Hondata

Vehicle: Lotus Elise Mk1 with Honda K20A + JSRC from a Euro Type-R
O2 Sensor: PLX SM-AFR wideband with Analog and Digital connection
Hondata KPRO4, bought from CPL Racing in May 2015, serial 40496
Honda ECU PRA 37820-PRA-E13 Serial 399261-4Y30
K-Manager Version 4.3.3.0

Hello !

I am trying to understand if and how compensation for elevation change is working.

I am currently in southern France driving over some of the regions highest mountains here for a few days. Today I was starting in the morning using a working calibration for my car at around 1000 meters (3000 feet) above sea level and drove up the col de la bonette. At the summit at about 2800 meters (about 9000 feet) the car was pretty much undriveable under full throttle.

I saw 10.0:1 AFR on the PLX gauge, the minimum the gauge is showing. In the valley the AFR on full throttle was about 12.0:1

The car smelled of petrol a lot.


So I was wondering it there is actually a compensation built into the ECU or the KPRO that should somewhat or completely make adjustments in such a case. The PA sensor had registered about 940 mbar of atmospheric pressure in the valley and close to 700 mbar at the summit. The road up this hill was about 10 miles long, so the changes in pressure appeared in a short period of time.

Is there a special procedure that I need to follow to enable this compensation ?


Thank you,

TC

By their nature speed density systems compensate for elevation changes. From your calibration I'd say that the 70 kPa region has not been tuned. There are big differences in the fuel tables between different cam angles, both on the low and high speed cams. But the thing that sticks out is that the high speed cam VTC table is really advanced at those pressure readings - 50 degrees.

Thank you for the feedback!
Will have a few regular runs to generate some logs for the adjustments tomorrow.


TC