Author Archives: Darren Tilman

20 years in business & kudos from a customer

Happy New Year to One and All!

We are proud to announce that 2019 marks Power Flow’s 20th year in business and that we now have over 5,400 of our “Bolt-On Horsepower” Tuned Exhaust Systems installed and flying worldwide.  

Delivering a great product that meets or exceeds our Customer’s expectations is an important part of what do, but we truly believe that it is the service after the sale that really sets us apart.

We recently received unsolicited feedback from a customer whose Cessna 172 is used in a busy flight school and who needed a replacement part. He initially contacted us and told us that his technician would be calling or sending us pictures of the needed component.  But when a day went by with no follow-up, we took it upon ourselves to “close the loop”and called the owner / Customer back. We were able to figure out what was needed, sent the part out within 45 minutes and gave him our newly discounted UPS pricing for expedited delivery.

Here is what his follow-up email to us said:

Thank you very much for the help and responsiveness.  I mentioned to my mechanic that day how customer service focused Power Flo [sic] seems to be and its refreshing in this industry and quite frankly, society nowadays!  Appreciate the extra effort!

We are happy to have been of help to the customer and appreciate the compliment!

Incidentally the part needed is the only part in our exhaust system that is a wear item. For Cessnas with Classic systems, and most of our other exhaust designs with a 3.5 inch tailpipe, the tailpipe contains an inner assembly called the muffler insert.  

This sound chamber/cartridge consists of a perforated tube (2.0 inch diameter, welded onto a ring that is screwed into the base/aft portion of the muffler). We put a specially designed material consisting of two interwoven layers to absorb sound around the outer portion of the perforated tube so that the exhaust (and noise) comes down from the upper part of the exhaust and runs through the middle of the perforated tube, losing both velocity and volume as it goes.  

This allows a large volume of sound to be absorbed (and thus quieted) without impeding the gas flow so what we have is a “pass-through attenuator.”  Over time the sound absorbing material deteriorates due to its contact with the hot exhaust gases and it eventually disintegrate after about 400 to 800 hours flight hours.   Once this occurs the exhaust system gets louder but provided the inner perforated tube is still intact, it remains safe and legal to operate.

Pictured: Muffler Insert (note the plastic wrapping on the outer portion. Don’t remove it!)

So how can we help you?

How to use our new Illustrated Parts Catalog (IPC)

Rev. 12/16/18

Power Flow Systems, Inc.

How to use our Illustrated Parts Catalog (IPC)


  1. Go to the Power Flow Systems Website ( and click on Installation Guides/ICAWS.
  2. Once on the web page, find your aircraft’s manufacturer, and then click the plus sign next to the manufacturer’s name. (This document will follow the procedures for a Cessna 172.)
  3. This will open up a sub-menu that contains all of the Power Flow Systems documentation for that manufacturer.
  4. Next, look for your aircraft model (bolded and underlined). This section will contain all documents pertaining to that aircraft model.
  5. If there are multiple systems for your aircraft type, you will need to determine which exhaust kit is on your aircraft. This can be done by looking at the black serial number tag on your exhaust heater shroud. Typically the black serial number tag can be found on the right-hand side of the exhaust system either on the plate where the two headers enter the shroud or on the bottom of the shroud. This is what an exhaust serial number tag looks like:

    There is an alternate way to determine which kit is on your aircraft and it is to read the product descriptions next to the kit numbers and use the Illustrated Parts Catalogs to narrow down which one is on your aircraft.

