Tuning w/ N20 TMAP to see 22+ Boost

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Jeffman

Captain
Jan 7, 2017
1,340
DOH!
Update: I'm surprised nobody else caught my goof-up here. I now know what I did wrong. Silly stupid mistake! Props to the first person who can figure out what I did wrong.

I have IJEOS MHD MBoost option, N20 option checked, N20 TMAP. E50 custom map. I should to be able to measure boost pressures higher than 22 psi but this log clearly shows the boost pressure being clipped at 22 psi at the 3rd-4th gear shift.
http://datazap.me/u/jeffman/2016-06-13-v95-spx-e40-e50-jeff-80f-3rd-4th-shift?log=0&data=4-22

How do you get the data logging to report more than 22 psi?
QUOTE
 
Last edited:

Liteweight13

New Member
Jun 30, 2017
8
You will have to voltage scale the map sensor. There is a few threads on setting this up. Basically the map will read stock up to 10psi. After 10psi it reports half the amount of boost to be able to run over 22psi. This affects a lot of load based tables as load points will be much lower for boost levels than with the stock map sensor. Unless you are planning on running 25+ psi i wouldn't bother. If you are you will need a custom tune setup for scaled voltage.
 
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Jeffman

Captain
Jan 7, 2017
1,340
You will have to voltage scale the map sensor. There is a few threads on setting this up. Basically the map will read stock up to 10psi. After 10psi it reports half the amount of boost to be able to run over 22psi. This affects a lot of load based tables as load points will be much lower for boost levels than with the stock map sensor. Unless you are planning on running 25+ psi i wouldn't bother. If you are you will need a custom tune setup for scaled voltage.
Yup. I've been working on my own custom scaled tune. I have scaled the three box TMAP voltages in the MHD folder in TunerPro. But checking the N20 TMAP box in MHD when flashing automatically scales the three-box TMAP voltages. But maybe I need to set the standard TMAP two-box voltage scale to ~50 psi at 4.5 Volts?

I also scaled all the loads above 150, etc. in many tables and am currently playing with the Load-to-Torque 1-3 tables. I had shrunk my Y-axes (load) in the LTQ tables but still not measuring above 22 psi...maybe I should leave the highest load on the Y-axis > 200???

Any other advice about which tables to focus on?
 

jyamona

Captain
Platinum Vendor
Nov 7, 2016
1,069
Philly
But checking the N20 TMAP box in MHD when flashing automatically scales the three-box TMAP voltages.
No, it just sets the regular sensor range in the OEM 2-cell table. For scaling, it must be done manually as it requires changes to all load based tables.
 
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Jeffman

Captain
Jan 7, 2017
1,340
No, it just sets the regular sensor range in the OEM 2-cell table. For scaling, it must be done manually as it requires changes to all load based tables.
Understood. Thanks, Jake.
Now I don't want to pull you away from your very important FLEXFUEL coding that we've all been waiting for...but I'm still trying to figure out why my reported boost looks to be flat-lining at 22 psi - either something funky in my bin, or somehow my MBOOST license was not recognized during flashing.

Any ideas? Let me know and I'll buy you lunch sometime.
 

dyezak

Major
May 4, 2017
1,768
Plano TX
Understood. Thanks, Jake.
Now I don't want to pull you away from your very important FLEXFUEL coding that we've all been waiting for...but I'm still trying to figure out why my reported boost looks to be flat-lining at 22 psi - either something funky in my bin, or somehow my MBOOST license was not recognized during flashing.

Any ideas? Let me know and I'll buy you lunch sometime.
The answer is in the post you quoted. You selected the N20 option at flash time but haven't changed any of your tables manually. So the sensor is sending the voltage that the N20 option expects, but the voltage is still mapped to your old values, the most pertinent being the max load. FYI, playing with this stuff without understanding everything fully is a quick way to an early n54 death. Might want to pay someone to rescale all your load based maps.
 

Jeffman

Captain
Jan 7, 2017
1,340
Hmmm... Didn't I say several posts up that I'm working on my own custom scaled tune, which involves scaling all the loads above 150 which corresponds to the 10 psi mid-point crossover of the three voltage TMAP table? Happy to buy you lunch as well for some useful advice. :)
 

dyezak

Major
May 4, 2017
1,768
Plano TX
Sorry, didn't mean to come off like a dick. And I'm not in a position to give advice on that. I'll have to earn lunch some other way.
 
