Bolt-on HORSEPOWER? Tuned Exhaust Installation - Power Flow Systems

and that's the original

exhaust

, you see the problem with these right here, they all leak, that's good, we're not even in vy cool, that's cool, zero zero 22 degrees centigrade sitting for vy at a thousand feet a minute with three people aboard 901 Cross return is approved for our base call. Crosswind turning is approved, no other. We will wait for your call, so we have done extensive research. I know it's a lot to absorb, but you know, I feel under pressure. I'm Josh, a pilot and I fly. Instructor who loves the sky, sharing it with those around me and using it to see the world from a new perspective.

Flying may seem super complex, but my mission is to promote safe practices while enjoying the beauty this world has to offer. Subscribe to scale. the cockpit in future adventures this is aviation 101. new orleans clearance on departure maintain 2000 feet chelsea and i have

flow

n in november 80991 from san marcos, texas to daytona beach, florida home of

power

flow

systems

last two videos on youtube they cover the It took me two days of flying across the country to get here and include a really good look at my creation process and how I work on my planning when it comes to long trips.

Definitely check out those previous videos here on aviation 101 and the full edits of those flights are also in the cockpit club. I have been looking for a

power

flow

tuned

exhaust

system for our cessna 172 for eight years since we bought it and started chatting with power flow

systems

in 2019 about how I could really encompass the benefits of their

tuned

exhaust system for YouTube and we finally made it happen in early 2021. This video will actually cover four days of footage before the test flight with the original exhaust and power flow

installation

and after the test flight on the new exhaust and a brief Summary of the data we collected on both flights in that time, we also installed a Challenger air filter kit, it's basically a high performance air filter that is stc and we also made a dynamic propeller. balance that doubled the power flow exhaust warranty to 24 months or 500 flight hours and actually showed that my prop was very unbalanced to begin with, sure enough, the Challenger air filter will help the engine breathe better and the flow of power The exhaust will help the engine breathe better.

We started this video at the power flow factory in Daytona Beach, where we got some insight from Jim Shafer on how the tuned exhaust does this when the engine is rated. They do this on a dyno with four inch neutral stacks that put absolutely no load on the engine, as soon as those neutral stacks are removed and any exhaust system is put on it will restrict the power to a certain extent and what the Standard designs on most general aviation aircraft actually reduce. the rated

horsepower

between 25 and 35

horsepower

and what the power flow will do will give you back most of that loss up to about 95 percent of the loss, so instead of losing 25 to 35 horsepower on a 160 horsepower engine, you will be generating around 157 to 158 horsepower with a power flow equipped engine, you are not increasing the horsepower rating beyond the rating level, you can't do that , but you're getting a lot more nominal horsepower developed, uh, delivered to the propeller, okay?

Basically, the gist is that the stock exhaust on these older engines is not tuned for performance and efficiency, and because that was not a priority in the design, they actually restrict the flow of exhaust air out of the cylinders and , therefore restricting fuel airflow. charge of air and fuel into the cylinders, basically the engine doesn't breathe as freely and efficiently as it is capable of with this old set of pipes and a big can muffler. Chelsea Darren Tillman of Powerflo and I are taking the November 809.991 to the Atlantic Ocean. hence the inflatable life jackets and we are going to run a comprehensive performance profile to gather data on how my engine performs with the stock exhaust.

We will pay close attention to the revolutions per minute of the engine, the fuel flow which is measured in gallons per minute. cylinder head temperature per hour, chts and a reading of the exhaust gas temperature of each cylinder egs. I learned a lot of things on this flight. One element is the ratio between chts and egts, which is really important in determining the efficiency of the exhaust system. More information about That then okay, so let's do a normal power flow test profile, which is where we want to establish the performance differences between the stock exhaust system like the one you have now and once you install the flow of power and let's go.

