[Mk2] [Turbo] Oil pressure readings

[mr2nut123]

What do people usually get with pressures on their cars? Should it increase slowly whilst revving the engine to reach a max psi, or should it shoot up quickly to the max psi as soon as you accelerate from say 3000rpm?

[bishop]

in engines where the oil pump is driven from the crank (either directly or via belt/chain) the oil pressure will rise with engine speed until it reaches the point at which the pressure relief valve (if it has one) releases the additional pressure above the maximum operating pressure.

basically the engine has a wide band of oil pressure inside of which the engine will operate safely. it shouldn't spike to maximum pressure immediately but its not uncommon for colder oil to reach its maximum working pressure quickly, this will reduce over time as the engine warms the oil.

[mr2nut123]

in engines where the oil pump is driven from the crank (either directly or via belt/chain) the oil pressure will rise with engine speed until it reaches the point at which the pressure relief valve (if it has one) releases the additional pressure above the maximum operating pressure.

basically the engine has a wide band of oil pressure inside of which the engine will operate safely. it shouldn't spike to maximum pressure immediately but its not uncommon for colder oil to reach its maximum working pressure quickly, this will reduce over time as the engine warms the oil.

I thought that was the case. Basically, new Stack oil pressure gauge idles perfectly at around 20-psi once fully warmed up, but as soon as the accelerator is pushed all the way down at lets say 3000rpm, the psi almost instantly hits the full 80-82 psi and holds all the way until redline. Does that sound like a faulty sensor..? Oil temp reads perfectly between 92-100 degrees so I know the engine is fully warmed up (good 30 mins just to be sure).

[jimGTS]

from my project page, hes what i see




oil pressure

Cold start
5.7-6bar
when ambiant temps near freezing, ive seen 8bar.

With oil temps at 95-98c
This is at stand still.

Idle, 850rpm = 2.2bar
1.5k = 3bar
2k = 4bar
3k = 5.2bar
4k = 5.7bar

When on boost high revs
6-6.5bar from what I can see.

[mr2nut123]

from my project page, hes what i see




oil pressure

Cold start
5.7-6bar
when ambiant temps near freezing, ive seen 8bar.

With oil temps at 95-98c
This is at stand still.

Idle, 850rpm = 2.2bar
1.5k = 3bar
2k = 4bar
3k = 5.2bar
4k = 5.7bar

When on boost high revs
6-6.5bar from what I can see.

Cheers Jim. Ah ok, I didn't do those tests whilst revving on the spot. If under load, would I expect the psi to shoot up to 80 psi and hold there throughout the rev range, or should I still see the same figures as revving on the spot in neutral?

[jimGTS]

i can only go from memory, but when on load, 3k over i am pretty much at 6bar

on a recent track day, i dont think my oil pressure gauge showed much below 6bar most of the time, lol.

[mr2nut123]

i can only go from memory, but when on load, 3k over i am pretty much at 6bar

on a recent track day, i dont think my oil pressure gauge showed much below 6bar most of the time, lol.

Haha! I'll give the rev tests a try when I get home then and report back. So basically, can anyone else confirm that ON LOAD, you will see max psi through the entire rev range, but when on the spot, it will increase slightly depending on rpms?

[gnzyza]

BGB says warm engine, 4.3 PSI or more at 3k 3-71PSI this will be at the stock location for sender and using recommended oil 10-40?

[C35Rob]

BGB says warm engine, 4.3 PSI or more at 3k 3-71PSI this will be at the stock location for sender and using recommended oil 10-40?

that's taken from the sensor in the head though isn't it? most people quote pressures from a oil filter sandwich plate or the ports on the oil filter housing

[gnzyza]

yeah will be thats why I mentioned stock location to avoid confuson

I think the OP is taking readings from the port next to the oil filter so will be different. higher maybe?

[GreddyMR2]

I am afraid of my oil pressure.
When warmed up, it's just under 1bar on idle and raise only to around 3bar at redline.
But I was racing quite a lot with this pressure last year and everything still seems fine. I have not checked engine bearings yet though...

All engine bearing gaps are in specs, but on the limit of the biggest gap. And also some of camshaft caps are a bit weared down so I might loose pressure there.

Pressure sensor is fitted to stock location in head.

