sutton exhaust system
- Thread starter deerhunt
- Start date
Speedo
FOUNDER
TN
It's a clean installation that leaves plenty of room between the accessory case and the firewall. The only trouble I've had with it is removing and replacing the fasteners that hold the exterior shroud. The shroud needs to be removed for inspection during the annual, and the fasteners are hard to get to. If you don't get the fasteners tight when you re-install them they will vibrate their way loose. It helps if you have tiny but powerful hands.
The standard length exhaust tube (the part that passes through the lower cowling) is longer than the stock tube, and some folks don't like the way it looks. Personally, I think it's better: it means the exhaust dumps out farther from the door, and on my plane no exhaust gets in the cabin. It does leave exhaust stain on the gear leg, but that's really not a big deal.
The Sutton exhaust eliminates the 100 hour recurrent inspection, which is nice. It's well fabricated, and you will probably like it.
The standard length exhaust tube (the part that passes through the lower cowling) is longer than the stock tube, and some folks don't like the way it looks. Personally, I think it's better: it means the exhaust dumps out farther from the door, and on my plane no exhaust gets in the cabin. It does leave exhaust stain on the gear leg, but that's really not a big deal.
The Sutton exhaust eliminates the 100 hour recurrent inspection, which is nice. It's well fabricated, and you will probably like it.
I put the Sutton exhaust system on my homebuilt supercub (NorthStar). It is engineered just like the Cessna 180/185 exhausts; downtubes coming directly into a horizontal muffler. I chose the option of enhanced heat output (increases heat transfer inside the heat shroud). Shroud is easily removed via 6 sheet metal screws across top. With muffler up front, lots of room behind engine.
Stack length: I cut it down and put the angled-back piece on it, because on 180s, adding extra length of stick-out with for instance a seaplane extension increases stress where the stack comes out of the muffler. This is a very common place for cracks, and often difficult to repair weld.
The Suttons have their system fabricated by Dawley; they are an excellent PMA shop and do beautiful work. Everything fits perfectly, welds are great. I DID find that inlet air to exhaust was in front of #1 cylinder, and outlets to carb heat/cabin air were on left, necessitating reversing inlet tube to carb air box and modifying front baffles. This all required A LOT of rework to CubCrafters baffles and carb air box. Oh well, it's an experimental, with a capital E.
Stack length: I cut it down and put the angled-back piece on it, because on 180s, adding extra length of stick-out with for instance a seaplane extension increases stress where the stack comes out of the muffler. This is a very common place for cracks, and often difficult to repair weld.
The Suttons have their system fabricated by Dawley; they are an excellent PMA shop and do beautiful work. Everything fits perfectly, welds are great. I DID find that inlet air to exhaust was in front of #1 cylinder, and outlets to carb heat/cabin air were on left, necessitating reversing inlet tube to carb air box and modifying front baffles. This all required A LOT of rework to CubCrafters baffles and carb air box. Oh well, it's an experimental, with a capital E.
JMBreitinger
Registered User
Minneapolis, MN
I have the Sutton Exhaust on my 160 HP PA-18. I love it right up until winter. I am not getting nearly as much heat output from mine as I did from the stock system that I replaced. I know that there is a cold weather kit. Has anyone had experience with this?
Bugs66
Registered User
Spokane WA
Not the Sutton exhaust, but I have the Custom Aircraft dual exhaust and had it studded for extra heat. I thought I would be cooked out but been getting a little chilly in cabin, especially for my rear seater. Need to figure out something. I am "ok" up front, but could be warmer. Been flying in 20F OAT.
Sutton exhaust test
Gentlemen:
A couple of years ago, I had my O320 on a test stand @ Lycon. After the straight pipe performance test were completed, we bolted the Sutton exhaust and reran the last test. It dropped the horsepower by about 20 hp out of the box. If you use this system, cut the exhaust pipe off as short as possible. Lycon's thoughts are that the long pipe is building up back pressure. After we cut the pipe down, we got back most of the lost power. A friend of mine is running it on his 18. After these test, we cut his off and he noticed the difference.
