Oil Pressure Sender

madjak · Postby **madjak** » Thu Mar 05, 2015 6:36 pm

I'm looking at installing a second oil pressure sender to feed directly to the ECU. Has anyone used the cheap $30 ebay specials or do I need to fork out for the $200 'proper' ones?

The senders are the 3 wire 0-5v output ones not the stock resistance variety.

plohl · Postby **plohl** » Thu Mar 05, 2015 11:19 pm

I have been looking into this too. I am leaning towards geyting a proper honeywell etc sensor (expensive). At least they have spec files so they can be calibrated correctly.

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Magpie · Postby **Magpie** » Fri Mar 06, 2015 11:20 am

Lessons I have learnt...

Mount any sensors on the body of the car and run hoses to them. This way the sensor is supported and not vibrating with the engine. This reduces strain on where you would normally mount the sensor. It also makes wiring them easier. This is the next plan for my car.

When I had 2 oil pressure sensors off a t piece on the engine it fatigued and cracked!

madjak · Postby **madjak** » Fri Mar 06, 2015 1:04 pm

Magpie wrote:Lessons I have learnt...

Mount any sensors on the body of the car and run hoses to them. This way the sensor is supported and not vibrating with the engine. This reduces strain on where you would normally mount the sensor. It also makes wiring them easier. This is the next plan for my car.

When I had 2 oil pressure sensors off a t piece on the engine it fatigued and cracked!

Yeah my plan is to mount this sender in a -10AN male to -10AN female fitting with an 1/8npt hole. This means I can place it inline at any connection point in my oiling system, either before or after the oil cooler.

I'm going to give the cheap one a whirl. If it fails I doubt it will give me a leak and the computer would cut power anyway if that was the case. Apparently they read 0PSI at 0.5v, 50PSI at 2.5V and 100PSI at 4.5V which is nice and linear. I can compare it against my gauge and it's mostly there for safety only... so to detect oil loss and cut power to the engine. If it's out 10PSI I don't really mind.

madjak · Postby **madjak** » Fri Mar 06, 2015 1:43 pm

Actually, what oil pressure do you guys see on your engines at full temp and speed? I have an external oil pressure regulator so I'm interested in what would be ideal to run on the track. Currently it's set to around 65PSI I think. Does anyone know what the stock regulator is set to?

Magpie · Postby **Magpie** » Fri Mar 06, 2015 2:10 pm

I will go through some old data when it was a 1.6ltr as like yours, my oil pressure is controlled externally.

rascal · Postby **rascal** » Fri Mar 06, 2015 2:16 pm

madjak wrote:Actually, what oil pressure do you guys see on your engines at full temp and speed? I have an external oil pressure regulator so I'm interested in what would be ideal to run on the track. Currently it's set to around 65PSI I think. Does anyone know what the stock regulator is set to?

Mines an NB8A so maybe different but I see around 60-70 psi at redline.
Think the old rule of thumb of 10psi per 1000rpm is pretty close to the mark..

madjak · Postby **madjak** » Fri Mar 06, 2015 2:22 pm

The pressure regulator caps it though. So I see it drop at lower revs / idle but under power lifts till it hits my limit and then stays there throughout the rest of the rev range. I do see higher values when the oil is cold, around 90PSI but thats because the regulator itself flows less then. (it's a ball and spring valve)

I rev my engine to 8000rpm so I'm not sure if it should be higher than 65 PSI or not. You don't want it too high as it will add more friction etc and might pop seals.

Magpie · Postby **Magpie** » Fri Mar 06, 2015 8:00 pm

Had a look at some recent data doing the QR National track last year (attached).

Peak RPM and speed it is around 50 PSI, however the sender is (alleged) to be reporting about 10 PSI less than it actually is.

Also attached is one from Lakeside in 2013 when it was a 1.6 ltr (same sensor so similar reporting issue).

Peak RPM and speed it is around 50 PSI as well.

Interestingly both engines show the same behaviour at 5,000 RPM at about 70kmh, high oil pressure. I could do them with G force instead of speed if that is more usable.