ethernectar

So I went for a drive today up over Tioga Pass (Hwy 120, Yosemite NP) and its pretty close to 10K' elevation. I started to notice it really at around 8K' - pretty sluggish in the bottom end. Like it wanted much more throttle than normal from a start. On the drive back I paid more attention to it and it seemed to go away around 5 or 6K elevation.

Is this normal for a turbo?

PikkaGTR

iTrader: (4)

higher elevation means lesser air density
I'm sure you'll notice this with an NA car as well
an engine is nothing more than an air pump---less air less efficiency

impreza-tux-121

I live in Minnesota does that count?

Wingless Wonder

iTrader: (7)

This is normal for any internal combustion engine. That's the reason why turbocharging and supercharging are often desirable for small aircraft using car engines. Air becomes less dense with altitude. Engine management can compensate to a degree by leaning out the fuel to maintain correct stoichiometric ratio, but with less air (oxygen) in the cylinder, it's gonna make less power. Yes, it's normal to have to put your foot into it deeper as elevation increases.

If you look at ¼-mile elapsed times and mph trap speed for any given car, the performance will suffer at high altitude drag strips. Irwindale drag strip in southern California is at 250 feet above sea level, while Bandimere drag strip in Colorado is located 5800 feet above sea level. Thin air does more than affect power - it also reduces downforce on cars with aerodynamic aids.

Race cars that traverse mountainous terrain such as the World Rally Championship in the Mexican Rally and the Pikes Peak Hill Climb must spend a lot of time calibrating their engine controls for maximum power and reliability as they ascend the mountain.

ethernectar

Thanks, so does it make sense that when its rainy here (at sea level +100') the car feels a little punchier? Or is that just my newfound pleasure at the sight/sound of rain falling?

Wingless Wonder

iTrader: (7)

Cooler air is more dense and makes more power, hence the reason why factory turbo cars have intercoolers.

Humidity does not add power - it displaces the oxygen content of air and does not act like a water injection unit, which should be calibrated to work in conjunction with engine management tuning.