Engine Protection - Minimum Oil Pressure

[Roadrunner]

My Adaptronic ECU has some pretty good engine protection modes built in and I've just installed an oil pressure sensor and wired it in.
Now I need to tell the ECU what minimum oil pressure at what RPM it should cut revs or kill the engine.
This is the first time I've ever been able to monitor oil pressure on any engine so don't know what "normal" is.
The photo below is Adaptronics example image from their website for reference.
Any suggestions for what minimum oil pressure at what RPM you'd want an engine shut down to prevent damage from lack of oil pressure?



Thanks

[greenMachine]

Track car? I'd link oil pressure and TPS. You are likely to get oil surge under brakes (BPs are prone to this), and that is probably going to be low enough to trigger a warning light. My light was set to (iirc) 40psi in the racecar, and I was getting it come on at the hairpin at SMP, which is slightly downhill to boot. I wasn't too worried, as the engine was at low revs and low load, and it was only a brief flash. But I installed a mid-sized accusump anyway, and never saw the warning light again.

If I was setting up a racecar ECU I'd be looking at say <35-40 psi and >50% throttle, but then again I would not be setting any EP mode for oil pressure in a racecar ECU - I would stick with a big, bright warning light mounted right in the drivers eye line, and an accusump if you are seeing brief periods of low oil pressure that are clearly a result of surge. The other precaution is to run more oil in the sump, my dipstick came marked for this higher level.

Street car? Probably 20psi, and I wouldn't worry about linking TPS.

[bartmanftw]

Best way to find out is to leave the protection off initially and take a lot of data logs over the entire rpm range and at different oil temperatures, then analyse the data to determine your min/max pressure values and any offsets you can implement in the software.

[GR124]

reading with interest. I'm about to set up my engine protections on an elite 1500. I had in mind 20psi at grater than 2000 RPM for a track car. My engine is dry sumped so oil surge.

[Roadrunner]

Ahh of course. That makes sense to do. Thanks Bartman!

GM. I have a red LED in the dash for low oil pressure but I can guarentee without a doubt the ECU can react quicker than I can in a sudden engine killing low oil pressure situation. Or especially if someone else is driving the car and assumes a dash light is something thats fine to be on till they get home to tell me about it
Hopefully the sump baffle that was installed during engine rebuild will help with the braking oil surge issue but I'll have to actually get to a track day one day to see.

[greenMachine]

Yes, of course it can, but the unasked question was do you want the engine to shut down for a momentary dip in OP? The prevalence of oil surge in BPs means that there is high probability of false alarms. Maybe the best of both worlds is a 40psi warning light for OP dips, and an ecu cut at 5 or 10 psi for disasters such as the oil pump failures or burst oil lines.

[Roadrunner]

Yes definitely will be using both. You raise a good point with engine cut from false alarms due to surge under brakes. A scenario I never considered. I'll follow bartmans advice of running some logs for a while to see what normal is and then set the protections a bit lower than that.
I suppose my main concern initially was full loss of pressure or the situation of too low oil pressure under accelleration at high rpm (not sure what scenairo would cause that). Ie full throttle 4000rpm and up, if say 50psi is what its pumping normally, if it drops to 30psi for some reason is that too little pressure at that rpm causing bearing damage? is 20psi ok? 10psi? What psi does bearing damage start?

The pressure dip under brakes will have to be factored in as the protection mode is only rpm vs pressure. A possible/likely scenario is a heel/toe blip upping the RPM while under hard braking (and pressure dipping die to surge) may cut the engine

Hmmm.... time to go record some logs and do some "brake performance" tests

[greenMachine]

If OP is your concern: Baffle sump, new 'full' mark on dipstick (and keep topped up of course), and an accusump if worrying dips still occur. Look at the hot viscosity of your oil, increase if appropriate. Some people on Mt.net talk about polishing the relief valve housing, as stuck-in-relief is a 'thing' and will lead to low oil pressure, it has happened once to me after the car had sat unused for some months; I never did anything except loosen it and get it working, and it never recurred.

ALWAYS run a harmonic damper on the crank nose, and never even think about replacing it with a solid pulley - crank harmonics kill BP oil pumps. Some people safety wire the spin-on oil filter (or otherwise stop it loosening and dumping the oil, I use a hose clamp working against a stop).

You can put a Boundary Engineering pump in, but they are not failure-proof and no magic bullet.

... and then the warning light and EP cutout are your last lines of defense.