XHP DCT - Experience Thread
- Thread starter JohnDaviz
- Start date
Anyway I can buy into the testing? I have a 335is with M3GWS, MDSC, M3 Kombi, and SZL
But why, if you already have m3 gws? Just flash gts))) sure you need some fine tune, ie max shift rpms.
It's all done now. Both my cars are running it without any issues.
There is a slight issue with compatibility with MHD but hopefully that will be sorted soon.
Thanks. I would like to try it out. How much would it cost? I have xHP but I’m not convinced the shifting is better. I mainly continue to use it because I need the auto shift and creep disable functions.
@Olza is the man for that
I had the same feeling about xHP. It was nice being able to adjust shift maps and disable creep but the shifts were still slow compared to the GTS cars.
You'd never get a log looking like this with xHP:
The shift times are down so low that most times the torque reduction doesn't even show on the logs because it falls between the 10Hz logging intervals.
With xHP I just felt that the torque punch and reduction sliders did nothing other than make the shifts feel aggressive rather than making them better. And the stage 3 maps have that awful jerky downshift affect under braking that makes you appear like a learner driver. €400 completely wasted.
@carabuser do you have a z4? was the gts flash not available from mhd for that car? Mhd for my f82 gives me the option to flash gts tcu software.
on another note ive done alot of testing on the xhp and i may be able to help. Seem like youre a little better at reading logs than me but i take torque actual at clutch value before the shift multiple it by .66666 then use that as my reduction value. Also tp at 2 +/- 1 seems to help times. Do you think normal gts flash is quicker? I kinda need the 20 bar line pressure on xhp. Torque reduction cant be more than the value before the 1-2 shift becayse youll get torque lim 1024 i believe aka min power aka stall lol.
on another note ive done alot of testing on the xhp and i may be able to help. Seem like youre a little better at reading logs than me but i take torque actual at clutch value before the shift multiple it by .66666 then use that as my reduction value. Also tp at 2 +/- 1 seems to help times. Do you think normal gts flash is quicker? I kinda need the 20 bar line pressure on xhp. Torque reduction cant be more than the value before the 1-2 shift becayse youll get torque lim 1024 i believe aka min power aka stall lol.
to add the torque punch is basically a multiplier applied to the clutch pressure the dct calculates is needed for the shift to complete. So if load to torque tables are accurate 1 should be fine. Ive been recommending 2 and people seem to like it. I believe cary has my table too low so ive been running 3-4 all though im still testing
I have a Z4 and 335i, both are DCT cars. The issue with MHD is that part of the standard logic changes is one that removed the effect of lambda on the target load. It was a fix that was put in place by COBB originally and has been carried forward by MHD. I have tested removing this logic change on my own cars and also on a few customer cars so hopefully this is something that can be added as an option by MHD.
With the GTS flash you can adjust the line pressure up as high as you like. Olza is a real wizard with the DCT. The file he produced for me is essentially the GTS flash converted for the Z4/335i hardware and with the RPM limits changed to match the lower redline of the N54 and the line pressure bump.
I did put a lot of time into understanding the torque reduction and came to the conclusion that the xHP torque reduction slider has really no effect on the torque target that the DCT sends to the DME. You can set the value to 0 or 1000nm and the limiter value that the DCT sends will not change. The reduction and punch sliders do make the shifts feel different but don't make them any faster, certainly nowhere close to the GTS flash.
The easy way to see how good shifts are is looking at the duration of the timing reduction. If you are seeing timing drop for any longer than a single scan of the MHD logging then shifts are sub-optimal. The shift should be complete and engine timing reduction be removed within 100ms. MHD is too slow at logging to see it completely but I'd estimate that the shift is completing within 60ms given how often I see the logging catch it.
I did ask xHP about this a few times and they weren't really interested. I also suggested the possibility of supporting GTS conversions with their app but I don't think there's any more money left in the Gen1 DCT platform so it's down to the community to get things perfected.
I did ask xHP about this a few times and they weren't really interested. I also suggested the possibility of supporting GTS conversions with their app but I don't think there's any more money left in the Gen1 DCT platform so it's down to the community to get things perfected.
I’ve talked to Olza a while back and was going to pay for some of his mappings but car funds got cut off lol. The problem with the f82 is it’s gen 2 dct and he doesn’t have a way to flash the map. XHP is locked up and I’m not sure how MHD flashes their tcu tune to the car. Gen 2 options seem to be one of the gts tubes by MHD, bm3, or Thor and then xhp
So.. what's the consensus here? I also have a Z4 with DCT. Is there a better flash out there now? The stock shift pattern is horrible, which is my main complaint. It wants to row through the gears very eagerly. If I push the shift lever to the left it gets much closer to what I'd like all the time, but the shifts are really jarring for everyday driving.
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