Is a Power Flow System worth the $$

[David M20J]

My co-owner showed me this exhaust from Power Flow Systems, Inc.  Does anyone here have this installed?  My biggest thing is the performance gains worth the almost $6k price tag... this is copied from this link https://www.powerflowsystems.com/products/mooney/mooney-200210hp-io360

 

• 5 -7 knots faster cruise speeds

• 10% – 15% increase in rate of climb

• 0.5 – 1.5 gph reduction in fuel burn at equivalent airspeed

• Improved Take-Off Performance (100’ – 300’ reduction in ground roll)

• Increase in Service Ceiling of 2,000’ – 5,000’

• Cooler CHT’s

 

...We just bought a new prop, so it would really need to be worth it for me to buy it right now and then wait 6 months or more to get it...

[201Steve]

Wow… 5-7 knots increased cruise speed. I would think they’d be flying off the shelves if that were accurate. I am suspicious and have never heard real world example of such, but curious to read the replies as they start coming in….

[Ragsf15e]

There are quite a few installed.  Rumor on the street is they help out the carbureted models more than the injected models.  There is slightly increased mx required, but there’s a lot of debate about that.

 I believe we have some older threads on PF before/after and performance was  not as big as hoped for, however I don’t have one.

[Ragsf15e]

Read through this thread…

 

[David M20J]

Thanks guys, we have injected and with just dropping for a new prop I think we'll hold off.  Ill try to look for the previous thread you mentioned

@Ragsf15e beat me to it

Edited April 18, 2022 by David M20J

[1980Mooney]

Same exact question from a J owner in 2020….

”

 

[carusoam]

Roughly…

For the older Mooneys…. Their intake and exhaust system were not as perfect as the newer Mooneys… room for improvement!

If it is a forever-plane… there are some additional benefits… just not a lot… looks pretty… less likely to rust/fail/generate CO in the heater…

For any plane… if you are relying on the speed numbers given… to improve your efficiency…. Expect those numbers are derived during flaming dragon mode flights…. Not LOP at 65%bhp…

Older versions of the PowerFlow have a giant exhaust pipe sticking out in the wind… an obvious aero-goof up….

Make sure you are getting the newer aero-dynamic version…

Somewhere… read up on the efficiency vs. heat output… less restrictive exhaust may have slightly less heat output…

Looks like… if you have the dough for a forever-plane, and your exhaust system is worn out, for a few bucks more your steed gets a nicer exhaust system…

CBs May prefer… an OH’d exhaust system from a company like knisely… comes back brand new like…works like original system did back before engine monitors were around…. 

Fuzzy PP memories only, stuff I have only read about around here…

Best regards,

-a-

[BaldEagle]

I have a Powerflow on my J (installed by previous owner).  I’ve not flown a J without one, so I can’t speak to any performance gains, although my understanding is that the gain on a J is likely barely measurable, if at all.  Something else to consider: the STC requires that your prop is balanced and at every annual you have to disassemble it and apply high temp lubricant and reassemble, which is maybe an additional couple of hours labor each year.

[philiplane]

I've put them on F and J models, mostly because the original systems were shot anyway. You do get better climb, and better fuel efficiency at the same speed. Or use the extra HP to go faster on the same fuel. We saw 4 knots increase on the same fuel flow. So your total trip time decreases, or it stays the same with a lower fuel bill, your choice. Not enough to pay for the system anytime soon, but then again, you will have a brand new exhaust system, with many years of service ahead. Peace of mind. 

I've seen bigger gains on Cessna 172's and Piper Cherokees, because their exhaust designs are much worse than the Mooney.

Edited April 18, 2022 by philiplane

[Mooney217RN]

The PowerFlow exhaust is worth every single cent, IF you need to replace your exhaust.  My exhaust on my former E Model kept having cracks develop, and at a certain point, enough was enough.  I spent the $$$, got the PowerFlow tuned exhaust, and couldn't have been happier with it.  Performance increased, in particular at higher altitudes.  I am based at a high altitude field, so that was a huge benefit.  Probably picked up an extra inch of manifold pressure from it at higher altitudes.

The downside is the ambient sound level was higher than the stock exhaust.  That's the only downside.

[ArtVandelay]

I have a Powerflow on my J (installed by previous owner).  I’ve not flown a J without one, so I can’t speak to any performance gains, although my understanding is that the gain on a J is likely barely measurable, if at all.  Something else to consider: the STC requires that your prop is balanced and at every annual you have to disassemble it and apply high temp lubricant and reassemble, which is maybe an additional couple of hours labor each year.

Js have an improved system, both exhaust and intake ( ram air was eliminated in later years)

Pictures I’ve seen shows the PF sticking out into the airstream instead of being tuck up against the cowling, the extra drag might exceed any minimal performance improvement.

