Power Flow Exhaust Opinion

[PTK]

I'm going to have a visit with the exhaust department at next annual and was thinking about powerflow.

Anyone would like to share real world experiences with it. Is there any performance gain worth the cost?

Thank you all in advance for any input.

[Jeff_S]

I know one guy who has put the PowerFlow on his J.  He said it showed a greater improvement on his prior F model but that he feels he gets at least a bit more power in the takeoff and maybe a slight speed increase.  PM me if you want and I'll give you his contact info. He lives in Augusta GA but I don't think he frequents Mooneyspace.

[rbridges]

I thought I read that the performance gains weren't as apparent on the J models vs the older models.  I know people that have put them on O-320 and O-360 engines that seemed pleased with them.

[Bob_Belville]

I have PFS on my E. Unfortunately I found that my exhaust system was bad shortly after buying the plane and took that "opportunity" to upgrade so I have no solid "before" data. More subjectively, I am well satisfied. But I now have a JPI EDM 930 so I have excellent numbers now.

 

I took some pics of Aspen and JPI on a 10/1/2013 flight MRN/MFV. MAP was 20.3 @ 11,000', the highest I've been - first flight since adding O2.

LOP I was making 146 KTAS - see Aspen pic. I don't have a pic of the 930 while ROP but the data analysis indicates I was pulling 66% HP ROP vs 61% LOP. JPI also  indicates the GS dropped by 8 K when I leaned to 8.3 GPH so ROP @ 11,000 was 154 KTAS. (The JPI does not show TAS, only GPS GS.) 

 

I was running about 2550 RPM so I would think I would have been close to 70% and 158 KTAS @ 11,000 @ 2650 RPM.

 

This is quite close to the original '66 Super 21 manual which most folks considered pretty optimistic even for a new plane -- mine is a little grey around the temples at 48 years old. I would have to credit the tuned exhaust for some hp improvement.

[Marauder]

Bob -- with the factory coming back, you can buy a new set of yokes! I did mine in the 90s changing from these:

[Bob_Belville]

B26, that pic is ugly! You don't think the yokes are not up to the standard of the rest of my panel/interior?

Bob -- with the factory coming back, you can buy a new set of yokes! I did mine in the 90s changing from these:

 

Honestly, I kind of like my old style, thin, yokes vs. the 201 heavy style. They feel good and are less in the way of reaching/seeing panel - e.g. tuning the Aspen.

When maneuvering ISTM the pilot is more in touch with the plane. I stripped off some kind of wrap material that a previous owner had covered them with. I would like to have refinished them when they were off during the panel replacement but the shop told me the feds frowned on powder coating the "plastic" yoke - gets the polymer too hot.  

 

I wonder if I'm the only one who likes a thin yoke?

[pirate]

Power Flow was the best performance upgrade I've done, I also like having less chance of carbon monoxide problems.

[Bob_Belville]

Pirate, interesting. Can you elaborate? What model Mooney? Comparison data?

 

Bob

[Marauder]

B26, that pic is ugly! You don't think the yokes are not up to the standard of the rest of my panel/interior? Bob -- with the factory coming back, you can buy a new set of yokes! I did mine in the 90s changing from these: Honestly, I kind of like my old style, thin, yokes vs. the 201 heavy style. They feel good and are less in the way of reaching/seeing panel - e.g. tuning the Aspen. When maneuvering ISTM the pilot is more in touch with the plane. I stripped off some kind of wrap material that a previous owner had covered them with. I would like to have refinished them when they were off during the panel replacement but the shop told me the feds frowned on powder coating the "plastic" yoke - gets the polymer too hot. I wonder if I'm the only one who likes a thin yoke?

The reason I upgraded was due to the AD on the control rods. Upgrading mine eliminated the AD (BTW -- I think it was an AD). I actually liked the beefy yokes. Especially in heavy turbulence, gave me something to hang on to. The downside it was hard to mount all of the AP hardware on it and be able to reach everything easily.

[fantom]

The Power Flow people made a presentation to the Mooney group down here, maybe 5 years ago, and under questioning they said that there was little if any speed increase for a J model. The only benefit was said to be a slight one in takeoff/climb. They also freely admitted that a fair number of the J exhausts were sent back to them after the guarantee period.

 

There is about the same amount of irrefutable speed data for this exhaust as there is for the Lopresti Cowl

[PTK]

Interesting Gary. Thank you. At least they're honest about it.

 

My impression was similar based on what I've been hearing and reading.

 

Just not as dramatic and resounding.

[Mooneymite]

Perhaps someone with a better memory can help, but I seem to remember that there is a problem with Mooney Power Flow exhaust longevity.  I think I read "somewhere" that after a few years, the interior pipes collapse and restrict the exhaust....

 

Anyone else remember?

 

 

[carusoam]

A small increase in HP shows up in T/O distance... 10% more HP, gave my O 30% shorter ground roll...

280 HP. 1200' ground roll. (Source POH)

310 HP. 800' ground roll. (source STC and measured by CloudAhoy app.

So, if ground roll improvements would be helpful, this could make sense...

Using 90's technology to improve airflow through the engine makes sense...

Both intake and exhaust improvements...

