XHP DCT - Experience Thread

WedgePerformance

Specialist
Platinum Vendor
Nov 2, 2016
75
Portland OR
So my next Update:

Support at XHP seems not to know why i can´t change the rev limit. Even further there seems to be some kind of issue going on as the shifts are not smooth.
First shift at 6680rpm, second shift at 6613 but before that, rpm was at 6646 and declined a bit before shifting (felt strange) and hitting long tq limit 4 after the shift.. which is again..strange?

I may be the only one affected with this strange issue but also i never heard of anybody running stock turbos and shifting at 6.6k rpm. Everybody i know shifts around 5.8-6k..

View attachment 42067

The recommendation now is to use stock shiftmap. Sounds like a workaround to me.
Flashing stock and everything is fine and also in the true manual mode i can hit 7k rpm. Only during automatic modes in D and S not.

What is your experience with V1.1?

I guess there will be ppl who like the new downshift behaviour but it is not my thing.
What i don´t like: When i drive towards a red light and being e.g. in 6th gear and i brake a bit harder the car hits 3rd and 2nd gear in so harsh that smooth braking is not possible anymore. Really uncomfortable.

Over all i don´t understand why XHP introduces a new Rev Limit and this downshift logic hard into the OTS maps. First one should be left for ppl to adjust in the Max RPM table and latter might be an on/off option. In the end my 335 is not a race car and i dislike this downshift logic as it makes the car less comfortable in D in different situations. Overall it still is not an M car and many ppl (who i know) use it as a daily and even family car. At least here in Germany.

Another thing is that my car is now shifting like 4 times as much as before that "upgrade" in daily city use.

I hope that XHP will change their policy of introducing/dictating "Features" that may be unwanted for some ppl and would be a great on/off option.

One thing I noticed, if I wasn't in sport+ with traction off, my shifts were always below 7000. As soon as I turned traction control off in sport+, I was able to rev to 7500 without any issues.

I don't know why people just assume torque limit 4 is normal. I guess they don't want listen because I must not know what I'm talking about because someone else said it was normal... but I digress.

We think there is a checksum that is not getting calibrated for the DCT cars when boost target is changed. This is one reason why we don't change that value for the MHD OTS maps anymore like we did for v5. If you set boost target back to 1.28 and ensure the hex value is correct, the torque limit 4 will go away. You just need to use MHD MBoost tmap scaling with a 3.5 bar to get a higher boost target without changing that table value which causes the torque limit 4. I'm using a 5 bar on my Z4 so I can run over 30 psi. See the log below, increased shift points and no torque limit 4.


7500 rpm DCT xHP.jpg
 
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JohnDaviz

Sergeant
Jan 6, 2019
254
My tq limit 4 must be something different. i NEVER had it before xhp dct and i made a lot of miles. My boost ceiling is at 1.28 as i am running stock sensor.
And if you look closely my tq limit 4 is right after the shift. not during. And this is only during auto shift. Next what happens is that i get misfire code.

Did you change the max rpm tables for 7.5k rpm? in dsc off and sport+ i can rev to a little over 7k i think before rev limiter activates.
 

WedgePerformance

Specialist
Platinum Vendor
Nov 2, 2016
75
Portland OR
My tq limit 4 must be something different. i NEVER had it before xhp dct and i made a lot of miles. My boost ceiling is at 1.28 as i am running stock sensor.
And if you look closely my tq limit 4 is right after the shift. not during. And this is only during auto shift. Next what happens is that i get misfire code.

Did you change the max rpm tables for 7.5k rpm? in dsc off and sport+ i can rev to a little over 7k i think before rev limiter activates.
Could just be your toque actual is too high and it's triggering a torque limit 4. Would need to see logs as to why your car misfires, could be something as simple as coils and plug gap. If you're not running Delphi or Eldor coils with a good 1 step colder NGK gap to .020 then it's possible you have misfire issues which cause fuel mode 15. When that happens your trims go zero, o2 sensors stop working, and injector window max's out dumping as much fuel as possible to prevent detonation, then you get a hard misfire. But again, without a full log, just speculation.

I run a built motor with my rev limit set to 7800 rpm so I can pull through 4th gear to get a better 100-200 kph / 60-130 mph dragy times. This way I only have 1 shift. Otherwise I don't normally rev that high, just an example that the option does work.
 

carabuser

Corporal
Oct 2, 2019
142
Tq Limit 4 is completely normal on cars in the fast torque reduction path. The channel that MHD logs shows the slow path which shouldn't be active.

Tq Limit 4 is present on stock maps though. I've seen stock DCT logs for 3 cars and they all had torque limit 4 active in the slow path.

