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ZF 6HP transmission
Posted: Mon Jul 09, 2018 10:27 am
by FLATSPOT
Hello i own a E89 3.0 sDRIVE with a 6hp transmission I'm not sure if i have got a problem or not when I'm driving at 30 mph the car is in 4th and the engine Revs are a round1600 rpm the same at 40 the car is in 5th and the Revs are at1600 can anyone tell me if this is normal or is there a problem with the transmission
ZF 6HP transmission
Posted: Mon Jul 09, 2018 11:58 am
by djstan
Does it feel like something's wrong? What's your concern?
ZF 6HP transmission
Posted: Tue Jul 10, 2018 12:16 am
by ronk
Sounds ok to me !
1600 rpm - what are you expecting it to be?
What’s it doing at 50mph?
ZF 6HP transmission
Posted: Tue Jul 10, 2018 4:46 am
by FLATSPOT
It just seems like it wants to be in fifth at 30 mph and sixth at 40 mph just to bring the revs down a little if you drive it in manual mode you can put it in fifth at 30 mph and sixth at 40 mph the revs come down to 1200 the car feels happy at that its not labouring the 3.0 E85 I use to own would be in top gear at 30 mph and the revs were at 1200 that was a 5 speed auto
ZF 6HP transmission
Posted: Fri Jul 13, 2018 12:01 am
by ronk
FLATSPOT wrote: ↑Tue Jul 10, 2018 4:46 am
It just seems like it wants to be in fifth at 30 mph and sixth at 40 mph just to bring the revs down a little if you drive it in manual mode you can put it in fifth at 30 mph and sixth at 40 mph the revs come down to 1200 the car feels happy at that its not labouring the 3.0 E85 I use to own would be in top gear at 30 mph and the revs were at 1200 that was a 5 speed auto
I think that the gearbox knows best!
Yes you can force the gearbox to change up to a higher gear - it’s just like a cyclist with strong legs, he can push the pedals using his big strong legs - but gets better efficiency when he uses a lower gear with a good cadence.
Let the engine spin and let the box do it’s thing - 1600 isn’t excessive!
ZF 6HP transmission
Posted: Tue Nov 01, 2022 9:35 pm
by clintel
Hi to all 6HP owners........
Better late than never I hope.....
[I just tried to send this to ZF but their enquiry form wouldn't work....]
At min throttle on level, 6HP shows 1500rpm at 50kph
How can this give most economical BMEP from the engine?
Even the 1.3 Honda Jazz CVT gives 60 kph at 1500 rpm level cruise [ 5.2L /100km urban] from higher BMEP>>>>>Lower SFC.....
Your claims regarding low speed TCC engagement don't seem to apply in practice.....
There appear to be millions of cars running very smoothly but burning vast amounts of fuel unnecessarily
How this helps with all the climate hysteria is not at all clear.....
ZF 6HP transmission
Posted: Tue Nov 01, 2022 11:44 pm
by B21
What happens when you put it in sports mode?
ZF 6HP transmission
Posted: Wed Nov 02, 2022 1:13 am
by clintel
I haven't dared to try sport mode.....this could only make downshifts occur at even lower RPM/lighter throttle....
With petrol at current prices I could go broke...
I've also tried disconnecting the battery & then doing the 'adaptations'
The car is actually doing better than factory-claimed economy but I drive light-footed urban anyway...
There seem to be numerous strange behavior patterns with this trans. reported on other forums/fora but NOBODY can remap the TCM
Cheers.
ZF 6HP transmission
Posted: Wed Nov 02, 2022 9:51 am
by B21
The ZF6HP in the E89 TCU can be remapped using xHP…
I’m struggling to understand what your specific issue or concern is?
These boxes have several different shift programs based on which mode they are in, plus adaptions..
How many miles has the car done?
How long / how many miles have you driven?
Has this situation suddenly appeared?
