Oil Temp for Street and Track. How Low is Too Low?

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HX520W

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We finally installed an engine oil temperature gauge and a transmission temperature gauge on the CR-Z before going to Road Atlanta last week. The car currently has an Earl's 19 row wide oil cooler with a 200F Mishimoto thermostatic sandwich plate. The front bumper cover has been replaced with a C-West cover, and all the gaps and holes around and leading up to the radiator have been blocked off to help duct it better (super impressed with Honda's CVT cooler in the radiator. It never exceeded 186F). We also made a box that the oil cooler is mounted in to act as a duct and so that it can be taped off on the street to help keep temperatures up. With the oil cooler fully open at Road Atlanta, oil temperatures never exceeded 208F by the end of 20 min track sessions. However, even with tape blocking air flow to the oil cooler on the street, the oil temperature is only 140-150F on the highway. The hottest it's ever gotten on the street is 179F when stuck in traffic in downtown Atlanta. Usually, it never gets above 155F.

Last year, I measured the temperature of the oil cooler in the paddock with an infrared thermometer (which seems to be within ~5F of the gauges) after a run at Memphis International Raceway at 230F. Are these temperatures too low? What oil temperature is considered too low? Would we be better off switching to a smaller oil cooler now or should we wait to see what temperatures we get at other race tracks? Currently, the longest we plan to run the car on the track is 40 min.
 
I would want the oil to get at least above the boiling point of water, so 220 F. That cooling seems like overkill when only doing 20-40 min races.

Normal operating temp for the oil in my 1er is about 250 F.
 
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Sounds like you have more cooler than you need. But you can add or remove tape to adjust for conditions. What oil are you running? Weight? Synthetic? Brand? If you are running full synthetic, I think if it's in the region of 260-280F, that's plenty safe for an Xw30. If it's a 20-weight, subtract 20F.

As far as running on the street is concerned, the higher the temperature, the lower the viscosity of the oil, and the better your fuel economy will be. If you are running at 155F, the oil is costing you fuel economy, and is not hot enough to quickly get rid of water from the blowby gases, which will degrade oil life. 180F is where most oils have thinned out to within ~10% of their KV100, and is hot enough to evaporate off the water.
 
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Yeah, wow, I get a little uncomfortable that my oil doesn't get over 185F or so in normal driving in my NSX. 230F is just fine on the track. I run about 275F on a hot day. Red Line and Mobil have both told me that's just fine.
 
The car is currently filled with Castrol Edge High Mileage 10W-30. One of Honda's manuals for the racing modified version of the L15A7 shows that the maximum allowable oil temperature is 284F (not sure what viscosity they use).

How would you go about increasing oil temps? I'm tentative to go out and buy another oil cooler before hearing other peoples opinions/experiences. Building mounts for oil coolers takes a lot of time and requires more holes to be drilled in the car.
 
As a point of reference. My 2008 Z06 Corvette ran at 160-165 degrees of oil temp in the summer, in the fall and spring when it was cold outside it was difficult to get temperatures above 145 if not impossible. All my UOA came back with great TBN, low insolubles, and no water. I think the concerns about over cooling are blown out of proportion. I think you're in a great place with well controlled oil temps. I wouldn't change a thing.
 
When your oil reaches 212*F or 100*C it is at the correct viscosity. I don't see any issue running it at the temps you mentioned.
 
I should also mention that I have an Earl's 10 row narrow oil cooler sitting around. I'm not sure if that's enough...
 
Originally Posted By: HX520W
The car is currently filled with Castrol Edge High Mileage 10W-30. One of Honda's manuals for the racing modified version of the L15A7 shows that the maximum allowable oil temperature is 284F (not sure what viscosity they use).

How would you go about increasing oil temps? I'm tentative to go out and buy another oil cooler before hearing other peoples opinions/experiences. Building mounts for oil coolers takes a lot of time and requires more holes to be drilled in the car.


Bypass the cooler for street driving. Could be done with a t-valve and some tubing. One valve position flows all oil through cooler, other position flows all oil through bypass loop
 
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Originally Posted By: FlyNavyP3
As a point of reference. My 2008 Z06 Corvette ran at 160-165 degrees of oil temp in the summer, in the fall and spring when it was cold outside it was difficult to get temperatures above 145 if not impossible. All my UOA came back with great TBN, low insolubles, and no water. I think the concerns about over cooling are blown out of proportion. I think you're in a great place with well controlled oil temps. I wouldn't change a thing.