To do it under ideal conditions, the same conditions, the exact same weights, the same pilot techniques, the same types of air speeds, so the first thing we're going to do is climb from sea level, so what we're going to do it's because we're close to the ocean, we go a couple of miles out to sea that way we don't have a real lift effect from the ground because we're over the ocean, we also avoid a lot of traffic and the idea is that we'll go down about seven hundred eight hundred feet. positioned so that we can do a straight climb without any turns unless we have to do it because of traffic and we're going to climb straight from a thousand feet to 8,500 feet, okay and what we're going to do is once we pass for a thousand feet you're going to slow the plane down to v and you're going to set v and you're going to go full power maintain your pace v and so between 700 feet and 1000 feet that's your time to fine tune your pace we don't start timing until we get to a thousand we get there to a thousand, we're going to start a timer, okay, every 500 feet, you're going to give me a, you're going to call me, hey, getting closer to 1500, getting closer to 2000.

Once we get to that, ideally one of us will do it. find out who can read the time or better we will tell the time and you are going to tell me the average speed that you have been maintaining, okay, I am going to record the air speed, the outside air temperature, rpm and I am going to try to record as many chd, egts and fuel flows as possible. Fortunately, the camera will back it up properly, so what we'll have when we're done is we'll have time cuts every 500 feet, okay, let's go. To record the rate of climb let's calculate it, okay, it's easier, yes, because it's instantaneous instead of the actual average.

Once we get to 8,500 feet we'll transition to a cruising speed profile, so what are your favorite rpms that you like to cruise at? I like 2450. 24.50 is a great number for the 172. Also perfect rpm for the power flow, okay, because the problem is not super secret is that the tuned exhaust system has a totally maximum rpm response, it's at 24.50 perfectly, you've accidentally been perfect for the test right there, so what we're going to do is we're going to go up to 8,500 feet and we're going to start with a lower power setting for a lower cruise speed, let's say 2300 rpm, we're going to set the engine at 2300 rpm and Tilt it, we'll do it using your normal technique and then we'll need a couple more techniques.

One of the other things you'll see with Power Flow is that you can actually lean the engine at its peak safely and effectively. Same output at dramatically colder temperatures so we'll get our baseline data for that, we'll choose 2450 and we'll also do a wide open throttle number because in the end more power should mean more rpm and up to 8,500 we can do it safely then we'll go down At 5,500 feet we will repeat those numbers, are you ready? I'm ready, sir. Okay, so just to recap as you go through the thousand, let me know you're coming up to the start time.

Shout out the airspeed and I'll record as much as I can, okay, okay, I'll try to keep 80 here and at full power and we're going to keep this track of about three five zero, well done, good. We're set at 80 maximum power crossing 1000 now 82 knots I've got it all right outside air temperature I'm going to go with 17 degrees Celsius 2460 rpm fuel flow seems to be 14.6 good number crossing 1 500 now 52 seconds 81 knots now because it's carbureted, the fuel flow will get a little sluggish, you know, it jumps a little bit, so we look at it and try to take a weighted average to catch it three thousand three minutes 49 seconds 81 knots we copy that outside air temperature 12 degrees back at 24 40 now your egts are amazing yeah they're definitely a lot lower now than after the carburetor was done there's 3 500 4 minutes 56 seconds 82 knots crossing 5 000 8 minutes zero seconds 80 knots copy that eight degrees all right , crossing seven 13 minutes and eight seconds 80 knots okay getting ready to cross 85 17 minutes 51 seconds 81 okay we'll call it 80 knots 80 knots 7 degrees Celsius 470.

I write things down as best I can 9.0 okay, you can level this in 8 500 Okay, what we're going to do is once we've gotten your settings and we think we've got the speed stable and the motor stabilized, we're going to start a timer and wait at least three minutes before recording the data. Alright? plane to establish its balance we have been maintaining 82 knots this whole time level at 85 or more than three minutes, so I'm going to record 82, the time is three minutes, our fuel flow leaned towards you, you're giving us five. eight to six two the outside air temperature here is six, I have it all recorded, okay, oil temperatures, sitting there at 181, that's really good, go ahead and rich, okay, and your new target rpm is 2450, start leaning very slowly, okay?

