I tried combinations of running the old bottom spring with the new top one, old top one with new bottom one, as well as both old springs. Tried different tensions on the nut as well, nothing seemed to make any noticeable difference:



Old and new ISCV springs.

The old spring is definitely stronger than the new one, but also significantly shorter.

Unfortunately I have no way of logging any data or checking AFR; I'm just using a standard narrowband Bosch sensor.