Power at High Altitude

[Lelandjt]

I don't think I'll be able to test drive a new BRZ/86 above 6000ft, and that would require a 2hr drive each way to a dealer. I do nearly all my driving between 9,000 and 11,000ft. My last sports car was a turbo and my NA cars (2.2l Impreza, 3.6l Ford Transit, 2.0l Mazda 3) have all felt torqueless. In the videos of the new twins (shot near sea level) we see them effortlessly powersliding out of turns, presumably in 2nd gear, but I'd love to hear that these are done in 3rd gear. What kind of power loss can I expect above 9,000ft? Will this car have the power to slide around and can it accelerate as well as the average mom-mobile? I really don't want to do aftermarket forced induction. I want a sub-3000lb sports car with enough power to hoon and not feel slow relative to the average modern car but I suspect I need a turbo and that means either a 3000+lb Por$che or a 3400+lb Nissan.

[MuseChaser]

If your desire is to be a be able to throw the back end around, why not just use less grippy or slightly worn tires?

[Pete]

I can't speak directly about the twins, but a few years back I drove my 06 Cayman S to Colorado and most of the way up pikes peak. (the very top was closed due to it being unseasonably snowy up there still) Coming from near sea level in Texas to the mile high city already made the Cayman feel positively anemic. On the way up the mountain it felt more like a Miata lol. The power loss for NA cars at altitude is striking. If you are really looking for power to slide around at 9000'+ in my opinion I'd say you will want to do aftermarket FI or just buy something else. Maybe wait and see how the new Z drives.

[dragoontwo]

Originally Posted by Lelandjt

I don't think I'll be able to test drive a new BRZ/86 above 6000ft, and that would require a 2hr drive each way to a dealer. I do nearly all my driving between 9,000 and 11,000ft.

Your best bet is likely to wait for the aftermarket and install a low boost turbo(or supercharger). Or get an older twin and do the same. Altitude = less air and less fuel. You will be down on power.

[Baldeagle]

Originally Posted by Lelandjt

I don't think I'll be able to test drive a new BRZ/86 above 6000ft, and that would require a 2hr drive each way to a dealer. I do nearly all my driving between 9,000 and 11,000ft. My last sports car was a turbo and my NA cars (2.2l Impreza, 3.6l Ford Transit, 2.0l Mazda 3) have all felt torqueless. In the videos of the new twins (shot near sea level) we see them effortlessly powersliding out of turns, presumably in 2nd gear, but I'd love to hear that these are done in 3rd gear. What kind of power loss can I expect above 9,000ft? Will this car have the power to slide around and can it accelerate as well as the average mom-mobile? I really don't want to do aftermarket forced induction. I want a sub-3000lb sports car with enough power to hoon and not feel slow relative to the average modern car but I suspect I need a turbo and that means either a 3000+lb Por$che or a 3400+lb Nissan.

Here is one approach to answer your question. The Earth’s atmosphere is about 21% O₂. A shown in the link below, at 10,000 feet elevation the effective O₂ percent is 14.3%. That implies a 32% decrease and confirms the rule of thumb that O₂ decreases by about 3% for every 1,000 foot increase in elevation.

https://hypoxico.com/altitude-to-oxygen-chart/

A 32% decrease in O₂ implies a 32% decrease in power. If the new twin has 228hp and 184 lbs-ft of torque at sea level, it will have about 155 hp and 125 lbs-ft of torque at 10,000 feet. If you want to extend this thought process further, the website below estimates ¼ mile times and speed based on car's weight and HP.

https://robrobinette.com/et.htm

As a baseline, it estimates that a 2,900 pound car with 228 flywheel HP should complete the quarter mile in 14.1 seconds at 101 mph. (That might be a little optimistic based on other estimates for the 2022 twin, but still very close.) Using the same set of underlying assumptions, a 2,900 pound car with 155 hp (equivalent to 10,000 feet of elevation) should complete the quarter mile in 16.0 seconds at 89 mph, which is consistent with a car that needs about 8 seconds to reach 60 mph. Compared to a 6.0 second 0-60 time at sea level, it will feel much slower. Only you can determine if 8 seconds to 60 mph is too slow for your needs.

[Pete]

Originally Posted by Baldeagle

Here is one approach to answer your question. The Earth’s atmosphere is about 21% O₂. A shown in the link below, at 10,000 feet elevation the effective O₂ percent is 14.3%. That implies a 32% decrease and confirms the rule of thumb that O₂ decreases by about 3% for every 1,000 foot increase in elevation.

https://hypoxico.com/altitude-to-oxygen-chart/

A 32% decrease in O₂ implies a 32% decrease in power. If the new twin has 228hp and 184 lbs-ft of torque at sea level, it will have about 155 hp and 125 lbs-ft of torque at 10,000 feet. If you want to extend this thought process further, the website below estimates ¼ mile times and speed based on car's weight and HP.

https://robrobinette.com/et.htm

As a baseline, it estimates that a 2,900 pound car with 228 flywheel HP should complete the quarter mile in 14.1 seconds at 101 mph. (That might be a little optimistic based on other estimates for the 2022 twin, but still very close.) Using the same set of underlying assumptions, a 2,900 pound car with 155 hp (equivalent to 10,000 feet of elevation) should complete the quarter mile in 16.0 seconds at 89 mph, which is consistent with a car that needs about 8 seconds to reach 60 mph. Compared to a 6.0 second 0-60 time at sea level, it will feel much slower. Only you can determine if 8 seconds to 60 mph is too slow for your needs.

