flow exhaust

[orhepxo]

Has anyone tried the power flow exhaust.. display was at sun n fun...DOES IT WORK AS WELL AS MANUFACTURE SAYS

[RoundTwo]

Try this search in Google… power flow exhaust site:mooneyspace.com

[A64Pilot]

On 12/9/2023 at 9:34 AM, orhepxo said:

.DOES IT WORK AS WELL AS MANUFACTURE SAYS

Nothing works as well as claimed, nothing. My 201 for example, well it’s not really a 201.

How well a power flow works is a function on how poor is the exhaust it’s replacing. I don’t think for example if there is one for my J that it would make much difference, the J’s exhaust seems well thought out to me.

Having said that a J’s exhaust isn’t average, normally performance isn’t really part of an aircraft exhaust design, see the airplane manufacturer build the exhaust and they aren’t usually engine people, they are more concerned with making the thing fit and keeping costs down. I think someone who knew what they were doing designed the J’s exhaust

Worst exhaust I’ve seen was on a Maule, Maule has one muffler for pretty much every engine, on my 540 equipped Maule the exhaust tubes were honestly smaller that the exhaust valves, a well designed exhaust would probably really make a difference on a Maule.

[PT20J]

A few years ago at MoomeyMAX, the company rep said they work best on 6 cylinder engines and don’t make that much difference on four bangers because the exhaust pulses are closer together on the sixes.

[BaldEagle]

I have a Power Flow exhaust on my J (installed by previous owner).  I can't speak to performance improvements (although I suspect any improvement is barely measurable), but a couple of notes: when installing, replacing the air filter for a K&N is recommended; the prop needs to be balanced and as part of the STC the exhaust needs to be disassembled at each annual and lubricated with a high temp paste.  This is about 2 hours labor.

[GeeBee]

On 12/13/2023 at 11:13 AM, PT20J said:

A few years ago at MoomeyMAX, the company rep said they work best on 6 cylinder engines and don’t make that much difference on four bangers because the exhaust pulses are closer together on the sixes.

Interesting. Yet 90% of their STC's is for 4 bangers. The only 6 cylinders I see is the Cessna 180 series.

[201Mooniac]

I added one to my J when I needed a new exhaust.  There was no measurable change in speed but I did notice after awhile that I used about 0.2 gph less fuel at the same power settings.  I'm not sure if that was really due to the exhaust change but it did show up in my engine monitor data.

[1980Mooney]

53 minutes ago, 201Mooniac said:

I added one to my J when I needed a new exhaust.  There was no measurable change in speed but I did notice after awhile that I used about 0.2 gph less fuel at the same power settings.  I'm not sure if that was really due to the exhaust change but it did show up in my engine monitor data.

The fine print on the Power Flow site says:

• "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."

So if your shop rate is $100/hour it will cost you an extra $200 every year or equivalent to about 33 gallons @$6/gal. If you fly 60 hours per year that is equivalent to an extra 0.5 gallon per hour.  That seems to eat up any savings.  And for no increase in performance plus a much higher purchase price than a stock exhaust.

Edited December 18, 2023 by 1980Mooney

[DXB]

The metal is thicker on the powerflow, which may contribute to durability.  There was a  modest useful load loss when mine went in for this reason.

Installing it did have dramatic effects on my carb'd O-360. Depending on how you run it, there's more efficiency or more power (and unfortunately more heat as well).  

The IO-360s don't seem to derive the same level of benefit - perhaps their factory exhaust design is better.

[Skates97]

23 minutes ago, DXB said:

The metal is thicker on the powerflow, which may contribute to durability.  There was a  modest useful load loss when mine went in for this reason.

Installing it did have dramatic effects on my carb'd O-360. Depending on how you run it, there's more efficiency or more power (and unfortunately more heat as well).  

The IO-360s don't seem to derive the same level of benefit - perhaps their factory exhaust design is better.

Power flow weighed 2.5lbs more than the stock exhaust on my O-360 so I didn't lose much. Like you I saw benefits. With over 800 hours in the plane with an engine monitor before installation I have a pretty good base to work from. Stock exhaust I saw 166 mph TAS on 9.8-10. gph, with the power flow at the same fuel flow I see 170 mph TAS. I can lean it out down to 9.1-9.2 gph and still see the same 166 mph TAS. In the climb from 100' MSL up to 9,500' I average an additional 300 fpm which gets me to cruise faster.

I have not seen additional heat issues.

The additional cost during annual isn't a factor because I do owner assist so it's my time not the mechanic's time to disassemble and add anti-sieze to the joints.

I also like the reduced (almost completely) risk of CO poisoning.

[PT20J]

McFarlane sells a low viscosity moly lube for exhaust joints. I'll bet that will seep in without tearing it apart every year.  https://www.mcfarlaneaviation.com/products/product/DAM20-4.0/

[Fly Boomer]

4 minutes ago, PT20J said:

McFarlane sells a low viscosity moly lube for exhaust joints. I'll bet that will seep in without tearing it apart every year.  https://www.mcfarlaneaviation.com/products/product/DAM20-4.0/

What happened to Mouse Milk.  I thought that was the go-to stuff.

