Originally Posted by Jhill

What’s the ea15k 50? I’ve been using the ea15k 12 with no issues. I’ve heard amsoil have a similar issue with one of the Toyota v6 engines in the past (I don’t remember which now) but that was with one of the 25k filters and they even took it off their site as the filter to use for such vehicle. Just checked tonight and see the ea15k 12 is still the recommended one for the 370z. I’ve been using it since I got the car and done track and street driving and oil test always came back good. I’ll continue to use this one since I just did a change and then I’ll see what a sip says on next change.

Oh and I do 10k with signature series. Not comfortable with 15k and signature series is a bit pricey to be changing as often as OEM.