fireball

i've used mobil1, shell ultra, royal purple, valvoline synpower, plain castrol gtx... over the 9yrs i've had the car with a oil pressure gauge.. there is no diff in oil pressure between the oils, nor is there a diff in oil pressure from the time i put the oil in to the drainage time ~5000km later.. and this is checking oil pressure cruising on the highway at 100kph with oil temp at ~85C

so imo using oil pressure to check when to change oil is a FAIL

2007 Zx-10

what's the resolution on your gauge, and what make is it? 5000 km (about 3100 miles) is not a very long OCI, so I wouldn't expect to see a significant change in viscosity that quick

fireball

i have a blitz gauge and it reads oil pressure in hkpa

eg cruising on the hwy at 100kph would give ~ 5.9kpa =~85.5psi

gauge is accurate to the .1 hkpa

PWRMKR

How about when/if the oil pump starts wearing prematurely? Or the bearings start to fail and babbitt starts clogging up the filter?