Let's look at all these exhaust gases. This is now observing the sea. All exhaust gas temperatures. Something will bow first and we are watching to see which will bow first. Now you can feel the power coming off. We are on the poor side right now. Okay, stop there for a second, let it keep coming down now that we've lost 130 rpm. You will have to adjust your hole well. You are doing a good job. You are maintaining pitch. We want to maintain altitude, so we are. I'm going to lose a lot of speed now, this indicator is confusing because it's like really your peak no, not really, but this is where you feel most comfortable, right?

Would you feel this is a good cruise? Yes, I mean just feel. the engine feels like it's leaning a little bit, it's okay, but it feels good, you're not like, oh my god, something is trying to escape from the hood, no, not at all, there are no parts coming off, so it's a hallmark of a really good inclination. especially on a peak, it's okay how close the for example are to each other and, since your smart device says there is a 58 degree difference between the hottest and the coldest, that's more normal for a stock carbureted exhaust, I got it when we get the energy flow there I hope we see a difference well we should do it it's been about three and a half minutes our speed as you predicted has increased again to about 93 93 what I would call 93 to 94 .give it a little benefit, your fuel flow is doing pretty good six, well, right after I said that, right after you said that right, six zero to six three, I think that would be an accurate number for that air temperature. outer which is now seven phts dht 337. 1417 number two is 323 1434 349 14 61 38 1398 okay, so you can enrich on the plane and then take us down gradually.

We'll probably play with some clouds at 5500, I hope not, see if you can get us to 5500. and we'll do the next round of testing set at 5500 with the power flow system, the maximum rpm available will generally increase by 100-150 rpm, so So, if you are looking at a particular power setting, say 2450, it will take a smaller percentage of the available throttle to reach that 2450 rpm level. It is a smaller percentage of 2700 than 2500, which was probably the previous power flow. maximum rpm, so the engine spins less quickly, it doesn't burn, it doesn't. We burn the most fuel in a cruise flight because you can get the same power with a lower percentage of the throttle.

We flew the rest of the altitudes and power settings and gathered all of our data on Darin's performance profile and then returned to Daytona. Beach International, where we then began removing the old stock exhaust to make way for the

installation

of the power flow tuned exhaust system, output Daytona Tower 942 Foxtrot. I'll go ahead and load dirt there so it's less work for us and that's too poor. missing four four zero eight number one or only two five left cover for the option before we float a little grab that sideslip gun now let's go down here in ground effect let the plane tell us when it's ready to stop the sensor hit took off from the Daytona tower change my frequency one two zero point seven holes short row and two five to the left okay, we can dolet the whiskey see the problem with these right here, they leak all many times in the original exhaust you will have cracks in this can right here, especially if the plane is used for training, this is what's under that cover, this is our manifold assembly, the idea behind the tuned exhaust system is a couple of things, number one balanced length, so each cylinder must have a balance length, but it must also have the correct diameter, so what matters It's both the diameter and the length, turns out it's three and a half feet per cylinder, that's a lot of tubes, but that's why you see this big long, winding section. it's so we can get to the right length, but now this section is a large radiator, there are sealed tubes, the only welding is to join the end plate here, these four tubes stick out through this end plate, they are welded all the way to the end . plate, you can see there's like a star in the middle, so the stars are soldered and then we solder the rest and then we do something that most other exhausts don't do.

We send this out for heat treatment in particular. It's called annealing, it's a bright vacuum annealing, so all of this is sent out and under an intense vacuum it's heated up to I think 1825 degrees and then for 20 minutes it's held there and then It goes off quickly to make this material as smooth as possible. Every time you run the engine you are functionally relieving the stress, but annealing takes all the strains and all the stress from this thing that is built, formed, the welding goes on and brings everything back into solution, so there is no a particular hard spot or stress.

