About the only case where a better oil cooler added power was on the old air cooled VW, since it stopped the overheating on that side.
A water oil cooler will heat the oil faster in warm up, they can help a little in the first few minutes.
If cooler oil reduces pre-ignition then that might add power, but you have bigger problems.
Seat of pants Dyno is notoriously inaccurate. Changes that make car or bike slower but sound better are perceived as more power, but the real dyno does not lie.
Rod
A water oil cooler will heat the oil faster in warm up, they can help a little in the first few minutes.
If cooler oil reduces pre-ignition then that might add power, but you have bigger problems.
Seat of pants Dyno is notoriously inaccurate. Changes that make car or bike slower but sound better are perceived as more power, but the real dyno does not lie.
Rod