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Lynn Matteson

Joined: 10 Jan 2006
Posts: 2778
Location: Grass Lake, Michigan

Posted: Wed Aug 22, 2012 6:20 am Post subject: Newest GAMI lean test...probably off-topic for most

I hadn't done a Gami Lean Test since I first installed my Rotec TBI  

back in 2009, and so yesterday and today I did another few tests.  

Back when I first installed the TBI, the Gami spread was 0.1 on one  

test, and two other tests showed a 0.3 spread. This was done using  

the Jabiru intake manifold and the rubber tube connecter. Thinking  

back, the 0.1 might have been a fluke, or bad reading. Since then, I  

had built three different intake manifolds out of aluminum tubing and  

plate, using different configurations...updraft, backdraft, etc. The  

latest manifold is a "ram induction" manifold with runners 19" long.  

I've had this one on for about 16 months.... 236 hours flying time.  

Because things were going well with this manifold, I had just  

forgotten about actually giving the engine the Gami lean test.



Over the last two days, the tests, at 7000 feet yesterday, and 3300  

feet today (MSL), all showed a spread of 0.1......from 2.8 gph to 2.7  

gph at 2900 rpm and 7000 feet, and 3.4 to 3.3 gph at 2900 rpm at 3300  

feet. During these tests, when going from one fuel flow reading to  

0.1 less fuel...leaner....all four EGT readings would drop at the  

same time. They would be stabilized at one fuel flow setting, and  

about a half-turn of the vernier mixture knob, and all four would  

start dropping....every time. So this latest manifold is a keeper, as  

far as distributing fuel is concerned.

And that is probably the reason that I can dawdle along, burning as  

low as 2.5-2.6 gph and the engine still lives...knocking on wood!



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)

_________________
Lynn
Kitfox IV-Jabiru 2200
N369LM

marvinlnaz(at)yahoo.com
Guest

Posted: Wed Aug 22, 2012 7:34 am Post subject: Newest GAMI lean test...probably off-topic for most

OK Lynn, I'll bite.  Tell us 'dummies' exactly how you performed your GAMI Lean Tests.  Sounds interesting.  Also, how about some photos of your latest intake system.



Nice to hear from you.



Marvin





        From: Lynn Matteson <lynnmatt(at)jps.net>

 To: jabiruengines(at)yahoogroups.com; jabiruengine-list(at)matronics.com 

 Sent: Wednesday, August 22, 2012 7:19 AM

 Subject: Newest GAMI lean test...probably off-topic for most

  

 

 --> JabiruEngine-List message posted by: Lynn Matteson <lynnmatt(at)jps.net (lynnmatt(at)jps.net)>



I hadn't done a Gami Lean Test since I first installed my Rotec TBI back in 2009, and so yesterday and today I did another few tests. Back when I first installed the TBI, the Gami spread was 0.1 on one test, and two other tests showed a 0.3 spread. This was done using the Jabiru intake manifold and the rubber tube connecter. Thinking back, the 0.1 might have been a fluke, or bad reading. Since then, I had built three different intake manifolds out of aluminum tubing and plate, using different configurations...updraft, backdraft, etc. The latest manifold is a "ram induction" manifold with runners 19" long. I've had this one on for about 16 months.... 236 hours flying time. Because things were going well with this manifold, I had just forgotten about actually giving the engine the Gami lean  test.



Over the last two days, the tests, at 7000 feet yesterday, and 3300 feet today (MSL), all showed a spread of 0.1......from 2.8 gph to 2.7 gph at 2900 rpm and 7000 feet, and 3.4 to 3.3 gph at 2900 rpm at 3300 feet. During these tests, when going from one fuel flow reading to 0.1 less fuel...leaner....all four EGT readings would drop at the same time. They would be stabilized at one fuel flow setting, and about a half-turn of the vernier mixture knob, and all four would start dropping....every time. So this latest manifold is a keeper, as far as distributing fuel is concerned.

And that is probably the reason that I can dawdle along, burning as low as 2.5-2.6 gph and the engine still lives...knocking on wood!



