Tuned exhaust for 4 cylinder Maules (?) In development

[DavZeeMXT]

Can you give us an approximate time on how long it would take to install this new exhaust from taking off the cowl to putting it back on? I know different mechanics work differently but this is a cost that I would want to factor in as well as the product cost.

[LT4247]

Interesting twist on all this:

http://www.avweb.com/avwebflash/news/Po ... 672-1.html

[st8cop166]

That IS an interesting twist. I think they have a good product so it's not worth it to me for that shoot-down. My problem is the cost with it, but it's a plane part. As my dad used to say, if you can't afford to fly, don't own an airplane. I haven't done a good job of following that advice. I fly and then complain about the cost. Seems to work out better that way and gives me satisfaction.

[cooker]

I'll start by saying I fully support trying new/different/better/just an idea things .... I fly experimental after all.

But i will suggest power flow could have approached this crowd differently. With the ships we fly I have NEVER seen anyone jump up and down and say "wow i gained 6mph at wide open throttle" ..... as Curtis said dyno tests would be good but even simpler for powerflow would be a static thrust test. An impressive static thrust test may turn heads here as that could be translated to real world take off performance which is what maules do best.

The point i am trying to make is the comparisons shown on the web page seem to be at power settings not applicable to a maule but i have never run a 180hp engine so i don't know for sure.

Now the philosophical game ... Lyc has produced and certified the engine to produce 180hp, correct me if i am wrong but i believe they also suggest 75% (or 135hp) is the max cruise power setting. After the exhaust is installed the engine must produce more power at the same setting (burning more fuel and going faster) and perhaps one should back off on the throttle some in extended cruise so that the engine is only producing the 135hp (75% rated) this would likely result in the same cruising speed likely little less fuel burn.

I wish i had a Lyc 180hp operator’s manual here because this doesn't seem right ... WO/2300/50ROP ..... Does anybody run their engine wide open and 50ROP at 4500'??? Seems like a setting for high CHT's

That being said, i suspect my engine produces more than rated hp but i only really use that for takeoff during cruise i back off quite a bit, no sense burning all that fuel it’s not going to go much faster....

Powerflow, thanks for your efforts GA can only benefit from people looking for a better mouse trap. But sorry to say i don't think your test indicate what these guys are looking for. They need somthing to prove they are gonna get off the ground faster!!

[bobguhr]

Seems like we're looking for different things from an upgraded exhaust. Personally, I'd like to have an exhaust that I don't have to worry about when I'm on a two or three week trip into remote Canada ( future bucket list thing). I've had the header to muffler pipe clips crack, I've replaced the flame tubes once, I've had the muffler exit pipe crack around the circumference, Ive had the front inlet pipe to muffler crack at the weld seams and I've had a crack on the front inlet to muffler pipe itself. I replaced the entire muffler once and weld repaired the rest of the times. The funny thing is my repairs do not fail it's always a different section of the system, at one point in time I was welding every 30 hrs although I haven't had an issue for the last 150hrs or so. Maybe I just worked out the major contributing causes. All of my exhaust joints are loose (within reason), I installed the carbon spinner and bulkheads, prop has been brought back to zero time by Sensineich and also dynamically balanced. Its probably cheaper for me to continue repairing what I have than to invest in a $5000 exhaust, but if I relied on my plane for commercial ops or extended remote flying I'd go with the new system or have a quality rebuild/upgrade to the existing exhaust. The reliability and lower maintenance would be my focus any power upgrades would be an added bonus. Just my 2C

[Powerflowsystems]

I would estimate the total start to finish installation time in the 5-7 hour range. There aren't any holes to make in the cowling, but there is going to be time spent rerouting SCAT hoses (heater hoses) and you will have to swap out the induction air "funnel" with ours (also supplied). The kit will include any additional SCAT tubing that is necessary that isn't likely already on your aircraft.

We actually swapped the exhaust back and forth in about 2.5 hours start to finish but that is because we had routed the SCAT in such a way to accommodate both exhaust designs.

Once installed, the exhaust system should be able to removed, disassembled, inspected, slip joints lubricated and reinstalled during an annual in about 1.0 -1.5 hours by the typical mechanic. We can do it faster, but we quote reasonable not best case.

Can you give us an approximate time on how long it would take to install this new exhaust from taking off the cowl to putting it back on? I know different mechanics work differently but this is a cost that I would want to factor in as well as the product cost.

[aero101]

Almost ANY exhaust sys out there is better then the Maule 1940's - 1950's antiquated system, it slops around, has choke points at cylinder to muffler, cracks mufflers, crack tabs at heads, wears out locating pins for tailpipes, all due to nothing built in to allow for expansion, tailpipe must leave lose or rip ends right off mufflers so pins wear out. This is especially true on the 180 HP versions because on top of old engineering, this engine shakes more then most due to large rotating mass with no damper system. To the extent of having to add a damper to front of engine if longer CS prop installed. Of course that's added weight way out front which you don't need!! I needed longer prop as TO performance very important to me, so went fixed pitch, everything is a compromise...

