Oil temps with JR SC and JR oil cooler
 

NJMP track, around 70F ambient, oil temps consistently just over 245F. @CSG Mike, is this in the ballpark of what's expected? I know that the JR oil cooler is pretty new, looking for other points of reference.

Also, checked water temp with the Koyo rad a couple of times and it was in the 200-teens.

Your temps are higher than what we've seen. What weight oil are you using, and are you using a custom tune? Is your Koyo radiator shrouded and ducted like the stock one?

Also, custom tune or Jackson Racing tune?

Oil temps with JR SC and JR oil cooler
 

I will defer to @PrimeMotoring and @JuniorAWD for details. They used Motul 8100 0W20 oil and it's a custom dyno tune.

Have your tuner drop your fan activation point to 200F, will keep coolant at 198-205F on the track and drop your oil temps down by 10F.

I am on 0W20 as well and after about 25-30 minutes oil temps hit 245F on my setup as well. In the straights they tend to drop to around 230F.

Oil temps with JR SC and JR oil cooler
 

Update (@Dezoris, @CSG Mike): Got a new car after the "flying wheel" accident, this time MT. Peak oil temps were 256F on track. Tried new tuner @moto-mike who discovered a bad tune, fried/shrunk header cat, slightly shrunk front pipe cat, exhaust leak at the header due to two missing header nuts on one side and another small leak at the front pipe flange. Once fried cat element was removed (cut/remove/weld), car retuned, and oil changed to euro Castrol 0w30, oil temps got up to 226F with hard driving on track at low 70s ambient. Replacing P&L catted return pipe with catless, P&L front pipe and Perrin (had a lot of soot with the old tune) to start new, and touching up tune, this Wednesday at moto-east. All is well.

Sounds good! Lower temps are always better when running hard.

If you have an opportunity, do a stress test on the oil cooler by going on the highway, and sitting in 3rd gear. The goal is to keep the RPMs really high, which is where the oil temp really comes from.

These results are excellent, Id like to see your cruising temps as well. How long were your sessions when you hit 226F?

Different car, but our cruising temps are usually 185-195 at "normal" RPMs. If its stop and go traffic, it may get up to 205, but I've not yet seen higher, even with 105F + ambient temps.

Under spirited driving, it usually stabilizes at about 215-230F, depending on how hard I'm driving and ambient temp.

At the track, going for hot laps, oil usually stabilizes at 245F or so, in 110F + ambient.

On the highway, stressing the engine purposely (sitting at 7000 RPM) in 3rd gear at 75-80MPH, we can also get the oil up to 245F, but this is done only to prove a point. You'll never actually be sitting at this RPM, even on track.

YMMV, but chances are 99% of end users will see lower temps than us, since we're purposely stressing the system as hard as we can, and do our testing in the desert.

I will pay closer attention (tune is just over a week old) but street/hwy temps are somewhere in the 175-195F range. I didn't need to stay at redline for long on this track and sessions were 20min long. 226F peak temps were consistent even when I pushed the hardest...stayed in 4th gear near redline for a little while on NJMP Lightning before turn 7 and read 226F peak several times on the P3. I think I was at about 185F warmed up before going out. Average speed 77 to just over 80mph.

Just checked, in more stop and less go traffic at 72F ambient, oil peaked at 208F.

Same ambient, cruising, 175-180F

Would benefits be had by using a larger setrab oil cooler possibly?

I have the NA JR oil cooler (I am NA with stock tune, using 0w20 300V) on my car and have a max oil temp of 235F at Thunderhill in ~103F ambient. Is this abnormally high? In cooler weather before getting the oil cooler I was easily hitting 270F, probably peaking at or close to 280F (didn't have good logging then).

This matches what I see with the Perrin cooler (which I believe is the same as the JR). I've seen others post the same temps for NA.