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...           - The JabiruEngine-List Email Forum -http://www.matronics.com/Navigat=               - MATRONICS WEB FORUMSList ====



 

 

  

 [quote][b]

Lynn Matteson

Joined: 10 Jan 2006
Posts: 2778
Location: Grass Lake, Michigan

Posted: Wed Aug 22, 2012 9:53 am Post subject: Newest GAMI lean test...probably off-topic for most

Hi Marvin-

I wish I had taken better pictures, but these two pretty much show  

what I did. When I was building it, I was thinking 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 the "oil  

box". In this picture, the box is still partly there. I would have  

had 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.



  This shot shows the basic tubes completed, and I'm just starting to  

build the plenum box around the tubes. From looking at these shots, I  

can see that I need to take some better pictures of the final product.



As far as the Gami lean test is concerned, you start with a rich  

mixture, and then start to lean the engine in small increments,  

according to the fuel flow meter, watching the EGT readouts. The  

temperatures 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 at 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 Jabiru manifold) the rear  

two cylinders peaked first, then one of the fronts, and finally the  

last one peaked. This was over the course of leaning that covered a  

0.3 gph range. On a small engine like the Jabiru 4-cylinder, that  

shows that the fuel distribution in the intake manifold is not real  

good, but not terrible, either. But with the current manifold that I  

built, the EGT's will peak, and the next 0.1 gph reduction in flow  

(leaning), causes them all to start dropping right now. This shows  

excellent fuel distribution according to the Gami method of lean  

testing. The writings of people that I have read....John Deakin, Mike  

Busch, to name a couple...say that most carbureted engines don't have  

very good fuel distribution, so I'm pretty tickled with my results.



The address for the lean test is:   http://www.gami.com/gamijectors/ 

leantest.php



Some interesting reading about engine operation is found in John  

Deakin's writings. Here is the address for a complete index of his  

articles, Pelican's Perch:



http://www.avweb.com/news/pelican/182146-1.html



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 22, 2012, at 11:03 AM, Marvin Williams wrote:



 	  Quote: 	
		   OK Lynn, I'll bite.  Tell us 'dummies' exactly how you performed  

 your GAMI Lean Tests.  Sounds interesting.  Also, how about some  

 photos of your latest intake system.



 Nice to hear from you.



 Marvin

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_________________
Lynn
Kitfox IV-Jabiru 2200
N369LM

kayberg(at)aol.com
Guest

Posted: Wed Aug 22, 2012 1:03 pm Post subject: Newest GAMI lean test...probably off-topic for most

Glad to hear things are going well for you, Lynn.  Others have not been so lucky with the Rotec contraption.   At least two other people that I know have tried the Rotec and tossed it.  Granted, it was the 3300 Jab, but the engines never ran right and were not reliable enough to fly with.

    

   To others who are considering the Rotec, be prepared to work your way thought some disappointment.

    

   In my opinion.

    

   Doug Koenigsberg

 

 

 

   --

marvinlnaz(at)yahoo.com
Guest

Posted: Wed Aug 22, 2012 1:15 pm Post subject: Newest GAMI lean test...probably off-topic for most

I have been satisfied with my Rotec on theJabiru 3300. 

Installation needs to be as specified. 



Marvin



Sent from my "Geeky" iPhone

On Aug 22, 2012, at 2:02 PM, kayberg(at)aol.com (kayberg(at)aol.com) wrote:



[quote] Glad to hear things are going well for you, Lynn.  Others have not been so lucky with the Rotec contraption.   At least two other people that I know have tried the Rotec and tossed it.  Granted, it was the 3300 Jab, but the engines never ran right and were not reliable enough to fly with.

    

   To others who are considering the Rotec, be prepared to work your way thought some disappointment.

    

   In my opinion.

    

   Doug Koenigsberg

 

 

 

   --

marvinlnaz(at)yahoo.com
Guest

Posted: Wed Aug 22, 2012 4:04 pm Post subject: Newest GAMI lean test...probably off-topic for most

Thanks Lynn and Barry.



I assume 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 bigger also.  Am I wrong?



I read the GAMI lean test article.  Seems to me that this test replaces the EGT spread criteria for proper cylinder balance.  Again, is that what you discern?



The article talked about an engine having a fuel flow spread of .7 gph after GAMIs are installed.  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 just 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?