  6. You will then click on Illustrated Parts Catalog (IPC) which will download the file to your computer.
  7. Open the IPC. The IPC contains several drawings containing every single configuration that was produced, and the last page shows a table (called Bill of Materials, or BOM) listing the parts description with notes.  The IPC will look something like this:Let’s say a customer is looking to replace the muffler insert on his or her Cessna 172.
  8. The customer will navigate to the page depicting the tailpipe sub assembly. Once the customer gets to that page, he or she will notice that there are two different tailpipes.
  9. The customer will then need to look at his or her aircraft and identify which one is on the plane. For this example, the customer will have the short stack configuration. The customer will then notice that there is a number 21 pointing to the cone shaped insert.
  10. The customer will then proceed to the Bill of Materials (BOM) table at the end of the document. From here, he or she will be able to notice that number 21 corresponds to a silencer cone. The last column states the part is included in PFS-80011 (Tailpipe assembly) or PFS-8310 (which is the insert and the hardware to hold it in the tailpipe).  Items in bold represent what is typically or commonly ordered and is also directing you to the correct part number for ordering.  In this case, PFS-8310 is what you want to order.If you look at the layout of the BOM, the top level assembly (or the complete assembly) of the short stack tailpipe is our p/n 80011.  It consists of (1) 8011 + (1) 8310 + (3) An526C832R6 Screws + (3) MS21042L08 Nuts. Items that are indented are sub-components of that top level assembly.If you were to order a PFS-8310, that part number will also include the 3 screws and nuts – as noted by the last column that states “INC. IN PFS-80011 OR PFS-8310”.
  11. The customer will then contact Power Flow Systems at (386) 253-8833 to order the new silencer cone, our p/n PFS-8310 and that will include both the Silencer Cone and the necessary hardware to install it. One important thing to remember:  Power Flow Systems, Inc. will sell parts to the registered tail number/registration mark of a particular aircraft for the specific kit we have a record of selling to that specific aircraft.  If the aircraft that the Power Flow exhaust system is installed on was not the original aircraft that the kit was sold for, you will have to request an STC transfer from Power Flow Systems, Inc. before you can purchase any parts for the exhaust system.  As of the time of this writing, the STC transfer fee is a one-time licensing fee of $300.00 (subject to change).

If you have any questions, please don’t hesitate to contact us at: (386) 253-8833 or

Possible fit conflict with carburetor air temperature probe and Power Flow exhaust

Some aircraft equipped with an optional carburetor heat probe are finding that there is close contact between the probe and the Power Flow tuned exhaust system. Here is what we recommend:

Unfortunately some of the probes and the outer spring around the wire used for carburetor air temperature are very long and the outer spring portion makes the wire want to stick straight out of the probe by 1.5-2.0 inches thus running into or very near the Power Flow heat shroud. When we encounter this and it is the spring portion of the probe that is the problem, our advice has been to allow for an indention in the heater shroud provided that contact is not made with the underlying tubes and accept that the probe spring portion will have to be bent. This seems to have no ill effect on the operation of the probe.

An indentation on the Power Flow shroud is not a warranty violation provided it does not make contact with the underlying tubes.

Rusty Pilot Takes Up GA Flying Again

November 19, 2018


Rusty Pilot Takes Up GA Flying Again

     Fernandina Beach, FL – Tom Piscatello, who recently turned 78, has returned to GA flying in a Grumman Tiger. He never got away from flying completely as he traded his first Grumman for an LSA. Attracted to Sport Flying by the absence of a medical requirement and the economy of flying with a fuel burn below 5 GPH, lower maintenance costs, and reduced insurance rates, Tom embraced LSA flight for ten years, and served on the LSA’s ASTM Committee.

     Like a number of people before him, however, the trade-off in economy caught up with his desires to fly cross country. Over his decade of involvement, Tom lost a number of his like-minded friends to “aging out” and passing. He also grew a little tired of what he called the “go nowhere in particular type of flying”. So, after landing on a sod strip and losing his LSA to a soft patch of sand that won an argument with his nose wheel, he decided to return to the world of Part 23 General Aviation.  The decision was made easier by the fact that he had been maintaining currency as both a CFI and an IFR rated pilot all along. Desiring to preserve the economical aspect of flying, he bought another AA5B, and, as was the case when he got his original Tiger, he immediately installed a Power Flow Tuned Exhaust System, in order to reduce the fuel flow and enhance his climb performance. “Now I’ll have one of the best birds in the sky again,” said Tom. “It’s nice to be home flying faster and going further. I don’t regret my LSA experience, and consider myself extremely fortunate to have made a safe transition back to a Part 23 aircraft.” Tom takes a safety pilot along, when he can, for flying IFR and enjoys taking three kids up for Young Eagle flights instead of one, in VFR conditions.

To learn more about the benefits of installing Power Flow Systems visit

EASA approvals for Power Flow STCs now available

Updated: 03/01/2018

Power Flow Tuned Exhaust Systems – Now Sporting a Certain “European Flair”!

Up until December 2017, European fixed-wing pilots have not been able to easily install Power Flow exhaust systems onto their EASA registered aircraft.  Unless Power Flow already held EASA validation on the STC’d kit specific to their aircraft, the governing agency would not approve the installation.   The company had attempted a couple of EASA validations on their STCs at a cost of several thousand dollars but encountered a variety of obstacles which prevented full validation.

Now, thanks to a recent policy change, EASA registered aircraft may apply for a specific single airframe serial number approval from EASA for a one time application fee of 200 Euros.  EASA says that provided that the STC meets seven specific criteria (all of which are met by all of the company’s Tuned Exhausts), they will issue the approval.  EASA further guarantees that they will either issue an approval specific to that aircraft or they will refund the Customer’s application fee.    

