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Exhaust

SuperCub MD

SuperCub MD

Registered User
Collins, Wisconsin
New exhaust systems have been introduced for Super Cubs, or at least Lycomings. The Leading Edge system seem interesting, http://www.borntoperform.com, it is now STC'd. Anyone who has knowledge of RPM gain, fuel burn improvements, or cylinder head temps on any aftermarket system, please post. I am looking for unbiased opinions from people who are actually useing them, not a sales pitch.

Mark Drath
 
I have a customer who is thinking about installing the exhaust system fron Leading Edge.The bottom line is if you can justify the $3000.00 price tag.Real world improvements probably would'nt be that noticeable unless you had a tuned system.I would like to see it installed just to eliminate the AD.
 
Mark,
I was out talking to Lutz at B.J.s last summer while they were still trying to get the STC. They told me all the info on the webpage, but having talked to a friend who has one...He said that He did get better climbout, and more RPM. Runs a bit louder, and he felt that he was getting a bit more HP out of it. Like around 8-10 hp.
The question that I have, and B.J.s agreed that it is a good one, is if it runs the cylinders hotter, thus decreasing the TBO. This is something I imagine will come out given time, meanwhile, I am going to get one as soon as I can afford it.
There seems to have been alot of research and testing put into this, and I am here a few people around here saying good things.
But time will tell!
Andy
 
Hotter heads? That's a little discouraging. I've heard claims of lower temps due to more efficient flow. All I want is to get 160 hp from my 150, less fuel burn, cooler heads, and still keep the low compression, easy hand proping, cheap fuel burning 150. To much to ask? Probably. The latest Northern Pilot has a good article on the LEES system. It says they are also working on a oil sump/cooler system to replace the stock cooler that would allow the pilot to regulate temp in flight. This would solve the other headache I have under the cowl. It all sounds good so far, I'm going to keep welding my rotten old system back together, signing off the AD, and saving my penneys.

Mark Drath
 
Mark.......I installed the adjustable door flap in front of my rear mounted oil cooler (from Dan's) that I can regulate from the cabin. I found it works great in cold weather.......typical oil temp is around 140 and I can boost that to 180 by closing the flap. Waiting to see how hot it runs open this summer.
 
Yup, the flap would be nice when I either forget to install or remove the cover before a flight and have to land somewhere inroute to do it. The N.P. article said something about completely removing the stock cooler and modifying the sump to act as a cooler. Big weight loss, no breaking mounts, no leaky lines, sounds pretty good if they can certify it. With my big flat prop and lots or drag, (less cruise speed, more RPM), lack of heat is not a problem. I'd like to get rid of some of it.
MD
 
I talked with two guys that had this exaust system. One said he could not notice the difference but weighed it before putting it on and said it weighed 8lb more then the stock one he took off. The other guy said he got better performence but that the heat it put out almost ran him out of his Cub. This would be hard on the scat hoses and windshield where the defrosters hit it. He had also just had the engine rebuilt, so this one is questionable. The first guy also said it made him sit lower in the seat, being $3,000.00 less in his wallet. Greg
 
8 lbs? How can this be considering the crossovers are removed? Is it made from sewer pipe? Lead core muffler? Someone have their foot on the scale? Can't imagine having to much cabin heat, close the valve a little maybe? I'm not a big proponent of this system yet, just on a quest for truth.
Mark Drath
 
Exhaust System

They use thicker wall tubing for the header pipes as well as far more length then stock crossovers, they also use .048 for the collector. Even different stock mufflers have big weight differences. An Atlee Dodge muffler weighs 3-4 lbs more being made out of .048 rather then a Univair at .035. Just telling what the Guy said. As far a the heat output, one of the reasons the project was so late was the carb heat readings were hard for the FAA to believe. they were so high. Also the heat boxes on these Cubs all leak a little. My Atlee Dodge rear seat heat about cooks me out in the summer (shut off) to the point I have to stuff a rag in the hose. Crash
 
I believe it could be heavier, 8 lbs of additional steel just seems like a lot. I have never weighed one, but I would not have guessed that a stock system weighed more than 10 lbs. Almost doubling this seems excessive. The next stock system I take off, I will have to put on the scale. And did they try running more cooling air over it? This would seem like a simple way to bleed off some of the heat.
Mark Drath
 