Point there, now everything is kind of homogeneous, so what we have here is a Cessna 172 power flow tuned exhaust system with our short stack option, so this would be right here, as far as these headers go, they are relatively shorts. Here and they're going through the long section, on the other side, these really long tubes, we're trying to get the length right because what they're coming in is this, they're going on a shorter length of this tube, so we. We've done everything we can to achieve this, which is why those tubes are so long. We're trying to get the balance length or the correct length because that's what the tuning system has to do to work properly and that's where you can see this section here is the carburetor heat this section here is the cabin heat this is the same part it has a cover the tuned exhaust design allows the engine to develop a greater percentage of its rated power we don't do anything the engine is not designed to do we just let it run the way it is intended It was designed and without restricting flow which the normal standard exhaust does on most GA aircraft, it is a choke point for engines and for most people.

I can feel that because you can feel that when you give it the throttle it wobbles a little bit, usually before it starts to open up and develop its full power, so this is the exhaust pipe, what is this, a two inch outlet, continue two inches and, in fact, it stays. two inches wide, but inside, where these screws are, that assembly that goes up to here is a sound chamber, it's an attenuator, it's a technical term, in fact, it's called a non-obstructive attenuator because the gases don't have to pass through no path that simply continues straight.

I'm going to show you what the inside looks like. What's there is one of these. Look, I can see through it so the gases go in and out. The path has not changed for them, but they are there. running through the sound chamber so here's my cheesy demo but it will work I'm going to take off my mask so you can hear it this is my voice this is my voice this is my voice this is my voice this is my voice It's a pretty effective Fader but Does not interfere with a traditional exhaust system. The gases have to diffuse through their tubes and orifices and they wear out.

This will eventually wear out, but what wears out is this fibrous outer layer that has a 400. With a life expectancy of 800 hours, we specifically designed the exhaust system to be easy to maintain, so when that happens, it will Hold on with four nuts and

bolt

s, get a new one, put it in, align it, drill the new holes and off you go. with the new hardware you're done in half an hour from start to finish, no need to send the muffler out to be rebuilt or anything like that, okay, so we're getting ready to do the test flight, now let's get ready with our life. vests, the wind is pretty strong, it's blowing out of the west right now and we've got some clouds here over the Daytona airport and then we've got a little bit of clouds to deal with out over the ocean, so we're going to take a little bit of an approach. little different about how we are going to do this climb and descent profile because we need a constant airspeed and an uninterrupted climb practically in a straight line, so we are going to find a long stretch of ocean that has clear skies or as clear as we can, put it over the top and from there we will begin the climb at about 700 feet again, start the stopwatch at a thousand and maintain the airspeed until the end, very excited to feel the difference of the plane and hear the difference.

On the engine, I'm very excited to see what the egts and chts are going to do, and the fuel flow is what I'll be very excited about if we can actually reduce it while putting the same amount of power. We went out as much as we could beforehand so that everything was installed. We are done with the preflight topped off with gasoline. We are going to get dressed in our survival gear, life jackets and everything, since we will be on the water. Let's make this post. installation test flight I'm very excited to see how it feels good, the mixer is rich, let's get ready for a climb here, I think everything else looks good, do you remember the sequence and the calls, I think so, well.

They're on the right as far as I can see, okay, and we'll level out right here, it looks a lot better that way, yeah, let's go south, that's good, let's go south, okay, we're leveled off at about 81 .82, is that okay? pass that thousand start the stopwatch please okay turn up the power set the time to 1000 feet 81 knots and we are crossing 3 000 3 minutes and 30 seconds 82 knots the stock climb speed has now flowed dramatically , it's only gone up one grade, okay? in the last 500 feet, which is where we normally see, so this condition represents the worst case scenario.

