---------------------------------------------------------- JabiruEngine-List Digest Archive --- Total Messages Posted Thu 08/23/12: 9 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 07:30 AM - Re: Newest GAMI lean test...probably off-topic for most (Lynn Matteson) 2. 07:51 AM - Re: Newest GAMI lean test...probably off-topic for most (BobsV35B@aol.com) 3. 09:05 AM - Re: Newest GAMI lean test...probably off-topic for most (Lynn Matteson) 4. 09:25 AM - Re: Newest GAMI lean test...probably off-topic for most (BobsV35B@aol.com) 5. 09:33 AM - Re: Newest GAMI lean test...probably off-topic for most (Marvin Williams) 6. 10:42 AM - Re: Newest GAMI lean test...probably off-topic for most (Lynn Matteson) 7. 10:42 AM - Re: Newest GAMI lean test...probably off-topic for most (Lynn Matteson) 8. 10:48 AM - Re: Newest GAMI lean test...probably off-topic for most (Lynn Matteson) 9. 11:08 AM - Re: Newest GAMI lean test...probably off-topic for most (Marvin) ________________________________ Message 1 _____________________________________ Time: 07:30:17 AM PST US From: Lynn Matteson Subject: Re: JabiruEngine-List: Newest GAMI lean test...probably off-topic for most A couple of other possible reasons for the successful Gami lean test could be the "swirling device" that I built in April, and the exhaust system that I built/installed in June. I built the swirler and installed it, but it didn't seem to do a lot for the EGT spread that I was seeing. I built 5 blades into the swirler, thinking that if I wanted to change something, I could just rotate the device one bolt hole either way and the 5 blades would change their orientation relative to the intake runner tubes. I have never touched it since I installed it. This was also about the time that I began to disregard the one cylinder that was always about 80-100 deg. F. cooler than the rest, EGT-wise. Since that cylinder was always looking good plug- reading-wise and exhaust pipe color-wise, I just quit chasing that "rogue" and lived with the off-reading. Then in June, I bought a 4-into-1 collector and megaphone, tuned to the specifications of the Jabiru engine. I had to build the pipes leading to the collector. (The rear pipes on both sides are a few inches shorter than the front pipes for now, but I plan to correct that in the near future, further equalizing the breathing of each cylinder.) So with the swirler atomizing the incoming charge, and the "almost tuned" exhaust system helping to scavenge the exhaust gasses....and thus helping bring in the fresh air/fuel mixture...I feel both of these features help make the engine breath easier and more equally between cylinders. Lynn Matteson Kitfox IV Speedster, taildragger Jabiru 2200, #2062 Prince prop 64 x 30, P-tip Electroair direct-fire ignition system Rotec TBI-40 injection (sleeved to 36mm) Status: flying with 1336 hrs... (since 3-27-2006) ________________________________ Message 2 _____________________________________ Time: 07:51:28 AM PST US From: BobsV35B@aol.com Subject: Re: JabiruEngine-List: Newest GAMI lean test...probably off-topic for most Good Morning Lynn, Both items look elegant to me! Any idea how much those tail pipes weigh? Happy Skies, Old Bob In a message dated 8/23/2012 9:30:51 A.M. Central Daylight Time, lynnmatt@jps.net writes: A couple of other possible reasons for the successful Gami lean test could be the "swirling device" that I built in April, and the exhaust system that I built/installed in June. I built the swirler and installed it, but it didn't seem to do a lot for the EGT spread that I was seeing. I built 5 blades into the swirler, thinking that if I wanted to change something, I could just rotate the device one bolt hole either way and the 5 blades would change their orientation relative to the intake runner tubes. I have never touched it since I installed it. This was also about the time that I began to disregard the one cylinder that was always about 80-100 deg. F. cooler than the rest, EGT-wise. Since that cylinder was always looking good plug- reading-wise and exhaust pipe color-wise, I just quit chasing that "rogue" and lived with the off-reading. Then in June, I bought a 4-into-1 collector and megaphone, tuned to the specifications of the Jabiru engine. I had to build the pipes leading to the collector. (The rear pipes on both sides are a few inches shorter than the front pipes for now, but I plan to correct that in the near future, further equalizing the breathing of