[TurboWeasel]

Originally Posted by Watsey

From experience I think the XHP developer (RBT Tuning) will respond to say 'that's how it is'.

I contacted them a few times regarding the DSC programme. For my car, running XHP Stage 3 (although I think the characteristic is the same for the other Stage maps) activating DSC now drops two gear ratios and increases the rpm way above where I'd like it to be.

Diesels, especially with remaps, develop very healthy torque outputs and there's simply no need to drop the gear ratios. DSC behaviour 'should' be as per OEM => a relaxing of the stability control programme to allow a bit more 'slip'n'slide' at the rear. It's very easy to adjust the cornering angle using the throttle pedal and torque - the engine doesn't need to be doing 2500-3000rpm.

RBT's stance is that DSC is for 'maximum fun at the track' and that it won't be even giving the option to have DSC characteristics as a toggle setting in the App.

Yeah I got a canned answer - "Edit the shift points" but they either didn't get where I was coming from, or pleaded ignorance.

The actual issue is in the Relaxed mode's pedal speed map. They have retuned it to ignore slow and/or gentle inputs.

It is exactly what I want for daily meandering as it means the box won't downshift at the slightest whiff of an inclination, but they've tuned it poorly.

The Relaxed map allows me to pull 7th from 950rpm. I know diesels are robust and torquey, but high load and ultra low rpm is extremely bad for pistons and rod bearings. Stock would over ride that request and downshift way before 950rpm.

Yeah I saw your DSC issues in other threads when researching xHP. Not good really. As you say, diesels don't need to rev. That is the whole point of them.

Anyway, I think I've got it to where I want it. 8th is still an issue, but I think that is more to do with the cold weather / warm up behaviour as stock is also sluggish to engage 8th during warm up.

[TurboWeasel]

FWIW, I reset the gearbox adaptations yesterday with ISTA and went out for a 100 mile relearn drive. It's the best it's ever been, stock or xHP'd.

Apparently other brands of car that use the ZF 8HP always clear the adaptations after a fluid flush, but BMW don't mention it. It seems to work though, and makes sense to relearn after fresh oil and a filter as the clutch mbar readings will be different.

[moppity]

Quick spin today in Sport and manual mode. Ooof, fabulous fun 🤩

[TurboWeasel]

Yeah Sport is even sportier than the standard Sport I don't know why, but my 30d feels waaaaay more responsive and punchy in Sport Manual with xHP than it did before. Not sure if you've found the same in your petrol? It's not just the rev band and shift points.....it's almost like it's bringing the boost in sooner.....or something.

I rarely use it though. Just for some fun blasts occasionally and getting past tractors swiftly.

In other news, Stage 2 with the relaxed shift map has increased my mpg from 49 to 52 over the last 1300 or so miles since I flashed it.

And to answer my own question - it can indeed be flashed back to stock, but it still leaves the gear number in D, so it's not quite 100% back to stock.

[moppity]

Yes, it just feels so much more responsive! I think it's the throttle mapping — whatever they do there makes it feel so much livelier.

Loving it

[SkyJawa]

My mpg has dropped since going stage 3, I struggle to hit 40mpg on shorter varying speed journeys now where as before it was easy. But I think that could be down to 2 things, I’m “playing” a lot more to see how well it goes, and the weather/temps….

Will be having a longer run on Sunday so will be a fairer test on a mway journey.

[TurboWeasel]

Yeah it's probably just the weather. Very strong head winds and cold temps can cause a slight mpg drop. The shift speed shouldn't really affect mpg, but shift points can

[Eddamoo]

Originally Posted by SkyJawa

My mpg has dropped since going stage 3, I struggle to hit 40mpg on shorter varying speed journeys now where as before it was easy. But I think that could be down to 2 things, I’m “playing” a lot more to see how well it goes, and the weather/temps….

Will be having a longer run on Sunday so will be a fairer test on a mway journey.

Its worth noting that XHP doesn't de-clutch the gearbox at standstill as of the v1.8 map for the 70HP/Diesel model. Its a bug that i've reported that they struggle to acknowledge.

If you do lots of stop/start, this will have an impact on MPG - by my cigarette-packet calculations, the car consumes about 6-8x more fuel at idle with the TC still engaged. I and other here have come to accept it and plop the car in neutral themselves.

I personally have found a modest MPG gain with XHP, although its hard to prove. My shifts are configured lower and I've made them faster, which causes less TC slippage.

[TurboWeasel]

Originally Posted by Eddamoo

Its worth noting that XHP doesn't de-clutch the gearbox at standstill as of the v1.8 map for the 70HP/Diesel model. Its a bug that i've reported that they struggle to acknowledge.

If you do lots of stop/start, this will have an impact on MPG - by my cigarette-packet calculations, the car consumes about 6-8x more fuel at idle with the TC still engaged. I and other here have come to accept it and plop the car in neutral themselves.

I personally have found a modest MPG gain with XHP, although its hard to prove. My shifts are configured lower and I've made them faster, which causes less TC slippage.