I am in the Rocky Mountains or a mountainous area. I have to keep doing the sustained climb correctly, so you are very demanding. much of the engine, we are running ahead of the original exhaust even though it is four to five degrees Celsius hotter and much wetter today five thousand feet seven minutes 48 seconds 82 knots copy that your Honda cylinder has now just approached the mark of 400, it is 404, but it is by no means a particular concern, since we are running almost 30 seconds faster at a hitherto cold altitude and that is with worse temperatures, the worst temperatures, so there is more performance if there were It was ideal and we could have done everything like this. that, but that didn't work for us and okay, okay, crossing 6,000, that's 10 minutes and 12 seconds, 80 knots, it holds that rpm number for quite a while still at 2480, which is where it's been for 2000 feet. , what is it.

Really impressive, now your kids are starting to go back as their power density, that's all going down a little bit and now the kid is starting to go up a little bit, but very barely because you just hit the mix, you turned the mix up. about 40 degrees in that egg on the egt, so that's enough for you to know, hey, you gotta get out of a bad situation, there's a little bit more in there, 8,500 feet, 17 minutes and 17 seconds, 80 knots, copy that, so in the end about 30 seconds faster to reach altitude even though it started off significantly well, reasonably warmer normally, when the power flow is activated we anticipate seeing more air in the cylinder and generally the flow of fuel will increase a bit with the wide open throttle setting, however on this climb they were showing a 20 to 30 rpm gain at the lowest fuel consumption with the power flowing not by much two or three tenths and yet , was 20 to 30 rpm higher and was three degrees Celsius warmer on average.

The video itself shows the most appropriate thing as a segway is stay tuned, yes, you know, stay tuned for the only thing I can say, be perfect for what I'm doing, that's right, stay tuned particularly for your escape, exactly right from time to time when, when someone really starts to be nice. to make a bit of fun joking I said you know I'll say we've done extensive research I know it's a lot to take in but you know and then they say oh please stop, you're killing me, I'm like me I'm sorry, you feel under pressure, yeah , bad, that's good, let's go full throttle now, okay, because that's how we're going to start at full speed anyway, we might as well go full speed and play with it, so let's go. go ahead and go full throttle and lean at the best power like you've seen and after that we're going to play with the mixture to see how far we can take it with the engine good and I would like you to To start slowly leaning the engine, I want to see how many rpm we can get out of the engine without problems, so when you start to affect the shift, just stop, wait a moment or two, right there, wait a second and let everything equalize. look what happens with the cgts, they will level out and start to go down, yes, I see how you would characterize this something soft something soft, is this, beyond your comfortable point, yeah, I would probably want to go a little richer, so let's play richer and let's just give it a second because you can see how much you affected that, yeah, so I think there's a sweet spot somewhere in the middle.

What I want to try and do is get us to 2450. because if I'm doing it right we should be able to max out and save fuel and run the engine cooler and get the same airspeeds of course I'm trying to show you on camera with this all the different things that you're going to be able to play while you're flying and doing a lot of off-roading, so don't be afraid to do this kind of stuff because Lycoming number one says if you want the engine to run cooler, lower the engine temperature. the cylinder head lower the oil temps, well you're going to do everything right no matter what, for example all you're doing is cooling the air with extra air instead of excess air instead of excess fuel, that's it.

I'm doing um and right now this is trying to say hey, we think you have a peak tilt of seven degrees. I'm not sure I buy that, um, but you're a carbureted engine, so this is really cool now. We're down to a third, less than a 40 degree difference, I think we may have finally found our sweet spot, so it really wasn't 26 10. We ended up starting at 25 30. We brought it down to 24. Well, I was trying to take it at 24.50 and now it is 24.30. So previously on the rich side of the peak we were burning a gallon an hour or more, one to a point two gallons an hour.

The only other one we could get would be a completely open one. Accelerate well please, now it's good that you're getting more net rpm. Previously you could see maybe 26.90, that's pretty good when it's been stable, it's been 27 30. Yeah, 27 28 to be exact, yeah, yeah, so I mean it's kind of solid, okay? It clearly makes more power, you know you can go forward and turn around if you want and you can go back and descend and all that so your plane can actually get up and fly. That's really good. Daytona Tower Skyhawk eight zero and then. another straight on two five left hear zero nine on a daytona left to clear the line two five left clear to land eight zero now another one, but what's the other thing that's going to happen?

