MHD+ OTS Map Shift Point Issue

[Danimal]

Flashed my car with MHD Stage 2 OTS map - car is a tuneable 2021. In ‘normal’ mode, the up and down shifting is not right. In my limited testing around town, it seems to up and down shift based on vehicle speed only. No amount of throttle input would cause it to shift at anything higher than like…1200 RPM, and I never got it to downshift by hitting the accelerator. Admittedly, I was a bit of a chicken because burying the throttle in 7th gear going 35 MPH at something like 1000 RPM is against my religion.

Anyone else have this experience? No issue in sport mode. I like it in Sport mode some of the time, but I have a long road trip coming up and I expect to want to use normal mode…. I’d rather not flash back to stock for this road trip - playing with MHD+ features on-the-fly is one of the things im most looking forward to on the trip…

Searched and didn’t find anything - also figured I’d check here before seeing if I can get a hold of anyone at MHD.

Dan

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[Phantomx]

The DME and flash just control the engine tune the trans is controlled through a different tune all together. Could be throttle response is messed up in normal try the stage 1 map see if there is a change or flash to stock (but don’t relock the DME just stock map 0) and drive it.

what options on stage 2 did you pick for fuel?

 

[Danimal]

Tried stage 0 and stage 1 - seems the same. Also, I overstated the issue - I can tell that throttle % does have an impact on gear selection for all maps. It just seems to bias way too high of a gear and requires too much throttle input to downshift - especially between 30-60MPH in traffic. You have to be willing to build boost at 1000RPM for a second or sometimes a few seconds before a downshift. I’m not comfortable doing that, plus there’s a lot of vibration in the cabin when you have high cylinder pressures at such an abornally low speed. Makes my skin crawl because I know that’s likely not good for the engine ?

I assume the DME commands a gear and the trans control unit executes the shift. Assuming I’m right, it’s an MHD OTS map issue.

I did get a (brief) response from MHD over the weekend asking some questions - quite impressed with that! I’ve offered to send them a log if they’re interested. I know I can utilize one of the many talented tuners around me in my area to adjust this, but at least wanted the MHD team to know my feedback with their stock maps. No one else seems to complain about this, from my Googling, so this is either a new issue with the multi-maps on a 6-port b58, or it’s something specific to my car (seems unlikely), or I’m more aware/sensitive to this than others. Might be that last one since I’ve been doing engine and transmission integration and shift strategies for a long time in my engineering career.

Dan

 

[Danimal]

The good folks at MHD got back to me with a 2nd follow-up and also stated that the TCU is in charge of shift points and overall shift strategy, as Phantomx also stated above. Therefore, my assumptions were incorrect and apparently what I’m observing is the stock shifting behavior with the updated engine tune.

The outcome of this, for me, is a lot of respect for the MHD team and their super quick responses and feedback. I simply put a comment in on their website form and got a reply the next day (Germany time) and quick follow up 2nd email - the first response was over the weekend. I’m also quite happy with MHD+ overall - super easy and fun to use.

Dan

 

[Ruslan]

Flashed my car with MHD Stage 2 OTS map - car is a tuneable 2021. In ‘normal’ mode, the up and down shifting is not right. In my limited testing around town, it seems to up and down shift based on vehicle speed only. No amount of throttle input would cause it to shift at anything higher than like…1200 RPM, and I never got it to downshift by hitting the accelerator. Admittedly, I was a bit of a chicken because burying the throttle in 7th gear going 35 MPH at something like 1000 RPM is against my religion.

Anyone else have this experience? No issue in sport mode. I like it in Sport mode some of the time, but I have a long road trip coming up and I expect to want to use normal mode…. I’d rather not flash back to stock for this road trip - playing with MHD+ features on-the-fly is one of the things im most looking forward to on the trip…

Searched and didn’t find anything - also figured I’d check here before seeing if I can get a hold of anyone at MHD.

Dan

I'm having same issue with my supra. Were you able to fix the problem?

 

[nanaisu]

I'm having same issue with my supra. Were you able to fix the problem?

In short, you'll want to look to xHP for transmission tuning. The MHD Universal adapter should be able to flash the TCU.
It's on my to-do list sometime this or next month.

 

[Danimal]

I'm having same issue with my supra. Were you able to fix the problem?

As nanaisu states - my assumptions in the OP were incorrect. Shift scheduling is handled by the ZF TCU, so the fix is tuning with xHP. I’ve not spent the cash yet, so I do a lot of manual shifting or ignoring of the stupidly low RPMs of the stock shift points and associated reverberation and rattle I sometimes get in the cabin.

 

[Danimal]

Actually, come to think of it, I wonder if the TCU relearned shift points, as I don’t think it’s as bad as it used to be? Not sure.

 

[stormgreysupra]

I would recommend getting XHP. It improves the shifting and driving experience a lot. Even in comfort the car feels a lot better.

 

[Twisted Tuning]

yes, TCM does the grunt of the work for shifting by design. throttle input and etc does have an influence.

Im assuming based on your issue description that you are experiencing very fast upshifting at low vehicle speed. Like 7th/8th gear at like 40mph or so?

 

[Danimal]

Yes, exactly.

 

[Twisted Tuning]

Yes, exactly.

yes, that can fixed in the DME tune as well as the TCM tune.

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