each cylinder.) So with the swirler atomizing the incoming charge, and the "almost tuned" exhaust system helping to scavenge the exhaust gasses....and thus helping bring in the fresh air/fuel mixture...I feel both of these features help make the engine breath easier and more equally between cylinders. Lynn Matteson Kitfox IV Speedster, taildragger Jabiru 2200, #2062 Prince prop 64 x 30, P-tip Electroair direct-fire ignition system Rotec TBI-40 injection (sleeved to 36mm) Status: flying with 1336 hrs... (since 3-27-2006) ________________________________ Message 3 _____________________________________ Time: 09:05:54 AM PST US From: Lynn Matteson Subject: Re: JabiruEngine-List: Newest GAMI lean test...probably off-topic for most Hi Bob- I didn't happen to weigh the whole thing, but the 4 bends (1.31 lbs. ea.) that I got...16 ga.....came to about 5.24 lbs, but I didn't use all the length, so call that 5 lbs. The collector and megaphone (18 ga.) I'm guessing came to about 5-6 lbs, so maybe 11 lbs total. I'll weigh it when I go to the hangar later today, as I need to take the collector and megaphone off soon anyway, so I can polish the stainless steel again....one of the drawbacks to having an exposed exhaust system. : ) By the way, here's a shot of one of the two heat muffs that I built...so there's an additional 3-4 lbs per side. Geez, it may be heavier than I thought...horsepower cost money, they say. Lynn Matteson Kitfox IV Speedster, taildragger Jabiru 2200, #2062 Prince prop 64 x 30, P-tip Electroair direct-fire ignition system Rotec TBI-40 injection (sleeved to 36mm) Status: flying with 1336 hrs... (since 3-27-2006) On Aug 23, 2012, at 10:50 AM, BobsV35B@aol.com wrote: > Good Morning Lynn, > > Both items look elegant to me! > > Any idea how much those tail pipes weigh? > > Happy Skies, > > Old Bob ________________________________ Message 4 _____________________________________ Time: 09:25:58 AM PST US From: BobsV35B@aol.com Subject: Re: JabiruEngine-List: Newest GAMI lean test...probably off-topic for most Hi Lynn. I am sure it is lighter than a turbo and undoubtedly a lot more efficient! Being able to run lean of peak saves weight on fuel required. Ya just gotta make long enough flights to take advantage of the efficiency. I love it! Happy Skies, Old Bob In a message dated 8/23/2012 11:06:25 A.M. Central Daylight Time, lynnmatt@jps.net writes: Hi Bob- I didn't happen to weigh the whole thing, but the 4 bends (1.31 lbs. ea.) that I got...16 ga.....came to about 5.24 lbs, but I didn't use all the length, so call that 5 lbs. The collector and megaphone (18 ga.) I'm guessing came to about 5-6 lbs, so maybe 11 lbs total. I'll weigh it when I go to the hangar later today, as I need to take the collector and megaphone off soon anyway, so I can polish the stainless steel again....one of the drawbacks to having an exposed exhaust system. : ) By the way, here's a shot of one of the two heat muffs that I built...so there's an additional 3-4 lbs per side. Geez, it may be heavier than I thought...horsepower cost money, they say. Lynn Matteson Kitfox IV Speedster, taildragger Jabiru 2200, #2062 Prince prop 64 x 30, P-tip Electroair direct-fire ignition system Rotec TBI-40 injection (sleeved to 36mm) Status: flying with 1336 hrs... (since 3-27-2006) On Aug 23, 2012, at 10:50 AM, BobsV35B@aol.com wrote: > Good Morning Lynn, > > Both items look elegant to me! > > Any idea how much those tail pipes weigh? > > Happy Skies, > > Old Bob ________________________________ Message 5 _____________________________________ Time: 09:33:52 AM PST US From: Marvin Williams Subject: Re: JabiruEngine-List: Newest GAMI lean test...probably off-topic for most Thanks for the photos Lynn!- Nice job!=0A=0AI also modified my air passag e into my TBI, but not nearly like yours.- I merely bent the top (horizon tal)- blades of an air straightener I bought from AS downward so as to di rect more of the intake air accross the TBI spray bar.- It changed the EG T spread, but can't say that it made it significantly better.- i.e., chan ged which cylinder was the hottest.- I believe that were I to take enough time to make numerous changes in the air intake to the TBI that I could ge t my EGTs (thus fuel flow spread) much closer than they are now. Maybe what I should do is just build a 'swirler' like yours and forget the store boug ht 'straightener'.=0A=0AAs you well know, just changing the power setting c hanges EGT spread.