So I've got a 2013 crew cab with 3.92 rear gears, 8HP70 swap, and 392 swap with MMX NSR cam, stock bottom end, ported manifold, etc. This oil (Redline 5w-40) runs HOT and we're not even into summer (I am in TX).
Little background - fall of 2020 my 165K stock 5.7 decided to tire out and with the cost of new trucks and what I had recently put into the truck, I decided to keep it and upgrade the engine. Then I spent the following 2 years dealing with weak transmission issues and ended up swapping to an 8HP70. I finally got everything buttoned up and have been daily driving the truck since last summer/fall. At that time, when cruising 90 down the highway, I noticed the oil would routinely get well over 240-250F and raise the coolant temp up to around 220F - I have a 185F coolant thermostat that actually works but the delta between the engine's fluids could only be so high. Even putting around, the oil would always get over 220F and would probably average around 230F with reasonable highway speeds (60-70MPH), the coolant could somewhat manage this delta and would lower a bit, maybe around 200F.
So late last fall I put on an oil cooler (34 row 59K BTU) with 185F thermostat in the filter sandwich adapter. One of the problems with this setup was I had to use the small oil filter due to the 1.75" thick sandwich adapter. I thought the oil pressure was down ~5 PSI but I think it may be closer to a 10 PSI drop with the large cooler, I foolishly wasn't recording oil pressure and temperature on my logs until recently. Well that cooler got me through winter (great temps, pressure not so much) but I never liked the small filter and stumbled across a low profile sandwich adapter that allowed me to use the large filter (RP 20-820) and I put this on around mid-January. I did not realize that this low profile adapter did not have a thermostat of any kind and was full flow to the cooler all the time. So I took that off after two weeks and removed the cooler entirely and have been running nothing for about a month now but this oil is HOT and our ambient temps are only around 80F in the evening when I drive home. The coolant gets up 200F with the oil well over 240F cruising at 90 MPH for around 15-20 miles. The coolant falls back down to 185-190F when cruising at reasonable highways speeds and the EOT falls to around 220-230F.
So without the cooler, for oil pressure I would have low 60s at cold start idle, high 60s into the 70s at cold cruising, high 50s/low 60s warm/hot cruising, and plummet to high 30s at idle (800 rpm for cam). So I adjusted my tune (HPT) to raise idle depending on oil temp and basically it is unaffected until around 176F I bump it up to 825 (800 base), 875 rpm at 212F, and 975 rpm @ 240F all scaling between and it keeps me in the high 40s oil pressure at warm-hot idle. I would prefer higher idle oil pressures but c'mon 975 rpm idle on a street engine with tiny NSR cam seems about the limit of reasonable.
So with that said, what are other 392 truck owner's experiencing? I know this engine has the oil squirters to keep the pistons cool and I am sure they are working which is heating the oil considerably more than the 5.7 but also lowering idle oil pressure. Any other engine I would be okay with that pressure but these engines, particularly the lifters and camshaft, don't like to idle with low oil pressure. What would you do in my shoes?
1. Run 5w-50 oil - I already have to keep this handy for the Roush-charged mustang so it would allow me to consolidate engine oils.
2. Remote dual filters (30-8A)
3. Run the large oil cooler I have with a remote dual filter setup, would be rather expensive in parts setup
4. Run a smaller oil cooler
5. Run a smaller oil cooler with remote filter(s)
6. Hellcat oil pump - last ditch effort, I don't really want to tear into this
7. Moroso High Cap oil pan - also don't really want to headache with this
8. Some fancy A2W setup - big $$$
9. Nothing, f'in send it!
10. Some combination of choices or other??
