I have a 2009 e90 320d lci - uk car,
Im looking at tuning options but dont want to exceed the gearbox torque limitations.
According to BMW TIS i have a ZF GA6HP19Z gearbox with q126 torque converter - max input tq=400nm
According to the ZF website this gearbox was uprated to the GA6HP21 version - max input tq= 450nm
I am still waiting on a reply from ZF to confirm what gearbox/TQ converter my car actually has.
My main question is why do aftermarket remap companies tune cars to over the max input tq ratings supplied by the transmission manufacturer?
For example they do a e90 320d with the 400nm limit gearbox to 440nm - surely this cant be safe for the gearbox, BMW performance tune only goes to 390nm.
If anyone knows why, or what gearbox/tq converter i definately have please let me know