[PT20J]

58 minutes ago, Fly Boomer said:

What happened to Mouse Milk.  I thought that was the go-to stuff.

People have used that forever. But, it's a penetrating oil. I doubt is survives vaporization the first flight after application. But it might unstick a slip joint that was stuck when it was applied.

[DXB]

1 hour ago, PT20J said:

McFarlane sells a low viscosity moly lube for exhaust joints. I'll bet that will seep in without tearing it apart every year.  https://www.mcfarlaneaviation.com/products/product/DAM20-4.0/

This is an awesome idea if it works - having to drop the exhaust every year is a setup for other maintenance induced issues.

[1980Mooney]

6 hours ago, PT20J said:

McFarlane sells a low viscosity moly lube for exhaust joints. I'll bet that will seep in without tearing it apart every year.  https://www.mcfarlaneaviation.com/products/product/DAM20-4.0/

 

5 hours ago, DXB said:

This is an awesome idea if it works - having to drop the exhaust every year is a setup for other maintenance induced issues.

It is an interesting idea.  However the Powerflow is installed per STC.  And the website says "disassembly, cleaning and lubrication are required Annually".  The moly lube only addresses one aspect of the STC Annual requirement.  I have not seen the actual STC instructions, but I bet you are still stuck with the extra labor every year.

[PT20J]

20 minutes ago, 1980Mooney said:

 

It is an interesting idea.  However the Powerflow is installed per STC.  And the website says "disassembly, cleaning and lubrication are required Annually".  The moly lube only addresses one aspect of the STC Annual requirement.  I have not seen the actual STC instructions, but I bet you are still stuck with the extra labor every year.

Well, it's kind of interesting, so I looked it up.

Manufacturers communicate their maintenance recommendations in an Instructions for Continued Airworthiness (ICA) document which the FAA requires. However, for Part 91 operators, most of this stuff is not legally required -- just like service bulletins. However, the ICA contains a section called Airworthiness Limitations which is approved by the FAA and becomes a legal requirement under FAR. Most manufacturers take pains to write NONE in this section. However, Power Flow included the disassembly and lubrication in this section, so technically your airplane is not airworthy if you don't comply. Your only way out is to get Power Flow and the FAA to agree that using an alternate method is acceptable. Good luck with that .

6.2 AIRWORTHINESS LIMITATIONS
“The Airworthiness Limitations section is FAA approved and specifies maintenance
required under §§43.16 and 91.403 of the Federal Aviation Regulations unless an
alternative program has been FAA approved.”
6.2.1 Mandatory Replacement Time – None. Any collector assembly that is damaged and/or
fails the pressure test described below must be rebuilt or replaced.
6.2.2 Structural Inspection Interval – At 100 hour or Annual intervals, depending on the service
regime of the aircraft. WARNING: Carbon Monoxide gas present in exhaust gases
can lead to pilot incapacitation and/or death. A damaged exhaust system has the
potential to allow Carbon Monoxide into the aircraft cabin. To prevent such an
occurrence, it is imperative that the exhaust system is inspected using the intervals
and procedures described in this report. It is recommended that in-cabin carbon
monoxide levels be measured periodically. Concentrations of greater than 50ppm
will require immediate exhaust system inspection and repair or replacement as
necessary.
6.2.3 All slip joints must be disassembled and lubricated with a high-temperature anti-seize
compound (MIL-A-907E or equivalent) at 500hr or Annual intervals (whichever comes
first). While disassembled, inspect for wear or galling. This should be performed more
frequently if headers seize between inspections.
6.2.4 Structural Inspection Procedure – See Section 6.6.

[Tx_Aggie]

On 12/18/2023 at 3:09 PM, Skates97 said:

Power flow weighed 2.5lbs more than the stock exhaust on my O-360 so I didn't lose much. Like you I saw benefits. With over 800 hours in the plane with an engine monitor before installation I have a pretty good base to work from. Stock exhaust I saw 166 mph TAS on 9.8-10. gph, with the power flow at the same fuel flow I see 170 mph TAS. I can lean it out down to 9.1-9.2 gph and still see the same 166 mph TAS. In the climb from 100' MSL up to 9,500' I average an additional 300 fpm which gets me to cruise faster.

I have not seen additional heat issues.

The additional cost during annual isn't a factor because I do owner assist so it's my time not the mechanic's time to disassemble and add anti-sieze to the joints.

I also like the reduced (almost completely) risk of CO poisoning.

How does it reduce the risk of co poisoning?

[ArtVandelay]

Whatever improvement in HP is countered by increased drag of the unsightly tail pipe, at least for the J.

[Skates97]

2 hours ago, Tx_Aggie said:

How does it reduce the risk of co poisoning?

It eliminates the muffler/heat shroud with the welds that can break/crack and allow CO to enter the hot air flowing to the cabin. Instead, there are solid pipes with no welds that the air passes by to be heated. One of the pipes would need to crack to introduce CO into the cabin.