Because your engine should be much more responsive, so if you ever had to rev the engine for a moment, that doesn't have to happen at all I have you two five left and contact the ground without delay travis accident in coastal wildlife 476 right at the end and contacts the ground without delay november not around one turn turning around not another 901 spark one two zero four one capable traffic left two five left I will call the crosswind turn left traffic 1204 in the squad look at the flaps up one that's good we're not even at vy cool that's cool five hundred Dollars have increased productivity at the end of airport sanity one two zero zero 22 degrees Celsius going down to vy doing a thousand feet per minute with three people at board and a crosswind turn is approved for a call to the base crosswind turn approved now another one, we will wait for your call and you already did your practice of turning well.

I was going to say you were telling me about how to harness the power in a lap and that's it. I have both the traffic and the view, Romeo's age is perfect, so you. re the number four following the south now turning the base from eight to five to the left numberfour all to the right the track is ours it was coming the inactive tracks were done oh make sure you keep going if you are developing chts in the 400 450 500 range that are seriously affecting your engine law. longevity and with this, with the power flow in a properly tuned engine, you generally see three maximum 380s even on climb, so it is important that you keep it in the healthy operating ranges almost as long as you can develop your full rated power at those rpm and at those engine settings, uh, without stressing the engine and you're never in a situation where you're trying to get more out of the engine than it's capable of producing, you're going to get rated power or very close to it at all the operating regimes of the aircraft darren spent many hours behind the desk compiling a summary of our before and after numbers on these flights all of this data has been corrected for temperature and pressure and this is what we saw time to climb from 1000 feet to 8,500 feet msl was 34 seconds faster with power flow, wide open throttle at 8,500 feet produced 6 knots more true airspeed with power flow exhaust, but with the same fuel flow. fuel than the original exhaust, which the engine tells me right there.

It's running much more efficiently at wide open throttle at 5,500 feet with the power flow installed, it produced 30 rpm more than the stock exhaust, five extra knots, and we burned 1.5 gallons per hour less, which is a perfect example of how the engine breathes better with the added tilt capability. with the powerflow exhaust is also super impressive, the stock exhaust with a rich peak at 8,500 feet at 2450 rpm produced 97 knots at 7.1 gallons per hour, while the powerflow tuned exhaust allowed us to run with a lean peak also giving us 97 knots, but now at gallons per hour at the same speed for 1.1 gallons per hour less, the oil was also reading 9 degrees cooler and all cylinders were also reading cooler which made this all finally come together for me it was when Darren described the egt and cht relationship to me in simple terms.

The power flow produces hotter egts when leaning because it is effectively sucking more heat from the cylinders than the stock exhaust. Heat has been transferred from the cylinder heads to the exhaust gases, hence lower chts, higher egts. This, combined with better intake through the Challenger air filter, means the 80991's engine breathes better than ever. Better breathing means better cooling, better performance and a longer lasting engine. I have been contemplating installing power flow for years and my first hand experience with the system and the company has shown me that I should have done this a long time ago.

They have a really amazing product line that is backed by data, the company and everyone. In it is an absolutely incredible big thank you to Power Flow Systems for making the process so easy and using their expertise to bring a much-needed product to the legacy general aviation fleet. You can learn more about power flow by visiting the link below in the description and Full versions of these high-performance flights are available at Aviation 101.com Cockpit Club. If you're interested in seeing them in the video below, Chelsea and I are desperately trying to get in touch with Daytona clearance.

We fly over NASA. Visit the factory. from an experimental aircraft manufacturer and we take a few days to cross Florida, where Chelsea gets more first-hand IFR experience as we head to Pensacola. Subscribe and turn on notifications so you don't miss the next content. Definitely leave a comment. below, I would love to hear your feedback on this video and all the technical content we had in it and until next time, everyone who knows the drill, stay happy, healthy, updated and most importantly stay competent, we'll see you in the next flight. protect you