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 worth it.  I'll be quick to add that technology has changed (improved) more than I know since then, and perhaps I myself am a little (but not much) wiser now than I was then and it just might be that I would recognize the improvement more now than then.  All conjecture obviously.



Fortunately, now that I have been introduced to Fuel Spread tests, I can easily run the test on our Jabiru 3300 with the engine analysis and recording equipment we have, it should be a snap.  Fixing (or improving) the issues will be the challenge.



Thanks again for the pictures and your post!



Marvin





        From: Lynn Matteson <lynnmatt(at)jps.net>

 To: jabiruengine-list(at)matronics.com 

 Sent: Wednesday, August 22, 2012 10:46 AM

 Subject: Re: Newest GAMI lean test...probably off-topic for most

  

 

 Hi Marvin-

I wish I had taken better pictures, but these two pretty much show what I did. When I was building it, I was thinking 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 the "oil box". In this picture, the box is still partly there. I would have had 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.



[img]cid:1.448378916(at)web140805.mail.bf1.yahoo.com[/img]



[img]cid:2.448378917(at)web140805.mail.bf1.yahoo.com[/img]



 This shot shows the basic tubes completed, and I'm just starting to build the plenum box around the tubes. >From looking at these shots, I can see that I need to take some better pictures of the final  product.



As far as the Gami lean test is concerned, you start with a rich mixture, and then start to lean the engine in small increments, according to the fuel flow meter, watching the EGT readouts. The temperatures 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 at 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 Jabiru manifold) the rear two cylinders peaked first, then one of the fronts, and finally the last one peaked. This was over the course of leaning that covered a 0.3 gph range. On a small engine like the Jabiru 4-cylinder, that shows that the fuel distribution in the intake manifold is not real good, but  not terrible, either. But with the current manifold that I built, the EGT's will peak, and the next 0.1 gph reduction in flow (leaning), causes them all to start dropping right now. This shows excellent fuel distribution according to the Gami method of lean testing. The writings of people that I have read....John Deakin, Mike Busch, to name a couple...say that most carbureted engines don't have very good fuel distribution, so I'm pretty tickled with my results.



The address for the lean test is:   http://www.gami.com/gamijectors/leantest.php



Some interesting reading about engine operation is found in John Deakin's writings. Here is the address for a complete index of his articles, Pelican's Perch:



http://www.avweb.com/news/pelican/182146-1.html



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 22, 2012, at 11:03 AM, Marvin Williams wrote:



 	  Quote: 	
		   OK Lynn, I'll bite.  Tell us 'dummies' exactly how you performed your GAMI Lean Tests.  Sounds interesting.  Also, how about some photos of your latest intake system.

 

 Nice to hear from you.

 

 Marvin

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Lynn Matteson

Joined: 10 Jan 2006
Posts: 2778
Location: Grass Lake, Michigan

Posted: Wed Aug 22, 2012 4:37 pm Post subject: Newest GAMI lean test...probably off-topic for most

That's too bad that those owners didn't have whatever it took to deal  

with the proper installation, Doug. I've heard of a few who didn't  

get it right the first time, but they got help, and are now flying  

with it just fine. All these installations have to follow the  

suggestions made by the factory...I'm wondering if they did?



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 22, 2012, at 5:02 PM, kayberg(at)aol.com wrote:



 	  Quote: 	
		   Glad to hear things are going well for you, Lynn.  Others have not  

 been so lucky with the Rotec contraption.   At least two other  

 people that I know have tried the Rotec and tossed it.  Granted, it  

 was the 3300 Jab, but the engines never ran right and were not  

 reliable enough to fly with.



 To others who are considering the Rotec, be prepared to work your  

 way thought some disappointment.



 In my opinion.



 Doug Koenigsberg

_________________
Lynn
Kitfox IV-Jabiru 2200
N369LM

Lynn Matteson

Joined: 10 Jan 2006
Posts: 2778
Location: Grass Lake, Michigan

Posted: Wed Aug 22, 2012 5:04 pm Post subject: Newest GAMI lean test...probably off-topic for most

The 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 more time  

for the mixture to atomize, and this makes for a smoother-running  

engine.

