Can you estimate the altitude?

[Oliver53]

Here is a OBD data log of my xsara picasso. Can anyone estimate the altitude?

Note:
RPM - Engine speed in rev/min
VKPH - Vehicle speed in km/h
MAP - Intake manifold absolute pressure in kPa

[Chlorate]

Half a bar?
That's quite high indeed. 4000m above sea level? (according to some graph on t'internet)

Or is your air filter just blocked

Alex

[Oliver53]

Half a bar?
That's quite high indeed. 4000m above sea level? (according to some graph on t'internet)

Or is your air filter just blocked

Alex

Yeah, half a bar When engine speed is zero, manifold pressure equals to ambient pressure
Although the ambient pressure isn't a linear function of altitude, very roughly, every 1000m increase in altitude would results in 10kPa decrease in pressure.

The answer is, about 5000m

The exact altitude is 5250m, find it on the map:
http://nok.it/Z2Xp8

[Chlorate]

Blimy!
I bet that was interesting.
World's highest Xsara Picasso perhaps?

When engine speed is zero, manifold pressure equals to ambient pressure

That and when your throttle is wide open MAP won't be far off ambient.

[Oliver53]

Blimy!
I bet that was interesting.
World's highest Xsara Picasso perhaps?

When engine speed is zero, manifold pressure equals to ambient pressure

That and when your throttle is wide open MAP won't be far off ambient.

Yeah, indeed it was fantastic Not sure if it's world's highest Pic, but it seems a bit hard to find a place higher than that and still approachable by a Xsara Picasso

[Oliver53]

Where the data was logged...

[Chlorate]

Very impressed!
Did you have a video camera on that plane?

[Oliver53]

Very impressed!
Did you have a video camera on that plane?

I had a remote controlled camera with me. However, during the trial flight I found that there wouldn't be sufficient lift for a camera because the air is way too thin, and battery performance was poor at low temp. So I had to give up



Checking data...


I posted some pictures here:http://www.frenchcarforum.co.uk/forum/v ... 21&t=41986

[Chlorate]

That's a real shame, thanks for sharing though

Any more extreme Citroening coming up?

[SaabC5]

Any more extreme Citroening coming up?

I'm driving through Peckham next week, does that count?

[jgra1]

[cachaciero]

Very good you seem to have got the correct answer but I don't see how, my reading of the data is 200mBar when the engine revs are zero. and 200mB is a lot higher than 5000Metres even with a low QNH about 7000 metres higher. This of course is perverse as one would expect the pressure to be highest when the engine is stationary but never the less thats the way it appears. What have I missed?

cachaciero

[Chlorate]

It's not so much what the pressure is when the engine is stationary, but what the highest pressure the MAP sensor has logged. It doesn't matter how fast or slow the engine is going, in a NA engine the manifold pressure will never be higher than ambient...cylinder pressure is another story...

Note the 50mB plateau on the MAP graph to the right hand side, that correlates to engine and vehicle speed being zero for some time.

[cachaciero]

It's not so much what the pressure is when the engine is stationary, but what the highest pressure the MAP sensor has logged. It doesn't matter how fast or slow the engine is going, in a NA engine the manifold pressure will never be higher than ambient...cylinder pressure is another story...

Note the 50mB plateau on the MAP graph to the right hand side, that correlates to engine and vehicle speed being zero for some time.

Ah! got it! the thing I was missing was the extreme RH side of the data

cachaciero