=0A=0AThanks again for the photos.=0A=0AMarvin=0A=0A=0A =0A=0A________________________________=0A From: Lynn Matteson =0ATo: jabiruengine-list@matronics.com =0ASent: Wednesday, August 22, 2012 6:04 PM=0ASubject: Re: JabiruEngine-List: Newest GAMI lean test...prob Matteson =0A=0AThe larger plenum is probably- part of the reason, Marvin. The tubes are the same size as the original...1-1/4" O. D. I built the longer tubes to take advantage of the "ram" effect, and that might be part of the reason as well. Perhaps the longer tubes allow for mo re time for the mixture to atomize, and this makes for a smoother-running e ngine.=0A=0ANo, this is exactly the same test. All you are doing in this te st is verifying that the fuel flow difference between when the first cylind er's EGT peaks, and the last cylinder's EGT peaks, is very, very close. Tha t determines how well the engine's air/fuel mixture is distributed to the e ngine. If the first to peak is at say, 3.5 gph, and the last to peak does s o when the flow meter reads 3.0 gph, that's a "GAMI spread" of a half-gallo n per hour, and that is not good distribution. If this were a direct-port i njected engine, the injector nozzles would be changed to bring the flow clo ser together between the first, and the last, to reach peak EGT. This is wh at the folks at GAMI do. But my engine, using a Rotec TBI, is basically a c arbureted engine, and you can't change individual nozzles like you can with the direct-port engines.=0A=0AThe EGT spread is still talked about, but no t the actual numbers from what I've read. First you have to get the flow sp read as close as possible, then when that is done, then you can safely run lean of peak EGT, knowing that each cylinder is enjoying very close to the optimum share of the fuel/air mixture. If the flow spread is too far off. s ome cylinders are too rich while others may be too lean, and the engine wil l run roughly when leaned. And that's what all this is about....being able to run LOP safely and comfortably. When the fuel-flow spread is close, the EGT spread is close, and the CHT spread will be close, and that is what mak es for longer-lived engines.=0A=0ALynn Matteson=0AKitfox IV Speedster, tail dragger=0AJabiru 2200, #2062=0APrince prop 64 x 30, P-tip=0AElectroair dire ct-fire ignition system=0ARotec TBI-40 injection (sleeved to 36mm)=0AStatus : flying with 1336 hrs... (since 3-27-2006)=0A=0A=0AOn Aug 22, 2012, at 8:0 4 PM, Marvin Williams wrote:=0A=0A> Thanks Lynn and Barry.=0A> =0A> I assum e that added volume in the intake system is one of the reasons you have had success Lynn?- The Jabiru intake 'manifold' sure doesn't have the volume that it looks like yours has.- Seems that your pipes to the heads are bi gger also.- Am I wrong?=0A> =0A> I read the GAMI lean test article.- Se ems to me that this test replaces the EGT spread criteria for proper cylind er balance.- Again, is that what you discern?=0A> =0A> The article talked about an engine having a fuel flow spread of .7 gph after GAMIs are instal led.- I just wonder what the full fuel flow rate is?- If it's 15-17 GPH then the flow rate spread would be approximately 5% of total flow rate.- I am no where smart enough to know what is good and what isn't.- I'll ju st have to take the 'big boys' word for it.- But I do find it interesting that EGT spread isn't talked about much anymore.- Or did I just miss it? =0A> =0A> FWIW, I had GAMIs installed on my Mooney TLS (TIO 540 as I recall ) a long time ago.- For what it cost at the time, I didn't think it was w orth it.- I'll be quick to add that technology has changed (improved) mor e than I know since then, and perhaps I myself am a little (but not much) w iser now than I was then and it just might be that I would recognize the im provement more now than then.- All conjecture obviously.=0A> =0A> Fortuna tely, now that I have been introduced to Fuel Spread tests, I can easily ru n the test on our Jabiru 3300 with the engine analysis and recording equipm ent we have, it should be a snap.- Fixing (or improving) the issues will be the challenge.=0A> =0A> Thanks again for the pictures and your post!