Legacy loses Power on A/c

[rastapasta]

Hi All,

Is it normal for a N/A boxer engine such as mine to lose power fairly dramatically going up a mountain with the A/C (weather outside is 28-32 deg C)?? The same road with similar traffic conditions (ie none) and lower tempratures outside can be taken in 4th gear as opposed to 2nd when the temp is higher and the A/C is blasting.

Cheers

[gforceg]

I suppose it depends on the altitude but nevertheless hot air is a fair bit thinner than cold air. I didn't think modern a/c compressors took much power out of an engine but maybe it does. The two combined could cause a problem. Much difference in load onboard?

[darker grapefruit]

Subaru dealers have a plug-in ECU update for the Mk. 4 Legacy which solves the problem of poor idling/ engine cutting-out when the aircon is on. Not sure if this would also help in your circumstances (if you have a Mk. 4...).

[rastapasta]

gforceg said:

I suppose it depends on the altitude but nevertheless hot air is a fair bit thinner than cold air. I didn't think modern a/c compressors took much power out of an engine but maybe it does. The two combined could cause a problem. Much difference in load onboard?

No just myself. I did think about this alright with regard to fuel levels etc but no.

[rastapasta]

darker grapefruit said:

Subaru dealers have a plug-in ECU update for the Mk. 4 Legacy which solves the problem of poor idling/ engine cutting-out when the aircon is on. Not sure if this would also help in your circumstances (if you have a Mk. 4...).

Hi yeah its a mark 5 2014 model year so I would imagine that the update was incorporated into this ecu. Ill have the dealer look at it at the next service.