Grumman AA5 above s/n 641 & AA5-A (O-320)

Bolt-On Horsepower. Complete replacement of your stock exhaust system. FAA approved by STC for later model AA5 Travelers (those with airframe serial numbers above 641) and all AA5A Cheetah aircraft with Lycoming O-320 engines.


New as of March 2018 - EASA individual aircraft STC basic approval now available.

Grumman’s AA5 series airframes are undoubtedly among the sportiest looking and handling aircraft in GA’s line-up. Unfortunately though, the stock exhaust system Grumman originally installed on the airframe’s rock solid Lycoming O-320 engine leaves these otherwise fine aircraft (and their owners/pilots) struggling to keep up appearances!


Power Flow offers you the perfect, cost-effective solution to this problem: Our “Bolt-On Horsepower” Tuned Exhaust System adds an immediate 10 - 15 Horsepower to the O-320’s output by virtually eliminating the loss caused by the restrictive design of the aircraft’s stock exhaust system. Here’s what you can realistically expect from that extra horsepower:


  • An increase of 30 – 130 rpm in static thrust
  • A take-off roll that is 100’ to 300’ shorter
  • An improvement in the aircraft’s rate of climb by 100 – 150 fpm
  • CHT’s that are 15 F – 30 F cooler across the board.
  • Reduced Fuel Burn (.5 – 1.5 gph) at equivalent cruise speed
  • A Service Ceiling that is 2,000’ – 5,000’ feet higher, with a corresponding improvement in performance at higher density altitudes

Don't just take our word for it - listen to what just some of our happy Power Flow customers have to say about the Power Flow tuned exhaust system on their aircraft:

You can also click on the "Reviews" tab near the top of this page and see other reviews and view more videos.


So, if you like your AA5’s sporty good looks, economy, and handling, but could stand to be a little more pleased with its take-off and climb performance, you will find our Tuned Exhaust to be a very cost-effective and worthwhile upgrade.


The Power Flow is a versatile, quality constructed, complete replacement of your entire exhaust system. The entire system is constructed of 321 grade stainless steel and includes minimal structural welds in the cabin heat section for improved safety.


All necessary parts are included for easy installation on your AA5 or AA5A. Our customers report an average install time of between five and nine hours. The system can be installed by one of our dealers, by your local A&P, or you can fly your plane to us for a local installation. Fly in with a standard Grumman, fly out (usually the same day) tuned for performance.


Our industry leading 60 day money back guarantee means that if for some reason you don’t see the performance benefits listed above on your Grumman (or even if you do but you just don’t like all that extra horsepower), you can return the system to us within 60 days of its installation for a full refund of your purchase price. Fine Print? You just read it.


Price for AA5, S/N 641 and above, and all AA5A with Lycoming O-320 Engine:


$4,650.00 with Polished Tailpipe / $4,850.00 with Ceramic Coated Tailpipe.


Polished or Ceramic?


The Ceramic Coated tailpipe is a cosmetic enhancement that hides the heat induced discoloration that is characteristic of stainless steel (think of the "bluing" you see on the muffler of a motorcycle).


This discoloration has absolutely no effect on performance or reliability but the ceramic coating covers it up permanently. Otherwise, the polished tailpipe begins to discolor after a few hours of flying time.


It can be re-polished anytime, but if you are proud of your Grumman’s appearance and would rather spend your time flying than polishing, the ceramic is a nice feature to have.


A couple of other important pieces of information:


#1.) We strongly recommend that the aircraft's propeller be dynamically balanced to within 0.2 ips (inches per second) upon installation of the Power Flow System and every two to four years thereafter. If the propeller is dynamically balanced within 25 flight hours of the installation of the Power Flow System and you furnish PFS with copies of the logbook entries confirming this, PFS will extend the warranty on the Tuned Exhaust System from 12 months to 24 months or 500 Flight Hours (whichever occurs first).


Doing so every 2 - 4 years thereafter will dramatically improve the useful life and the reliability of every component that is bolted to the engine, including the Power Flow System.


#2) The Power Flow System has no service life limit. It is designed and built to last several thousand flight hours and will quite likely be the last exhaust system you need to buy for your aircraft. As with any high performance system however, it must be maintained properly. Every 500 flight hours or annually (whichever comes first) the four slip joints on the system must be cleaned and lubricated with high temperature anti-seize compound.


Most Customers have this maintenance performed during the aircraft's annual inspection which adds about 2 hours of labor to the inspection. We have had several of our Tuned Exhaust Systems rack up over 4,000 flight hours of trouble free performance (7,000+ flight hours is the current record in a commercial operation) as long as this maintenance is performed as required.


Still not sure if a Power Flow is right for you and your airplane? For complete peace of mind, check out our:

Click the RFG graphic above for more details.