A new way to manage oil levels on track

[san40k]

fe1rx
> My practice is to add 7.0 liters when changing oil on my track car, with the intent of maintaining the oil level between 6.5 and 7.0 liters.

I've filled ~6.8 to my N54 335i and anxious about overfilling, so how do you maintain 7L without further overfilling? Add 500 when you see 69 mm or something more subtle ?

And thanks for finding it - seeing this in real time is a big relief

[san40k]

first datalog with oil levels, its all over the place during the session: https://datazap.me/u/can40/psr-track...zoom=6207-9843

[changster]

Originally Posted by changster

Sorry if I missed it but how do you add the oil level parameter in MHD?

Anyone?

[houtan]

Originally Posted by changster

Anyone?

You can find the information in the s p o o l s t r e e t n54 forum

[fe1rx]

Originally Posted by san40k

fe1rx
> My practice is to add 7.0 liters when changing oil on my track car, with the intent of maintaining the oil level between 6.5 and 7.0 liters.

I've filled ~6.8 to my N54 335i and anxious about overfilling, so how do you maintain 7L without further overfilling? Add 500 when you see 69 mm or something more subtle ?

And thanks for finding it - seeing this in real time is a big relief

Yes, that is exactly right. On a track day, I would want to see 73 - 74, so I might split the hairs a bit finer and I might add .25L if I saw 72 at the start of the day.

[fe1rx]

I have discovered an interesting failure mode in my oil level sensor. This sensor also provides the oil temperature signal to the ECU. I was monitoring oil temperature with a separate sensor at the inlet to the thermostat housing, and it was consistently about 10°C colder than the reported engine oil temperature. Some difference can be expected, but his seemed like too much. The oil level indications still appear to be correct.

Comparing coolant temperature, outside temperature, oil temperature and sensors I have installed before and after the oil coolers after a night of inside storage should show all these readings pretty close. They ranged from 18°C to 21°C, except for the oil temperature gauge which showed 32°C.

I repeated the same test on my 3-series using a code reader, and live data showed the oil temperature matched the coolant and outside temperature closely, so a working sensor does properly report cool oil temperatures.

A high reading will prematurely result in an on-track power reduction due to "hot" oil, so it is worth making sure your oil temperatures are accurate if you are experiencing that. The overnight cold test is an easy way to do a sanity check if you have any doubt.

I have ordered a URO replacement level/temperature sensor and will report back if that resolves the issue.

[fe1rx]

I replaced the original BMW oil level sensor with a new URO sensor, and this resolved the engine oil temperature reading error.

Interestingly, the temperature when cold still reads 32°C vs. the actual 20°C, but with the new sensor, the error disappears as the oil warms up (above about 35°C) at which time the ECU engine oil temperature agrees with the measured oil thermostat inlet temperature within a couple of degrees.