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BMW 3-Series (E90 E92) Forum > E90 / E92 / E93 3-series Powertrain and Drivetrain Discussions > N55 Turbo Engine Tuning and Exhaust Modifications - 335i Tuning > Cobb N55 Throttle Mapping (Alpina Flash)



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      05-08-2014, 01:08 PM   #1
Unklejoe
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Cobb N55 Throttle Mapping (Alpina Flash)

Has anyone successfully manipulated the throttle vs. requested torque mapping on the N55 using Cobb ATR?

On N54 cars, there are OTS maps for linear throttle and stock throttle, however on the N55, there are no such OTS maps available.

Basically, in ATR, there is a map which correlates pedal position percentage to requested torque percentage.

However, on the ATR version for the N55, the two maps in this section are slightly different.

N54 version has "Requested Torque - High" and "Requested Torque - Low" where as the N55 has "Requested Torque - Auto" and "Requested Torque - Manual" or something along those lines. Based off of this, they seem to be the same type of maps.

However, the X axis on the N55 maps is in units of "TPS %" where as the N54 versions are in units of "Pedal Position %".

The X axis being in units of "TPS %" doesn't seem to make much sense. First of all, is this the Valvetronic TPS or the throttle TPS? Valvetronic I will assume...

Second of all, wouldn't the DME be using throttle position to modify the torque anyway? If so, why would there be a map for this?

I was under the impression that the map on the N54 cars was basically a mapping of Pedal Position % versus throttle blade % (and thus inadvertently, requested torque).

But the N55 map seems to be a little different. If it truly is a map of TPS versus requested torque, how does the DME control the requested torque for a given TPS?

Also, most importantly........why does the TPS% versus Requested Torque % map only reach values of about 80% for TPS values of 100% on the N55?

In other words, the DME is only requesting 80% torque when the TPS is at 100%.

Sorry if this is a bit convoluted. My intentions are to manipulate this map in such a way that the requested torque is lower for a given pedal position percentage. This is to try and make the D mode of the Alpina flash a little more drivable.

The TCU seems to use Pedal Position rather than requested torque in order to dictate its line pressure.
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      05-08-2014, 02:23 PM   #2
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i just paid $100 for the B3 flash to be done remotely. took all of about 10 mins - i have a cobb too.
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      05-09-2014, 12:28 AM   #3
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Quote:
Originally Posted by jamesey271975 View Post
i just paid $100 for the B3 flash to be done remotely. took all of about 10 mins - i have a cobb too.
how do you like it so far?
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      05-09-2014, 06:01 PM   #4
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Quote:
Originally Posted by BlueBimmer View Post
how do you like it so far?
11/10

changes the character of the car entirely. shifts are immediate and with a sense of purpose. D shifts are earlier to conserve fuel, but hold longer before downshifting (I like this, i have the torque w/JB + intake, soon dp's, soon, it just whoooses along like a goddamn prime mover). S mode is annoyed at me that i'm not testing the limits of grip - which, let's be honest, is perfect for S mode. And M shifts faster'n than Kardashian can S on that D, plus it matches revs so you can downshift better for corners (highway ingress/egress).

$100 for the Alpina TCU flash the best $100 you'll spend on your n55

Last edited by Knonsense; 05-09-2014 at 06:28 PM..
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      05-10-2014, 11:26 AM   #5
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Quote:
Originally Posted by Knonsense
Quote:
Originally Posted by BlueBimmer View Post
how do you like it so far?
11/10

changes the character of the car entirely. shifts are immediate and with a sense of purpose. D shifts are earlier to conserve fuel, but hold longer before downshifting (I like this, i have the torque w/JB + intake, soon dp's, soon, it just whoooses along like a goddamn prime mover). S mode is annoyed at me that i'm not testing the limits of grip - which, let's be honest, is perfect for S mode. And M shifts faster'n than Kardashian can S on that D, plus it matches revs so you can downshift better for corners (highway ingress/egress).

$100 for the Alpina TCU flash the best $100 you'll spend on your n55
+1

Best mod I've done. Like a new car in sport mode.
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      05-14-2014, 03:33 PM   #6
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So I contacted Cobb and they straightened everything out.

Cobb:
"So, N54 and N55 are a little different as you can tell for the requested torque tables. The only difference is that N54 has high and low. That is for when you change from Drive to Sport for autos gear shifter. N55 just uses one table. You can modify the Requested Torque % (Auto) or (Manual/DCT) and make it as linear or curvy as you would like."

Me:
"Why does the map only request 78% torque even at TPS values of 100%?"

Cobb:
"It has to do with BMWs algorithms. You can basically think of the 78% number as 100%."

Me:
"I see! So if I decide to make it linear, I'll just interpolate for all cells using 78% as the max value. "

Cobb:
"Correct. You make the 78 number your max and the scale everything accordingly"



Props to Cobb for educating me. Hopefully this can help anyone else who's wondering.

Once I get my VANOS recall done, I will re-install Cobb and the Alpina flash. I will then try to make the throttle map linear and see how it impacts drivability.
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      05-14-2014, 07:34 PM   #7
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Quote:
Originally Posted by jamesey271975 View Post
+1

Best mod I've done. Like a new car in sport mode.
I can vouch for this mod as well, well worth the cash!

Last edited by NoImDirtyDan; 05-15-2014 at 08:12 PM..
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