Power loss calulator or factor needed for density altitude

[RAAMaudio]

I am at 5200 ft but tuning is being done with the density at 6900, looking for the factor or calculator used to calculate loss in a turbocharged engine. We have pretty thin air and have been tuning in 90 degree ambient temps, I want to find out how much loss I am having over denser and sea level air.

I have used quite a few terms to search but just not the right one it seems.

Thanks
Rick

 

[D1JL]

Doesn't the car's barometric sensor compensate for air density?
Therefore shouldn't the PCM automatically adjust when you apply your tune to the car?




Dave

 

[RAAMaudio]

Great question, I am asking because Russ is tuning the car and said that is the figure he looked up for my area so I just want to get a realistic idea of how much power loss I am having. I guess I could of asked Russ, just thought of that

Thanks,
Rick

 

[Sekred]

I don't think you will find a calculator for a turbocharged engine. You could try searching turbocharged piston aircraft engines and may find some info.
A N/A engine is around 3% peak power loss per 1000ft.
With your turbocharger as air density decreases the turbine needs to spin faster to maintain your target boost pressure which causes increased efficiency losses.

 

[RAAMaudio]

You are correct, the threads I have found refer to piston engine aircraft but none show any kind of numbers to go on.

I just made a run and not bad for the altitude and thin air here, VD shows 280 WHP and 273 FT LBS at 24.3 PSI and it is no slouch and more tuning to go to smooth things out in the middle of the power curve and hopefully more bottom end, a bit laggy right now. I will post the VD stuff when things get better.

Thanks, I will keep looking,
Rick