To Powerflow or not to Powerflow - That is the question

[Bart Chilcott]

D Max has informed me that my stock exhaust on my 65 M20E has passed away.  In considering a replacement or repair, I've looked into a complete rebuild ($1800.00) or a Powerflow system ($4,000.00).  I've been told by my shop that he has have removed as many of the Powerflow systems as he has installed (excessive noise seems to be a major complaint)  I've read about the advantages of the Powerflow but I'd also like to hear from anyone who has had theirs removed and gone back to stock and why.  I figure if the shops are removing 50% of the sysytems, someone will surely be able to chime in.  Thanks in advance for your input!

[Raptor05121]

I've never flown one, but while they are widely acclaimed on the Pipers, they seem to not do as much on Mooneys. I was told our exhaust was tuned from the factory. I have also heard of Mooney owners having issues with them and also the slip joints requiring disassembly every annual as part as an "AD"

Just heresay, take it with a grain of salt.

[Bart Chilcott]

Just now, Raptor05121 said:

I've never flown one, but while they are widely acclaimed on the Pipers, they seem to not do as much on Mooneys. I was told our exhaust was tuned from the factory. I have also heard of Mooney owners having issues with them and also the slip joints requiring disassembly every annual as part as an "AD"

Just heresay, take it with a grain of salt.

Yes, disassembly and lubrication are required but I'm told its not a big deal.  I've talked to lots of people who have them but I'm still searching for the ones who have removed them.  As of right now, I'm probably going to stay stock based on the advise of my shop.

[jasona900]

I had one installed on my C.  I noticed a reduction in CHTs of about 25 degrees which I found impressive.  The noise levels were the same, but in my opinion a little higher pitched than stock.

The removal of the slip joints for inspection and reapplication of anti-seize adds less than 45mins to your annual.. or so I'm told.  

Didnt notice much increase in speed, but I did notice some increase in climb performance.  Don't have much data as my gear collapsed shortly after the install. But when I get my next Mooney (hopefully soon), I will get another Powerflow, should the stock exhaust require repair/replacement.

[Bart Chilcott]

20 minutes ago, bluehighwayflyer said:

We put a powerflow exhaust on our C about 10 years ago and have no complaints with it. It works as advertised and lubricating the slip joints is not required by AD but rather is required just to extend the warranty period.  Power output is definitely increased but so is fuel consumption, all else being equal. I am undecided as to whether I will install one on my J when the time comes but right now am leaning towards just overhauling it's stock exhaust system. 

Jim

Thanks Bluehighwayflyer.  That's what I'm leaning toward too.

[Yetti]

Had a Mooney driver A&P who put one on his E.   Took it off and sold it as no noticeable gain in performance.  Has other mods on his E such as a SWTA cowl

[Bob_Belville]

I've had PFS on my M20E for 5 years. 

1. I do not understand the noisy complaint, mine has the extended tailpipe and I don't think it is louder than conventional but I do have a real David Clark headset.
2. I do the slip joint lube at annual, it takes no longer than what ought to be done on a conventional muffler. 

Today I returned from PDK to MRN at 9000' pulling 22.1" MAP. 70% HP. I would credit PFS and Mooney Power Boost which added 1.2" MAP when I pulled it out. 

[pirate]

More noise ???? Strange comment, first time I've heard that. 

Most all negatives come from the ones who have never run PF

Slip joints, I do them every inspection 20min tops additional work.

I've run PF over 10 years and I personally would never go back. 

 

 

 

[KSMooniac]

Several anecdotal reports over the years indicate noticeable improvement for the C & G models with carbs, and much less for the FI models. I believe they have a 30 day guarantee where your only risk is paying labor to install/remove.

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[Wistarmo]

Did not improve performance on my M20J. 

Edited April 11, 2017 by Wistarmo

[rbridges]

Mine was installed prior to my ownership, so I can't give you any opinions on performance or noise.  I've had the plane >6 years, and I've had to replace the insert.  Other than that, no issues.

[Bob_Belville]

4 minutes ago, rbridges said:

Mine was installed prior to my ownership, so I can't give you any opinions on performance or noise.  I've had the plane >6 years, and I've had to replace the insert.  Other than that, no issues.

What did replacing the insert cost? Any idea why it failed?

[PTK]

14 hours ago, Whiskey Charlie said:

D Max has informed me that my stock exhaust on my 65 M20E has passed away.  In considering a replacement or repair, I've looked into a complete rebuild ($1800.00) or a Powerflow system ($4,000.00).  I've been told by my shop that he has have removed as many of the Powerflow systems as he has installed (excessive noise seems to be a major complaint)  I've read about the advantages of the Powerflow but I'd also like to hear from anyone who has had theirs removed and gone back to stock and why.  I figure if the shops are removing 50% of the sysytems, someone will surely be able to chime in.  Thanks in advance for your input!

I have not seen in the literature any definitive scientific data that's reproducible to support the dubious claims. It's a glorified exhaust that's too expensive not to deliver as promised.

