Automatic stop of engine if I loose oil pressure

[Lorcan]

That makes sense, thanks

[Holmz]

Not sure if the m800 etc can do it, but best is to monitor relative fuel pressure.

ie FP relative to MAP. If it strays too far out of expected, then there is a problem that warrants a limp or shutdown.

that keeps a tight control over it for safety.

If one can compensate for the pressure that not better then a limp mode?
When it gets beyond the region where one can compensate, then a cut can be enabled.

[stevieturbo]

Not sure if the m800 etc can do it, but best is to monitor relative fuel pressure.

ie FP relative to MAP. If it strays too far out of expected, then there is a problem that warrants a limp or shutdown.

that keeps a tight control over it for safety.

If one can compensate for the pressure that not better then a limp mode?
When it gets beyond the region where one can compensate, then a cut can be enabled.

Depends on the cause.

If that cause of reduced fuel pressure is a fuel leak spraying fuel over the hot engine compartment...trying to compensate and ignoring it for a bit isnt perhaps a safe option.

Now perhaps if it is a full race scenario where there is a lot at stake in terms of winning, yes maybe you might forego some safety aspects and allow compensation for longer.

But really...if fuel pressure is dropping beyond what it should, IMO it is an indication of a major problem that needs fairly prompt attention.

If you're talking compensation via adding fuel to maintain AFR's, that's a different feature altogether and could still happen.

I dont see any safe compensation for failing fuel pressure, unless you can switch to another pump or add another pump. But that isnt really a compensation as such and without knowing the cause of reducing pressure...again, caution may be needed with any automatic response.

Likewise with oil pressure. A drop in pressure vs rpm over and above normal could be a sign of many problems. It's up to each user how much faith they want to put in the safety feature and what outcome it needs to have for them.
Full cut, or just a reduced rpm mode etc.

[Holmz]

I think we are in general agreement.

I want to have FP logged.
If there is a drop of pressure I would like some idiot light like an SLM flickering to tell me how bad the situation is.

If there is some degradation of the pump or regulator (like maybe the adjuster) that causes the FP to slowly go down... Then I would like the duty cycle to slowly go up, just like the relationship between air density and fuel required.

In the olden days when we drove up into the mountains in the winter, we put a clothes pin to hold the choke open. Now that is done with a baro meter.

I want a yellow light for when the pressure is off by a few PSI, and the red light when it is off further.
I do not want to be looking at gauges for something that can be automated.
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Of course oil pressure is harder to compensate for. The wallet is the only thing have seen help.
It is probably ideal to monitor the pump's shaft speed, because that will likely precede the pressure drop if there is any hydraulic capacity... With "ideal" being defined as "in addition to the actual oil pressure".
Certainly if one gets both the pump speed and the pressure going to zero, then one way or the other the situation will result in coming to 'full stop', period!

I have a dry sump to install and I have been thinking about the fuel pressure - so my post is really more of a query of the logic, then a statement of fact. So I appreciate anyone picking it apart.

[stevieturbo]

When you refer to a failing pump and duty cycle going up...are you referring to pump duty going up ?

Again as any closed loop fuel control is a separate and independent feature vs any fuel pump/flow monitoring

Not sure over what time period you feel is a slow degradation, and whether that could largely be monitored via logs over days, weeks, race to race etc etc
I think most inbuilt safety strategies are for more immediate problems. At some point I think there will always have to be some human monitoring or intervention over the longer term.

But again a tight reign over FP relative to MAP inducing a limp would give early insight to a potential problem, forcing inspection. Which cant be a bad thing really.

If you have a dry sump with pulley driven pump. That again should be a fairly easy one in theory. Pump speed or pulley speed would be directly linked to crank speed. Any deviation from that would indicate a major problem
Not sure how easy that strategy would be to implement though without a specific feature.
Shouldnt be hard to add a reference tooth or few onto the pump pulley though and watch them.

But at the same time, oil pressure would fall pretty rapidly during a fail scenario too. So the rpm vs oil pressure falling outside normal limits should be a safe enough reason to either shut the engine down or severely reduce it's operating range to allow a limp home if the driver wishes to do so.

Of course any pressure based monitoring also relies in the reliability of any sensors used. Catch 22 with that one. You either trust them or you dont.