VS V6 Supercharged Into Suzuki Sierra

[ev351]

Hmm, ok, Im waiting for my ALDL interface to arrrive.. cant wait. But cant help thinking about the problem until that time... The setup in the car is pretty much stock, except for the lack of BCM. Does anyone know if the ECM relies on some kind of signal from the BCM to make decisions on TCC lockup?

[ev351]

Oh and another thing that im struggling with, I have been trying to adjust some shift points on the auto. Ath this point it holds onto gears way too long. To the point that every now and then it hits the rev limiter just before it shifts. So, to start with I have just been lowering the 1-2 upshift line. I have done this in cruise, normal and sport just to be sure, but it doesnt seem to matter how much i pull it down, it has no effect... Any ideas??

[Holden202T]

TCC is not controlled by the BCM so that will be fine.

all i had to do with mine to fix the same issue of hitting the limiter was to change the upshift line tables ....

[krusty]

I'm new to all this TP stuff Ev but different diff ratios could play a large part in the shift/ TCC lock up issue. Does the ECM know exactly how fast the car is travelling? Lock up is commanded by both rpm and roadspeed as far as I know

[Holden202T]

well the reason i had to change mine was a result of 3.45 diff and smaller tyres in my torana compared to the VS V6 .... but i can't see how it would make a difference, because as far as the engine and tranny is concerned nothing has changed between them so left untouched all the shifts should be right just that the speedo wouldn't match actual road speed but for some reason that wasn't the case.

[ev351]

Holden202, exactly, I cant see why the shift points should need to change at all. I mean, the VSS is reading tailshaft speed.. not road speed, so yes, the actual road speed at which shifts and TCC lock occur will be lower with the zukis diff, but relative to engine RPM, all should be good. Its good to note that the TCC does not rely on the BCM. Am i correct in thinking that once i can log whats happening from the ALDL, I will be able to work out at what part of the process the ECU is deciding that it does not want to lock the TCC anymore??

[yoda69]

The only problem you may get, is with a lighter car and lower gearing the engine is accelerating quicker than it would in a commodore, this can cause a problem as the ECU doesn't have time to change gear before the rev limiter.
I've also seen this with cars when trans temp is cold and people rev it straight out, thicker fluid slows the shift times and it clips the rev limit before the gear change is complete, although this is more of a case of abuse.

yoda69

[Holden202T]

yeah thats about the only thing that would make sense, especially in my case, the auto i had shifted alot slower than a stocker and my car is about 100-150kg lighter than vs commodore and with the smaller tyres and diff gears it probably was just enough to cause an issue

[ev351]

ok thta cool then, that does make sense as it obviously accelerates through the gears very quickly. I wil just try lowering the shift line even further until i see a difference.

now.. when that interface arrives i can start trying to figure out why the converter locks only once.....

[ev351]

Hi all, I have finally got some time to play around with the ALDL interface and see if i can figure out what is going on with my shift points on the 4l60e.

I am using the $51_SC_V6_VS_Commodore.xdf which i downloaded from here with tunerpro.

I am trying and failing to make the auto shit earlier to prevent the motor from hitting the rev limiter.

So far I have tried reduding the speed vs TPS 1-2 upshift line and also making sure that there is no clash with the 2-1 downshift line.

I ahve adjusted this for both power and normal mode settings just in case.

The changes i make seem to have an effect everywhere except full throttle.

When I watch the transmission dash in tunerpro, the box shifts much earlier as i have programmed at part throttle, as can be seen by the solenoid being turned on and off.


However, at full throttle, the exu seems to just wait until very late to shift 1-2 or 2-3. it would probably be ok in the commodore as was previously mentioned, but in the sierra thigns happen much faster and box does not shift in time.

Does anyone know if there are any other parameters that need to be adjusted for wide open throttle?? am i missing something here? I have seem some other people talking about max rpm for shift but i think that was for an LS1.