I'm still trying to figure out why MBoost breaks things. The scaling solution is a lazy workaround IMO, barely an upgrade on a JB4.
 

aus335iguy

Major
Nov 18, 2017
1,789
Down under
@Grunt suggest you log continuously so that you can capture what’s happening should it happen again. Though unlikely you have a tune issue as BQ had a good rep with DCTs your slippage could be tune related. Also suggest starting a seperate thread just for your issue.
 

RSL

Lieutenant
Aug 11, 2017
543
Tq Limit 4 is completely normal on cars in the fast torque reduction path. The channel that MHD logs shows the slow path which shouldn't be active.

Tq Limit 4 is present on stock maps though. I've seen stock DCT logs for 3 cars and they all had torque limit 4 active in the slow path.

I'm still trying to figure out why MBoost breaks things. The scaling solution is a lazy workaround IMO, barely an upgrade on a JB4.
Truth. As a matter of fact, DCT is in intervention mode on every single shift up or down, not just WOT. Fast path 4 or 8 with it, depending on direction, but would never know it unless slow path hits or you go looking for it.

The DCT ceiling "thing" might work both ways IIRC. Take those stock bin DCT cars that are hitting it, lower boost ceiling from 1.28 to 1.25-1.26 and see if they still exist. I vaguely remember trying that years ago as a test and it actually worked, or at least severely cut down their frequency.

At least on scaled, it doesn't mess with PT at all, but full scale is kind of ridiculous if you just want +3-4psi.

I haven't seen different checksums on shift with raised ceiling (and maybe that is a problem), but if it is a checksum issue, it should surely set an error flag somewhere that can be seen/logged to verify.
 

carabuser

Corporal
Oct 2, 2019
142
So my next Update:

Support at XHP seems not to know why i can´t change the rev limit. Even further there seems to be some kind of issue going on as the shifts are not smooth.
First shift at 6680rpm, second shift at 6613 but before that, rpm was at 6646 and declined a bit before shifting (felt strange) and hitting long tq limit 4 after the shift.. which is again..strange?

I may be the only one affected with this strange issue but also i never heard of anybody running stock turbos and shifting at 6.6k rpm. Everybody i know shifts around 5.8-6k..

View attachment 42067

The recommendation now is to use stock shiftmap. Sounds like a workaround to me.
Flashing stock and everything is fine and also in the true manual mode i can hit 7k rpm. Only during automatic modes in D and S not.

What is your experience with V1.1?

I guess there will be ppl who like the new downshift behaviour but it is not my thing.
What i don´t like: When i drive towards a red light and being e.g. in 6th gear and i brake a bit harder the car hits 3rd and 2nd gear in so harsh that smooth braking is not possible anymore. Really uncomfortable.

Over all i don´t understand why XHP introduces a new Rev Limit and this downshift logic hard into the OTS maps. First one should be left for ppl to adjust in the Max RPM table and latter might be an on/off option. In the end my 335 is not a race car and i dislike this downshift logic as it makes the car less comfortable in D in different situations. Overall it still is not an M car and many ppl (who i know) use it as a daily and even family car. At least here in Germany.

Another thing is that my car is now shifting like 4 times as much as before that "upgrade" in daily city use.

I hope that XHP will change their policy of introducing/dictating "Features" that may be unwanted for some ppl and would be a great on/off option.
You can sort out the aggressive downshifts and blips by using stage 2 instead of stage 3.
 

JohnDaviz

Sergeant
Jan 6, 2019
254
You can sort out the aggressive downshifts and blips by using stage 2 instead of stage 3.
Today i just went to V1.0 Maps and everything is fine. I prefer 1.0 over 1.1 a million times.
Aggressive downshifts ect gone. Also the weird clutch engagement during a take off is gone. @Grunt

Ah and one more thing i noticed. With 1.1 my idle rev was lower than with the 1.0. Not much but you could feel it. I don´t have a clue why. DME Rev is the same.

XHP has to have made something really wrong with their "average joe" rev limiter.
I flashed 7.1k RPM in all modes and still shifts at 6.7k RPM but now without tq limit active 4.
Funny note. Also a guy running single turbo is auto shifting at 6.7k rpm. I guess that was a wrong move by XHP.
I wonder why @RayBan is not communicating here lately. Hope he is working on reversing those two things.
 

Ryffis

New Member
Jul 14, 2020
1
Hey, im just curious if anyone tried to change diff ratio with xhp yet? We've been thinking about fitting 3.08 lsd to my mates car, and just wondering how this option works.

Aswell if anyone has some experience with that ratio in dct, would like to hear any comments.
Thanks.
 

JMVELA

Private
Mar 17, 2018
49
Hi guys! What should be the RPM limit set on the 335is with DCT trans? Using the XHP flash. 7,000 rpm? 7,200 rpm? Talking of a stock cylinder head, no springs, no retainers.

