Full time lock up mode

A forum for discussing applications and implementations of the MegaShift transmission controller code for the GPIO from B&G. This can control up to 8-speeds and 6 shift solenoids (plus a 16x9 table for controlling a PWM line pressure valve). It has manual and fully automatic modes (16x9 load x speed table), with under and over rev-limit protection, and full data logging of all inputs and outputs (among many other abilities). A TransStim to test your completed board is also available.
Bernard Fife
Posts: 1696
Joined: Fri Apr 04, 2008 1:28 pm

Latest Code Updates

Post by Bernard Fife »

gurov,

Yes, that's right. That's how the code has always been.

Lance.
"Never wrestle with pigs. You both get dirty and the pig likes it." - George Bernard Shaw
gurov
Posts: 164
Joined: Mon Jun 01, 2009 1:01 pm

Re: Full time lock up mode

Post by gurov »

wait... without full time lockup on.

i disable full time lockup by setting 9000/8000 rpm and 6th gear. and relying on minimum speed for lockup
Bernard Fife
Posts: 1696
Joined: Fri Apr 04, 2008 1:28 pm

Re: Full time lock up mode

Post by Bernard Fife »

gurov,

Yes, that's right. The code unlocks on downshifts, but stays locked on upshifts in 'normal' TCC mode.

The idea is that the TCC should only be locked if the load is low (if you are trying to accelerate briskly, then the TCC should normally be unlocked - both to avoid overloading the TCC, and to get the maximum torque multiplication from the converter), and an upshift is gentle when the load is low anyhow. So there's no need to unlock the TCC on upshifts.

Downshifts can happen if the car is decelerating quickly with engine braking (which can produce very low load levels), so the TCC is unlocked.

Lance.
"Never wrestle with pigs. You both get dirty and the pig likes it." - George Bernard Shaw
Bernard Fife
Posts: 1696
Joined: Fri Apr 04, 2008 1:28 pm

Re: Full time lock up mode

Post by Bernard Fife »

gurov,

BTW, in the next code (2.00F) I will disable the averaging if the speed is less than the user minimum setting. That should help a lot to let the speed rise properly if the min speed is set high, but keep it smooth above that speed.

I have a few other changes to make to make to the code, so this might take a few days.

Lance.
"Never wrestle with pigs. You both get dirty and the pig likes it." - George Bernard Shaw
gurov
Posts: 164
Joined: Mon Jun 01, 2009 1:01 pm

Re: Full time lock up mode

Post by gurov »

Lance wrote:gurov,

BTW, in the next code (2.00F) I will disable the averaging if the speed is less than the user minimum setting. That should help a lot to let the speed rise properly if the min speed is set high, but keep it smooth above that speed.

I have a few other changes to make to make to the code, so this might take a few days.

Lance.
cool, i drove it last night with no incidents or frustrations, sometimes even in auto mode.

my biggest problem is the gear shift table. and how little sense it still makes to me. maybe i do need to make that script to pull the data i need out of the logs to give me a hint.

will speed hysteresis ensure that there's only one shift (whether it's up or down) within a 10 mph window of the last shift (if my hysteresis is set to 10 mph) ? and is it +10 -10 or +5 -5 with 10 mph hysteresis ?

i need to start trying and actually tuning this table instead of making wild stabs in the dark at it.
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