powerflow exhaust needs repair. who can do it?

[rbridges]

Looked great when I left Destin, but when I put it back in the hangar, I noticed the insert hanging out the tip.  Left a message with my IA, but I'd like to hear from any of you that have had a similar situation.  I have a few more trips planned in the near future, and the less amount of time it's grounded, the better.

[N201MKTurbo]

Did you call Power Flow?

[rbridges]

Did you call Power Flow?

 

I'm doing it right now.  

 

Edit---Should have done that first.  They're sending me the insert.  Running me around $200 with shipping.  The guy at powerflow said it's a 30-60 minute job.  Awesome!

[aaronk25]

Good deal glad it was a easy fix! These powerflows' really make the 201 come alive.

[rbridges]

Good deal glad it was a easy fix! These powerflows' really make the 201 come alive.

 

and the C models, too!

[Hank]

Be glad, Rob. I just replaced my regular muffler and tailpipe at annual. Since I needed new, I looked at Power Flo and nearly fainted at the price, to say nothing of the labor required to mount it.

Will you be flying again Sunday, or do I need to divert?

[rbridges]

Be glad, Rob. I just replaced my regular muffler and tailpipe at annual. Since I needed new, I looked at Power Flo and nearly fainted at the price, to say nothing of the labor required to mount it.

Will you be flying again Sunday, or do I need to divert?

 

I should be good.  Part is arriving tomorrow, and we should be installing it Friday (fingers crossed).

[Guest]

Be glad, Rob. I just replaced my regular muffler and tailpipe at annual. Since I needed new, I looked at Power Flo and nearly fainted at the price, to say nothing of the labor required to mount it.

Will you be flying again Sunday, or do I need to divert?

Not just expensive to buy, they require regular disassembly for cleaning and lubrication of the slip joints.

Clarence

[aaronk25]

Not just expensive to buy, they require regular disassembly for cleaning and lubrication of the slip joints.

Clarence

Hey but show me so thing else that you can bolt on and make 5-10% more HP? With cooler cht? My 201 laid down another 6kts after install....

[Bob_Belville]

http://www.powerflowsystems.com/news.php?nid=99

 

[Guest]

Hey but show me so thing else that you can bolt on and make 5-10% more HP? With cooler cht? My 201 laid down another 6kts after install....

One of these will do that:

[aaronk25]

One of these will do that:

Weeeeeeeeee

[Bob_Belville]

One of these will do that:

IO720? Comanche 400?

[PTK]

Hey but show me so thing else that you can bolt on and make 5-10% more HP? With cooler cht? My 201 laid down another 6kts after install....

How are they measuring this HP?

Are they measuring torque?

Show me the data!

The only parameter they like to throw around is TAS. This can't be relied upon to measure performance.

Variables such as temp, DA and weight affect TAS.

Way too expensive for a questionsble 3 kt gain which is paid in gold by higher ff.

This tells me that my stock exhaust is not as inefficient as they'd want me to believe! Certainly not 5 grand worth!

[Guest]

IO720? Comanche 400?

That it is Bob, its a blast to fly! Less so at the fuel pump.

Clarence

[Bob_Belville]

That it is Bob, its a blast to fly! Less so at the fuel pump.

Clarence

I have 2.0 hours in my log book of PA24-400 time from 1979. My A&P/IA owned one. 100/130 was (under?) $2.  

[aaronk25]

How are they measuring this HP?

Are they measuring torque?

Show me the data!

The only parameter they like to throw around is TAS. This can't be relied upon to measure performance.

Variables such as temp, DA and weight affect TAS.

Way too expensive for a questionsble 3 kt gain which is paid in gold by higher ff.

This tells me that my stock exhaust is not as inefficient as they'd want me to believe! Certainly not 5 grand worth!

Hey don't worry about it then..you can scratch that off your purchase list right next to cam guard......the rest can enjoy.

Wanna race? Does your bird true at 170kts?

[Guest]

I'll race you! My best so far is 199KTAS at 7500'

Clarence

[carusoam]

According to that article...

They measured the torque using a dynamometer. The O320, they used, gained 24hp...(133 to 157 hp)

To gain 10% hp for the IO550, the STC alone costs 5amu...

The 10% increase should have a strong seat of the pants effect that would also be measurable using a WAAS SkyRadar combined with CloudAhoy...

Take off distances and climb rates are better and more noticeable than overall speed increases.

Additional fuel used for the shortened T/O will be hardly noticeable...

