Oil Pressure Readings
 

I've bugged a few of you about this so far. But I'm just looking for some more info.

I'm a few hundred miles away from my car, and will be back to work on it this weekend, but I'm trying to address a smoking issue with my new turbo, that could be a number of things. After a call to Precision, he first asked me if I knew what oil pressures the car generally runs to see if an oil restrictor is necessary.

So, anyone willing to share what oil pressures you read at idle/part throttle/wot? Pwease? I've heard a few different numbers so I'm hoping at least 5ish people will reply so that I can get a solid idea.

I'm just trying to stay a step ahead of the game, this way I can order parts and have them in transit a few days earlier.

Help me get this set of problems resolved so I can start tuning with Jake! Thanks in advance! :sombrero:

Generally:

Cold start: roughly around 80lbs
Idle: roughly around 20-23lbs (about 2-5lbs lower in hot weather)
P/T: roughly around 40-60lbs- depending on the exact location of pedal
F/T: I don't remember, I'd have to get back to you on this one in a few days.

Ive had up to 110psi for cold oil at F/T, 80psi is common for warm oil.
Ive never had less than 17psi at idle with warm oil.

Oil pressure is relative to RPM, not engine load.

Pressure will rise to the relief valve onset and then the rise will turn into a slow creep to redline. Thicker (cold, higher viscosity) oil will result in higher pressures.

Changing any of the components that make up the oil patch including turbo down to oil filter will affect pressure.

you might want to add where you are reading from..theres much higher pressure at an oil filter adapter plate then there is at say the turbo oil feed line...

that being said, im reading at the oil filter, usually gets up to 100psi cold idle and warm idle i think was like 20-40 and cruising i see 70-80...

right now my sender is def fucked up cuz its reading 100 psi steady at all times even when the car isnt started lol.

I forgot to mention but others have already stated. Location of sensor and like Lex said cold, higher viscosity oil generates higher pressure.

You should also take into consideration low pressure as well. Some of the common causes that will yield you with low pressure are:

A clogged up oil filter, air in the oil pump- a cause of not enough oil or excessive amounts of oil, oil pump wear, excessive clearances throughout, i.e cam bearings/journals, etc.....Also, in higher mileage engines worn crankshaft journals, main and rod bearings will be a factor in low pressure readings.

I'm curious to know from those who reached 60K+ miles on their cars to see if they see any drop in oil pressure- given you have a way of monitoring the pressure. 60K is not as much as much as 150K but given the fact that these cars get pounded on a daily basis would be a good indication to see if there could be anything at play.



Nobody thus far said that oil pressure was related to load.

I've got close to 70K, and I'll have a pressure gauge installed today or tomorrow. My numbers will be a tad lower since I'm adding a cooler.

06speed6 has close to 100k IIRC.

.so i have a metric oil pressure gauge mounted to a plate at the filter.

i read anywhere from 2.0 - 6.0 at idle (all over the place) usually around 6-8.0 i believe when cruising, not sure at WOT. this is in kpa x 1000... what's the proper conversion?

i've read 1 psi = 6.895 kpa

so 2.0 (x1000 kpa) is 290 psi? this is way above all the figures that 06speed6 is saying.

Yeah, I thought my numbers were a tidbit low as I was going off memory. I just came back from running an errand and this is what I hit:

Running Royal Purple 5W40 oil

With oil temps at 135 degrees F, the oil pressure at P/T (around 3K RPM) was 75lbs. At about 4K RPM the pressure was 85 and climbing. Thus as said earlier, oil pressure increases with RPM's- you will yield higher pressure (at X number of RPM) with colder, higher viscosity oil)

When my oil temps reached 185-200 degrees F the oil pressure at 3K RPM would this time be around 60lbs and it would only increase with the RPM.

In short:

Oil temp @ 135, 3K RPM- 75lbs of pressure
Oil temp @ 190, 3K RPM- 60lbs of pressure

Oil temp @ idle (cold start) ~85lbs of pressure
Oil temp @ 190F, idle, ~22lbs of pressure

Oil pressure will rise with respect to RPM; higher pressure with colder, higher viscosity oil lower pressure with warmer/lower viscosity oil. However, the difference is very minimal unless you're going to compare something like 5W-30 to 20W-50 or straight 30W or 40W.

Thanks guys for the input, keep it coming, it is greatly appreciated.


My predicament lies here..

Race Roots sent me this turbo with an oil restrictor fitting for the oil feed line. However, that was the piece that was just jammed the fuck in there, cranked to hell. So, once I touched it it basically fell right out.

After going through all the bullshit of having new lines made, and now this stripped piece, I was getting a bit impatient. I found a fucking awesome machine shop that made me a new fitting in 5 minutes, for free, but it did not have as big of a restriction in it. I was so impatient and pissed off at that point that I just threw it on the car without thinking about it.

Precision is saying that if my oil pressure ever exceeds 90psi, the journal bearing turbo will require a small restriction in the oil feed line. The smoking is not excessive until I take the car for a bit longer of a drive, then it gets to be a bit much.. could definitely be the oil pressure raising as it gets warmer and warmer.

^ Oil pressure DROPS as the oil gets warmer because the oil is less viscous.

Me = reading fail..

are you sure your gauge isnt x100? 200-600kpa is 29-87psi which would make more sense.
FYI Online Conversion - Convert just about anything to anything else

This is the same activity as mine. I see 90+ at wot.

Having boost and oil pressure gauges is fun when your doing wot pulls. Lots of needle action.

doesent the stock line have a restrictor in it?

I believe so, but this turbo is set up entirely different and the stock feed/drain lines were not usable. I had a braided line mane for the feed and RR supplied me with a shitty drain line, I think I'm going to take it out and get a nice braided one for that too.

Precision said restrictors are almost completely necessary on any car using a ball bearing turbo, but I am using a journal bearing. He said more often than not a restrictor is unnecessary.

I got mine at oil filter
Cold start- 90
Driving around before cars warm 80 - 120
Idle once warm 20 -25
P/T 40 - 60
F/T 80 - I forget

Mine is off the oil filter on a 3 ft braded hose. This is about what I see but the P/T warm is almost always closer to 60 then 40 and my idle ranges for about 18-23.

Mine sensors are on my spin-on adapter for the cooler. I'll probably re-locate them to the stock sensor hole soon.

Oil: 5W-40
Cold start idle: 90psi
Cold 3,000RPM: +100psi (my gauge only goes to 100psi)
160F idle: 35-40psi
160F 3,000RPM: 70-80psi

I'll get some further readings at higher RPM... once things warm up a bit lol

Don't worry about it Matt. This definitely ended up being my problem and my restrictor is en route. Thanks gaiz.

To the guy who was asking about high mileage engine oil pressure, I have 97k miles now and it hasnt changed enough to notice.

Under cruising type loads, ide bet the bearing in this engine would almost last forever due to their size.