that.

I’m asking if they’ve done exactly the same thing which was to limit the boost and no other changes.

They don't increase/decrease boost without mapping.

trey100 · 10-29-2022, 06:02 PM

I'm actually more surprised that 5+ more pounds of boost only netted 30 HP. I had read somewhere that the dynos of comp and non-comp were similar torque-wise so I assumed the boost delta was very small between the 2.

Hendo741 · 10-30-2022, 11:08 AM

The car and driver article is wrong and misleading. Not sure where they came up with those figures, but newer BMW engines (S58/B58) don't work on static boost tables. I have an M4 Comp xdrive and have seen the requested boost vary from <16 all the way to 21+ based on conditions. Never ever have i seen anywhere near 25. JB4 map 4 which suggests E30 is an absolute value of 25 psi.

IAT seems to have the biggest influence as it will run lower boost and higher ignition advance with lower IAT, and the boost gets higher and timing lower as IATs increase.

Regardless, yes the difference in the 3 engines will be ECU/DME mapping.

10-29-2022, 03:24 PM	#1
curtdragon Car'a'carn 665 Rep 1,012 Posts Drives: I drive one Join Date: Feb 2008 Location: Nashville iTrader: (0)	Thoughts on how the power is limited For the M3/4 I found this From Car and Driver "As a refresher, the standard $70,895 M3 comes only with a six-speed stick and produces 473 horsepower and 406 pound-feet of torque from a wonderfully smooth twin-turbo 3.0-liter inline-six. Opting for the $2900 Competition upgrade, however, necessitates the fitment of an eight-speed automatic, yet brings more turbo boost (24.7 psi versus 18.9) and an additional 30 ponies and 73 pound-feet." Do you think they just further reduced the boost? Or do you think they remapped the ecu
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10-29-2022, 03:36 PM	#2
GrannyShiftG80 Captain 1357 Rep 905 Posts Drives: G20 330i, G80 M3 6MT Join Date: Aug 2014 Location: Canada iTrader: (0)	Remapping the ecu = reducing the boost
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10-29-2022, 03:50 PM	#3
curtdragon Car'a'carn 665 Rep 1,012 Posts Drives: I drive one Join Date: Feb 2008 Location: Nashville iTrader: (0)	Yeah no. So getting a boost controller is remmaping the ECU? Yes I get that the turbo wastegate is electronically controlled by the ECU. But obviously I’m not talking about that. I’m asking if they’ve done exactly the same thing which was to limit the boost and no other changes.
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10-29-2022, 06:02 PM	#5
trey100 Colonel 1129 Rep 2,564 Posts Drives: 2020 M2 Competition Join Date: Jul 2007 Location: New York iTrader: (0)	I'm actually more surprised that 5+ more pounds of boost only netted 30 HP. I had read somewhere that the dynos of comp and non-comp were similar torque-wise so I assumed the boost delta was very small between the 2.
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10-30-2022, 11:08 AM	#6
Hendo741 Chief Petty Officer 667 Rep 530 Posts Drives: 22 M4CX / 22 X3MC Join Date: Dec 2021 Location: US iTrader: (0)	The car and driver article is wrong and misleading. Not sure where they came up with those figures, but newer BMW engines (S58/B58) don't work on static boost tables. I have an M4 Comp xdrive and have seen the requested boost vary from <16 all the way to 21+ based on conditions. Never ever have i seen anywhere near 25. JB4 map 4 which suggests E30 is an absolute value of 25 psi. IAT seems to have the biggest influence as it will run lower boost and higher ignition advance with lower IAT, and the boost gets higher and timing lower as IATs increase. Regardless, yes the difference in the 3 engines will be ECU/DME mapping.
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