 

 

[Bob_Belville]

10 minutes ago, PTK said:

I have not seen in the literature any definitive scientific studies with reproducible data to support the dubious claims. Folks find it too expensive for a glorified exhaust that  doesn't deliver.

Maybe so. As "Pirate" observes, it seems that most of the naysayers do not actually own PFS. Do you? Bottom line, someone is buying these systems every day, the company is still around even though they get a big premium vs. conventional. Jim Shaffer sold me my system 5 years ago and as far as I know is still the sales manager. That's not usually the case for companies selling smoke and mirrors.

[PTK]

7 minutes ago, Bob_Belville said:

Maybe so. As "Pirate" observes, it seems that most of the naysayers do not actually own PFS. Do you? Bottom line, someone is buying these systems every day, the company is still around even though they get a big premium vs. conventional. Jim Shaffer sold me my system 5 years ago and as far as I know is still the sales manager. That's not usually the case for companies selling smoke and mirrors.

No I don't. Show me the data.

[fantom]

55 minutes ago, Bob_Belville said:

Maybe so......Jim Shaffer sold me my system 5 years ago and as far as I know is still the sales manager. That's not usually the case for companies selling smoke and mirrors.

LOL

In aviation it's common, especially with so many of us spending too much time patting ourselves on the back for our smart, but subjective, choices, and precious little time admitting our mistakes. Sorta like unreported gear ups.

[rbridges]

1 hour ago, Bob_Belville said:

What did replacing the insert cost? Any idea why it failed?

It was under $200.  Kind of a PITA to replace; the screws holding it were hard to remove, and we had to grind them.  I think it's a programmed failure.  The guy at powerflow said they're good for so many hours.

[slowflyin]

I replaced my stock with PF on my F model. (J front end)    I usually fly 8-10k for 2-5 hour legs.   Long legs give me lots of time to fiddle and calculate.  Speed varies depending on the conditions but prior to the PF I ran 144-146 kts.  After I'm running 148-150 kts.   CHT on the hottest jug the same before and after (358-360 #3) all others at or below 350.  I don't have an Aspen to calc the true airspeed so I plug the numbers into the GTN650 after reducing the indicated to CAS per the poh.   I run LOP so CHT was, and is, my barrier to going faster.  It seems I can push a little more fuel for the same temps.  Not sure why?  Nothing scientific from me-just lots of seat time.  I'm a couple hundred hours past the change and very satisfied.  

[Bob_Belville]

I went by their booth in 2014 to pick up a supply of anti-seize and agreed to a short interview. What I said at 2-1/2 years is true at 5 years. 

https://www.powerflowsystems.com/products.php?cat_id=5&pid=46

[carusoam]

You get two choices...

1) A copy of the 1960s standard... for 2amu

2) A new Y2K standard... for 4amu

you need to decide...

1) the benefits when available are not gigantic.

2) If it were measured it would be shorter T/O run, and better climb rate.

3) If it is used to go faster, the cost of fuel kind of gets in the way...

4) the benefits, when it exists are the times when the engine is at full throttle. (A lot of Mooney flight)

5) As a CB I would ask for data to support the T/O and climb claims on my engine mounted on my airplane... (what this thread is about)

6) 2 amu can be a lot of dough for some less than tangible results.

7) where else can the extra 2amu go... 2020 ADSB...?

8) never skip the opportunity to discuss the cost/benefit with the technical people at the company.

A PP Thinking out loud....

Best regards,

-a-

 

[Davarron]

To those that have PFS, is it true that there is a reduction in heat to the cabin during the winter?

[pirate]

With PF my heat system is like a furnace, was like that with the stock system too. 

Another huge benefit with PF is a reduced possibility of CO in the cabin. 

[Hank]

57 minutes ago, Pirate said:

With PF my heat system is like a furnace, was like that with the stock system too. 

Another huge benefit with PF is a reduced possibility of CO in the cabin. 

How do you figure? asks a man with a 2 year old stock muffler and furnace-hot cabin heat that I couldn't run wide open in the winter even when I was based on the bank of the Ohio River . . .

That reminds me, need to go get my CO data from  last weekend off of my kneebkard, but I forgot to run much heat (less than 1/3 open at 44°F ground temp; same at 8500 msl).

[Bob_Belville]

I think there is less heat with the stock PFS than with the factory muffler. I don't need much heat in the SE US so I can't say for sure but I remember that my first Mooney's heater would indeed run me out if the heater was more than slightly open. You might check with Lee Fox who was considering going with an add on feature now available from PFS to boost the heat.

I agree that the PFS which uses heavier gauge 321 SS should be safer vis a vis CO. But I will always use my CO detector, even though I seldom open the heat valve.

[madjano]

Can't say enough good things about AWI. On time, as quoted, and fit perfectly. The welding really is art. Not knocking Bob or PF, I just don't like the looks of the tail pipe. Not so bad on Mooney's but I think they look ridiculous on 172s. Guess I'm in the CB club.

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