I am putting an O470L in a Stinson 108-3. Are there some exhaust systems better than others for an O470 as far as making more power? Thanks

Just put some straight headers on there. Who is gonna give you a ticket?
Then, it will sound like the baddest bush plane landing at JC !!!!!

OK... I will be serious this time.
On another thread there were some comments about exhaust components. I said at annual this year, the IA found holes in my collectors. We used the Knisley new collectors and reduced the parts count from about 10 to 3. They are about $700 per side. The shop sent my muffler in for overhaul... and the charge was $350. It looks brand new. I don't think they re-use many parts at all... on the old metal. My 470 dates from 1957 on the Cessna. Hope that helps a bit.
It just means they don't have to PMA a new part.

Getting more power from an exhaust system, as far as I have read, has been fairly discounted as far as producing any worthwhile extra HP. At least for these engines. I know from experience that exhaust makes a huge difference with motorcycles engines, and it's everything for 2-strokes, but I would be surprised to hear that any Powerflow users experienced noticeable performance increase. What does tuned backpressure get you anyway? I think the best use of exhaust is to make a quieter machine, like that "sneaky bastard" stealth Rans S7 guy.

Treefeller wrote:Getting more power from an exhaust system, as far as I have read, has been fairly discounted as far as producing any worthwhile extra HP. At least for these engines. I know from experience that exhaust makes a huge difference with motorcycles engines, and it's everything for 2-strokes, but I would be surprised to hear that any Powerflow users experienced noticeable performance increase. What does tuned backpressure get you anyway? I think the best use of exhaust is to make a quieter machine, like that "sneaky bastard" stealth Rans S7 guy.

These guys are claiming 15hp gain... if they would ever finish it.

http://www.wemakeyoufly.com/cessna-airc ... st-system/

Powerflow doesn't make exhaust systems for O470s, but they make the same sorts of promises for smaller engines. My IA has installed several Powerflows on O360 Lycomings, and while his customers feel that they derived some benefits, it's his opinion that they benefits are pretty small. Of course, after you've spent $4-5K on something that is supposed to give you more power, you'd probably want to believe that you now have more power! For my money, it would be better to get something that makes no promises of more power but instead promises to last longer.

Cary

My stock exhaust in the Skywagon is a bit short and Im tired of cleaning the belly. Thinking of going with a seaplane exhaust etc... Anyone have a good suggestion on where to look or a good upgrade?

Thx-

Check out Knisley exhaust, AWI can make you an "overhauled" one, but I couldn't detect anything other than brand new stainless. AWI is a great company, also made my seaplane mount.

Only issue I've had is one cone burned out in 300 hours, latest muffler has around 600 on it with zero issues. Never had any issue with rest of exhaust. Breaths much better than stock, and a way better design IMO.

Upgrade... there's a 1954 C180 for sale now on Barnstormers that has a Leading Edge exhaust system. It used to belong to a cousin (?) of our own Quickdraw-- maybe he can provide a pirep or an opinion on how much of an improvement it was.

Seaplane exhaust...seems like the ones I've seen were just standard exhaust systems with a longer tailpipe bolted on, so the exhaust trail would miss the float rigging. Knisley, Dawley, etc should be able to do something along that line.

I spoke with the AWI rep at OSH and am leaning toward that unit. They sell a seaplane unit. This has aprox 3" longer pipe along with a thicker muffler (.050)

bigrenna wrote:My stock exhaust in the Skywagon is a bit short and Im tired of cleaning the belly. Thinking of going with a seaplane exhaust etc... Anyone have a good suggestion on where to look or a good upgrade?

Thx-

My ride is fitted with a seaplane muffler.

It is from acorn welding: http://www.acornwelding.com/pdf/Cessna/ ... 82_185.pdf

The engine makes great power and sounds really good. I have had an issue with it. There is a bolt that threads through the clamps, header pipes and muffler that is used to prevent the muffler from rotating. The bearing surface on the muffler is not sufficient to constrain the muffler against rotation with the additional drag of the longer pipe. The exhaust pipe is rubbing against the cowling, eating away at the aluminum. Bad design detail, but I believe that this is unchanged from the stock installation. I am working with my mechanic right now to develop a solution.

There is this one as well: http://www.fadodge.com/index.php?option ... &Itemid=53

The price doesn't actually seem too bad on the Dodge muffler.

Have been working on the lee's exhaust put it on my 182B. Should finish up flight tests this week weather permitting. This is a life time exhaust. Very well built. Seat of the pants HP increase I think so.

The LEE perf claims sure would be nice... I do find it a bit hard to believe the stated 15HP increase. Bold statement out of a 230HP engine. Sure would be nice if its true. Price tag is a bit painful though. AND they want to stick you with an additional $750 to add a couple more inches on the pipe for the seaplane unit.

I installed a seaplane muffler from FAD on my 182. It has a better flame cone design without single cones on each end. It has one through pipe flame diffuser that seems to hold up much better then the old style. It must be heavy wall because it is very heavy. If you want a longer tail pipe they will weld one any length for pretty inexpensive. The tail pipe is an oval shape so you usually have to grind your shroud and sometimes the cowl hole.

bigrenna wrote:My stock exhaust in the Skywagon is a bit short and Im tired of cleaning the belly. Thinking of going with a seaplane exhaust etc... Anyone have a good suggestion on where to look or a good upgrade?

Thx-

Custom Air Parts in El Cajon CA has done 8-10 Skywagon collector/muffler sets for me. I think it runs 8-900 with shipping. He put the seaplane pipe on mine and it does a great job of keeping the exhaust off of my belly AND my pod. I think Clint is the guy to talk to. He is not a repair station, so you won't get a yellow tag. I think he reuses the holes, because they come back looking brand new. Text me tomorrow and I'll send some pics of his work if you'd like.

The outfit in El Cajon rebuilt an Avcon muffler for my C150/150. Very nice work, reasonable price, and quick turnaround. I'd use him again.

Thx all. Was impressed with them at OSH, so I went with AWI for the longer pipe. Ordered yesterday. Will have my stock exhaust (low time/perfectly fine) 4 sale here if anyone needs it. PM if interested.

AWI is good people, you'll be pleased with their products & service

Clinton Anderson is a personal family friend & the owner of Custom Aircraft Parts in El Cajon CA, He has been in aircraft exhaust business since 1975 & his shop does excellent work. I have had him do the exhaust for several of my planes with complete satisfaction. As a little side note, he was also 4 time World record holder in top fuel hydroplanes (235 + mph 1/4 mile) so he knows a little about making HP! He has an excellent crew that pay extra attention to detail.
http://www.customaircraft.com/

Vaughans