Exhaust Weight

Go over to Cubcrafters chat site under "Super Cub Exhaust 4-14-2002". A guy there sent his stock and Leading Edge system to Lycon for H.P. testing on their dyno. And yes, Lycon said it weighed 8lbs more. But no... don't take if from old Crash. Just kidding. Crash
 
Leading Edge Exhaust

Lycon came back with a 12-13 h.p. increase. On the airplane I got a 75 rpm increase static, 100 in climb, and 200 max cruise. This is with a 42 pitch prop, and next week I will be testing with a 43 and 44 pitch. I don't need 3000 rpm max cruise@5000'! Right now I'd say this exaust system is worth it to me.
Dick
 
Thanks DW,
What engine are you running it on, 150 or 160? Any info on temp differences, (cylinder heads, oil)? Or any fuel burn change? Please post any info you get.
 
exhaust

Mark,

I'm running a 160, stock B2B with standard (legal) compression pistons and no porting or flowing (the Lycon mods). When Lycon tested the system, they first tested it on a modified 160 (10:1 compression) and it only got 5-6 hp. I'm thinking LE has the exhaust tuned to eliminate backpressure, and the higher compression pistons create more backpressure that the LE system is not designed to eliminate. Those pistons are not legal for certified cubs anyway, and I like the 12-13 hp addition.
Unfortunately, I don't have any good numbers per your request. With spring here I just took the plate off my oil cooler, and my feeling right now is that the oil temp is going to run about the same. The other thing is I just came out of a 2 yr. rebuild, and the new engine baffling cooled me off about 15-20 degrees (!), so I don't have a good base to go from. I'm actually having trouble right now getting it up to 180 degrees, but when the oat gets to 50 or better it will get there.
I don't have cyl. head gauge, so can't help you there. After running the airplane the exhaust itself seems quite hot, but cools down quickly. My heat robber is currently disconnected, but I haven't noticed too much heat through my regular heater. I, too, have had to stuff a rag in the hose in the summer because of leakage through the regular heater valve with the stock exhaust. Too much heat is rarely a problem here in Idaho, especially when you're hunting coyotes!
I also just installed a fuel computer (after the exhaust) so am only now getting accurate fuel flows. Until I do some long trips for comparison I won't know for sure, but my guess right now is no increase, which surprises me a little. I'm indicating 7.5 gph at 2600 rpm at 5000' at 25 degrees rich now. I flight planned the old exhaust for 7.5 gph also.
I believe I'll end up with a higher pitch prop after more testing, as I'm getting more rpm than I need and want to bite the air better. This is a new concept for me, as I've always gone for rpm. However, recently we've been finding the airplanes are performing much better at a more optimum pitch (usually higher) because the prop is more efficient (i.e. biting more thin air). We are finding this particular true with experimental 180 cubs with the long (84") props.
By the way, visit Amazon.com for the video Mountain Flying with Dick Williams!

Dick
 
leading edge

Mark, I have one of thier exhaust systems coming soon. I have lots of experience with race cars etc and this system sounds good. It should work, will let you know.
John
Cubs Unlimited
 
I just received this SAIB yesterday regarding the Leading Edge System. As I read it, the STC is approved for the 150 hp O-320-A2A and A2B, but not the B2B or the O-360. There must be unresolved issues with the heating and cooling on the other engines. Can anyone explain?

Sorry, I scanned this so there may be a little lost in the translation.

murph

ftp://ftp.supercub.org/cubloads/murphpics/LEES.doc
 
Murph, I've got one on order, but will seek field approval 'cause it's to go on an A2B that's in a PA-14.

I'll be changing the length of the tubes to get aft of the -14 engine mount.

In my discussions with Dane of Leading Edge, we've talked of the incredible costs of the certification process, and I believe he intends to get some systems sold with the A2A/A2B STC now, and work on cert's for the other models when he has time and money.

He's also got a wonderful I0-520 system STC'ed for the 206's, and is working on a 180 system as well. I haven't been over to the shop lately, but will in the next week.

Unless you've been through the process of STC development, you might not imagine the scope of the hoops you must jump through. Sooo...call him up and chat, and be patient. This system is a good thing.

Dave Calkins.
 
Dave:

Thanks for the info. I know the approval process is an expensive hassle.