What is important, is the actual improvement over the stock Mooney exhaust. That is not covered in this article...

If you come out this way and want to borrow my SkyRadar....

My thoughts,

-a-

[PTK]

According to that article...

Take off distances and climb rates are better and more noticeable than overall speed increases.

-a-

And this is precisely because drag increases as the square of velocity. Reason why hp conversions, without involving prop, improve climb and takeoff distance a lot more than cruise speed.

But I have a couple of questions for the folks with power flow experience who claim they've gained considerable kts in cruise from it:

Are you seeing these speed "gains" ROP or LOP? and

According to your experience, how much hp would you say it takes to increase your cruise speed by those few knots you've seen?

[aaronk25]

And this is precisely because drag increases as the square of velocity. Reason why hp conversions, without involving prop, improve climb and takeoff distance a lot more than cruise speed.

But I have a couple of questions for the folks with power flow experience who claim they've gained considerable kts in cruise from it:

Are you seeing these speed "gains" ROP or LOP? and

According to your experience, how much hp would you say it takes to increase your cruise speed by those few knots you've seen?

Whoever answers answer very carefully this is a trap where a vague question gets asked and he's gonna hammer your answer with quoted engineered science......

In a effort to avoid the trap I will answer vaguely.

At peak egt speed has increased from 158 to 164kts. ROP gains are better. LOP gains are slim, with the difference being the engine doesn't like to run anymore than 20lop. The whole spectrum slides from operation at 20lop to peak egt, which the redbox fanatics will cringe at, however CHTs are 30 degrees less at any power setting so since the combustion chamber is cooler detonation margins are increased, therefor allowing operation closer to or inside the previous "redbox".

Egts are in the 330 range instead of 360 range.

What this exhaust system does is by utilizing proper design it allows for more hot exhaust gases to evacuate the cylinder during the exhaust stroke than what a more restrictive stock exhaust system does.

20lop gains equate to about 2-3kts or if same speed as previous is desired about .3-.5 gph less. Not huge, but the nice thing is that most climbs are ROP and since ROP operation yields more return the benefits result in shorter takeoff rolls and 200fpm better climbs.

The gains are also better at higher Rpms because this is where a less restrictive exhaust really shines; when there is less time for the exhaust gases to evacuate.

I will add something that doesn't apply to us certified aircraft is that a friend at my airport who flys experimental aircraft that has the same engine as our J uses has done extensive testing with MOGAS and the powerflow exhaust allows him to comfortably operate on Mogas where with a stock exhaust it wasn't practical as the mixture had to be run 150rop or 50lop to stay out of light detonation. Detonation margins are greatly effected by heat, and the powerflow evacuates more heat. But this doesn't really apply to our aircraft given the current state of FAA regulation but it's a interesting concept.

[PTK]

The laws of physics simply will not allow you to decrease hp and increase airspeed.

When rop it is airflow that determines hp. Study the hp curve. What do you see? Do you still think you're seeing increased speed at peak egt?!

The only thing a tuned exhaust does is increase airflow somewhat. Air flow is a function of rpm and mp, i.e. Rop.

Does a tuned exhaust make more sense on my high revving bike? You bet! On my Mooney? No!

Who am I to wake you from your dreams! Physics will however, set you free!

[Andy95W]

The laws of physics simply will not allow you to decrease hp and increase airspeed.

When rop it is airflow that determines hp. Study the hp curve. What do you see? Do you still think you're seeing increased speed at peak egt?!

The only thing a tuned exhaust does is increase airflow somewhat. Air flow is a function of rpm and mp, i.e. Rop.

Does a tuned exhaust make more sense on my high revving bike? You bet! On my Mooney? No!

Who am I to wake you from your dreams! Physics will however, set you free!

Where exactly did aaronk25 say he had increased airspeed but decreased horsepower?

[PTK]

Can we safely put you down in the "I am not sold on it" category?

Yes, in the "not sold on it" for worthwhile cruise speed gains with my slow turning engine/prop category!

Where exactly did aaronk25 say he had increased airspeed but decreased horsepower?

I asked aaron25 to share his experience by answering two very specific questions:

how much hp does it take to increase speed by those claimed few knots? He didn't have an answer.

and are those few knot speed "gains" seen rop or lop? Answer was peak! Peak?! Really?!

Which prompted my suggestion to revisit the engine curves and study them.

[aaronk25]

GeeZe...I want to change my story, after further studying I believe camguard deserves the credit for the additional speed gains.

Sorry for the confusion.