N54 HPFP VCV Tables

doublespaces

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I think hes talking about upshifts, the weird farting noise a lot of new auto or dkg cars do when upshifting.

I was under the assumption that was a vanos thing to bypass the boost. Pretty sure Terry mentioned this a long time ago when these BOV less engines first came out.
 

Tiron

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The sound is usually a large spark retard to drop power during the shift (which makes the shift faster and easier on the trans). Its essentially the same thing that happens to get the exhaust burbles on overrun, just during a shift when rpm is dropping more quickly.

I noticed xHP added the torque reduction setting if you choose to customize the OTS map, I'm sure if you max those out (pull out the most torque) you could probably get a 6AT car to get the bangs -- assuming the transmission will only reduce torque through timing, and not by dropping boost or cutting throttle. My 135i is a manual, but my winter beater chevy truck I've tuned to drop timing to -25° (its minimum) during shifts and it pops real nice. I believe my old GTI was -40° to give it the "DSG farts", but I don't have any data logs to go back and check.
 

Tiron

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Maybe with a bit of luck, xHP will add support for DCT someday. I don't think you'll get the sound you want without tuning the transmission controller -- and if you do accomplish it from the engine side only, I imagine the shift quality would not be very good (you'd basically need to lie to the trans about how much torque its making during the shift, and actually be pulling timing and making less than that).

The chevy truck has a table in the engine that determines how much timing to pull for a given torque drop, I'm sure there is something similar here just that no one has mapped it in the XDFs yet. Doing it in this way without a trans tune would likely also effect the operation during traction control events, making them pull tons of timing as well and just in general not behave very well.
 
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carabuser

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There's a table that controls the maximum spark retard for the shift torque intervention. It's quite hard to get a proper idea of what's going on during the shift though since we're logging at 16Hz and the shifts are around 2ms in a DCT.

The DCT makes a lot of noise during shifts when the traction control intervenes which is why you probably notice it more between 1 and 2. Both traction control and shift request have a call for retarded ignition timing, this overrides the normal minimum ignition table values and uses another lower minimum ignition angle value. I think this second table is a safety for the engine that BMW have added to prevent damage.
 
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Traf

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2ms shifts ? Even a F1 doesn't shift that fast, i believe our DCT are around 100-120ms.
 

AzNdevil

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Yeah :D I wanna make my car fart :D

Yes. I tune on my own. Any help is really appreciated.

Try setting these one or the other or both to 1023 and see if it works...units are based in Nm with reference to calculated load -> torque

1580729759981.png
 

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AzNdevil

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Thank you so much!! If this is it, i will be more than happy.

Can you go a little into detail what the description means?

normally dme retards spark and cuts fuel when the gearbox requests torque reduction for shifting
these two variables sets the approximate torque threshold for the dme to cut fuel

i suppose you can do a wot log and set it so it only farts when you go above a certain torque level...
but i doubt it will fart when turbos arent spooled anyways since rpms arent high enough to make a difference in sound

if you play around with the xdf i posted for the traction control stuff, you can tune out throttle closure requests from the dsc module...
when dsc kicks in, exhaust will sound different/louder due to spark retard... but of course... it will cause the EGTs to rise
it sounds pretty much the same

1580742953892.png
 

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JohnDaviz

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Very informative! Understood. May be it is clear to others but for me the question is how the fueling is being handled during the shift. Could imagine that it continues to flow as the target/actual AFR was before the shift in the specific load situation.
I guess the log will give us the information.

Sadly my car is in the shop.. I didn´t expect an idea so fast.

The description gives me enough trust that i do not see harming potential for the engine so it´ll be worth a try. The secondary Kitties might have trouble with that but they work until today also with my medium 1sec burble.

So as soon as i have my car back, the new turbos dialed in i will try that out.

it's basically when the computer continues to fuel through the shift, which our cars instead usually cut fuel (and timing in those cylinders that would be effected) since it's better for the trees.

This is what Justin said when i was asking him about the upshift farts. So i am pretty positive that you might have supplied us with the solution. Very excited!

Again. Your work is amazing for the small crowd using that information. The value here is extraordinary and i hope you feel rewarded by all the thanks from us as i do not think that you make any money with that work.

To keep you busy :D i have another question that might be of big value (at least for me). May be there is information out there but in the past. I talked to my tuner about the cold start sound of the car. The last what i remember that not everything causing this loud sound was revealed in the latest XDF. Have you ever researched in that direction and actually now all the tables responsible for the cold start duration? I mean having an idle sound with warm engine like the cold start sound.. uuuh
 
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Traf

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Can we make the DME treat the clutch pedal as TCU torque reduction request ?
 

all4bspinnin

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To keep you busy :D i have another question that might be of big value (at least for me). May be there is information out there but in the past. I talked to my tuner about the cold start sound of the car. The last what i remember that not everything causing this loud sound was revealed in the latest XDF. Have you ever researched in that direction and actually now all the tables responsible for the cold start duration? I mean having an idle sound with warm engine like the cold start sound.. uuuh


The cold start reduction table should be defined under ignition in the public xdf. At least the one table is.
 

AzNdevil

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Very informative! Understood. May be it is clear to others but for me the question is how the fueling is being handled during the shift. Could imagine that it continues to flow as the target/actual AFR was before the shift in the specific load situation.
I guess the log will give us the information.

Sadly my car is in the shop.. I didn´t expect an idea so fast.

The description gives me enough trust that i do not see harming potential for the engine so it´ll be worth a try. The secondary Kitties might have trouble with that but they work until today also with my medium 1sec burble.

So as soon as i have my car back, the new turbos dialed in i will try that out.



This is what Justin said when i was asking him about the upshift farts. So i am pretty positive that you might have supplied us with the solution. Very excited!

Again. Your work is amazing for the small crowd using that information. The value here is extraordinary and i hope you feel rewarded by all the thanks from us as i do not think that you make any money with that work.

To keep you busy :D i have another question that might be of big value (at least for me). May be there is information out there but in the past. I talked to my tuner about the cold start sound of the car. The last what i remember that not everything causing this loud sound was revealed in the latest XDF. Have you ever researched in that direction and actually now all the tables responsible for the cold start duration? I mean having an idle sound with warm engine like the cold start sound.. uuuh

to give you more comfort in testing...
1580755885773.png


cold start sound... you are referring to the spool helix pump yea? i think i mentioned my idea on fixing it on the first page
but of course... YMMV

it is not hard to lookup and define stuff thats alraedy there, the hard part is testing and making sure it works
i do understand why no one wants to do it... if shit happens then... it can brick/break your car
 

jyamona

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The cold start reduction table should be defined under ignition in the public xdf. At least the one table is.

Pretty sure he wants his warm idle to sound like cold start. Won't happen as timing is retarded a good deal for cold start to get heat into the cats. You'd have too high of EGT to keep it running that way after the cold start timer. Get a louder exhaust if you want loud all the time.
 
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jyamona

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Faster shifts, if the throttle stays fully open during shifts, it could help i think.

With MHD, use flash options for shift bog fix + PI safety. Then you can NLS without worry and the throttle will stay open. Lots of people doing this currently until I have time to finish the full NLS code.