Tiptronic project - couple questions

[azander]

Hello,

I'm interested in this Megashift as a solution for 'race prepping' an early Porsche tiptronic. The transmission is a ZF 4HP22 (4 speed) with a switch logic based shifter (PRND321) with a switched manual gate off of D. I would like to be able to program the controller to operate in the current hardware environment, essentially a plug-n-play unit. My interest is a controller purely for a true manual mode but with some basic programming for cycling through the auto gates. I've been trying out the TunerStudio 'offline' and a I have a few questions as far as the programming (through TunerStudio) goes.

Can a spare input be used to enter the Manual mode?
The current controller has a 'Full Time' TCC engagement which starts in 2nd gear at 2300rpm and releases at 1000rpm. The program doesn't seem to allow for this...

Would it be possible to see these features in a future update or would it be best to do this by editing a base C file?

Thanks

[Bernard Fife]

azander,

Manual mode can be entered simply by pressing either of the shift buttons. So if you want a 'manual mode' button, you can connect a momentary switch to ground either of the shift buttons. I am not sure if this is exactly what you were hoping to accomplish with another input, though. If you have another arrangement in mind, provide a bit more info and I will see what could be done.

For the TCC, see 'Full Time Lock Up' here: http://www.msgpio.com/manuals/mshift/V4tune.html#nt

Lance.

[azander]

Hello Lance,

Many thanks for your response.

The shifter is like this: http://www.oldbug.com/265%20047.jpg

The shifter mechanism has a unique switch for entering/exiting Manual mode and momentary switches for shift up and down. Entering manual mode is not a problem. However exiting back into D (auto) would be impossible right? Ideally it be best to have it enter Manual mode in the current gear and exists when back in D.

The question regarding the TCC routine is because TunerStudio (offline) won't allow for entering Full-Time Lock Up in anything less than gear 3. I'd need to be able to make that gear 2 with locking at 2300rpm and unlocking at 1000rpm. I can set the 'minTCC_gear' to gear 2, however that'd mean it would unlock everytime it falls below the 'minTCCspeed'. Would it be possible to only use the full-time lock up values and disable the min lock speed, etc.?

Quick question regarding the input patterns 1 through 4... Does 'input pattern in 4' correspond to D, i.e. looks to the autoshift table?

Thanks again!

[Bernard Fife]

azander,

I really need some electrical details of how the shifter works to say much about how this might work. Normally you would press both shift buttons at once to re-select automatic shift mode. A shift mode button could be wired using a couple of diodes like this with no changes to the code:



The full time minimum gear is easily changed in the INI with a simple text editor, and I can change the default if people generally find it useful. You would change the 3 value to 2 in this line:

Code: Select all

STCC_gear             = scalar,  U08,   628,                "",          1.00,    0.00000,        3,       8,     0    ; full time TCC lock up minimum gear

Yes, 4th is Drive (for a 4 speed transmission). However, auto mode (with the shift tables) can be used with the lever in any forward gear - the lever then sets the maximum gear that can be selected by the controller, regardless of the shift table. The shift table is still used to auto select gears equal to or less than the manual gear lever position. Of course, if the manual lever is in 1st, then NO shifting will occur - the trans stays in 1st.

Lance.