MHD E50 timing dip @low rpm under WOT

vadonchez

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Oct 29, 2023
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hi guys, i posted the question few time ago on another forum without any answers. I email MHD and the only answer was "you have a boost leak" but it seem's that they don't understand that I'm using MHD multimap stage 2+ with power slider set to 85 or 90% depending on the slot i'm using. no more answer fron them since my last explanation...
Maybe will I have more chance here!!

So there is my question:
Somebody has an idee about timing dip below 3500rpm I have with V8/9/10 on E30 and E50?
there is a picture:
timing dip.png


No problem with V7 E40 or 93oct and one time i tried V10 stage 2 93oct and no problem too.
because I'm looking for less boost an ethanol blend i would like to use V9 E50 and power slider to make my own boost target.
I can feel the power coming hard when timing is recovering normal value above 3500rpm. Sometimes I feel that timing is ok and car is much more smooth and powerfull between 2500-3500rpm. Would like to be always ok.

some datazap examples:

https://datazap.me/u/vadonchez/v9-2-...26&zoom=90-164

https://datazap.me/u/vadonchez/v8-28...6&zoom=116-191

https://datazap.me/u/vadonchez/stage...5&zoom=129-193

I already reset adaptation.


Thanks a lot!
 

wheela

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Hmm, I don't see any timing corrections there, and I don't see the torque limiters tripping. Are there other torque limiters you can monitor?

Another weird thing, with that big of a timing drop, I'd expect to see the modeled torque actual drop significantly, but that didn't happen. It actually looks like modeled torque actual starts rising abruptly around the time your timing tanks, and the reduced timing looks to be keeping the modeled torque actual relatively in order. Almost like it reduced timing to keep a torque spike in check?

If this was n55, I'd wonder if something is messed up in the load-to-torque table, but I'm not familiar enough with n54 to know how the torque modeling is handled. Plus it's an OTS tune, so if something was messed up there, I'd expect everybody would be having this issue.

Do you have traction control fully disabled when taking these logs?
 

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carabuser

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Oct 2, 2019
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As wheela said, it's related to torque reporting.

The reason no torque limiters are shown is because there is nothing actually limiting the torque output, rather than whatever changes have been made in the tune are causing a misalignment between the torque value that is being requested by the pedal and the torque that is calculated by the DME.

The underlying cause is the MHD logic and it's the reason I no longer use it to tune my own cars. I got sick of the random timing pulls and the shitty DCT shifts.

You can see the same behaviour in a few of your logs, it's very evident during shifts as your timing takes a massive dump:
1703068011188.png


With a DCT transmission your timing should look more like this:
1703068227005.png
 
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vadonchez

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Oct 29, 2023
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thanks

Could I see what you"re talking about (torque request vs torque actual) by logging the parameter "torque output req" in mhd and compare it with torque actual?
If yes I will make somes logs with that parameter and see if we can confirm that.

V7.1 2+ E40 was the best one for my car if i look at some logs i have done. I'm just concern about high boost target and WGDC wich cause my low rpm whine....:

https://datazap.me/u/vadonchez/v7-2...attle-fixe-10?log=0&data=3-21-26&zoom=259-402
https://datazap.me/u/vadonchez/v7-2-e40-remontage-dp-oem-rattle-fixe-10?log=1&data=3-21-25
 

carabuser

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thanks

Could I see what you"re talking about (torque request vs torque actual) by logging the parameter "torque output req" in mhd and compare it with torque actual?
If yes I will make somes logs with that parameter and see if we can confirm that.

V7.1 2+ E40 was the best one for my car if i look at some logs i have done. I'm just concern about high boost target and WGDC wich cause my low rpm whine....:

https://datazap.me/u/vadonchez/v7-2...attle-fixe-10?log=0&data=3-21-26&zoom=259-402
https://datazap.me/u/vadonchez/v7-2-e40-remontage-dp-oem-rattle-fixe-10?log=1&data=3-21-25
No, not accessible with MHD standard parameters. The torque target channel isn't representative of the actual torque the engine is targeting.

Timing looks off in all those logs during the shift but they do look better at spool. You'd probably see issues if you try part throttle runs though, that's where it's most noticeable.
 

logic vs emotion

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Aug 18, 2018
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Have you tried unaltered OTS map, instead of you tweaking the power out put of the map? Is the DCT option selected from the drop down list? I've looked all the lost you posted, some looks really good, except or the very low boost as the rpms get up there. However...one thing that I did notice...is the load vs actual load, where the logs show that the tune is over shooting the target load. Sorta like Target Boost/Celling vs Actual Boost, where throttle closure or waste gate manipulation is used to control it. I'm not sure if this your the issue, I'm just sharing my speculations.
1703193841988.png
 

vadonchez

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Oct 29, 2023
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thanks guys for your help!

Problem appears even with non altered map and yes I selected DCT option in MHD.
I already thinking about what you are speaking (actual load/request) but it seem's that timing dip appears without load target overshooting or doesn't apperas with overshooting.....:

This case show an overshooting but no timing dip (V8 map)

cas4.png


This case show a timing dip without load overshooting (V10 map):
cas5.png


That's why I think that's not the reason:disappointed:

One thing i would like to try is to use OEM throttle mapping, I think i was using oem throttle with v7.
Maybe there is a problem with my car and linear throttle
 
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carabuser

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I have added the 4 relevant parameters into an MHD logging file. This might give more insight into your issue.

Unzip the file and copy the xml file into your MHD folder. There should already be another xml file in there named as ...flashoptions.xml along with a couple of folders called datalogging and debugging.
Once you copy it in you should see 4 additional parameters at the top of the list in the logging parameters. Just add those, if you need space then untick the existing MHD torque channels.

Messing around with tickboxes and sliders isn't going to fix anything. You can tune around the issue by targeting a lot more torque so that the actual values don't get close to the target, but that only solves the issue at WOT, you will still see and feel it during part throttle as the car will be able to meet the target.
 

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vadonchez

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Oaaaa ! thanks carbabuser i just follow your procedure and yes I have 4 more parameters in my log options.

I will make other logs as soon as road will be dry here and log those new parameters if it can help.

This forum is awesome.
 
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vadonchez

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Oct 29, 2023
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thanks for your reply.
Can you explain to me the purpose of those parameters, what they mean (air,spark...)?
Why target torque show a "step" around 4000rpm? How can the tune be smooth with such kind of step?
I don't see actual exceeding target during some shifts:
timing dip mhd.png


I will try to log those parameters with V7.
 
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carabuser

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DME calculates the amount of ignition angle required to meet that target torque. As soon as you exceed that the torque is reduced proportionally.

I'll take a log on my own vehicle over the next week to show what it should look like. I don't actually have all those parameters selected together in an existing log.
 
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vadonchez

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Oct 29, 2023
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Hi

I did a log today after few miles done since adaptation reset and V7 E40 tune upload.

V7 E40 DCT Z4 35IS

This tune is much more smooth than V9 or V10 on my car, mainly du to timing wich is a lot more smooth without dip.

I see that actual torque is over the target yet i see none timing dip.

Carbauser or other guys can you please give me your feedback?

Thanks!!