Tuning for Coast or Altitude

[mps_za]

See my sig, i'm from south africa and have the european spec mazdaspeed (mps)

I want to install a tune, but this tune was developed at a high altitude, 2000m (6500 feet) above sea level. As i stay at the coast i want to know if this is safe and what to look out for. I already heard that a tune for high altitude may run leaner, and that some experienced worse performance at sea level with this even though the air has more pressure. What I dont know is if the tendency for knock is increased, or if the ECU automatically make the corrections. I am running 95 octane (unleaded ULP). I dont plan to run 98 octane as its too expensive and hard to find.

The pressure going from 6500 feet to 0 would relate to a difference of 4 psi of atmospheric pressure. As well as increased humidity ie water particles (vapor) in the air.

This tune is been tried and tested at the high altitudes but not at the coast, I want to know if it is safe.

 

[eg6motion]

I would say NO. A tune developed at sea level, that is then used at High altitude would be "safer" although generic tunes are rarely the best option.

 

[JAPMUSL]

It is safe to run a sea level tune in high altitude, you will just see lower boost.

If you run a high altitude tune at sea level it is unsafe. You will be maxing out your map sensor and seeing 22.X PSI

 

[mr_mazda329]

It is safe to run a sea level tune in high altitude, you will just see lower boost.

I thought at higher altitudes, the boost will be the same, just more lag cuz its harder to hit the target boost and the turbo has to spin faster than usual. Isnt this why Hillclimb cars use turbos instead of superchagers.

Looks like i am off to the mountains.

 

[mps_za]

I thought at higher altitudes, the boost will be the same, just more lag cuz its harder to hit the target boost and the turbo has to spin faster than usual. Isnt this why Hillclimb cars use turbos instead of superchagers.

Looks like i am off to the mountains.

Thanks guys, this answers my questions/suspicions. What i heard or understand is the turbo still makes the requested boost but works a little harder to achieve it at altitude. However the absolute pressure in the cylinder is more at the coast (increased coastal pressure) placing the fuel under more pressure and increase the tendency for knock, as well as more dense air leaning out the mixture. But i wanted to know if it is just me being paranoid.

 

[JAPMUSL]

Thanks guys, this answers my questions/suspicions. What i heard or understand is the turbo still makes the requested boost but works a little harder to achieve it at altitude. However the absolute pressure in the cylinder is more at the coast (increased coastal pressure) placing the fuel under more pressure and increase the tendency for knock, as well as more dense air leaning out the mixture. But i wanted to know if it is just me being paranoid.

The fix for higher altitude is more boost. In our situation more load.

That same amount of load at a lower altitude is gonna give you problems.

at 1k or below Ill get 19-20 PSI and hit my requirements, but at over 5k I will be lucky to hit 17