RT

What are the typical oil pressures seen with the engine at full operating temperature (after about 15mins driving)?

I have a Defi meter setup, with the oil pressure tapping at the sandwich above the oil filter. I used to get pressure of around 6.5bar @ 3000rpm. I assume that this pressure is that supplied directly from the oil pump, as this tapping position is upstream of the oil filter and HKS oil cooler.

Today, I had the sensor moved to the block to read the pressure at the supply line to the main bearings. (This would be downstream of the oil filter and HKS oil cooler.) With the engine fully warmed, I got a pressure of about 5.8bar @ 3000rpm. No other changes were made. The oil was not replaced completely, only topped up a tad (to replace what flowed out from the sensor tapping).

Is a 0.6-0.8bar drop in oil pressure across the oil filter and oil cooler typical? Has anyone else observed this?

Many tks.

RT

Jus did a quick "survey" with 2 others who have the oil pressure sensor in the same position (on the block).

JDM STI7 Type RA
30000kms+
Motul 15W-60
Oil Press @ 3000rpm: ~6.2bar

"Euro" STI7
4000kms+
5W-40 (running-in oil)
Oil Press @ 3000rpm: ~5.9bar

My JDM STI7 Type RA
30000kms+
Motul 15W-50
HKS Oil Cooler installed
Oil Press @ 3000rpm: ~5.8bar


Seems like there is a noticeable difference in "engine-hot" oil pressures with the different viscosities of oil. The oil cooler may also result in a slight pressure drop.

Can anyone else furnish some results?
Many tks.

Bob Rawle

Motul is one of the best oils for holding up pressure, my own car gained 1 bar pressure at idle when I put it in, my pressures ... 7 bar at 3000 rpm but I get to 6 bar by 1800 rpm, i do have a Roger Clark modified oil pump though but that is not stated to be uprated for pressure. With an oil cooler fitted the pressure drops thro the system are going to be different and so I would expect that you could see a lower oil pressure than a car not fitted with one. Having said that my previous oil pump generated 6 bar dead at 3000 rpm reaching that level at approx 2200 rpm.

Also bear in mind that there will be a greater resistance to flow and hence more apparant pressure adjacent to the oil filter.

RT

Cheers Bob! What oil are you using currently? Is your car a MY01 STI too?

I am pretty surprised to hear that the oil pump change resulted in 1bar higher pressures, as oil pressures are (supposedly) determined by the restrictiveness of the oil passages rather than the oil pump "power/efficiency"...