4L60e Slow Gear Changes

[brindo]

Hi,
OK, I have added a bit of oil and increased the shift pressures and no change. Dropped the desired shift times back down to 0.2 seconds.

I re-read the old post about increasing the TPS scalar to compensate for a bigger throttle body. I had already tried lifting the shift points 5 km/hr but didn't see an improvement. So have tried increasing the TPS gain up to 0.75 and shift times are back to being somewhat normal.

So is this changing the TPS Gain still the accepted approach? What else does this effect?

The engine now has a noticeable power surge about a second after a downshift now that wasn't there before. I don't have a wide band fitted yet so am yet to work out what it is but I'll get there.

I have altered the shift pressures again as now am seeing some higher slip values but it's mostly at points at 90 psi already.

Thanks

[krusty]

Power surge may be iac taking a gulp. Check steps on logs

[The1]

Hi,
Both the 1 - 2 and the 2 - 3 changes are slow.. The transmission does have a over 200 000 km on it but the changes were fine before the engine was modified and I am not confident that the slow changes are a result of the extra horsepower. It's not really slipping, just slow to change. I'll add a bit of extra fluid regardless and then try some increased pressures and see what happens.

I am sure a full rebuild along with a shift kit will be needed at some stage in the near future but I would like to get the transmission settings sorted before that happens.

When I originally bought the VT over 10 years ago I had one of DR Bobs memcals installed. This memcal was to of had the Torque Management altered. I think at the time it was referred to the Take the Fun Out Factor and he said it was there to prevent wheel spin on shift changes in the wet. I have no idea what was actually changed and think that memcal has gone to a better place.

Thanks

The torque limit tables for those are only to cut spark which the table for that is always zero in all the cals so wont do anything anyway, the other one is boost solenoid control on L67's

[immortality]

I've found you need to increase the line pressures quiet a bit in the low TPS areas because the larger TB will see you using a lot less TPS %age to achieve the same acceleration rates.

[The1]

ok i spent quite some time looking at the code, i have found a default table, TPS and RPM vs MAF airflow, it creates the reference TPS variable that all code uses to lookup 3d tables, so any changes in airflow you should relog this table using running average into a history table and then update it, this is obviously most noticeable with a Throttlebody upgrade as it's the biggest thing to change the airflow curve.

I will add the history table and 3d table into the current enhanced versions soon.

[mjs8672]

get it to read 100% then go up one increment. That's all ive ever needed to do with larger throttlebodies and the trans works as it did before. usually they around 0.55 - 0.57

Thanks for this, It helped me to sort out some issues I was having.