A bit of performance loss is to be expected when the air conditioning is running, but at what point would it be indicative of a problem?
There's a steep hill I drive from time to time. With no AC I can get up it comfortably in 2nd gear, with some ability to accelerate. With AC on, 2nd gear isn't possible without a running start. (320i vert).
AC Power Loss
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Cloggy Saint
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I don't ever use my AC for this reason. I can't say I've ever struggled to climb a hill but the power loss is noticeable. That coupled with the overly raised idle just makes it a pain. I guess it's fairly primitive technology.
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That is why they went with variable displacement pumps in the later cars. I am trying to use the AC pump that came with the M54B30 because it is variable displacement and talks to the engine DME. High rev and high load it lowers A/C and all other times it varies the engine with A/C demand,coopman wrote: ↑Tue Jun 06, 2023 2:11 amA bit of performance loss is to be expected when the air conditioning is running, but at what point would it be indicative of a problem?
There's a steep hill I drive from time to time. With no AC I can get up it comfortably in 2nd gear, with some ability to accelerate. With AC on, 2nd gear isn't possible without a running start. (320i vert).
Mind you not sure you really notice it on M54b30 too much compared with a M20B20
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Tzantushka
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Sounds like you might be down on power even before the A/C is switched on… at least you have a manual?
The original Bosch Behr compressor does have a perceptible drain on the engine when engaged compared to more modern wobble plate or variable displacement compressors…
But not being able to make it up the hill with it on sounds like more than a few hp being sucked away from the A/C compressor.
Probably worth checking everything else is tidy and within spec.
Example: plugs, leads, coil, filters, injectors, vac leaks, even sensors that feed your DME / ECU i.e. blue temp sensor, AFM and especially the TPS.
The original Bosch Behr compressor does have a perceptible drain on the engine when engaged compared to more modern wobble plate or variable displacement compressors…
But not being able to make it up the hill with it on sounds like more than a few hp being sucked away from the A/C compressor.
Probably worth checking everything else is tidy and within spec.
Example: plugs, leads, coil, filters, injectors, vac leaks, even sensors that feed your DME / ECU i.e. blue temp sensor, AFM and especially the TPS.
It's a big hill. Up from a beach in Sydney, so hot/humid air might not be helping things.
Plugs, leads, coil, filters are all good/new.
Injectors are probably original and in terrible condition.
Vac leaks were a big problem - every hose and connection was buggered. I've fixed things up, but might have missed something.
AFM is fine. Blue temp sensor and TPS need checking.
Plugs, leads, coil, filters are all good/new.
Injectors are probably original and in terrible condition.
Vac leaks were a big problem - every hose and connection was buggered. I've fixed things up, but might have missed something.
AFM is fine. Blue temp sensor and TPS need checking.