Performance at high altitude
 

I previously owned a 2013 FR-S and traded it in a few years later. At the time I lived in south Florida where it was flat, straight and uninspiring. But now I live at 7000 ft and I can get to some fun roads in 15 minutes so my mind keeps wandering back to the twins.

Realistically how much power loss am I looking at? Does it matter and if so what can I do to mitigate it without having to go with forced induction?

Weight reduction?

https://www.google.com/search?q=powe...+high+altitude

~3-4% for every 1000' or so. Or if you want to be precise you can calculate the difference in oxygen:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1114067/

To mitigate you increase the power to weight ratio by reducing weight.

Density of air should be around 81%. Oxygen should be about the same percent of that as at sea level. I used an online calculator because I'm too lazy to do math.

So you are looking at a 20% loss in power since NA engines are limited by the amount of air they can take in, then add fuel to match.

FI is the only thing you really can do about it, as you will likely get 20% less returns from bolt-ons which mostly make airflow less restrictive.

I spent several winters in the mountains of Utah (6200 ft), and sure there was a power loss, but nothing ridiculous. You don't need much power to go downhill on a winding mountain road. You just need a chassis that can handle it!

I had a blast commuting. Maybe power is more important to you. But I got by just fine.

Add header and tune for compensate the loss, also on curvy roads you will not feel the difference

Change the FD ratio to 4.88 :)

To add to @Celica00 's post.

I found that roaming around the US and Canadian Rockies in my miata, that I could expect to lose about 25% power (by butt dyno) at the highest altitudes (14,000 ft).

After running with a miata (NC) for 8 years and my FR-S for 4 years, I found that that they pull about the same at altitude.

As Celica00 point out, even going up hill, in the curves at least, it's more about the chassis hanging onto the road than power.


humfrz

i had a noticeable dip in power at 8000 ft. i had to downshift where i'd normally not have to. no big deal.

A couple weeks ago I was at 6000' with me and my wife in the car and the power loss wasn't a big deal, I barely noticed it. The roads we were on were very winding and handling was more important than power. I did notice that the clutch and brakes felt a little harder though.

intake/header/tune stage 2 so that helps.

@humfrz That's a gorgeous turn.

Thanks!

The even more interesting curves on Pikes Peak were on the unpaved portions of the road ...... :burnrubber:

Do see the guardrails .... ?? No, .... why not ..?? Because there weren't none along there......:eyebulge:


humfrz

Every car around you and going the other way are operating under the same conditions.
Even the boosted ones. Ain't no bigg.

The hills *are* more fun though.

I was under the impression that turbocharged cars have notably less power loss at high altitudes in relation to NA?