pcmhacking.net

fair enough, horses for courses

Having a look through the upshift / downshift tables, it looks like the VX actually changes gears depending on TPS and Speed. There is no indication that gear changes are decided by RPM. All research ive done also seems to support this fact, and what holden202 is saying sounds about right to me,

What im assuming will hapen is that if i drive easy, the car WILL change gears in time EG TPS@60% will change from 1st to 2nd at 50kmh, but since it is programmed to change from 1st to 2nd @ 100% throttle at 64km/h, i will hit 6,000rpm (standard gears are 5,300 at this speed) if i drive it hard.
So i have to change the upshift TPSvsKPH for 1-2 to max out at 57.5km/h (5307 rpm) to be close to the original values, and so on the the rest.

Does this sound about right? Thats how im understanding it...

Sounds about right to me, TPS is part of it, hence you can be cruising, hit the throttle and get a kick down for your overtake.

oh the other thing i forgot to mention i have 3.45 diff and also alot smaller tyre diameter than a commodore ......

oh and Jayme, there are alot of little reasons for getting the pcm right, tcc lock speeds, and various other things like lean cruise etc .....

The1 ..... the issues i had with the rev limiter were even before i changed any settings in the pcm, i think it was more the fact the engine increased rpm so much quicker than stock add to the fact the gearbox was lazy and it all made for a big rev limit issue .....

arh ok, i was thinking usual WOT shift time is around 1sec for auto with normal slip so must be quick!!

This may sound stupid, but what is WOT?

WOT = Wide Open Throttle = flat biscuit!

i ended up changing the line pressures in the tune and i got economy mode (normal mode whatever it is) to be just slightly quicker than my brothers stock vs, and then made performance mode more like a stage 1.5 shift .... that was the best i could do with the box, it was definately not healthy

Is there a guide as to where i would adjust transmission line pressures? And how to do this.... I wonder if anybody has made a template of some sort for a stock 4l60e tranny to get best shifts out of it.

the tables you want to look at are force motor pressure, there should be one for normal mode and one for performance mode.

there are also offset tables for specific gears, so if you want a change in all gears use the above ones, if you want it for certain gear changes the use the specific upshift/downshift tables for them.

anarklov3r wrote:Having a look through the upshift / downshift tables, it looks like the VX actually changes gears depending on TPS and Speed. There is no indication that gear changes are decided by RPM. All research ive done also seems to support this fact, and what holden202 is saying sounds about right to me,

What im assuming will hapen is that if i drive easy, the car WILL change gears in time EG TPS@60% will change from 1st to 2nd at 50kmh, but since it is programmed to change from 1st to 2nd @ 100% throttle at 64km/h, i will hit 6,000rpm (standard gears are 5,300 at this speed) if i drive it hard.
So i have to change the upshift TPSvsKPH for 1-2 to max out at 57.5km/h (5307 rpm) to be close to the original values, and so on the the rest.

Does this sound about right? Thats how im understanding it...

to be exact.. if you leave the ecu 100% stock untouched, at full throttle, even with the new diff gears it will still shift at 5300 like it used to. all the shift points will shift at their usual rpm. the reason is, the speed is calculated at the tailshaft, so the ecu thinks you are still doing 64km/h when it upshifts out of first even though in reality you are only doing 57.
if you change the pulses per kilometer in the tune, so that the pcm is looking at your real speed (I wouldnt) then you will have the scneraio you describe above, and will have to redo all of the shift tables. (wasted time in my opinion)