Barometer capability

[Bzogg]

First I’m apologizing if I’ve asked this question already, but I’m new to posting in forums. I would like to know if there is limitations to the elevations the barometer can work at? I was told well beyond 15,000 ft. The follow up question is the response time for mixing the fuel when traveling from sea level to, say 7,000 ft?
Thank you, in advance
Zog

[icarp]

3% loss of power per thousand feet, so maybe every 150-300 feet, about that,
this is due to the loss of o2, density altitude.

[GH85Carrera]

What roads are you expecting to get to 7,000 feet?

I have driven to the top of the Rocky Mountains National park which is 14,140 in my 85 911. It ran fine, but it felt like I was pulling a trailer with the lack of power. 7,000 feet will not be a big issue, but you will be down on power.

[spuggy]

Garret says in Turbocharging At Elevation:

As a general rule, a naturally aspirated combustion engine will lose 3% of its power for every 1,000 ft of elevation gain. If you have 100 horsepower at sea level by the time you get to 5,000 feet of elevation your engine is making 85 horsepower.

At 10,000 feet of elevation your engine will make 70 horsepower.
At 15,000 feet of elevation your engine will make 55 horsepower.
At 15,000 feet of elevation your engine will lose 45% of its power due to lower air density.

Forced inductcion is widely used by competitors at Pike's Peak, of course - surprised more folks living at or driving to serious altitudes aren't all over forced induction - as that was how they addressed this problem for aircraft 100 years ago Turbochargers: A History:

Also during the early years, aircraft engines were being set up with ‘chargers to test their benefits at altitude. In 1918, General Electric engineer Sanford Alexander Moss attached a turbocharger to a V-12 Liberty engine and demonstrated it a Pikes Peak in Colorado at 14,000 feet. He showed how forced induction counters the power loss brought on by the effects of reduced air pressure and density at high altitude. Two years later, a turbocharged 12-cylinder Liberty was mounted in a Le Pere biplane and flown to 33,000 feet with no loss of boost.

There are sizing/compressor map efficiency considerations as the "best" turbo for your motor at sea-level likely won't be the one that'll work "best" at the top of Pike's Peak, and a speed sensor can be useful to ensure you don't over-speed the turbine shaft - but it's all well established/understood tech at this point..