Some cars idle at 5psi oil pressure and it's under manufacture spec. Once fully warmed up.

Yup as oil warms its thins out.

I knew my LS1 was on it's last leg once the oil pressure dropped to 20lbs at idle. There is definitely something wrong with that. Five years of 30lbs at idle and then seeing a 10psi drop plus the pressure at higher rpms was lower as well.

-Alex

These same rules apply to engines of any age, loose or tight. Just because your engine is old does not mean it needs a thicker oil. It will need a thicker oil only if it is overly worn, whether new or old. Yet the same principals of 10 PSI per 1,000 RPM still apply. In all cases you need to try different grade oils and see what happens. Then choose the correct viscosity. dID YOU CHANGE OILS?

No. The oil pressure changed all of a sudden while at 45%.

-Alex

That is odd.

I'm on Amsoil 10w30. I chose to go with this oil because it isn't a huge leap from the recommended and most of the time it is pretty warm here in Texas so the slightly higher weight has it's advantages with heat. I've been on it almost 10k miles and am about to change and do analysis so I will share that here

Weight has no adavantage with heat. They all thin to about the same when warm. Startup is where its crucial that 10w-30 is thicker cold then the reccomened 5w20. 0W-30 grade oil is not thinner than a 10W-30 oil. They both have the same thickness at operating temperature. The 0W-30 simply does not get as thick on cooling as the 10W-30. Both are still way to thick to lubricate an engine at startup.

The reality is that motor oils do not need to be changed because they thin with use. It is the eventual thickening that limits the time you may keep oil in your engine. The limit is both time itself (with no motor use) and/or mileage use. The storage of motor oil in your garage, particularly mineral based oils, slowly ages the oil limiting its use later. Do not store huge volumes of oil in your garage that is exposed to extremes of temperature.

When you drive that car down the road mid-winter in upstate New York or mid-summer in Florida the engine and oil temperatures will be around 212°F. But your Florida vacation is suddenly altered by a hurricane. You have to get out of Tampa, but so do a million other people. It is now 95°F and you are in a snarl. Everyone thinks they need a thicker oil for this situation. This is false.

That and the amount of contaminates that get suspended in the oil over time, and the degradation of the anti-wear additives in the formula.

Yup thats what causes the thickening. I hate people that think if your oil isnt clean when drained its a bad oil cause it broke down fast. In reality a oil should be dirty because that means it is doing its job.

I assume the bearing were going out, as well as some of the internal clearances and tolerances. The car was driven pretty hard on a daily basis for over 140k miles.

Look forward to see the results.

-Alex

Track Pack cars are 5W-50

I know but dont know why

They use 5w50 due to having 50% more antiwear additives. Highest levels of Zinc and Phosphorous. The weight of the oil is meaningless as you already mentioned it being almost the same at temp.

I will most likely swap to the recommended track car oil as well. All the 0w20 recommended oils have very low Zinc and Phosphorous levels to protect catalytic converters and other emission equipment.

for Example 0w20 mobil 1 has 650 PPM of Phosphorous and 750 PPM of Zinc.

15w50 Mobil 1 has 1200PPM for Phosphourous and 1300 PPM for Zinc.

5w50 is in between the 2.

Smh. You put that much through your cats amd you wont like it. Your talking like all that zinc and blah blah is gna protect your engine. Nope. That oil thick. Real thick. Your oil pressure will be higher because its like honey but will it lubricate better? No. I firmly believe in the 10psi per 1k rpm rule. You dont need a thicker oil just to race. You need to log oil pressure for that track and conditins to see what kind of weight you need. When tracking your car you nee to change the oil at 1500-2k miles anyway so those additives arent really important. In diesels that use this oil and are a completely different make up it beneficial as they may see 15k between changes.

With winter approaching that oil will be extremely hard on the motor at start up but its your car.