I got really tired of weld repairs on original exh, so went field approval on later style design which has proved to be very reliable... I got really tired and concerned when flying along, hear a change in exh pitch, realize probably another crack to fix... Not only that, but it's a safety of flight item in that fires in the air are NOT GOOD, ever. And I have seen cowl damage including big burned out holes due to cracked systems on all the maules, with the exception of the 6 cyl Conti 360, which is probably smoothest engine out there.... Too bad Maule factory not as enthused as some of their clients, as with minimum investment on their part, there are many mods around that really work to improve performance and reliability. Part of it is economic I'm sure in these times, but it could also eventually get costly in case of lost life or lives. There are other options out there that Maule could do considerably cheaper them $4k on the powerflow sys at the factory and much easier for them to get approval then to do the STC route which is a goodly portion of where your $4k is going with Powerflow as it's an expensive, time-consuming FAA process and they have to be able to recover those R&D costs somehow... I think Maule would be better off forgetting the turbine or diesel M9's and spend that time and money refining what they have out here like most mnfr's do on newer models. The turbine or diesel will be a limited market at best, and how many million are tied up in that certification project already? Don't get me wrong, I love my Maule, they have much potential, are a good airplane for most as is, it's just that there is so much more potential there that is untapped by factory. I've got a book of 337's in my aircraft records to prove that, and would be happy to demonstrate where greatest bang for buck is at... I've got a workhorse that needs to be reliable and perform and now does that well!! That's my 2 cents worth anyway!

[andy]

While a slight increase in power and fuel efficiency are good things, my main goal in replacing the exhaust system on my MX-7-180 would be to eliminate (or at least greatly reduce) the cracking problems without a significant increase in weight. I haven't seen any hard data on whether or not the Powerflow system fixes the cracking problem on 4-cylinder Maules yet. Before I invest thousands of dollars to replace my current system, I need proof that it's a wise expenditure. I'm also not inclined to spend a lot of money on the exhaust system until it's necessary. My current system has been replaced over the years with new parts and there aren't any cracks at the moment.

[Kirk]

I've got an O-540 so this isn't a choice for me and haven't looked at PowerrFlow's site.
I can however, say that climb performance was quite a bit better on a 172 I flew before and after. For our airport it made the difference between a direct turn out to the south with PwerFlow or climb down the valley a while before turning without it.

Cost, weight, etc all hard things to quantify. But I wouldn't look at it as just a speed mod.

Kirk

[rjb]

bump in an effort to hook more supporters

I'd like to get this mod, but I'm pessimistic - oh well, I can always spend the money I should not spend on WAAS upgrade or LiftReserveIndicators or cameras or ...

[DavZeeMXT]

I'm interested also but there aren't many signing up. Only 6 so far listed on the Power Flow web site. Maybe more are like me and sitting on the fence watching to see if others sign up. The cost is high for this system. $4,400 for the exhaust. I'm figuring about $800 for the install. Their warranty seems to state that a dynamic prop balance is required for coverage. That's about $300. Shipping? Maybe about $50-75?
That total is a fairly decent amount of cash but it is an improvement as opposed to spending all kinds of money on the stock exhaust and all I get is back to where I started. Again.

[rjb]

You are pessimistic on the prop balance. Where I am at, not known for its low prices, it was about $150 but the measurements were taken and I was told I was already well balanced and was charged nothing.

I think I'm 5th of the 6 and, one of the reasons for signing on, was that I didn't believe that many others commit - in this case, I would be happy to be proven wrong.

[Hottshot]

The tuned exhaust for the 4 cylinder Maule is heavier than the original - but only by about 6 pounds, not the 16 as you saw with the AWI.

I think we kept things pretty simple but we also stuck to the formula that has a 15 year track record of success and durability. Hopefully the additional 6 pounds isn't a drawback when considering the increase in utility and performance of the aircraft.

We were slightly involved in the AWI pipes and the thing that gets lost in the race is the fact that every time you add more stuff you loose performance in useful load. The AWI pipes added 16# to the nose of the Maule and then the cost was high as well. I applaud Power flow and others for thinking out side the box but the name of the game (at least in my out look) is K.I.S.S Keep it simple stupid.... So I would personally rather have a lighter simple setup to keep my useful load where it makes money and a fat bird makes no money to pay the bills so with that in mind the new aircraft are getting a little thick from a pound here and a pound there now we are at a useful load of 600# from 1000# and we bitch about what we can't do with our planes. Now with that in mind I also would not hesitate to pay the higher cost if it is lighter and the performance is up to par.

my .02 (ramblings and insomnia)

Thank you for the info, I would like to take a better look and see what I can off set the weight with before I would jump. Again Not bashing or other wise as all of the power flow products I have seen are very high quality I am just counting ounces in a future build and want the lightest and best components I gan get.

[st8cop166]

I know this is a controversial topic but having spent quite a bit of money on repairs to my exhaust system, I thought I'd bring this topic back up again for as long as it would last. It appears there have been 6 pre-orders made for the 4 cylinder powerflow exhaust system. The deadline, unless it's changed, is 30 April.

I believe I'm going to pull the trigger on it between now and the 30th. I just don't see how I have much to lose but a lot to gain. I guess if it's not an improvement, then silly me. Maule appears to support the system and a brief discussion with Brent led me to believe he thought it was a good idea.

So . . ..if you are interested, and ONLY if you are interested, this is only a reminder that the cut-off date is quickly approaching.

[Maule988ms]

I'm in.