More modern oil options for a Porsche 944?

[AK944]

I've got an '85 Porsche 944 as a project car that I've been running 20w50 Valvoline VR1 in without issues. But, getting bored while the car is in storage, I figured I'd ask people who know way more about oil than I do if there is a better option I could try. This is mostly for my own curiosity, and the fact that its kind of annoying that they only sell the VR1 in 1qt bottles up here in Canada so I have to end up buying 7 small bottles every oil change.

The consensus I've seen in the 944 community is these engines need a heavy oil with lots of zddp (~1300 ppm) with the latter requirement being driven by the flat tappet design of the lifters. Based on things I've read on here about other older vehicles, it seems like the requirements laid out in the owners manuals tended to be driven by the available technology when they were new, and I assume we've come a long way in 40 years.

I know 80s BMW owners sometimes run more modern oils with lighter weights than the 20w 50 a lot of them were specified to run, but the valvetrain designs on those engines, to my knowledge, differ significantly from those of the 944 and the other 80s water cooled Porsches. Porsche Classic now sells their own synthetic 10w50 for the 924, 928, 944, and 968 but I haven't seen much feedback on it, probably because it costs significantly more than the VR1 everyone uses.

I'm mostly just wondering if there is a readily available/relatively affordable alternative to the VR1 which is worth trying, either with more modern technology or just an alternative conventional oil (ie. LiquiMoly's 20w50 offerings or Castrol GTX Classic).

 

[altaylar]

I’m a fan and have used 10W-30 conventional and synthetic in the Tempest but I don’t have a catalytic converter. VR1 heavy on ZDDP. Don’t you remember the rotten egg smell sitting at a light near a car with a spoiled converter? IMHO Mobil 1 5W-50 way to go.

they both (VR1 20w50 and Mobil 1 15w50) have almost identical zinc and P levels. but perhaps Mobil 1 is still more cat friendly. they both should have very low volatility

 

[LouC]

VR1 zinc and phosphorus levels vary by the grade. The 10/30 has less than the 10/40 or 20/50. Last time I checked the 10/30 had about 1,000 ppm for both. If the engine isn’t burning oil I don’t think that would harm a cat. The higher grades are at approx 1300/1400 ppm.