J Niesen
Gentlemen:
A couple of years ago, I had my O320 on a test stand @ Lycon. After the straight pipe performance test were completed, we bolted the Sutton exhaust and reran the last test. It dropped the horsepower by about 20 hp out of the box. If you use this system, cut the exhaust pipe off as short as possible. Lycon's thoughts are that the long pipe is building up back pressure. After we cut the pipe down, we got back most of the lost power. A friend of mine is running it on his 18. After these test, we cut his off and he noticed the difference.
J Niesen
20 horsepower I think you need to do some more testing. That's not even believable.
Dave Calkins
Registered User
Anchorage, Alaska
I had heard dyno testing had revealed a significant LOSS of HP with this exhaust. I am glad to see they got "most of it" back by shortening the outlet pipe.
How much is "most of it" back??
DAVE
Dave Calkins
Registered User
Anchorage, Alaska
virtually every "HOT ROD" Cub-style ("Kazoom", "SQ-2", and many more, etc.) with the pumped-up O-360 or an O-375 is using the Custom Aircraft Dual Exhaust. It is a thing of beauty, I been "around" several of them.
I know of one that had very long exhuast stack extensions and the poor O-375 was quite choked by the long stacks. Trimming them made ALLL KINDS of difference on this a/c. DAVE
Steve Pierce
BENEFACTOR
Graham, TX
20 hp from straight pipes to Sutton is how I read it. I take it this is no muffler, heater, carb heat etc. Not many airplanes I have seen run straight pipes.
S2D
MEMBER
Montana
I had the same problem. Tired of freezing my arse last winter, I redid my hoses, installed a Y so some of it would go thru my FADodge heat robber, and most importantly, added two finned bands inside the muff clamped to the exhaust. now I have more heat than my old system.
Steve Pierce
BENEFACTOR
Graham, TX
I am working on a Super Cub with the original Sutton muffler. Just sent it off to Dawley for the heat ribbons used on the later ones.
Jerry Gaston
Registered User
Bozeman, Montana
How short did you cut it?
Jerry Gaston
Registered User
Bozeman, Montana
Steve, you should have bought an Atlee Performance... nice and toasty in 604 plus PERFORMANCE and I didn't even have to cut a new hole... But hey it's not too late just reorder and put some duct tape over that hole (no one will notice) and you'll have a warm winter… How warm, why so warm I'm thinking about flying to Montana in my jammies and house shoes just so I’ll be comfy on the long trip!
Last edited:
Steve Pierce
BENEFACTOR
Graham, TX
Only heat your gonna get at those temps with the windows open is from a fire.
Steve Pierce
BENEFACTOR
Graham, TX
Um....I'm not worried about being cold. I was in the back seat when it burned my leg....really burned my leg and melted the plastic under the seat.
cafi
I guess I should have included a warning label with my modification.