Great, another bug. I wondered why that setting had no effect! Thanks for mentioning that I sit in traffic a lot, so do you happen to know which earlier version of the map that does work in?

That bug, no DTC in comfort mode and pretty poor shift consistency from cold to hot (sporadic and unwanted very early down shifts, which unsettles the car like a clumsy manual gearbox shift) is making feel like this product is a bit over rated tbh. As you say, the support is pretty naff as well. It seems people gush over it but never mention the negatives, apart from a few people.

I've been tempted to flash it back to stock permanently because it's more consistent and smoother, but I like the benefits of xHP too much. Hopefully it will improve over time, but the guy seems to be happy to offer custom tunes for 500 odd euros without fixing the OTS maps first

EDIT: Just realised v1.8 relates to Stage 3 only. Stage 2 is only at v1.4, so it probably does still work on that.

[SkyJawa]

I’m at Stage 3 v1.5 from 06/05/23 so shouldn’t be an issue at this version.

I put it down to cold weather/higher electrical use and the fact I’ve probably played more to see the differences rather than just drive.

Got a 100+ mile round trip this weekend so really interested to see what it gets.

[Eddamoo]

Originally Posted by TurboWeasel

EDIT: Just realised v1.8 relates to Stage 3 only. Stage 2 is only at v1.4, so it probably does still work on that.

Apologies, my grammar was poor. Pretty much every Stage2/3 version I flashed behaved the same - i assume its a global bug.

Easiest way to tell is shift to neutral while stationary - you can obviously feel significant load releasing from the drivetrain.

[TurboWeasel]

Originally Posted by Eddamoo

Apologies, my grammar was poor. Pretty much every Stage2/3 version I flashed behaved the same - i assume its a global bug.

Easiest way to tell is shift to neutral while stationary - you can obviously feel significant load releasing from the drivetrain.

TBH, I can't say I've noticed much difference between Stage 2 (decoupling enabled) and stock when sat at traffic lights. I normally stay in D with the handbrake up as to not blind people behind me (because I'm considerate like that, lol). I can't say I notice much of load change when switching to N or P when stationary, so maybe the decoupling is working? I'll try N again tonight to see what the creep is like now you've mentioned it.

I did report the lack of DTC in comfort mode, and decoupling not working earlier, just to get the numbers up, and got these lame responses:

"Most people want DTC in Sport mode" (so tough luck basically).

"Decoupling is enabled in the settings."

Gee, thanks for that

[Watsey]

Originally Posted by TurboWeasel

TBH, I can't say I've noticed much difference between Stage 2 (decoupling enabled) and stock when sat at traffic lights. I normally stay in D with the handbrake up as to not blind people behind me (because I'm considerate like that, lol). I can't say I notice much of load change when switching to N or P when stationary, so maybe the decoupling is working? I'll try N again tonight to see what the creep is like now you've mentioned it.

I did report the lack of DTC in comfort mode, and decoupling not working earlier, just to get the numbers up, and got these lame responses:

"Most people want DTC in Sport mode" (so tough luck basically).

"Decoupling is enabled in the settings."

Gee, thanks for that

It's one of the few things that I dislike about XHP. Rather than taking customer feedback on board the developer's attitude is pretty much "we've decided what you want".

[TurboWeasel]

For those interested, more info about Torque Converter decoupling at idle on the 8HP70. I've compared stock to xHP Stage 2 (v1.4) today and the behaviour is the same. It looks like it doesn't work with the handbrake, only the foot brake, which is annoying.

Originally Posted by ZF info from Jaguar as BMW don't tell us sh1t

Transmission Idle Control (TIC)

When a vehicle fitted with a conventional automatic
transmission comes to a standstill, if drive remains
selected the vehicle has a tendency to ‘creep’ unless
the brake pedal is firmly held or the park brake is
applied. This is due to the relatively small amount of
torque transmitted by the torque converter.

In order to accommodate the additional drag caused
by the transmission, throttle angle and/or fuel injector
duration must be increased to maintain an acceptable
idle. This has the adverse effect of increasing fuel consumption and emission levels (including CO2).

The 8HP70 transmission overcomes this through the
use of Transmission Idle Control (TIC). When the vehicle
comes to a stop (brakes applied), the internal shift elements of the transmission are decoupled, disconnecting
the power flow through the gearbox and eliminating the
drag normally associated with such a condition.

TIC Enable Criteria:

• Engine at idle
• Vehicle at a standstill (wheel speed zero)
• Brake pedal applied

TIC Inhibit Criteria:

• Output shaft speed detected
• ATF temperature below 68°F (20°C)
• ATF temperature above 212°F (100°C)
• Gradient above 20%
• Accelerator pedal pressed
• Brake pedal not pressed

[SkyJawa]

I wonder if that applies on my F10 with an electronic handbrake, but tbh I never drive it like that anyway…….


