Tuned Exhausts

L

lhaight

New member
I have had a 150 hp Decathlon since 1989. It worked great while I was in Illinois, but out here in Santa Fe (el 6348) it's a little anemic.

I've been following the development of tuned exhaust systems by Powerflow Systems, and I sure could use one on my plane. However, they are naturally interested in getting STCs for the more numerous aircraft--C172s, PA28s, etc., and it appears it will be a long time before they get around to Citabrias and Decathlons.

Technically, I wouldn't think this would be much of a challenge; they already have developed a system for the Lyc O320. It would seem the parts should fit pretty easily with some modified support for the muffler. The sticking point is undoubtedly the cost of proving the new installation to the FAA.

Is anybody else out there interested in pursuing a tuned exhaust system for 150 hp Citabrias and Decathlons? Perhaps we could petition Powerflow Systems, or ask the Bellanca Champion Club to weigh in with them?
 
I think a tuned exhaust is a great idea but I also feel we should be pursuing the 4 in 1 system used on most high performance aerobatic planes.

It would probably be cheaper and at least as effective.

Bill French
Decathlon C-GJXT
 
It would probably be cheaper and at least as effective.

Plus it would look better then the muffler hanging out. After seeing a 172 land with the muffler hanging by the support strap and beating up the cowling I would think twice.

The power upgrade I would like to see is a 160 HC for the 8kcab.

Doug
 
Powerflow seems to have two types of exhaust; one has the ridiculous muffler hanging off the bottom of the cowl... the other, just has a bigger than stock stack! The Husky and C-177 have the stack only!
Since these are already STC'd, how hard would it be to get a field approval on a Citabria?
Also, someone mentioned the "aerobatic" systems would possibly be better... I will disagree with that statement. I've seen many of those acro systems and owned one of them on an Eagle 2. They are a 4 into 1 design, but DO NOT have equal length primaries; this in turn eliminates the "tuned" effect of the exhaust system. They sure do make a lot of noise though!
Sergio
 
Don't underestimate the efficency of the Elano design. I am serious. It just lacks 'hype'.
The shorter tube extend into the collector thus having an equal length effect. These airplanes that showed large gains, all had poor exhaust to start with. Don't compare an apple and an orange. Sure, one of Powerflow's systems might add some horse power, but what if it only adds 2 HP? That worth the $6000? Only way to truely know is to do saw tooth climbs before and after; then reduce the data to standard day conditions. Beware anyone who flew it on a warm day at 1pm, then flew the new setup at dawn/dusk on a cold day.

TLDR: Until I see real data, I don't buy it.
 
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