But if looking for cruise speed improvements, drag is very powerful. Adding 50% more power helps...

Best regards,

-a-

[Bob_Belville]

The annual preventive maintenance involves putting anti-seize on the slip joints. Haven't heard anything about the useful life of the guts. Not to say that isn't an issue.  (My A&P grumbled but complied.)

[jetdriven]

The Power Flow people made a presentation to the Mooney group down here, maybe 5 years ago, and under questioning they said that there was little if any speed increase for a J model. The only benefit was said to be a slight one in takeoff/climb. They also freely admitted that a fair number of the J exhausts were sent back to them after the guarantee period.

 

There is about the same amount of irrefutable speed data for this exhaust as there is for the Lopresti Cowl

I asked them for a discount on a J exhaust as a sponsorship for air racing and in return I would put their name on the side of the plane and show real results in top speed. They refused.

[PTK]

http://www.planeandpilotmag.com/aircraft/modifications/accelerating-a-mooney.html

 

This article by Bill Cox seems to suggest that for the Mooney we should see "increasing benefits at higher altitudes."

 

He seems to think that the system delivers what it says it does. 

 

It's just that, for the J anyway, the benefits don't seem earth shattering.

 

Interestingly, he says that oil and CHT's showed a slight reduction.

[Shadrach]

The Power Flow people made a presentation to the Mooney group down here, maybe 5 years ago, and under questioning they said that there was little if any speed increase for a J model. The only benefit was said to be a slight one in takeoff/climb. They also freely admitted that a fair number of the J exhausts were sent back to them after the guarantee period.

 

There is about the same amount of irrefutable speed data for this exhaust as there is for the Lopresti Cowl

How does that work I wonder? Same displacement...same head design...same intake manifold (yes I know the J has a better air box, but with RA open, that is negated)... slightly different exhaust set ups, but last I looked the J was a mess of tubing welded together in a way that could hardly pass as an extractor.

So I wonder why they're able to get more HP out of an F or an E? Are the saying the A1B and A3B engines have more HP stock (real HP, not certified) than an A1A?

[Bob_Belville]

How does that work I wonder? Same displacement...same head design...same intake manifold (yes I know the J has a better air box, but with RA open, that is negated)... slightly different exhaust set ups, but last I looked the J was a mess of tubing welded together in a way that could hardly pass as an extractor.

 

So I wonder why they're able to get more HP out of an F or an E? Are the saying the A1B and A3B engines have more HP stock (real HP, not certified) than an A1A?

You don't think that Roy Lopresti would not have "tuned" the F exhaust to some degree while he was tweaking a veritable shopping list of little things to get to 201?

[Shadrach]

You don't think that Roy Lopresti would not have "tuned" the F exhaust to some degree while he was tweaking a veritable shopping list of little things to get to 201?

I'm not a propulsion engineer (and neither was Roy), but almost every aircraft exhaust I've ever seen has been designed space in mind, not performance. The stock J exhaust is no exception.  I don't beleive did anything to the J exhaust.

[KSMooniac]

I'm not a propulsion engineer (and neither was Roy), but almost every aircraft exhaust I've ever seen has been designed space in mind, not performance. The stock J exhaust is no exception.  I don't beleive did anything to the J exhaust.

 

I concur.  My opinion of the J exhaust is that it was designed by sticking a muffler in the biggest open space left, and then connecting 4 tubes up and one down/out and called it good.  I think some of the RV kit planes have some innovative exhausts since they have the freedom to optimize...

[Bob_Belville]

I concur.  My opinion of the J exhaust is that it was designed by sticking a muffler in the biggest open space left, and then connecting 4 tubes up and one down/out and called it good.  I think some of the RV kit planes have some innovative exhausts since they have the freedom to optimize...

Well OK. Then why can't the gurus at PFS improve on the unengineered J exhaust? No one who ever souped up a hot rod would say that the exhaust doesn't count.

 

I know nothing, just wearing my skeptic hat tonight with my Mooney 900 miles away being torn down and the Sox game 30 minutes away. I did get 5 cases of muscadine wine bottled today, not a complete loss.

[Wistarmo]

I have one on my 93 J model MSE and did not see any improvement. Please see the post by PTK and the article by Cox in Plane and Pilot. The exhaust was optimized for 11,500 feet.

[KSMooniac]

I bet some minor improvement is possible, but as pointed out PFS chose for some crazy reason to optimize it for 11,500 +/- instead of a more common and optimal altitude for E/F/J pilots at 7,000-8,000 feet.  I don't know enough about the physics behind the design to understand what would be different to tune it for a different altitude, but it was a bad choice IMO.  Perhaps they just tried to equalize the pipe lengths and see what they got, and the only improvement was shown at 11,500 at which point the marketing bunch took over and said it was optimized for that altitude?  

[Steve Dawson]

Does it heat the cabin as well or better than the original?

[kmyfm20s]

I asked them for a discount on a J exhaust as a sponsorship for air racing and in return I would put their name on the side of the plane and show real results in top speed. They refused.

You need to take advantage of the 60 day 100% satisfaction guarantee for us all and give us a PIREP! You would have the best metrics out of any of us.