Originally Posted by Sephiro
After resisting the temptation to fiddle with the SST TCU since the box was rebuilt at IGT a while ago I decided that it was worth doing another teach in on the box as I needed to help a fellow club member with a reteach and I'd prefer to refresh my memory on my own car first rather than break theirs (you'll be fine Davie honest)
Like most UK SSTs it's a 2008 box so is the 8631A749 TCU hardware version with the 8631A3790C by default so I did the usual upgrade to the 2009 SST firmware (8631A8270B) to enable the teach in and then ran through the process. I noticed however the July 2016 Mitsubishi TSB states that the 2008 boxes should then be flashed back to 8631A3790E (8631B413.cff) instead of the original 8631A3790C (8631A749.cff) that I've used previously. Does anyone actually know what the differences are between the C and E versions of the firmware actually are?
All I can say is that after performing the teach in and reverting to the E firmware the shifting is great, however I can't tell what is down to the different firmware or the teach-in itself or the box being up to temp for a change (I haven't tested the cold shifting performance yet as I need to leave it overnight to cool down).
I went through this kind of process with my last SST, although it was never reverted back to the original but left (on a few occasions) either with the very latest firmware or the teach-in version. And the only reason it was left with the teach-in version was to avoid the time hassle of making another firmware change after the actual teach-in.
Between the three versions I would honestly have to say I could not pick out a single significant difference in the way the car drove or performed. Perhaps there was just one occasion when I felt that with the latest version the gearshifts in Normal and light throttle acceleration were programmed at a few hundred rpm higher, but I never properly checked that out by comparing before and after logging.
But what I can say with great confidence is that the period up until selling the car a few months ago was that on the tech-in version the gearbox operation was as close to perfect as I think is possible with an SST. Even the very first gearshift of a cold morning was super smooth (in Normal)!
The only caveat to add here is that the clutch plates were of the first Dodson upgrade variety and it also had a heated sump.
And a note of caution that I've sounded before - if the mapper has made any changes to the SST tables in the main ecu then the comparison of performance between SST firmware versions may well be different/accentuated!