…..just don’t bother stopping at all

[TurboWeasel]

That would be nice eh? Unfortunately for me, 50% of my daily grind is sitting in slow moving traffic or idling. Hence why I'm so hung up on the low rpm shift behaviour

Come to a stop, foot on brake, slide into N, foot off brake, handbrake up. Then foot on brake, handbrake off, slide into D, foot off brake..... drive 3 feet forwards, rinse and repeat. Baaaaah, it's such a bind doing that 50+ times every journey.

Hence why I just use the handbrake in D

I can understand locking the shifter to the brake pedal when it comes to reverse when moving, but locking out N and D is fapping annoying in heavy traffic! They could have applied a 10mph limit, but nope, you HAVE to be at a complete stop to switch between N, P & D. And don't get me started on locking out N to engine rotation. Want to roll the car forward a bit to work on it without starting the engine?....nope. DENIED. Got a mechanical problem and need N to roll the car off the road quickly? DENIED.

It's the same dumb mentality with push (the clutch) to start on manual cars. Dry crank thrust bearings with all that clutch pedal pressure on them, great idea And there endeth my Saturday morning rant

[Watsey]

Originally Posted by TurboWeasel

They could have applied a 10mph limit, but nope, you HAVE to be at a complete stop to switch between N, P & D.

With the ZF8 in my 2012 build I can shift between N and D at speeds up to around 10mph. If I can see that I’ll be stopping in traffic for more than a few seconds I often select N as I’m still braking to a standstill.

If there’s enough of an incline for the car to roll forwards under gravity I can shift into D while the car is moving as long as there’s a slight touch on the brake pedal.

[moppity]

ACC FTW 😂

(Zero help, I know, sorry &#128514

[SkyJawa]

Run this weekend saw 44mpg there and 46mpg back home, another run to Reading this morning nudged just over 50mpg and settled to 48 by the end of the journey and it was a cold morning so looks like it’s fine and not really changed since xHP - when I’m not lead footing it for fun that is!

[TurboWeasel]

Originally Posted by Watsey

With the ZF8 in my 2012 build I can shift between N and D at speeds up to around 10mph. If I can see that I’ll be stopping in traffic for more than a few seconds I often select N as I’m still braking to a standstill.

If there’s enough of an incline for the car to roll forwards under gravity I can shift into D while the car is moving as long as there’s a slight touch on the brake pedal.

That would be ideal for me. I'll try it on my 2016 later, but I suspect it's been blocked in the LCIs. Do you need to press the 'release' button in, or just tap the lever forwards and backwards whilst moving?

[TurboWeasel]

Originally Posted by SkyJawa

Run this weekend saw 44mpg there and 46mpg back home, another run to Reading this morning nudged just over 50mpg and settled to 48 by the end of the journey and it was a cold morning so looks like it’s fine and not really changed since xHP - when I’m not lead footing it for fun that is!

Yeah, xHP shouldn't really impact mpg unless it's bouncing off the limiter all the time

First go with Stage 3 today, just in comfort mode. I can't say I can notice much difference to stage 2 tbh

I'm still getting some random and very jerky downshifts with Stage 2 and 3 though. It's always 20 minutes into a journey it starts, so I'm guessing that's when the oil is up to temp and the adaptations kick in. Seems to be OK again after 40-50 minutes.

Not going to lie, I'm not impressed with the warm up mapping. It's sh1te compared to stock. I'm guessing it uses a closed loop PID like wideband air fuel ratio fuel control. Needs improvement imo.

What am I talking about? Well, I'll be cruising along in 7th at 1500rpm, at 50ish mph, and it just drops to 6th for no reason, then back to 7th again. Sometimes it double shifts to 5th, then back to 7th again. It'll do it a few times in a 60 minute journey.

Stock and Stage 1 don't do that.

Stage 2 and 3 apparently have "optimised comfort mode for more driver orientated shifts". Looks like by that they mean changing down earlier, but it's naff.

Adaptations are all miniscule now after xHP has been doing it's thing, so I don't think I have any mechanical issues with a 60K old box.

I think we need a dedicated xHP troubleshooting and info thread? I feel like I'm the only one with issues

[SirBiggles]

Originally Posted by TurboWeasel

I've reverted back to the 'Neutral' shift map in Stage 2, and edited the shift points.

'Relaxed' labours the engine too much for my liking. The intention of Relaxed is to reduce the box's eagerness to down shift on slight inclines or slight load increases on level roads, but it's gone too far the other way.

I've reported it to xHP to see if there's a way to set a minimum downshift rpm of 1100, as per stock, but keep the same relaxed nature.

It's probably fine for a lot of people, but some of us have particular circumstances that troubles the gearbox, which is the great thing about xHP, you can tune it out

Yeah I get this a little bit on me x40i with Neutral mapping Stage 3. I find the car holds higher gears, e.g. if you're cruising in auto, then want to accelerate (in a manual car you'd downshift and go). So basically I want the transmisson to be psychic and understand when I tap the accelerator I want to downshift!

I like the urgency of shifting in Sport mapping, but dislike that gearchange jolt when in Comfort mode. So mine is Neutral with +10% upshifts and -8% downshifts (roughly).

Sport mode = epic (when you don't want to cruise!)