Wow! Nice breakdown!

[Lelandjt]

Originally Posted by MuseChaser

If your desire is to be a be able to throw the back end around, why not just use less grippy or slightly worn tires?

I would definitely get the less grippy tires instead of the optional PS4Ss.

[Lelandjt]

Originally Posted by Baldeagle

Here is one approach to answer your question. The Earth’s atmosphere is about 21% O₂. A shown in the link below, at 10,000 feet elevation the effective O₂ percent is 14.3%. That implies a 32% decrease and confirms the rule of thumb that O₂ decreases by about 3% for every 1,000 foot increase in elevation.

https://hypoxico.com/altitude-to-oxygen-chart/

A 32% decrease in O₂ implies a 32% decrease in power. If the new twin has 228hp and 184 lbs-ft of torque at sea level, it will have about 155 hp and 125 lbs-ft of torque at 10,000 feet. If you want to extend this thought process further, the website below estimates ¼ mile times and speed based on car's weight and HP.

https://robrobinette.com/et.htm

As a baseline, it estimates that a 2,900 pound car with 228 flywheel HP should complete the quarter mile in 14.1 seconds at 101 mph. (That might be a little optimistic based on other estimates for the 2022 twin, but still very close.) Using the same set of underlying assumptions, a 2,900 pound car with 155 hp (equivalent to 10,000 feet of elevation) should complete the quarter mile in 16.0 seconds at 89 mph, which is consistent with a car that needs about 8 seconds to reach 60 mph. Compared to a 6.0 second 0-60 time at sea level, it will feel much slower. Only you can determine if 8 seconds to 60 mph is too slow for your needs.

That's a very mathematical and definitive way of confirming what I already strongly suspected. I really want a new Twin and was desperately hoping they'd offer a turbo. Unfortunately, I think I'll be disappointed with any NA sports car up here. I really want my last ICE car to be really refined and efficient so that writes off aftermarket FI in my book. Though I'll still try to test drive a Twin down in Denver I'll probably buy a Nissan Z or maybe Cayman 2.5T.

P.S. Yesterday a C8 Z06 in heavy leather disguise was parked in the small lot my Breckenridge bike shop shares with a breakfast joint. The altitude is so extreme here we frequently see manufacturers doing final testing and calibration of near production ready vehicles. I asked the two guys eating on the patio if it's a Z06. They winked and said, "Could be." I replied, "I bet it'll be obvious when you fire it up." They laughed. 15 minutes later I heard what sounded like a Ferrari start up and that solidified it. Maybe that NA engine would have enough power to spin the tires up here...

[Pat]

You own the shop next to the brewery? I've been in there a few times.

[Lelandjt]

Originally Posted by Pat

You own the shop next to the brewery? I've been in there a few times.

I don't own Avalanche Sports but they've sponsored me for 20 years and I've wrenched for them 10 years. Great spot to hang out on the edge of town.

[Pat]

Originally Posted by Lelandjt

I don't own Avalanche Sports but they've sponsored me for 20 years and I've wrenched for them 10 years. Great spot to hang out on the edge of town.

Ahh, gotcha. Or what used to be the edge of town. My family has had a place at the Ski & Raquet Club just up the hill since the early 90s.

[Baldeagle]

Originally Posted by Lelandjt

That's a very mathematical and definitive way of confirming what I already strongly suspected. I really want a new Twin and was desperately hoping they'd offer a turbo. Unfortunately, I think I'll be disappointed with any NA sports car up here. I really want my last ICE car to be really refined and efficient so that writes off aftermarket FI in my book. Though I'll still try to test drive a Twin down in Denver I'll probably buy a Nissan Z or maybe Cayman 2.5T.

Yes. The ability to drift or pull out of turns is best described by trap speed. Given that the new twin will realistically trap around 98-99 mph at sea level, if it loses 12 mph in trap speed at 10,000 feet, the twin will probably have a trap speed equivalent to 86-87 mph up there. That’s not quick enough for most enthusiasts. The new Z and Cayman are obvious options. If you are open to AWD, the lasted generation 6MT Golf R may be another. Best of luck…

[Lelandjt]

Originally Posted by Pat

Ahh, gotcha. Or what used to be the edge of town. My family has had a place at the Ski & Raquet Club just up the hill since the early 90s.

Ha! My condo is the building at the bottom of the steep trail that comes down through the woods from the Ski & Racquet pool house. In fact my unit is the stairs directly in front of the trail. Hi neighbor.

[Pat]

Whoa. I've walked (or in many cases stumbled) along that trail many times over the last 30 years.