Hi Guys,
I figured I'd better chime in since it appears I am either cutting half your power, freezing people, or cooking them...:lol: I guess the first thing I should address is the dyno comment. I have always found it funny how you can get so many different results from different guys operating their dyno's. Because of this, I have always thought thrust testing was my most reliable source of information. As you can probably guess, it would not have been possible for me to get this STC if it had in fact caused a deterioration of power. That being said, many engine builders have fun putting thier engines on test stands and then running them way above red line to show some miraculous power achievement. The problem is that it cannot be transferred into thrust efficiently. I have no doubt that under this type of circumstance you can show a power decrease with about any type of exhaust system when comparing it to straight pipes. The fact is, our system is designed to be optimum when running within the engines prescribed limits. If you are running high compression pistons, or are doing some other type of engine modification, it may help to shorten the pipe, or have me build you one with a full three inch tailpipe. However, in normal certified installations, the necked down tailpipe should be optimum. Please keep in mind that it would be easier, and cheaper just to have it built with a full sized, straight tailpipe. We are not necking it down just for fun, or so we can rob you of power...:lol:
As far as the heat goes, this is usually an issue which depends on many variables. Since our entire muffler can is used for cabin heat, there is much more surface area available for heat transfer when compared to the stock system. That being said, I realize that many of you operate in extremely cold climates so I have the "heat ribbon" option which increases heat transfer even more. If you are running the heat ribbon system and you are still cold, it may be hard to get much of an improvement short of lighting the plane on fire... However, I would recommend looking closely at the shroud and ductwork to make sure everything is installed correctly and not leaking. You can do this by hooking up your vacuum cleaner pressure side to the muffler air intake. Then go around and look for leaks, and seal them up accordingly. The guys at Dakota Cub even streamlined the corners of their cabin heat box to increase the flow. (Thanks for the tip Mark:smile
Just keep in mind that it is all about collecting and transferring a limited amount of energy. If you are running a low RPM for hours at a slow speed, you now have less BTU's to capture, and less forced air through the system. Other than using a highly restrictive muffler, which is not an option for obvious reasons, about all you can do is go about reducing the drafts in your cabin. This is usually the biggest area for improvement in Cubs anyway. Keep in mind that this system is used on many four passenger airplanes with much larger cabins, and works perfectly fine without even using the heat ribbons. Therefore it really should be capable of heating the smaller cabin area associated with a Cub. As far as too much heat, I guess we will have to stick with Steves' warning label..:smile: If you have any questions, please feel free to give me a call. Sometimes its pretty hard to cover everything in writing.
Brian Sutton
Professional Pilots inc.
219-696-8726
I figured I'd better chime in since it appears I am either cutting half your power, freezing people, or cooking them...:lol: I guess the first thing I should address is the dyno comment. I have always found it funny how you can get so many different results from different guys operating their dyno's. Because of this, I have always thought thrust testing was my most reliable source of information. As you can probably guess, it would not have been possible for me to get this STC if it had in fact caused a deterioration of power. That being said, many engine builders have fun putting thier engines on test stands and then running them way above red line to show some miraculous power achievement. The problem is that it cannot be transferred into thrust efficiently. I have no doubt that under this type of circumstance you can show a power decrease with about any type of exhaust system when comparing it to straight pipes. The fact is, our system is designed to be optimum when running within the engines prescribed limits. If you are running high compression pistons, or are doing some other type of engine modification, it may help to shorten the pipe, or have me build you one with a full three inch tailpipe. However, in normal certified installations, the necked down tailpipe should be optimum. Please keep in mind that it would be easier, and cheaper just to have it built with a full sized, straight tailpipe. We are not necking it down just for fun, or so we can rob you of power...:lol:
As far as the heat goes, this is usually an issue which depends on many variables. Since our entire muffler can is used for cabin heat, there is much more surface area available for heat transfer when compared to the stock system. That being said, I realize that many of you operate in extremely cold climates so I have the "heat ribbon" option which increases heat transfer even more. If you are running the heat ribbon system and you are still cold, it may be hard to get much of an improvement short of lighting the plane on fire... However, I would recommend looking closely at the shroud and ductwork to make sure everything is installed correctly and not leaking. You can do this by hooking up your vacuum cleaner pressure side to the muffler air intake. Then go around and look for leaks, and seal them up accordingly. The guys at Dakota Cub even streamlined the corners of their cabin heat box to increase the flow. (Thanks for the tip Mark:smile
Just keep in mind that it is all about collecting and transferring a limited amount of energy. If you are running a low RPM for hours at a slow speed, you now have less BTU's to capture, and less forced air through the system. Other than using a highly restrictive muffler, which is not an option for obvious reasons, about all you can do is go about reducing the drafts in your cabin. This is usually the biggest area for improvement in Cubs anyway. Keep in mind that this system is used on many four passenger airplanes with much larger cabins, and works perfectly fine without even using the heat ribbons. Therefore it really should be capable of heating the smaller cabin area associated with a Cub. As far as too much heat, I guess we will have to stick with Steves' warning label..:smile: If you have any questions, please feel free to give me a call. Sometimes its pretty hard to cover everything in writing.Brian Sutton
Professional Pilots inc.
219-696-8726
