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Oil Temperature


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I now have my sandwich plate fitted (between the block and the oil filter) which houses the oil pressure and tempurature sensors.

After some fettling with the DL/1 software, I took the car out for a "calibration run" yesterday for a couple of hours.

Despite my best efforts, I couldn't get an oil tempurature reading above 70 deg C - I have checked the wiring and the sensor calibration and can't find any problems.

Is this right - seems a bit cool to me, I would have expected something nearer 90 deg C. Anybody got any thoughts

Saving up for a sequential gearbox
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Del,

You want the oil temp high enough to boil off any moisture in it and flow properly. Just normal driving may not get the oil temp hot enough, high rpm and load raises the oil temp. I like to see oil temp around 100 to 110 deg c, once it goes over 120c I start to get worried. It depends where the oil temp sensor is located. Are you checking temp before or after it flows through the cooler? 70 deg c is too cold.

Dan

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The sensor is fitted at the oil filter - not sure whether this is before or after the oil cooler. I assume the circuit goes something like sump -> pump -> filter -> cooler -> engine -> sump. Not sure where the accusump plugs in but my guess is that the oil in there doesn't get circulated.

Sadly I was on public roads so didn't get the opportunity to keep the engine under much load (other people kept getting in the way) :lol: .

The engine temps were normal (86 deg rising to 94 in traffic) and intake air temperature varied between 10 and 24 deg C (the latter when I managed to open it up a bit).

I am rather hoping that it is just because I wasn't putting enough work into the system given the low ambient air temp (10 deg C) and the uber efficient oil coolers.

Saving up for a sequential gearbox
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My experience with all my Loti (Cup255, Cup240 and 2Eleven) fitted with oil temp gauges was that the oil never got that hot. At the track, on a 105 degree F day, the highest oil temp reading was 215 and on cooler days, oil temp never exceeded 190 F. Also, it takes some time to get the oil temp above 170 degrees F.

As Dan mentioned, one would like to see oil temps above the boiling point of water on occasion. It may be the placement of our temp sensor ... all of my cars used the same "sandwich adapter" at the oil filter location as your current setup, so maybe our readings err on the low side. However, my recollection of the oil temp data collected by those using a sensor in the oil pan was that they also experienced relatively low oil temps. Those two front oil coolers may just be be too efficient. :lol:

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The coolers are termostat controlled (its the little screw next to the banjo bolts on the sandwich adapter) so shouldn't be cooling when the engine is cold. Over cooled oil is as bad as overheated.

If you have mounted the oil temp sandwich plate underneath the existing sandwich plate then it should go sump -> pump -> filter -> sensors -> cooler -> engine as I believe th oil go down the middle of the filters path and then gets pushed through to the outside and back up to the engine.

Oil temp will rise above 100 even doing nothing. A good test is to let the car idle - that'll heat the oil nicely. My other car has a built in oil temp gauge and that sites at 110 pretty much in all circumstances but that (I think) has a oil-water cooler which would help stabilise the temps.

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Ads - thanks for the info.

My sensor sandwich plate is fitted beneath the oil cooler sandwich plate.

I have tried letting the car idle for some time (about 30 minutes) and max indicated oil temp went up to about 80 deg C which dropped back to 70 within a minute or so of moving the vehicle.

I calibrated the temperature sensor before installation by placing it in hot water (and using a standard temperature probe to measure the temperature of the water). Using this method, I got good consistent readings from the sensor for temperatures up to 95 deg C. This suggests that it is not the sensor at fault. I have checked the wiring numerous times now and can find no intermittent connection or additional resistance - I have even swapped the wires between the temperature and pressure sensors (as the pressure readings are what I would expect) as a test, with no change in readings.

The next step is to connect up the original (analogue) guage as opposed to feeding the sensor direclty into the data logger. I don't think the sensor mapping is the problem as I managed to achieve pretty good correlation between guage reading and the data logger reading when messing around with the hot water.

Hopefully I will get some track time soon and will see what happens when I can put the engine under load.

Del

Saving up for a sequential gearbox
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  • 1 year later...

Old topic but thought I'd add my readings.

Normal driving I see exactly the same - 70 deg maybe 75.

Even in traffic jam it never really got to high.

On track at brands it climbed up to 86-90 but was very difficult to get above that (I start to flag before the car does).

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My observations are about the same , with an air temp around 25c I recorded the following at the local track.

Lap 1 to 2 - warm up- 74c to 85 c

Lap 4 to 5 medium Hard laps 85c to 90c

Lap 7 to 8 hard laps 90c to 91c

So much the same results .

Question is , should the oil be hotter ?

Thoughts ??

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I've always thought that for oil it is good to get it up over 100c to ensure any moisture is evaporated out of it.

But measuring at the oil filter generally gives slightly lower values as the truely hot oil should be dripping into the sump so I don't think theres a problem.

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