Thanks
 

JohnDaviz

Sergeant
Jan 6, 2019
254
Hi guys! What should be the RPM limit set on the 335is with DCT trans? Using the XHP flash. 7,000 rpm? 7,200 rpm? Talking of a stock cylinder head, no springs, no retainers.

Thanks
Did you change the rev limit?

Until this day my Rev Limit in D and S Mode is 6700 RPM although i set it to 7200. Only when DSC is completely off i seem not to have this issue.
@RayBan and his company are resilient to help me and understand that.
 

Grunt

Lurker
Jul 30, 2019
14
Lancaster, P
Did you change the rev limit?

Until this day my Rev Limit in D and S Mode is 6700 RPM although i set it to 7200. Only when DSC is completely off i seem not to have this issue.
@RayBan and his company are resilient to help me and understand that.
My rev limit is at 6700 as well although I rarely go above 6400. Being on stock snails, it doesn't get me anything going any higher and the old school mentality of no need to push it if it doesn't gain you anything.
 

JMVELA

Private
Mar 17, 2018
49
Did you change the rev limit?

Until this day my Rev Limit in D and S Mode is 6700 RPM although i set it to 7200. Only when DSC is completely off i seem not to have this issue.
@RayBan and his company are resilient to help me and understand that.
I did changed it but as Grunt said, I barely goes above 6400 rpm so I haven't test it. I do have big turbos, so I maybe do some testing when go to the dyno. No date yet.
 

houtan

Sergeant
Nov 2, 2017
306
Did you change the rev limit?

Until this day my Rev Limit in D and S Mode is 6700 RPM although i set it to 7200. Only when DSC is completely off i seem not to have this issue.
@RayBan and his company are resilient to help me and understand that.
I still haven’t bought the flash based on all of the up and down feedback. But I wanted to ask, does the documentation say the raised rev limit should work in all modes?
 

JohnDaviz

Sergeant
Jan 6, 2019
254
I still haven’t bought the flash based on all of the up and down feedback. But I wanted to ask, does the documentation say the raised rev limit should work in all modes?
Yes. You "should" be able to change the Rev Limit for all modes.

I am crazy disappointed by the attitude this enterpreneur is presenting when asking to resolve this issue. To me he is not a professional.
I described multiple times that i tried to change the rev limit and that it is a bug for MY car. as it is NOT working. I have shown data here and explained it three or four times.
Here, via Support and over Facebook.
His answer "it is no bug. You can change it in the settings if you want." Clemens DIDNT EVEN READ what i was actually expressing.
Just a go away waving at me. I now understand that some ppl don´t want to feed that guy with money.
 

houtan

Sergeant
Nov 2, 2017
306
Yes. You "should" be able to change the Rev Limit for all modes.

I am crazy disappointed by the attitude this enterpreneur is presenting when asking to resolve this issue. To me he is not a professional.
I described multiple times that i tried to change the rev limit and that it is a bug for MY car. as it is NOT working. I have shown data here and explained it three or four times.
Here, via Support and over Facebook.
His answer "it is no bug. You can change it in the settings if you want." Clemens DIDNT EVEN READ what i was actually expressing.
Just a go away waving at me. I now understand that some ppl don´t want to feed that guy with money.
That sucks. Unfortunately, it’s happened to me so many times I just expect it now. Even worse, just like the engine tuning sw, they are the only show in town so we don’t have much of a choice. Anyway, hopefully your issue gets resolved.

Do you or anyone else know what I would need to disable auto shift at redline? Can I just purchase the flasher and disable it in my stock bin? Or do I still need to purchase the map pack?
 
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JohnDaviz

Sergeant
Jan 6, 2019
254
Do you or anyone else know what I would need to disable auto shift at redline? Can I just purchase the flasher and disable it in my stock bin? Or do I still need to purchase the map pack?
xhp is calling it true manual mode and as far as i understood it is only available through their map pack.
 
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JMVELA

Private
Mar 17, 2018
49
Hi everyone! I have installed XHP software and all pareas to have been working fine. So far IO like the software, but have someone experienced gear not up shifting at high RPM with lot of power? I have had gear "locked" on 4th gear when attempting to shift to 5th gear at high rpm (over 6200 rpm) and when car is going with lot of power (26 psi of boost). This has happened to me twice. Have you heard this happened to someone else. Any advises??
 

houtan

Sergeant
Nov 2, 2017
306
Hi everyone! I have installed XHP software and all pareas to have been working fine. So far IO like the software, but have someone experienced gear not up shifting at high RPM with lot of power? I have had gear "locked" on 4th gear when attempting to shift to 5th gear at high rpm (over 6200 rpm) and when car is going with lot of power (26 psi of boost). This has happened to me twice. Have you heard this happened to someone else. Any advises??
Thanks for posting an update.

Did you have the same issue prior to the xhp flash?
 

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