+1

Generally lubrication systems are designed to operate in cool temperature at a desired operating viscosity .... at minimum cost to society.

Cool operating lubricant temperature specifically promotes longevity of lubricant oils and seals within the system.

If operating temperature is on the high side, use a thicker oil....... increase sump size ......
or when necessary add a circulating oil pump of varying capacity at higher cost .......
and as a 'last' resort add a cooler of varying capacity/size.

If operating viscosity at cool temperature is on the thick side, select oils of thinner viscosity grade or vice-versa.
 
I would use an oil cooler with a thermostat.

Otherwise it will be terrible esp. in the winter.

I would want the oil to run at least 180f in normal driving.

And stay below 250f
 
If your easy street driving is not getting the oil up to approx 175-180 deg. then you are not reaching the levels to ensure the additive package is fully working. That means more corrosion and wear of your engine. Handing around 145-165 deg is not a good idea. I think the mfg wear sequence tests are conducted in the worst region (135-150 deg F. or something close to that).

Lower oil temps are probably fine for gear oil and transmissions, not so much for maintaining acidic oil conditions where your TBN gets used up much more quickly.
 
Originally Posted By: HX520W
The car is currently filled with Castrol Edge High Mileage 10W-30. One of Honda's manuals for the racing modified version of the L15A7 shows that the maximum allowable oil temperature is 284F (not sure what viscosity they use).

How would you go about increasing oil temps? I'm tentative to go out and buy another oil cooler before hearing other peoples opinions/experiences. Building mounts for oil coolers takes a lot of time and requires more holes to be drilled in the car.


I appreciate you not wanting to install another cooler and drilling more holes in your car! Something as simple as getting a flat sheet of plastic (Lexan, for instance) and making a blockoff plate to cover half of the cooler would be a good way to start. Drive around and see how hot the oil runs under different conditions and adjust the blockoff plate size until you have enough cooler exposed to cool the oil during a hot track session, yet enough blocked off to let the oil warm up during gentle street driving. Maybe you can find a happy medium there. Or just have different blockoff plates for street and track.
 
Originally Posted By: robertcope
I run about 275F on a hot day. Red Line and Mobil have both told me that's just fine.


The oil can handle that...
but most rubber seals lifespan goes down faster over 250*F
 
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Thanks for all the responses so far. I'm starting to get an idea of what the low end of the temperature range I should shoot for is.


Originally Posted By: PeterPolyol
Why would you need an oil cooler on such a low output engine? The Turbo-DI version of this engine doesn't even have an oil cooler of any kind.
Because the car is tracked. If the car was only used on the street, I'd never even think about oil viscosity or temperature. It's basically impossible to stress an engine on public roads in North America.

There's basically no information about using these engines/cars on the track. I've pretty much just had to make educated guesses and go from there. A few years ago, I decided to get an oil cooler before I could afford a nice set of gauges. I settled on a 19 row wide oil cooler based on a CR-Z build thread that I found. The guy in the thread tracked his MT CR-Z occasionally and had a set of gauges to monitor temps. Based on that, I figured a 19 row wide oil cooler would be fine with the engine continuously screaming at redline through the CVT for 40 minutes. And as it turns out, it is..... just not on public roads where the engine is asleep...

Right now, I'm trying to work out a setup that will keep the car cool when it's at 100% output for 40 min AND keep the car warm enough when it's asleep outputting 20-25 hp on the highway.
 
Originally Posted By: HX520W
Right now, I'm trying to work out a setup that will keep the car cool when it's at 100% output for 40 min AND keep the car warm enough when it's asleep outputting 20-25 hp on the highway.


Doesn't the cooler have a thermostat? And the idea that oil that doesn't get above 150 won't boil off water is nonsense. The oil temperature is just an average from where the sensor is taking a reading. Wherever the oil comes into contact with bearings, pistons, cylinder walls, etc. whose parts are well over 212, will allow any water to vaporize.
 
I believe that you need a thermostat if you don't have one installed. This would allow the engine to use the cooler to keep the oil from getting too hot (e.g. on the track) but allow optimal operative minimum temperature to be attained in normal driving.

Superman and Batman don't wander around ready to fight, they rise to the demand when called upon.

Don't ask me where that illustration came from... I don't know.
 
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