Turbo-Normalized SR22 (Long)

Emailed Tim Roehl with Gami/Tornado Alley Turbos to find out more information about what it would take to turbo-normalize the Continental engine in the SR22. The first thing they need is customer #1 who would be willing to part with their SR22 for several months while the installation and STC are completed. There is a huge discount available not to mention the undying gratitude of Cirrus Owners everywhere. Won’t be me but rumor has it that some of the Cirrus owners have more than one plane in the hangar. Something to consider.
Beyond that, Tim needs several customers who are willing to commit to an installation once the STC is approved. Didn’t know much about TAT or the turbo-normalization process so I asked Tim a bunch of questions and thought I’d post them in case anyone was interested.
Tell me a little about the company.
We have three web sites http://www.gami.com>http://www.gami.com,http://www.taturbo.com and http://www.engineteststand.comDeakin on the subject but in short it is the addition of a turbocharging system to engine with limitation of MP to that which the engine would have available at sea level. Using an automatic wastegate, absolute pressure controller, and pressure relief valve, the system is easily operated much as one operates the NA engine, but the system is protected from overboost and maintains the MP to 20,000’ if desired. The system includes an intercooler.
What other modifications (cowl flaps, etc.) will you have to make to the plane?
We’ll have to see whether that’s necessary or not. Probably not, to meet certification requirements but we might consider some additional cooling provisions.
What will the conversion cost and how long does it take?
Probably about the same or less as our Bonanza conversions- $43,000 installed and it typically takes 3-4 weeks to complete.
How much does it weigh and how will that affect the W&B in the SR22?
It is 79 lbs in the Bonanza and will likely be heavier in the Cirrus. I’m not familiar with the CG conditions on the SR22. Send me your W & B and I’ll look at that. Sent Tim the POH.
Expected Performance, climb, cruise, etc?
Send me the performance tables and we’ll do some calculations. In our Bonanza, which is not as slick, we see 210 KTAS at 20,000 on 17.5-18 GPH and no cylinder hotter than 380F.
The SR22 is limited to 17,000 feet right now, will you try to increase that with the STC?
Depends on what is limiting it to that- I’ve had our V Tail to 33,000 still climbing- came home from AOPA at 27,000’ over the weather.
What about the future of 100LL. Cirrus has been reluctant to build a turbo-charged engine because of this.
Got that covered with our PRISM electronic ignition! It will run that or the same fuel without lead- octane = 92.
Any chance to do some concurrent STCs like built in O2 or increasing the take off and landing weight.
Just got our 115 cu. ft. built in system approved in the Bonanza. As for increasing the weight, we would like to but not sure if the BRS has been tested at higher weights, not optomistic.
Misc stuff like TBO, rebuild cost, shock cooling, speed brakes, etc.
TBO hours are the same and the cost will be slightly higher, maybe $5,000 more. As for shock cooling, it never gets hot so it is hard to shock cool. Won’t need speed brakes. Easy technique to allow for high rates of descent.
What sort of discount would be available for the test bed plane?
Significant discount, probably about $25,000.

That’s all the questions I thought to ask. I will forward this link on to Tim and hopefully he will monitor the discussion and be able to field questions or weigh in with any additional comments. If you want to email Tim directly here is his address troehl@gami.com.


As an SR20 co-owner I can only fantasize about the capabilities of a turbonormalized SR22… but I sincerely hope that some SR22 owners step to the plate and go for it! (My reasons are only partially selfless — I really want a ride!)

This would really be a remarkable airplane, and would be a serious competitor to the Lancair Columbia 400 (still under development).

Thanks for opening the door to such a project!


a turbo-normalized SR20 would also be fantastic. Would they go for this too?

Timm Preusser N747TG

The under powered 20 needs help more than the 22 and would have more of a market. Price would have to be well below the price difference between the two aircraft or else just opt for a 22.

Bob: Yu’ve got a lot more experience than I, so I ask this question with my total respect, what makes a plane underpowered?

I’ve seen for years that early models of aircraft are often considered ‘underpowered,’ and then post introduction powerplant upgrades make the plane acceptable to the aviation cognoscente. For insatnce the early 180 HP Cessna 177a was underpowered, but the latter C-177RG with the extra 20 HP was a terrific airplane. Likewise, the early commander 112s were underpowered, but the later 114s are OK.

My opinion was always that if the plane did not climb sufficiently, take-off performance lagged, or its useful load was inferior to aircraft in its class, it would be called ‘underpowered?’ Is this just an example of more power is always better?


For instance the early 180 HP Cessna 177a was underpowered, but the latter C-177RG with the extra 20 HP was a terrific airplane.
I think the 177A is actually pretty good — it’s the original 150-hp Cardinal (Model 177) that was definitely underpowered.

In this case there was a standard against which the 177 could be regarded as underpowered: the 172, which the Cardinal was intended to replace for the 1968 model year and which had the same 150-hp Lycoming O-320. The Cardinal looked faster than the 172, but it wasn’t. (Take a look at the frontal area of the Cardinal and you’ll see one reason why.) The original Cardinal’s climb rate was also the subject of much ill-natured hooting and guffawing by 172 pilots.

Cessna got cold feet and kept the 172 in production for 1968. They added 20 HP to the Cardinal for the next model year, and later added another 20 HP and retracted the gear. They haven’t had too many new ideas for single-engine piston airplanes since.


Marty- In jets it is called thrust to weight ratio. When I was flying the A7 it had a thrust to weight ratio of about 1 to 2. In other words lets say the engine provided 18,000 pounds of thrust and the plane weighed 36,000 pounds. This made for some long takeoff rolls and during air to air combat training you were good for about three high G turns before you were losing airspeed, altitude and ideas. Newer fighter aircraft have thrust to weight ratios in excess of 1 to 1. In other words they have more thrust available than they weigh. The Canadian F-18 demonstration pilots would walk the airplane around an airfield at extremely high angles of attack balanced solely on thrust rather than airspeed. This was very tricky to do but impressive. The most impressive part of the demonstration was after going all the way around the field he would get in front of the crowd use full afterburner and accelerate going straight up. I think that my SR-20 is just a little to heavy for 200 horses. It eats up a little more runway than other light aircraft on take-off. Not much more, just some. Coming across the United States a few months ago I met Casey Gilfeather in Billings Montana. We had dinner and told some lies and in the morning the weather was a little stormy. We decide to let him lead since he had a storm scope. On take-off the tower called him to see if something was wrong with his airplane since he wasn’t climbing very fast. When I took off I just told them I wouldn’t be climbing very fast either. This was not a hot day. Higher altitude flying in the 20 is like driving on the German autobahn in that it is not a spectator sport. You need to pay attention and have a plan for the unexpected. Coming out of Missoula Montana with a west takeoff you might want to climb several miles straight out before turning east and don’t take any vectors or short turns from ATC either. Just say unable and tell them what you are going to do. The guys out west are very accommodating. Much more so than New York Approach. My wife and I live at sea level and there are only two of us. The 20 will do us fine and I made that decision because of finances. But just East of us are the Cascades and I don’t jump over there without planning. I think that we may want to emphasize higher altitude or mountain flying into CPPP a bit more in the future as an adjunct to the weather module.

In reply to:

Higher altitude flying in the 20 is like driving on the German autobahn in that it is not a spectator sport. You need to pay attention and have a plan for the unexpected.


Unfortunately, it appears the accident record proves exactly what you’re saying. [:(]