autobox characteristics..info needed please!

zen · Oct 11, 2014

tuning up my zf24hpeh box in the 2 door range rover classic..as its got full adaptability plugged into my ecu, including flappy padels etc..

but, this is the first auto i have had!!never really liked them, but since i can fully control it am giving auto a try.

now..is this normal.???
..it appears to "coast" if lets say driven up to 30mph in 3rd,(now say at 1200rpm) lift off throttle, rpms die back to tick over (600rpm)..put back on power gently, takes a wee while for gearbox to apply power to drivetrain...its like engine speed has to be back at 1200rpm again before anything happens..its disconcertibg as used to instant response from manual gearboxes..

thoughts please..thanks

3.5 efi · Oct 11, 2014

Stop tickling it, just floor it.

jamesmartin · Oct 11, 2014

you need enough revs for the t/c to put out enough torque to overcome the torque from the wheels

3.5 efi · Oct 11, 2014

It'll feel like it's running away from you at first when you get off the gas but you'll get used to it. It's fluid power and needs to catch up to road speed.

tomcat59alan · Oct 11, 2014

shouldn't you get engine braking effect even with the auto box?

zen · Oct 11, 2014

3.5 efi said:
Stop tickling it, just floor it.

thats a different matter!!its so much quicker in accerating than the manual i have in sally, no more 2 sec gear changes!!,(getting sub 6 secs 0-60!) and nicer in london traffic..but sooooooooooooooooooooo different to drive...still alot of ecu map tuning to do!!

but this is normal then..thats good cos was about to start tuning the line pressure tables..

please can anyone give me the standard p38/even rrc ..

1st to 2nd gearchange speed..
2nd to 3rd
3rd to 4th
and TCC lock up speed

ALL ABOVE AT LOW THROTTLE, ie not kick down, just gentle cruising..

in particular torque convertror clutch lock up speed..

just so i have a ball park figure to start from, as dont want to burn out clutch packs etc..(ESPICALLY destroy tcc crt)

i am using tps as reference to gearchange points vs road speed..i can use map vs road speed, but i prefer the way the gearbox ecu uses the code tps vs speed..

NEXT..is there any problems having zf24 change up early in relation to road speed/engine revs??i ask as will be enabling full manual over ride asap via steering wheel padels, BUT DONT want to harm box by say engaging 2nd at 5mph (engine will pull it) but finding out i have damaged tc or gearbox

thanks..

Datatek · Oct 12, 2014

Sounds normal to me, torque convertor will not be locked at that speed. You'll get used to it.

zen · Oct 12, 2014

yes, but i can set gear changes, tcc lock up to any speed i like, at any load i like..also have multiple maps to play with..

i am trying to gauge what LR do as standard, so i have a ballpark figure to start with..ie i could set TCC to lock at 15mph in any gear, but i expect that would be BAD!..lol

so after figures that LR deem correct to start with and will fetle from there..

thanks

pwood999 · Oct 12, 2014

As far as I can tell there's no set upshift & downshift MPH. Can't even find anything in RAVE.

My guess is it's a combination of Speed, Torque Conv Load, Throttle, Actual Engine Revs, etc. all fed to Auto ECU, which then decides !! Look at all the ECU Inputs, and then guess the decision matrix !!

Pete

zen · Oct 12, 2014

there you may be right..but i guess there must be a mininum value..

ie min it will change to 2nd is 20mph..min TC will lock is 50mph?

i ask as i wish not to harm box..ie clutches..TC clutch etc.

trying to set up the economy map for max mpg
the sporty map is easy..

using MAP can bus(ed) from megasquirt engine ecu to gearbox ecu) to control gearchanges and TPS (again can bus) to control "kick down" at the moment..it also takes into account line pressure, gearbox temp etc..

StuckAgainSteve · Oct 12, 2014

Zen - we're both north London - you're welcome to take my car for a spin (same box) to see what "normal" is.

Datatek · Oct 13, 2014

TC locks at about 35mph in third and 50mph in top, load and throttle dependant, shifts are also load and throttle dependant.

zen · Oct 14, 2014

thanks..i may take you up on that..and thanks for ttc info...now for tuning..!!

autobox characteristics..info needed please!

zen

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3.5 efi

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jamesmartin

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3.5 efi

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tomcat59alan

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zen

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Datatek

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zen

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pwood999

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zen

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StuckAgainSteve

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Datatek

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zen

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