aircon vs full throttle

[RallyD]

my 525i does not turn the compressor clutch off during WOT,
every other car I have owned did shut down the compressor.

Its more about luxury than being the first one there, i guess.

[pingu]

Eh? The a/c gives, in effect, some extra friction to the engine. The torque (i.e. energy) that gets used up in overcoming this a/c friction can't be used to drive the dyno and thus won't be measured by the dyno. Or did you mean something else?

[pingu]

That's so impressive I want to make sure I've not missed something:

- the 540 M60 is spec'd at 286 bhp.

- and a 540 with 270,000km (about 160,000 miles) still manages to achieve about 286 bhp?

Impressive - and good to know!

[Jan]

That's so impressive I want to make sure I've not missed something:

- the 540 M60 is spec'd at 286 bhp.

- and a 540 with 270,000km (about 160,000 miles) still manages to achieve about 286 bhp?

Impressive - and good to know!

You have not missed anything

This is my second 540 and the other one as dynoed at 285,1hp and 398nm, with about 250.000km.

[Jan]

how are they correcting the dyno reading to give you the numbers at the crank? because obviously, it's not 285 at the wheels.

During deacceleration, it measures the loss in trans etc. and then add that to the reading, to give crank hp and torque.

[genphreak]

Eh? The a/c gives, in effect, some extra friction to the engine. The torque (i.e. energy) that gets used up in overcoming this a/c friction can't be used to drive the dyno and thus won't be measured by the dyno. Or did you mean something else?

... FW(L)IK.... the ECU shuts down the AC when it so chooses... and on the Motronic 1.3, I am sure this means near and at WOT only.

[pingu]

Did you done anything (e.g. cleaning up the intake manifold) to the engines other than just routine replacement of oil/filters?

My car has had no major work other than routine stuff (oil, filters, thrust arm bushes etc). Those figures are so impressive I just want to make sure that they would apply to me!

Thanks!

[Ross]

I don't think so. Many cars, especially little wheezers like the 525 shut off the a/c compressor under large loads. I'm not sur what determines when but would guess it's tied to the vacuum signal.

[Guapo]

I don't think so. Many cars, especially little wheezers like the 525 shut off the a/c compressor under large loads. I'm not sur what determines when but would guess it's tied to the vacuum signal.

I'd be more inclined to think it'd work off throttle position sensor voltage. I don't know about the BMW, but my 300ZXTT does shut off the compressor at WOT.

[Jan]

Did you done anything (e.g. cleaning up the intake manifold) to the engines other than just routine replacement of oil/filters?

My car has had no major work other than routine stuff (oil, filters, thrust arm bushes etc). Those figures are so impressive I just want to make sure that they would apply to me!

Thanks!

I am working on a new M62/S62 engine, so I just do routine replacements on the engine in the car.