aircraft are FAA approved (STC) with the Power Flow Exhaust?
» What about experimental (homebuilt/amateur)
» If your aircraft model is not listed,
and you have a Lycoming four cylinder engine
» Can I get an FAA Field approval for
» What type of performance gains can
» Will I get climb or cruise performance?
» Will it increase my RPM?
» Will I go over RPM Redline?
» Will I get Altitude or Service ceiling
» Will my EGT probe fit in your exhaust?
» What type of fuel savings should I
» Does the tail pipe have to stick out of
» Does the classic tailpipe increase drag?
aircraft are FAA Approved (STC) with the Power Flow Exhaust? back to top
Aviat Husky: A-1, A-1A, A1B, A1C-180 with Lycoming O-360
Beechcraft Sport, Sundowner: Beech 19 or 23 series with Lycoming O-320 or O-360
Cessna 172: 172, 172A-P with Lycoming O-320
Cessna 172: 172, 172A-Q with Lycoming O-360
Cessna 175: 175, 175 A-C with Lycoming O-360
Cessna 177: 177 B with Lycoming O-360
Cessna 177: 177, 177A with Lycoming O-360
Cessna 177: 177 with Lycoming O-320
Cessna 177RG: 177RG with Lycoming IO-360 (or IO-390)
Diamond DA40: DA40 with Lycoming IO-360
Diamond DA40F: DA40F with Lycoming O-360
Grumman AA5: AA5, AA5-A with Lycoming O-320 (s/n above 641)
Grumman AA5: AA5 with Lycoming O-320 (s/n below 641)
Grumman AA5: AA5-B, AG5-B with Lycoming O-360
Mooney M20: M20 B,C,D,G with Lycoming O-360
Mooney M20: M20 E,F,J (201) with Lycoming IO-360 (or IO-390) (original or LoPresti cowling)
Piper PA28: PA28-150, 160, 180 (under s/n 1761) with Lycoming O-360
Piper PA28: PA28-150, 160 (under s/n 1761) with Lycoming O-320
Piper PA28: PA28-140 with Lycoming O-360
Piper PA28: PA28-140 with Lycoming O-320
Robinson R22: R22, Mariner, HP, Alpha, Beta with Lycoming O-320
Symphony: SA160, OMF-100-160 with Lycoming O-320
or Field Approval required for the following. back to top
Sportsman: Sportsman 2+2 with either Lycoming O-320 or O-360
Glastar: Glastar with either Lycoming O-320 or O-360
Cessna 170: 170 with Lycoming O360 (Field approval required)
If your aircraft type is not listed and you have a Lycoming
engine: back to top
Our engineering and R&D resources are limited. We are
developing and certifying the aircraft models that are the
most popular. Currently our exhaust design has been proven
on 4 cylinder, Lycoming engines. As resources permit, the
smaller aircraft markets will be entered into the certification
process. You can let us know that your are interested in
an exhaust system for your aircraft by filling out our information
Can I get an FAA Field Approval for my aircraft? back to top
Power Flow Systems does not do field approvals
here at the facility. There are limited instances of people
being able to do field approvals on their own with their
mechanics. Please contact us if you have further questions.
What type of performance gains can I expect? back to top
Each aircraft will experience different
results in a real world application. Please go to the aircraft
product page that corresponds to your aircraft to see results
that are based on your aircraft test results and customer
Will I get an increase in climb or cruise performance? back to top
The types and amount of improvement that you will see depend
on the aircraft and the type of propeller configuration
(fixed or constant). Please refer to the individual product
pages for the specific ranges for each individual aircraft.
Below is a general explanation between constant speed and
fixed pitch improvements. The numbers stated may not be
valid for all aircraft.
For a constant speed prop application,
the Power Flow exhaust will allow you to generate the same
amount of power as before, using less throttle and lower
Manifold Pressure. As compared to the stock exhaust system,
if you set the same power settings with manifold pressure,
mixture, RPM and Fuel flow, you will ultimately generate
more power and higher cruise airspeed. Constant speed equipped
aircraft report a top airspeed gain of between 3 and 11
miles per hour when measured with the throttle set at wide
open (full). Your fuel flow may be higher than you are used
to because your engine is generating more power than it
ever did before. As a result of greater power available
to the engine, your aircraft will climb at a greater rate
than stock. An O-360, constant speed aircraft reports an
average 200 FPM increase in rate of climb at the same airspeeds.
For a fixed pitch prop, at cruise, airspeed
is directly related to RPM. During each rotation of a fixed
pitch prop, the prop can only pull the aircraft forward
as far as its effective pitch. If you generally cruise at
a specific engine RPM, say 2300, the prop turns at 2300RPM
and still provides the same airspeed. You will note that
it doesn't take as much throttle to achieve that 2300
RPM. You can utilize the extra RPM our exhaust provides
to increase airspeed, but you would have to allow the RPM
to increase. To boost your ultimate top speed, your only
possible alternative is to consider "re-pitching"
your propeller. In climbs, your engine turns at a faster
rate and therefore you climb at a faster rate. The typical
fixed pitch C172 customer reports an average 150-225 FPM
improvement in rate of climb.