ZF 6HP transmission
Posted: Wed Nov 02, 2022 10:17 am
by hopz121
Have you ever serviced the gearbox?
XHP is a great tool to make the gearbox even better if you can do it.
ZF 6HP transmission
Posted: Wed Nov 02, 2022 8:53 pm
by clintel
Apology....Confession...Explanation....
In reverse order.......
To B21 The 6HP is not actually in a BMW so XHP remap not poss.
This discussion started by FLATSPOT was the only ref. I could find to this problem [which appears to refute claims about the 6HP.. e.g.... 'That’s why we get decent mpg from this tranny. In other words it is more like a manual tranny with torque converter working only at very low speeds and low rpm."................
https://www.bavlogic.com/?p=3738]
Specific issue or concern is that, like the starting post by FLATSPOT for this topic I find the shift points far too high for normal driving, [e.g. the Subaru XV 2L does 1000 rpm at 30 mph level cruise] thus causing far higher fuel consumption than necessary.
BMEP is too low so SFC is too high..........
https://www.researchgate.net/figure/Bra ... _273986854
I've only owned the trans for a few months so I don't think the problem is recent.
To hopz.121 The car has done 56000 miles so no servicing should be needed.....
Cheers . .
ZF 6HP transmission
Posted: Wed Nov 02, 2022 9:21 pm
by B21
Lets wait for the OP to respond!
ZF 6HP transmission
Posted: Thu Nov 03, 2022 8:58 am
by hopz121
clintel wrote: ↑Wed Nov 02, 2022 8:53 pm
Apology....Confession...Explanation....
In reverse order.......
To B21 The 6HP is not actually in a BMW so XHP remap not poss.
This discussion started by FLATSPOT was the only ref. I could find to this problem [which appears to refute claims about the 6HP.. e.g.... 'That’s why we get decent mpg from this tranny. In other words it is more like a manual tranny with torque converter working only at very low speeds and low rpm."................
https://www.bavlogic.com/?p=3738]
Specific issue or concern is that, like the starting post by FLATSPOT for this topic I find the shift points far too high for normal driving, [e.g. the Subaru XV 2L does 1000 rpm at 30 mph level cruise] thus causing far higher fuel consumption than necessary.
BMEP is too low so SFC is too high..........
https://www.researchgate.net/figure/Bra ... _273986854
I've only owned the trans for a few months so I don't think the problem is recent.
To hopz.121 The car has done 56000 miles so no servicing should be needed.....
Cheers . .
They recommend a gearbox service at 60,000 miles so you aren't that far off it! I imagine its an older car as well so i guess the oil is well past its best.
ZF 6HP transmission
Posted: Thu Nov 03, 2022 9:24 am
by axelleveau
Age of the oil and adapatation is unlikely to affect ups and down shift maps, they would mainly affect the valves controls, clutches and how jerky the shifts are.
Shift maps are calibrated by the car manufacturer and result in an engine RPM vs vehicle speed dependant on the diff ratio as well as tyres. They are a difficult comprimise between fuel economy, responsiveness and NVH. There probably is a way to bias this more towards what you'd like but it does not mean there is a greast consiparcy between ZF and the car maker
ZF 6HP transmission
Posted: Thu Nov 03, 2022 9:01 pm
by clintel
Hopz121:
Re ATF change.......There is nothing wrong with the smoothness etc. of the trans.
Most car makers claim for the 6HP: 'Sealed for life',.........[The drain plug is VERY difficult to undo.]
axelleveau:
I agree with you 100% including 'great conspiracy between ZF and the car maker'
BUT There is a serious Automotive-engineering design issue here in that cars are NOT getting minimum practicable CO2 emissions which will hasten the greenies' efforts to kill the car as we know & enjoy it.
I for one [as well as FLATSPOT above] don't enjoy driving when the trans. kicks down at the lightest touch on the accelerator..
More cheers...................[I'll do an example calculation to clarify the point.]