Working through their Authorized Dealer in the U.K., Airspeed Aviation, LTD in Derby, the company has successfully received approval for two Cessna 177RG aircraft. They have also received approval for a Mooney M20J that had been trying for over five years to navigate the difficulties of obtaining EASA approval for the installation as well as a Diamond DA40.

The EASA approval process generally takes less than 30 days and requires that Power Flow provide a letter of authorization specific to a particular aircraft.  Power Flow provides this letter at no cost.  For UK customers, we direct all inquiries through our exclusive UK Authorized Dealer, Airspeed Aviation.

“We are thrilled that EASA has created a pathway through the regulations to allow EASA aircraft owners to benefit from the terrific safety and performance improvements that a Power Flow exhaust adds to their aircraft.” stated Darren Tilman, General Manager of Power Flow Systems.

For more details on the EASA rule change, go to:

Change for Cessna Short Stack Installations

November 10, 2017 – After feedback from installations in the field and our own experiences in-house, we have implemented a change in our installation that affects C172, C175, and C177 fixed gear aircraft with short stacks.  Over the years we received a few reports that the installation of the Power Flow exhaust short stack could result in the exhaust stack not being centered when coming out of the existing cowling hole.  When this occurred, it was typically displaced to the outboard side.

Typical Stock Exhaust:


The Power Flow as originally installed, pre-modification:


To address this, beginning with kits that were shipped in October, we have added an additional step to trim the 4 to 1 (the part that the short stack slides onto on the main heater section) slightly to allow for a more centered placement of the short stack.


This change also affects aircraft with the classic installation, however the tube coming out of the cowling on the classic installation is a 2.0 inch diameter instead of a 3.0 inch diameter, so displacement was not noticeable and had not been reported.

This will result in a nicer looking final product, easier installation and improved clearance for exhaust fairings.

We are always striving to make all our products, both future and existing, the very best we can produce. We always appreciate feedback from our customers, as it helps us to achieve this goal.

Changes to 1967/68 C177 with Lycoming O-320 and/or Original First Year Cowlings

November 10, 2017 – One of the many things that are unique to the first year of C177 aircraft is the cowling. The lower cowling has an integral airbox built-into the cowling, as shown in the image below.


The cabin heat source is an oval shape designed for a 3.0 inch diameter SCAT tube.


On the original Cessna exhaust system, there is sufficient clearance for the SCAT tube to work its way over to the original exhaust’s cabin heat source.


The Power Flow second generation shroud was designed to fit all models of the C177 aircraft from 1967-1977.  Unfortunately, we weren’t aware of the difficult job of routing the 3.0 inch SCAT hose through what turns out to be a 2.5 inch space.


Installers in the field would have to squash the SCAT hose to get into the tight clearance and then rapidly turn the tube up at a 90 degree angle to go into our shroud.


Clearly this is not ideal and can result the SCAT tube rubbing against the aluminum airbox.  We are sorry to say that we weren’t aware of the magnitude of the problem until recently. So in our relentless pursuit of perfection, we have implemented a number of changes in a complete redesign of the shroud exclusive to the first year Fixed Gear Cardinal.

– The cabin heater input is now an oval tube that comes out of our shroud at a right angle and extends over the shroud.


Here is the view as installed and seen from the left side:


Here is a view of the new clearance to the airbox:


– Originally, the carburetor heat came out at an angle that was awkward for the 1968 cowling, resulting in a lot of carb heat SCAT tube twisting as depicted below.  Note how close the output is to the input.   


Here is the new carburetor heat output – it allows for a shorter length of tubing that doesn’t have to twist or turn nearly as much:


– The original 1968 C177 uses a very long throttle arm – too long in fact to allow full travel in some instance as pictured below.


The solution?   Trim the throttle arm to remove the furthest hole and move the throttle cable to the middle arm.  Problem solved.  This step will be incorporated into our installation instructions.  See the below picture for the final results.


One more change on the way:

We are going to change the cabin heat output to angle down and outboard so that the 3.0 SCAT hose can work its way around the mess of fuel hoses and header tubes and enter the shroud on the lower left hand corner.

Customer shipments for 1968 Cardinals starting in January 2018 will have the new shroud design.  Any existing C177 can replace with the latest shroud starting then as well.

We hope you like the changes! We are always striving to make all our products, both future and existing, the very best we can produce. We always appreciate feedback from our customers, as it helps us to achieve this goal.

Thank you!