Will it increase my RPM? back to top
Yes, on a fixed pitch aircraft the PFS exhaust will increase
your available RPM for Static (ground run), takeoff, climb
and cruise. The typical range that people have seen an increase
is from 30-130. The average fixed pitch aircraft has seen
60-70 RPM increase.
On a constant speed prop, the PFS exhaust
will not increase your available RPM. If you set 2500 RPM
with your prop control, the engine will regulate at 2500
RPM. As your engine may be making more power than before,
the blades will be driven to a higher pitch resulting in
higher rates of climb or faster forward airspeed than you
saw with the stock exhaust.
Will I go over RPM Redline? back to top
No, on a constant speed equipped aircraft you won't
go over redline unless you have a pre-existing problem that
allowed you to go over redline before the PFS exhaust installation.
On aircraft equipped with a fixed-pitch
prop, it is more likely that you may exceed redline at full
throttle at lower altitudes. Power Flow recommends that
you do not exceed redline. You should reduce throttle accordingly
to match your manufacturers' recommendations. Some
of our customers have reported that experienced prop shops
have re-pitched their propeller to obtain a better cruise
performance by sacrificing some of the improved climb performance
from installing a Power Flow Systems Tuned Exhaust.
Will I get Altitude or Service ceiling increases? back to top
Yes. Most of our customers have reported an effective increase
in service ceiling by up to 5000 feet. The average gain
is 2500 feet, depending on how big of a gain the PFS exhaust
provided you. Power Flow Systems, Inc. does not guarantee
a specific increase in the aircraft service ceiling and
it is highly recommended that you evaluate and test your
aircraft's performance prior to counting on a particular gain or service ceiling.
Will my EGT probe fit in your exhaust? back to top
Our exhaust is manufactured with thicker stainless
steel tubing that stock, but EGT probes can be mounted in
the exact same manner as they were in your previous exhaust
and will operate normally. We recommend that you install
the same distance as before or to the probe manufacturers
recommended distance. All probes should be installed the
same distance; otherwise temperatures may not be accurate.
If the probes are installed in a different location than
with the stock exhaust, a different reading may occur.
Power Flow recommends the use of engine monitors. Drilling
holes for the EGT does not void the warranty or money back
What type of fuel savings should I expect? back to top
The Power Flow, when leaned correctly has been
able to save up to 2.5 gallons per hour. If you fly faster
or climb faster than before, you may burn more fuel. With
the Power Flow you can fly the same speeds, but it requires
less throttle, therefore saving fuel. Many flight schools
and clubs use our system and have successfully saved 1.12
to 1.9 gallons per hour. Refer to individual product pages
for a more accurate fuel savings numbers.
Does the tail pipe have to stick out of the cowl? back to top
Yes and No. There are several reasons behind the
distinctive exhaust: performance, heat concerns,
durability, etc. In April 2005 we announced a revolutionary
new look to our product: the short stack.
The Short Stack exhaust is available for all Pipers, Grummans, & Cessna 172 and 177s. For Pipers and Grummans, there is no performance loss from the use of the short stack as that system's design is of the same length as the original classic. We were able to find an engineering solution to routing as much of that tubing inside the aircraft cowling as possible.
For C172 and C177, the Cessna short stack comes out of the cowling at exactly the same angle, length and diameter as the stock exhaust. As it is a shorter length than the ideal tuned length, the average Cessna sees only about 80% of the improved benefits as compared to the Classic original exhaust. If the look of the exhaust was a concern and you don't want to squeeze every ounce of power out of the exhaust, then we recommend the short stack. If, on the other hand, you want to have maximum gain for the exhaust, then the Classic is the only way to go. Key differences between the Classic system on a C172 are listed as follows:
C172 RPM gain on the ground with classic: 75 RPM; With short stack :69 RPM
C172 gain in average rate of climb with classic: 225 FPM; With short stack: 200 FPM
C172 gain in service ceiling: with classic 4500 feet; with short stack: 3000 feet
C172 ability to lean lean of peak: with classic is excellent - able to remove up to 300 RPM from engine smoothly below 65% power; With short stack: moderate - ability to lean lean of peak approximately 50-100 RPM smoothly.
Does the classic tailpipe increase drag? back to top
We have accomplished flight-testing and found that
drag caused by the tailpipe is overcome by thrust coming
out of it. During testing we have also examined the use
of fairings. Our testing indicates improvements in cruise
speeds as well as engine temperatures from the use of exhaust
fairings. We have an exhaust fairing available for the Classic
C172 exhaust. Cessna C177 (Cardinal) and Grumman owners
can also use the existing fairings on the market with our
products, however, some realignment may be required.