Being that Speed was one of my primary criteria for picking a plane, choosing the SR22 Turbo seemed like a no brainer. Plus there is a lot of buzz around the SR22 Turbo and the idea of owning the “Turbo” of anything seems pretty appealing to me. I had also read from COPA members that Cirrus is selling more Turbos than non-turbo (about a 70/30 split). But I had a lot to learn about what Turbo means to an airplane engine. My first clue that something is different about turbo airplanes was that both the Turbo and normal versions of the SR22 have the same 310 horsepower. Huh? In cars, a turbo engine almost always has another 50 or more horsepower, so what’s the deal here? How could they have the same horsepower?
Then, I found this:
This graph shows the performance of the SR22 Turbo vs. the Non-Turbo. Seeing this graph totally blew me away because as you can see, the SR22 non-turbo actually OUTPERFORMS the SR22 Turbo below 10,000 ft Pressure Altitude. That was a major eye opener for me. I figured this data had to be wrong, but when I checked with the Cirrus sales rep, he did confirm the graph is accurate. Below 10,000 ft pressure altitude, you can expect to get the same or better performance out of the non-turbo SR22. Most SR22 owners don’t know that! Even fewer Turbo owners know about the performance difference.
I don’t know the details of how it works (maybe a reader can fill us in with a comment), but essentially, in airplanes, a Turbo engine can perform like it’s at sea level altitude, all the way up to its ceiling altitude. In the SR22 case, that’s 25,000 ft. So a Turbo SR22 could climb between 15,000 and 20,000 ft the same way it would climb from 0 to 5,000 (that’s the idea anyway). However, the extra weight and modifications to the engine to allow for the Turbo cause the sea-level performance of the Turbo to be significantly less than the non-Turbo. It makes up for this shortcoming as the airplane gains altitude. That’s way different than the performance improvement you can expect from a Turbo on a car. Could you imagine if a BMW M3 only performed well when you were on top of Mount Everest?
So contrary to popular belief, there are significant disadvantages to the SR22 Turbo, including:
- Worse performance below 10,000 ft Pressure Altitude
- Higher maintenance costs and more things that could go wrong
- Higher up-front cost (of approximately $60,000)
- The Turbo engine costs an extra 50 lbs which is deducted from the useful payload
Plus, for the real benefits of the Turbo, you need to be at oxygen-required altitudes. Although the SR22 Turbo GTS comes with built-in oxygen, I just don’t see myself or passengers ever wanting to use Oxygen for most of my travels. I suspect that most of the time, I’ll be right at that 10,000 ft level, so my performance benefits would have been near zero. My decision would have been totally different if either a) there was a pressurized cabin option or b) I expected to do most of my flying alone. But knowing that I want to use the plane largely for business travel and with other people, Oxygen would put a damper on the whole experience.
And that’s how I selected the SR22 GTS, Normally Aspirated engine.