=0A> =0A> Marvin=0A> =0A> =0A> From: Lynn Matteson =0A> To: j abiruengine-list@matronics.com=0A> Sent: Wednesday, August 22, 2012 10:46 A M=0A> Subject: Re: JabiruEngine-List: Newest GAMI lean test...probably off- topic for most=0A> =0A> Hi Marvin-=0A> I wish I had taken better pictures, but these two pretty much show what I did. When I was building it, I was th inking of having the tubes go through a chamber that would have engine oil pumping through it, but later decided against that and sawed off some of th e "oil box". In this picture, the box is still partly there. I would have h ad to finish enclosing the box...a HUGE job, so I quit thinking along those lines. The actual intake plenum is the trapezoid-shaped box immediately in front of (to the left) the TBI. The rest of the box...like where the bolt heads are showing, was to be the oil box.=0A> =0A> <100_1055.jpg>=0A> =0A> =0A> <100_4853.jpg>=0A> =0A> =0A> This shot shows the basic tubes completed , and I'm just starting to build the plenum box around the tubes. >From loo king at these shots, I can see that I need to take some better pictures of the final product.=0A> =0A> As far as the Gami lean test is concerned, you start with a rich mixture, and then start to lean the engine in small incre ments, according to the fuel flow meter, watching the EGT readouts. The tem peratures will rise as the engine is leaned, and then you will see the EGT' s reach a peak temperature, and further leaning will cause the temperatures to start to drop. Normally this "peak and drop" will happen one cylinder a t a time, over the course of leaning in very small increments....in my case I was leaning by 0.1 gph according to the flow meter. When I did this test back in 2009 right after I installed the TBI, (and using the original Jabi ru manifold) the rear two cylinders peaked first, then one of the fronts, a nd finally the last one peaked. This was over the course of leaning that co vered a 0.3 gph range. On a small engine like the Jabiru 4-cylinder, that s hows that the fuel distribution in the intake manifold is not real good, bu t not terrible, either. But with the current manifold that I built, the EGT's will peak, a nd the next 0.1 gph reduction in flow (leaning), causes them all to start d ropping right now. This shows excellent fuel distribution according to the Gami method of lean testing. The writings of people that I have read....Joh n Deakin, Mike Busch, to name a couple...say that most carbureted engines d on't have very good fuel distribution, so I'm pretty tickled with my result s.=0A> =0A> The address for the lean test is:- http://www.gami.com/gamije ctors/leantest.php=0A> =0A> Some interesting reading about engine operation is found in John Deakin's writings. Here is the address for a complete ind ex of his articles, Pelican's Perch:=0A> =0A> http://www.avweb.com/news/pel ican/182146-1.html=0A> =0A> =0A> =0A> Lynn Matteson=0A> Kitfox IV Speedster , taildragger=0A> Jabiru 2200, #2062=0A> Prince prop 64 x 30, P-tip=0A> Ele ctroair direct-fire ignition system=0A> Rotec TBI-40 injection (sleeved to 36mm)=0A> Status: flying with 1336 hrs... (since 3-27-2006)=0A> =0A> =0A> O n Aug 22, 2012, at 11:03 AM, Marvin Williams wrote:=0A> =0A> > OK Lynn, I'l l bite.- Tell us 'dummies' exactly how you performed your GAMI Lean Tests .- Sounds interesting.- Also, how about some photos of your latest inta ke system.=0A> >=0A> > Nice to hear from you.=0A> >=0A> > Marvin=0A> >=0A> ====================== ________________________________ Message 6 _____________________________________ Time: 10:42:17 AM PST US From: Lynn Matteson Subject: Re: JabiruEngine-List: Newest GAMI lean test...probably off-topic for most I didn't have the gumption to polish the collector and meg, but I DID take it off and weigh it....2 pounds....and they are both 18 ga. The Jab muffler...and 6" of extra tail pipe on each exit pipe....weighed 5 pounds. So probably 4 pounds for the original muffler as it came from the factory. All in all, the whole new exhaust system and heat muffs probably weighs 11 pounds. I was way off on my original guess of the collector and meg, so I was also probably off on the heat muffs, too....getting old is a bitch! Lynn Matteson Kitfox IV Speedster, taildragger Jabiru 2200, #2062 Prince prop 64 x 30, P-tip Electroair direct-fire ignition system Rotec TBI-40 injection (sleeved to 36m) Status: flying with 1336 hrs... (since 3-27-2006) On Aug 23, 2012, at 10:50 AM, BobsV35B@aol.com wrote: > Good Morning Lynn, > > Both items look elegant to me! > > Any idea how much those tail pipes weigh? > > Happy Skies, > > Old Bob > ________________________________ Message 7 _____________________________________ Time: 10:42:18 AM PST US From: Lynn Matteson Subject: Re: JabiruEngine-List: Newest GAMI lean