Hondata

Car: 2002 RSX Type S, K20A2
Mods: Pistons, Rods, Cams, Intake Mani, Full Exhaust + Header, Air Intake
Hondata Software: 1.2.2.9

We tuned this Car on the dyno and run into a random power loss problem.
On some runs the engine had less power in the range of 4700 to 7400 RPM. The loss is around 10HP! Below and above this RPM range the power isn't different from other runs.

This happend when we worked on a different RPM range. (Very small changes in the RPM range below)

ECU is in open loop all the time, VTC seems to work (on the Hondata Sensors Screen the Cam position is the desired angle), VTEC works, too (at 5700 RPM, as we set). The A/F is dead on and the same as in the other runs, too.

Any ideas?

datalogs and calibrations showing the problem?

I experienced the same problem. While tuning, we shut the car off to check oil, and stuff. The next run, the car made a LOT more power with same air fuel ratio and same calibration, and it stayed like that.

I did not really investigate the issue, but I guess it could be related to a sensor of some sort reading false values or enourmous heat soaking.