Racers. Do you worry about oiling issues, or do you just drive?

[AZ986S]

I admire what Chris Cervelli is doing for the dry sump solution, and I had read that post. The problem is that he does not say what the issue is, only somewhat vague statements on how some common fixes don't help, namely, Accusump, extended oil sumps, oil baffles and Dual scavenge pumps. No doubt the ultimate solution IS Dry Sump, but, to what the Radium King said, why did the X51 and all subsequent engines have an additional oil scavenging pump if that is not at least part of the issue? Also, how can an Accusump NOT help, even if oil is pooling in the heads? Accusump also adds a couple quarts of oil to the system, so that certainly helps to keep temps down. So, short of spending $20K on a dry sump system, I'll go with the "band aids" for now

[Bebbetufs]

Originally Posted by AZ986S

I admire what Chris Cervelli is doing for the dry sump solution, and I had read that post. The problem is that he does not say what the issue is, only somewhat vague statements on how some common fixes don't help, namely, Accusump, extended oil sumps, oil baffles and Dual scavenge pumps. No doubt the ultimate solution IS Dry Sump, but, to what the Radium King said, why did the X51 and all subsequent engines have an additional oil scavenging pump if that is not at least part of the issue? Also, how can an Accusump NOT help, even if oil is pooling in the heads? Accusump also adds a couple quarts of oil to the system, so that certainly helps to keep temps down. So, short of spending $20K on a dry sump system, I'll go with the "band aids" for now

I'm with you and your thoughts mirror the reasons I started the thread. I'm also with you on the cost issue, but if you follow the cost argument further...what if the most important factor is driving style and the band aids actually do nothing to stabelize oil pressure and are purely there for as a comfort blanket and to fill vendor's pockets? If so we might as well just stop after doing all cooling mods (confirmed) and just drive...We keep the money for a future rebulid. Unless the mods add power of course.

The reason I'm sceptical to the accusump is that I have read, and I suspect, it simply has too much lag to fill in the pressure dips. Also, all air bubble sucked in by the pickup, (or from pump cavitation due to high RPMs?)is already in the systen when the pressure drops and the only way to purge it is via the bearings. As Chris says it may help for extreme cases where the pickup continues to suck air for a longer period, but that is not what is causing pressure dips. If you have lost pressure for that long you have also lost your engine, in my opinion.

When it comes to the dual scavenge pumps they may be needed for other issues.In more powerful high-revving engines where the oil flow is higher. Pooling, backpressure and areation from the moving valve train come to mind. Anyway, they surely can't hurt our engine.

Chris states that the X51 baffles may work in the rear mounted 911s, but if the logs show the same pressure dips as before the installation in a mid-mounted engine it clearly does not alleviate the specific problem of pressure drop spikes in our cars, at least not in the tested engine.

[AZ986S]

I've finished installing my new Race Capture Track and AnalogX CANbus sensor input module. I have the following sensors installed for data logging:

Input --- Sensor Type --------------- What is measured ----------- Location
---1 --- Relay -------------------- Accusump Activation -------- Accusump press. switch
---2 --- 0-5 VDC pressure sensor -- Accusump Air pressure -------Accusump air side
---3 --- 0-5 VDC pressure sensor -- Oil Pressure ----------------- Pre oil filter
---4 --- 0-5 VDC pressure sensor -- Oil Pressure ----------------- Standard oil pressure switch location (cam cover)

The pre filter oil pressure is basically the pressure at the oil pump with maybe a small pressure drop due to the remote oil filter lines. The other oil pressure sensor will provide the pressure at the standard oil pressure switch location in our Boxsters. I will be able to calculate realtime (25-50 Hz) what the pressure drop is across the filter, the cooler and the engine. I will also be able to calculate the "Lag" that is assumed between the time the Accusump pressure switch detects the drop, opens the solenoid valve to release pressurized oil, and how long it takes for the pressure to rise at the cam cover position. I can tell you from just doing some preliminary (static) testing and observing the values that once the Accusump pressure switch opens the valve, there is almost an immediate rise in the oil pressure at the cam cover. Regardless, I will have the data to quantify this.

This coming weekend I will test with the Accusump pressure switch (current setup). The next event after this one, I will probably want to bypass the pressure switch and keep the Accusump valve open during the entire session to see if there is a benefit or quicker reaction and lower pressure drop than with the pressure switch activation.

I do have an oil temperature gauge but I do not have a sensor for data logging. Since oil temp does not change that quickly, I can estimate from the gauge. My next project!

I'll report what I find.

[Robert986]

Originally Posted by AZ986S

I've finished installing my new Race Capture Track and AnalogX CANbus sensor input module. I have the following sensors installed for data logging:

Input --- Sensor Type --------------- What is measured ----------- Location
---1 --- Relay -------------------- Accusump Activation -------- Accusump press. switch
---2 --- 0-5 VDC pressure sensor -- Accusump Air pressure -------Accusump air side
---3 --- 0-5 VDC pressure sensor -- Oil Pressure ----------------- Pre oil filter
---4 --- 0-5 VDC pressure sensor -- Oil Pressure ----------------- Standard oil pressure switch location (cam cover)

The pre filter oil pressure is basically the pressure at the oil pump with maybe a small pressure drop due to the remote oil filter lines. The other oil pressure sensor will provide the pressure at the standard oil pressure switch location in our Boxsters. I will be able to calculate realtime (25-50 Hz) what the pressure drop is across the filter, the cooler and the engine. I will also be able to calculate the "Lag" that is assumed between the time the Accusump pressure switch detects the drop, opens the solenoid valve to release pressurized oil, and how long it takes for the pressure to rise at the cam cover position. I can tell you from just doing some preliminary (static) testing and observing the values that once the Accusump pressure switch opens the valve, there is almost an immediate rise in the oil pressure at the cam cover. Regardless, I will have the data to quantify this.

This coming weekend I will test with the Accusump pressure switch (current setup). The next event after this one, I will probably want to bypass the pressure switch and keep the Accusump valve open during the entire session to see if there is a benefit or quicker reaction and lower pressure drop than with the pressure switch activation.

I do have an oil temperature gauge but I do not have a sensor for data logging. Since oil temp does not change that quickly, I can estimate from the gauge. My next project!

I'll report what I find.

Any updates on this?

[AZ986S]

Hey Robert986, I'm posting some data on this Thread:

Accusump - some data


I've updated my summary with the data from the latest event that includes the effect of adding an Accusump bypass switch to run it open.