I installed an Autometer electric engine oil temp gauge with a sensor in the side of the oil pan. I was a little surprised to see how the oil lost temperature as much as it did when cooling between rounds. On initial warmup coolant will get to 180-200 and I'll let it heat soak, oil temp will be about 150. after cooling pulling the coolant gauge down to the peg which is 100 or less the oil temp will cool down right along with it. making a pass oil temp will be up to 150 again when I get back to the pits and again after cooling it drops right down. Temps have been in the 70's and 80's while racing.
Is this what others are seeing on gas? On alcohol when you don't cool between rounds I'm guessing the oil will maintain temperature. People talk about getting the oil hot enough to get the moisture out when running methanol, how hot can you get the oil?

The solid line is 55* weather, the dash line is 92*. Both these runs are 3rd rd after sitting for 1.5 hrs. Both are 189* finish line. On the return road after the ET shack, oil temp will be over 200*. On methanol and gas PP. 10w30

This temp display is using an Autometer 2258 probe and Holley dash programmed to the sensor values.

I like a diaper for helping keep oil temp consistent.

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Originally posted by DragRaceResults:
I like a diaper for helping keep oil temp consistent.

That's a good point, do you have any data on that?

2BKING

Eman my experience just about mirrors what you are seeing. I do run a diaper also. I can get my oil to 180 or so before a pass with my oil heater but if I do my car pick up significantly so I just try to maintain 120-150 so I can keep the consistency. 180 range is hard to keep up with.

I'm guilty of not having the diaper on. I just put the motor in and left the diaper off so I could check for any leaks and I hadn't put the pan heating pad on yet.
Markemark, Your graph shows a minimum oil temp of 179* is that how hot it was on start up? What type car and motor? Mine is a 355 in a door car, nothing special with a 7qt. pan.

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Originally posted by Eman: markemark, Your graph shows a minimum oil temp of 179* is that how hot it was on start up? What type car and motor? Mine is a 355 in a door car, nothing special with a 7qt. pan.

The data log is 12 seconds long and starts when I press the TB button which is just under 3 seconds before TB release. 3rd Gen, Little M, 14 -1, 6 qt total oil capacity with diaper.

The Primer Plus on 93 octane indicates 1050* EGT when running at idle, is excellent for cold weather starting and does much to heat the engine quickly. My engine is running on PP much of the time when not on racing surface prior to switching the EFI ON and running on methanol.

Yesterday I purged the EFI system of methanol and filled with 93 octane, same as PP system. Changed the EFI map from methanol to gas. Engine was at 55* being in garage and it was 30*outside. It took 18 minutes of 1450 rpm idle time to achieve 195* oil temp. I was cycling between the PP and EFI while maintaining 185* water temp. Never any water in my oil samples. I’m officially done racing for 2023.

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Originally posted by Eman: On initial warmup coolant will get to 180-200 and I'll let it heat soak, oil temp will be about 150. after cooling pulling the coolant gauge down to the peg which is 100 or less the oil temp will cool down right along with it. making a pass oil temp will be up to 150 again when I get back to the pits and again after cooling it drops right down.

Have you ever tried racing with the coolant temp in the 170’s? It’s easy to maintain this temp and requires very little to no effort to cool between rounds even in hot weather. I don’t understand why one would initially heat the engine to 200* only to take the temp back to double digit afterwards.

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Originally posted by markemark:
The solid line is 55* weather, the dash line is 92*. Both these runs are 3rd rd after sitting for 1.5 hrs. Both are 189* finish line. On the return road after the ET shack, oil temp will be over 200*. On methanol and gas PP. 10w30

This temp display is using an Autometer 2258 probe and Holley dash programmed to the sensor values.

Can you post with water temp and trans temp? Thought I'd be interesting to see the correlation between the three.

I heat soak up to 200° but don't cool to double digits. 165° seems to be a good # in the water for me on alky.

quote:

Originally posted by markemark:

quote:

Originally posted by Eman: On initial warmup coolant will get to 180-200 and I'll let it heat soak, oil temp will be about 150. after cooling pulling the coolant gauge down to the peg which is 100 or less the oil temp will cool down right along with it. making a pass oil temp will be up to 150 again when I get back to the pits and again after cooling it drops right down.

Have you ever tried racing with the coolant temp in the 170’s? It’s easy to maintain this temp and requires very little to no effort to cool between rounds even in hot weather. I don’t understand why one would initially heat the engine to 200* only to take the temp back to double digit afterwards.

I don't know how you build so much oil temperature. I have to work really hard to keep heat in my oil, even with a diaper on.

Also if you don't have a PP/EFI, in my experience, it's not that easy to keep water temps at 170° or above and I run a thermostat and use a heater in my radiator.

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Originally posted by M120:

quote:

Originally posted by markemark:
The solid line is 55* weather, the dash line is 92*. Both these runs are 3rd rd after sitting for 1.5 hrs. Both are 189* finish line. On the return road after the ET shack, oil temp will be over 200*. On methanol and gas PP. 10w30

This temp display is using an Autometer 2258 probe and Holley dash programmed to the sensor values.

Can you post with water temp and trans temp? Thought I'd be interesting to see the correlation between the three.

I heat soak up to 200° but don't cool to double digits. 165° seems to be a good # in the water for me on alky.

If you look at the left side of this pic, you’ll see all the channels that are being recorded, but only the two that are selected with check mark, are on the chart graph. Water temp is the CTS and Trans Temp is below Oil Temp. The top number is the 55* weather temp run and the bottom number is the 92* weather temp run.

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I don't know how you build so much oil temperature. I have to work really hard to keep heat in my oil, even with a diaper on.
Also if you don't have a PP/EFI, in my experience, it's not that easy to keep water temps at 170° or above and I run a thermostat and use a heater in my radiator.

The oil system is 6 qts 10w30 total. Cooling system holds almost 11 qts using a small radiator (7psi cap) and standard volume Meziere pump. The fan cycles On/Off at 171* (adjustable for weather). Although the PP will aid in heating quickly, the EFI system can remove 30% fuel at idle when enabled, and raise the exhaust temps into the 900’s and add heat same as those using a lean-out valve. This EFI method of adding heat that I programmed this year, works very good, and is self-cancelling when the throttle position is greater than 6%.

After rolling my car off the trailer, I start engine and achieve 170* water and 120* oil temp in 7 -8 minutes. The car never moves. When they call TT or first rd, driving to staging will have water temp of 160 – 170’s and oil 140*+. It’s ready to race. The diff has two qts synthetic, trans TES 295/668 and warm enough driving to staging lanes.

In this pic, the top numbers are the very first TT run of the 80* day. The bottom numbers are the very last run 8 rds and 10 hrs later in 75* weather. The last three runs were all in the same 60 minute period. The car ran 6.210 in TT and 6.211 in Rd 8.

In a perfect world I would have the oil temperature at 170-180 and the water temperature at 140 when I pull into the water box. When the temperatures are different (higher or lower) I simply change the dial-in accordingly.

Over the last few months I've made significant changes to the cooling system and air flow through the radiator, these changes should help stabilize the water temperature. I also added a 16 volt alternator to eliminate charging the battery between rounds. The only between round maintenance I have is adding a little fuel and downloading data from the previous run into the computer. During the winter months I run 10W-30 Royal Blue synthetic oil, in the summer I change the viscosity to 10W-40.

We constantly monitor the ground temperature at the starting line since it's the one variable I can't control. Just knowing what it is helps narrow the dial in variance.

Bob