I have an A2B on a PA-18. As I read the SAIB, there is no issue with putting the LEES on my aircraft. I just want some good honest performance figures before investing the $$$. I'd like to boost my hp without going through the hassle of updating my narrow-deck engine.

If you get some good numbers from Dane, I'd appreciate you passing them along. Also, I'd appreciate it if you can post his phone#.

If you've seen the system on a -18, what does it look like? The ones I've seen on a 172 look kinda ugly with the stack sticking out under the cowl and creating drag.

Thanks again,
murph
 
Murph, that's not Dane's system. The one with the external muffler is a Powerflow. It's a good system on a 172.

The Leading Edge system is all in cowl. It doesn't cross-over in front. It is possible to remove only one stack at a time if you like. The tubes are all close to equal length, and are mandrel bent to eliminate reduced volume in the bends. Attention to detail on the product is excellent. Dane is a completely detail oriented guy with a mind that buzzes with ideas. If you catch him at a time when he can talk to you, you'll be impressed.

Northern Pilot magazine ran a product info. section with photos of the LEES system in the Feb./March 2002 issue. You can still get back issues and/or subscription info on the magazine at 907-258-6898 888-477-4568 www.nothernpilot.com

Call 907-248-1188 for Leading Edge.
 
SAIB

The FAA Special Airworthiness Information Bulletin # CE-03-02 dated October 8th 2002 expressly states that the Leading Edge Exhaust system is only to be used on Piper PA-18-150 with A2A and A2B engines only. Any installations on 160hp and 180hp PA-18's are quote..."unauthorized, inappropriate, and unsafe". Most of the guys I know that have them, installed them on 160 or 180hp Cubs. Stoddards has a pile of good used PA-18 exhaust systems that have been removed to install the LEE system. It will be intresting what these guys do at annual when their A&P won't sign their plane off as airworthy with this system on it. Crash
 
Re: SAIB

Crash said:
The FAA Special Airworthiness Information Bulletin # CE-03-02 dated October 8th 2002 expressly states that the Leading Edge Exhaust system is only to be used on Piper PA-18-150 with A2A and A2B engines only. Any installations on 160hp and 180hp PA-18's are quote..."unauthorized, inappropriate, and unsafe". Most of the guys I know that have them, installed them on 160 or 180hp Cubs. Stoddards has a pile of good used PA-18 exhaust systems that have been removed to install the LEE system. It will be intresting what these guys do at annual when their A&P won't sign their plane off as airworthy with this system on it. Crash
Click to expand...


It is my understanding that service bulletins are not mandatory.

Sounds like one guy in the FAA is trying to discourage the legal installation of the system on 160 hp cubs. Admittedly, the installation on the 160 hp is done through a loophole in the wording but is was approved by the FAA with that wording.

I think the bulletin is unenforceable hot air, as written.
 
SAIB's are not manditory, it's says so right on top.

But if they have revised the STC to limit it to PA18-150's with A2A or A2B engines, that is.

Remember that the STC applies to the AIRCRAFT, and the aircraft is still a PA18-150 even if it has a 160 or 180 installed on it.

There is no such thing as a PA18-160, so if you have a PA18-150 with a 160 engine legally installed, you could have legally installed the exhaust system on the PA-18-150 AIRCRAFT if the installer found it to be "Compatible with all previously installed modifications" (like a 160 engine), and been legal.

If the STC now specifically reads that is can only be installed on a PA18-150 with a A2A or A2B this could not be done, and will require a field approval, which the SAIB may make hard to get.

It seems that LEES will probably have to complete testing, and jump through all the legal hoops again on the 160 and 180 modified PA18's before it can be installed on these by STC only.
 
Bulletin

The bulletin says "an anmendment to STC # SA02183AK". If the system is to be installed under the STC it can only be installed on a 150 A2A or A2B engine, period. They have closed the loop hole. You could try a field approval but I think it would be an up hill battle. I am not a big fan of the FAA either but rules is rules, plane and simple. Dane did not do the tests or get approvel on the 160 or 180 hp Cubs and since this mounts directly to the engine they feel they need the tests. Crash
 
I would have to read the STC change before commenting on it but I bet it doesn't read like the bulletin. STC's usually dictate change but the bulletin recommends it???

It just makes me feel warm and fuzzy knowing the FAA is looking out for our best interests.
 
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