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doublespaces

Administrator
Oct 18, 2016
7,945
AZ
The best thing about a single city block, is it has four corners. Opportunity everywhere, murica!
 

jyamona

Captain
Platinum Vendor
Nov 7, 2016
1,069
Philly
Understood. Thanks, Jake.
Now I don't want to pull you away from your very important FLEXFUEL coding that we've all been waiting for...but I'm still trying to figure out why my reported boost looks to be flat-lining at 22 psi - either something funky in my bin, or somehow my MBOOST license was not recognized during flashing.

Any ideas? Let me know and I'll buy you lunch sometime.
Hey email me your bin, I will take a look!
 
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Jeffman

Captain
Jan 7, 2017
1,340
Could be on the map side. Sounds like it's still pegging at the 1.5bar limit

Also get a log with Boost Setpoint, WGDC after PID, and WGDC base value.
Thanks for the suggestion. Btw, I was previously plotting "Boost" via MHD logs which is from the MAP sensor in the manifold (vacuum to 1.5 Bar). In the new log below I am plotting "Boost mean" which is from the N20 TMAP in the charge pipe (my stupid mistake! Lol).
Take a look at this log of 3rd-4th-5th gear changes and let me know your thoughts. Thanks.
http://datazap.me/u/jeffman/74f?log=1&data=3-4-15-29-30-31&solo=3-4-30&zoom=30-120
 
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jyamona

Captain
Platinum Vendor
Nov 7, 2016
1,069
Philly
Thanks for the suggestion. Btw, I was previously plotting "Boost" via MHD logs which is from the MAP sensor in the manifold (vacuum to 1.5 Bar). In the new log below I am plotting "Boost mean" which is from the N20 TMAP in the charge pipe (my stupid mistake! Lol).
Take a look at this log of 3rd-4th-5th gear changes and let me know your thoughts. Thanks.
http://datazap.me/u/jeffman/74f?log=1&data=3-4-15-29-30-31&solo=3-4-30&zoom=30-120
Boost, Boost Mean, and Boost Target will all log as scaled when using the 3-cell TMAP table. You can see it is working correctly, since your boost target is 24.2psi. In unscaled form, max boost target is 21.X - 22.1ish psi based on your local baro.

Boost is not read from the manifold sensor. Boost is derived from a complex calculation (based off of boost mean, which is a direct rolling mean avg. directly from the T-Map sensor), but designed to calculate losses for flow over the throttle plate and into the intake manifold, hence why it is usually a few 1/10ths of a PSI lower than Boost Mean.

Make sense? :)
 

[email protected]

Lieutenant
Nov 14, 2016
655
North Wilkesboro
Boost, Boost Mean, and Boost Target will all log as scaled when using the 3-cell TMAP table. You can see it is working correctly, since your boost target is 24.2psi. In unscaled form, max boost target is 21.X - 22.1ish psi based on your local baro.

Boost is not read from the manifold sensor. Boost is derived from a complex calculation (based off of boost mean, which is a direct rolling mean avg. directly from the T-Map sensor), but designed to calculate losses for flow over the throttle plate and into the intake manifold, hence why it is usually a few 1/10ths of a PSI lower than Boost Mean.

Make sense? :)
It truly does make you think why BMW designed the boost control like they did, which explaining the PID based boost control to someone new is virtually impossible. Basically, get 250$ in gas and play with it. It will link up in your mind quicker than words will make it link up.

But, yes this is correct. Even with the new sensor the DME will only see ~22PSI(Depending on your local air pressure, altitude blah blah.. )
 

Jeffman

Captain
Jan 7, 2017
1,340
Boost, Boost Mean, and Boost Target will all log as scaled when using the 3-cell TMAP table. You can see it is working correctly, since your boost target is 24.2psi. In unscaled form, max boost target is 21.X - 22.1ish psi based on your local baro.

Boost is not read from the manifold sensor. Boost is derived from a complex calculation (based off of boost mean, which is a direct rolling mean avg. directly from the T-Map sensor), but designed to calculate losses for flow over the throttle plate and into the intake manifold, hence why it is usually a few 1/10ths of a PSI lower than Boost Mean.

Make sense? :)
Yes indeed!
Learning something new everyday.
 

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