[mr2nut123]

BGB says warm engine, 4.3 PSI or more at 3k 3-71PSI this will be at the stock location for sender and using recommended oil 10-40?

that's taken from the sensor in the head though isn't it? most people quote pressures from a oil filter sandwich plate or the ports on the oil filter housing

Just to confirm, I'm taking both my readings from a sandwich plate

[mr2nut123]

I am afraid of my oil pressure.
When warmed up, it's just under 1bar on idle and raise only to around 3bar at redline.
But I was racing quite a lot with this pressure last year and everything still seems fine. I have not checked engine bearings yet though...

All engine bearing gaps are in specs, but on the limit of the biggest gap. And also some of camshaft caps are a bit weared down so I might loose pressure there.

Pressure sensor is fitted to stock location in head.

From my experience, ~6bar around redline seems to be the average for a MK2, that seems like a very low reading?

[GreddyMR2]

I am afraid of my oil pressure.
When warmed up, it's just under 1bar on idle and raise only to around 3bar at redline.
But I was racing quite a lot with this pressure last year and everything still seems fine. I have not checked engine bearings yet though...

All engine bearing gaps are in specs, but on the limit of the biggest gap. And also some of camshaft caps are a bit weared down so I might loose pressure there.

Pressure sensor is fitted to stock location in head.

From my experience, ~6bar around redline seems to be the average for a MK2, that seems like a very low reading?

Probably readings from head and from sandwich plate differs a lot as a head is a top point and pressure is lowest there. I guess I will check the pressure from sandwich plate when I have some time

[mr2nut123]

I am afraid of my oil pressure.
When warmed up, it's just under 1bar on idle and raise only to around 3bar at redline.
But I was racing quite a lot with this pressure last year and everything still seems fine. I have not checked engine bearings yet though...

All engine bearing gaps are in specs, but on the limit of the biggest gap. And also some of camshaft caps are a bit weared down so I might loose pressure there.

Pressure sensor is fitted to stock location in head.

From my experience, ~6bar around redline seems to be the average for a MK2, that seems like a very low reading?

Probably readings from head and from sandwich plate differs a lot as a head is a top point and pressure is lowest there. I guess I will check the pressure from sandwich plate when I have some time

I think it's safe to say that your car is ok. It you were constantly seeing that same pressure and you drove away from the circuit...you're good

[mr2nut123]

Surely someone can confirm if oil pressures should be different with revving in neutral, as opposed to being under load? Also, does the 10psi per 1000rpm guide apply to the MR2, so I should see progressive pressure as I accelerate fully to redline?

[jimGTS]

heres some silverstone action.

my central gauge is oil pressure.
reading taken on one of the spare ports by the oil filter.

viewing this video for a minute or so shows i very rarely deviate from 6bar of oil pressure throughout most of the revs, id guess 4-7k rpm, no difference.


when we have to come into the pits because someone went off around the 6 minute mark, my pressure come back down.
but is straight back up to 5-6bar soon as im on it again

https://www.youtube.com/watch?v=7Jv05Ctj3ts

[mr2nut123]

heres some silverstone action.

my central gauge is oil pressure.
reading taken on one of the spare ports by the oil filter.

viewing this video for a minute or so shows i very rarely deviate from 6bar of oil pressure throughout most of the revs, id guess 4-7k rpm, no difference.


when we have to come into the pits because someone went off around the 6 minute mark, my pressure come back down.
but is straight back up to 5-6bar soon as im on it again

https://www.youtube.com/watch?v=7Jv05Ctj3ts

Cheers for the vid Jim! It does look to perform the same as mine actually. When I start mine up, I see a good 85-90psi on the gauge at idle, but it settles down to about 20psi when fully warm. From this point on, it's either bouncing straight to about 80psi when on boost (from 2500rpm upwards) or settles back at 20psi at a set of lights.

I was told that it should be progressive when accelerating (i.e. 40psi at 4000rpm, 50psi at 5000rpm etc etc) but it just seems to like bouncing straight to max psi like yours.



p.s. Nice driving

[mr2nut123]

I was speaking to Stack today. He was saying that the new stepper motor gauges react extremely fast, and basically don't have the 'inbetween' like the old gauges have (i.e. 10psi per 1000rpm guide). The new sensors either work or don't to be honest, so it sounds like it's fine. Hope this helps anyone else using new electrical gauges.

My pressure is around 70-80psi constantly when under any kind of load, regardless of revs. The only exception is when you come to a set of lights and dip the clutch. The pressure drops back down to 20psi nicely.

[gnzyza]

I have the same gauge going into one of the ports near the filter. I will let you know once I fire her up.