Does the stock K-series ECU have a table by which it adjusts fuel based on altitude (i.e. atmospheric pressure)? Is such a feature upcoming or under consideration for K-Pro/K-Manager? I am just wondering how well my vehicle would handle a drive from where I am (2300 feet above sea level) down to sea level.
Thanks.
Ben
Altitude
Thanks for responding.
Please bear with my ignorance.
Intuitively that makes sense, but at the same time a calibration that I had running perfectly on my car was giving another EP owner lean-cuts like crazy at sea level. I had reasoned that it was due to the greater air density at sea level compared to where I am (1730 ft)...i.e. that the relationship isn't straightforward/linear.
Couldn't you argue by the same token, then, that temperature compensation tables aren't necessary as the greater density of cold air would be reflected in both the atmospheric pressure and MAPs being higher (i.e. relative shift in all points)? My understanding was that the relationship between temperature, air density and air pressure isn't linear or otherwise straightforward, making further compensation based on IAT necessary. I was wondering if in the same way the relationship between altitude, air density and air pressure was also such that further compensation based was necessary and/or present. I don't know if this even makes sense.
Recently I also read in someone's notes from one of your seminars that the calibrations (part throttle sections) have to be tuned for higher altitudes. I can email or PM you the link if you like.
Thanks again.
Ben
Please bear with my ignorance.
Intuitively that makes sense, but at the same time a calibration that I had running perfectly on my car was giving another EP owner lean-cuts like crazy at sea level. I had reasoned that it was due to the greater air density at sea level compared to where I am (1730 ft)...i.e. that the relationship isn't straightforward/linear.
Couldn't you argue by the same token, then, that temperature compensation tables aren't necessary as the greater density of cold air would be reflected in both the atmospheric pressure and MAPs being higher (i.e. relative shift in all points)? My understanding was that the relationship between temperature, air density and air pressure isn't linear or otherwise straightforward, making further compensation based on IAT necessary. I was wondering if in the same way the relationship between altitude, air density and air pressure was also such that further compensation based was necessary and/or present. I don't know if this even makes sense.
Recently I also read in someone's notes from one of your seminars that the calibrations (part throttle sections) have to be tuned for higher altitudes. I can email or PM you the link if you like.
Thanks again.
Ben
The ECU will use a different column at sea level than at altitude, but it is self-compensating. If you have a vehicle running lean at sea level, then columns 9 & 10 need more fuel.
MAP pressure does not measure density. If a given volume of air is heated, using PV=nRT, the number of gas molecules (n) per unit volume must decrease as temperature increases (number of molecules per volume is density). The pressure stays the same as the air is not heated in an enclosed volume. For a more detailed explanation, there are 1000's of references to the ideal gas law on the internet.temperature compensation tables aren't necessary as the greater density of cold air would be reflected in both the atmospheric pressure and MAPs being higher
Hondata
I think you've misunderstood both what I was saying and what I was asking -- I suggested a relationship between density and MAP, but not that MAP was a reflection of density -- but that's ok. The question probably wasn't worth asking in the first place. Just to clear one thing up, though, we *did* understand that he was running lean (hence my stating that he kept getting lean cut) and we *did* understand how to fix that problem (increasing fuel). The question was really as to *why* he was running lean, but I guess the obvious answer is that his car isn't a carbon copy of mine and therefore isn't going to run the same as mine. I can accept that. I'll just have to give it a go and drive from here (1730 ft) to Vancouver (sea level) one of these days and see. Anyway I'll post up when this experiment's done. Thanks.