test...probably off-topic for most I can go up and fly around for an hour and use about 3.0-3.2 gallons of fuel, and that includes the takeoff. I no more than get to 1000-1500' AGL, and I'm leveling off and pulling back on both the black and the red knobs. I've gotten to where I can grab them both in one hand and either push or pull...and these are vernier controls....I must be a frustrated airline pilot. : ) Lynn Matteson Kitfox IV Speedster, taildragger Jabiru 2200, #2062 Prince prop 64 x 30, P-tip Electroair direct-fire ignition system Rotec TBI-40 injection (sleeved to 36mm) Status: flying with 1336 hrs... (since 3-27-2006) On Aug 23, 2012, at 12:25 PM, BobsV35B@aol.com wrote: > Hi Lynn. > > I am sure it is lighter than a turbo and undoubtedly a lot more > efficient! > > Being able to run lean of peak saves weight on fuel required. Ya > just gotta make long enough flights to take advantage of the > efficiency. > > I love it! > > Happy Skies, > > Old Bob ________________________________ Message 8 _____________________________________ Time: 10:48:06 AM PST US From: Lynn Matteson Subject: Re: JabiruEngine-List: Newest GAMI lean test...probably off-topic for most Thanks, Marvin. Yes, changing the rpm will change the EGT readings all over the place....the spread AND the location of the hottest cylinder. And with a 3300, I'd guess it's even worse. Lynn Matteson Kitfox IV Speedster, taildragger Jabiru 2200, #2062 Prince prop 64 x 30, P-tip Electroair direct-fire ignition system Rotec TBI-40 injection (sleeved to 36mm) Status: flying with 1336 hrs... (since 3-27-2006) On Aug 23, 2012, at 12:33 PM, Marvin Williams wrote: > Thanks for the photos Lynn! Nice job! > > I also modified my air passage into my TBI, but not nearly like > yours. I merely bent the top (horizontal) blades of an air > straightener I bought from AS downward so as to direct more of the > intake air accross the TBI spray bar. It changed the EGT spread, > but can't say that it made it significantly better. i.e., changed > which cylinder was the hottest. I believe that were I to take > enough time to make numerous changes in the air intake to the TBI > that I could get my EGTs (thus fuel flow spread) much closer than > they are now. Maybe what I should do is just build a 'swirler' like > yours and forget the store bought 'straightener'. > > As you well know, just changing the power setting changes EGT spread. > > Thanks again for the photos. > > Marvin > ________________________________ Message 9 _____________________________________ Time: 11:08:29 AM PST US Subject: Re: JabiruEngine-List: Newest GAMI lean test...probably off-topic for most From: Marvin Just a quick question Lynn. Do you swirl the TBI input or output air? I'm guessing output. Marvin Sent from my "Geeky" iPhone On Aug 23, 2012, at 10:48 AM, Lynn Matteson wrote: > > Thanks, Marvin. > Yes, changing the rpm will change the EGT readings all over the place....the spread AND the location of the hottest cylinder. And with a 3300, I'd guess it's even worse. > > Lynn Matteson > Kitfox IV Speedster, taildragger > Jabiru 2200, #2062 > Prince prop 64 x 30, P-tip > Electroair direct-fire ignition system > Rotec TBI-40 injection (sleeved to 36mm) > Status: flying with 1336 hrs... (since 3-27-2006) > > > On Aug 23, 2012, at 12:33 PM, Marvin Williams wrote: > >> Thanks for the photos Lynn! Nice job! >> >> I also modified my air passage into my TBI, but not nearly like yours. I merely bent the top (horizontal) blades of an air straightener I bought from AS downward so as to direct more of the intake air accross the TBI spray bar. It changed the EGT spread, but can't say that it made it significantly better. i.e., changed which cylinder was the hottest. I believe that were I to take enough time to make numerous changes in the air intake to the TBI that I could get my EGTs (thus fuel flow spread) much closer than they are now. Maybe what I should do is just build a 'swirler' like yours and forget the store bought 'straightener'. >> >> As you well know, just changing the power setting changes EGT spread. >> >> Thanks again for the photos. >> >> Marvin >> > > > > ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message jabiruengine-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/JabiruEngine-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/jabiruengine-list Browse Digests http://www.matronics.com/digest/jabiruengine-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.