[carusoam]

11 hours ago, ArtVandelay said:

Pictures I’ve seen shows the PF sticking out into the airstream instead of being tuck up against the cowling,

This was the old vs. new design mentioned above….

Something to be aware of when ordering… to make sure you are getting what you are expecting…

Its possible the old design is gone by now….

 

It was odd having the discussion about improved performance… then having a giant pipe sticking out in the air… when it didn’t need to be…

Something must have gotten lost in the PF Marketing group…

PP thoughts only, not a mechanic… nor a marketing specialist…

Best regards,

-a-

[David M20J]

23 minutes ago, carusoam said:

This was the old vs. new design mentioned above….

Something to be aware of when ordering… to make sure you are getting what you are expecting…

Its possible the old design is gone by now….

 

It was odd having the discussion about improved performance… then having a giant pipe sticking out in the air… when it didn’t need to be…

Something must have gotten lost in the PF Marketing group…

PP thoughts only, not a mechanic… nor a marketing specialist…

Best regards,

-a-

The website did mention make sure you get the right version if you have a J or newer , they said they had 2 gen versions based off what you had so im hoping thats what what changed was that massive pipe i kept hearing about

 

[ArtVandelay]

The website did mention make sure you get the right version if you have a J or newer , they said they had 2 gen versions based off what you had so im hoping thats what what changed was that massive pipe i kept hearing about
 

I don’t think so, looks like changes to the exit pipes:

[A64Pilot]

To get an idea as to what works best for a four cylinder exhaust system. it may be best to look at 4 cyl Japanese motorcycles, their exhausts are really efficient

Then realize the exhaust is the aircraft manufacturers decision / responsibility, and some do  better than others, Maule’s for example are horrible, the tubes inner diameter is smaller than the exhaust valve on their 540 because they use the same tube for every engine, but many manufacturers are primarily concerned with light weight, packaging as in making it fit and not be too complex ”expensive” So going from bikes to get the exhaust to actually scavenge, that is to have an actual low pressure in the pipe when the exhaust valve opens, you need equal length pipes and they have to have a restriction and an expansion immediately after and the position has to be just as the exhaust pulse passes when the exhaust valve opens, that will create a slight vacuum to suck out the exhaust slightly increasing the volumetric efficiency of the engine, aircraft are uniquely suited for such a design as the tube length as to where it will work is influenced by RPM, high RPM shorter pipes, lower longer of course, but aircraft engines operate in a very narrow RPM range so they are uniquely suited for a “tuned” exhaust.

Is it worth the weight, expense, likely difficult work area etc for a few percent increase in power? Plus are they equal length tubes, cause if they aren’t then it’s not going to properly scavenge

Its not even close to worth it to me as I don’t think the numbers they advertise are remotely close to reality, but that’s normal for airplanes. Everyone stretches the truth.

The big pipe sticking out in the airflow could possibly have been there to cause a low pressure area to cause a vacuum, but it’s possible that it’s drag could have overcome any possible power increase.

My belief is that such systems were originally intended and designed for 172’s and adapted for other aircraft, and what works on a 172 due to its lower speeds may not work on faster aircraft.

My personal belief is you would spend way over 6K as this thing has to be installed and signed off by an IA and be hard pressed to measure any real improvement, but I’ve not run one.

If their numbers were real, I’d bet most would be running them, many Mooney drivers would kill for 6 kts faster cruise 

Edited April 20, 2022 by A64Pilot

[201Mooniac]

I added one many years ago when I needed a new exhaust.  While with careful measurements I was able to see a small increase in climb and cruise but in most situations it is really minimal.

[INA201]

On 4/20/2022 at 12:19 PM, 201Mooniac said:

I added one many years ago when I needed a new exhaust.  While with careful measurements I was able to see a small increase in climb and cruise but in most situations it is really minimal.

I’d say go for it with most pre J models.  One plus of Power Flow is they seem honest about their results with various aircraft.  I had my old muffler rebuilt for an AMU or so instead of grabbing a Power Flow.  

[Culver LFA]

I attempted to install a Powerflow on my M20F but ran into an issue where the muffler was interfering with the alternate air door. Powerflow was fantastic to work with offering to pickup my airplane in Atlanta GA and fly it back to their factory in FL to make a system for my airplane.  While I appreciated the offer I declined and reinstalled my worn stock exhaust.

A year and a half later the old exhaust system was finally shot so I sent it in to AWI and guess what, absolutely even cht/egts and noticeably better performance all around. I’m very happy with AWI.

 

I think the stock vs. Powerflow comparison really needs to be apples to apples not old/worn out vs new.