No, this is exactly the same test. All you are doing in this test is  

verifying that the fuel flow difference between when the first  

cylinder's EGT peaks, and the last cylinder's EGT peaks, is very,  

very close. That determines how well the engine's air/fuel mixture is  

distributed to the engine. If the first to peak is at say, 3.5 gph,  

and the last to peak does so when the flow meter reads 3.0 gph,  

that's a "GAMI spread" of a half-gallon per hour, and that is not  

good distribution. If this were a direct-port injected engine, the  

injector nozzles would be changed to bring the flow closer together  

between the first, and the last, to reach peak EGT. This is what the  

folks at GAMI do. But my engine, using a Rotec TBI, is basically a  

carbureted engine, and you can't change individual nozzles like you  

can with the direct-port engines.

The EGT spread is still talked about, but not the actual numbers from  

what I've read. First you have to get the flow spread 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. some cylinders are too rich while others may be too lean, and  

the engine will 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 makes for longer-lived engines.

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 22, 2012, at 8:04 PM, Marvin Williams wrote:

 	  Quote: 	
		   Thanks Lynn and Barry.

 I assume 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 bigger also.  Am I wrong?

 I read the GAMI lean test article.  Seems to me that this test  

 replaces the EGT spread criteria for proper cylinder balance.   

 Again, is that what you discern?

 The article talked about an engine having a fuel flow spread of .7  

 gph after GAMIs are installed.  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 just 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?

 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 worth it.  I'll be quick to add that technology has changed  

 (improved) more than I know since then, and perhaps I myself am a  

 little (but not much) wiser now than I was then and it just might  

 be that I would recognize the improvement more now than then.  All  

 conjecture obviously.

 Fortunately, now that I have been introduced to Fuel Spread tests,  

 I can easily run the test on our Jabiru 3300 with the engine  

 analysis and recording equipment we have, it should be a snap.   

 Fixing (or improving) the issues will be the challenge.

 Thanks again for the pictures and your post!

 Marvin

 From: Lynn Matteson <lynnmatt(at)jps.net>

 To: jabiruengine-list(at)matronics.com

 Sent: Wednesday, August 22, 2012 10:46 AM

 Subject: Re: Newest GAMI lean test...probably  

 off-topic for most

 Hi Marvin-

 I wish I had taken better pictures, but these two pretty much show  

 what I did. When I was building it, I was thinking 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  

 the "oil box". In this picture, the box is still partly there. I  

 would have had 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.

 <100_1055.jpg>

 <100_4853.jpg>

 This shot shows the basic tubes completed, and I'm just starting to  

 build the plenum box around the tubes. >From looking at these  

 shots, I can see that I need to take some better pictures of the  

 final product.

 As far as the Gami lean test is concerned, you start with a rich  

 mixture, and then start to lean the engine in small increments,  

 according to the fuel flow meter, watching the EGT readouts. The  

 temperatures 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 at 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 Jabiru  

 manifold) the rear two cylinders peaked first, then one of the  

 fronts, and finally the last one peaked. This was over the course  

 of leaning that covered a 0.3 gph range. On a small engine like the  

 Jabiru 4-cylinder, that shows that the fuel distribution in the  

 intake manifold is not real good, but not terrible, either. But  

 with the current manifold that I built, the EGT's will peak, and  

 the next 0.1 gph reduction in flow (leaning), causes them all to  

 start dropping right now. This shows excellent fuel distribution  

 according to the Gami method of lean testing. The writings of  

 people that I have read....John Deakin, Mike Busch, to name a  

 couple...say that most carbureted engines don't have very good fuel  

 distribution, so I'm pretty tickled with my results.

 The address for the lean test is:  http://www.gami.com/gamijectors/ 

 leantest.php

 Some interesting reading about engine operation is found in John  

 Deakin's writings. Here is the address for a complete index of his  

 articles, Pelican's Perch:

 http://www.avweb.com/news/pelican/182146-1.html

 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 22, 2012, at 11:03 AM, Marvin Williams wrote:

 > OK Lynn, I'll bite.  Tell us 'dummies' exactly how you performed  

 your GAMI Lean Tests.  Sounds interesting.  Also, how about some  

 photos of your latest intake system.

 >

 > Nice to hear from you.

 >

 > Marvin

 >

_________________
Lynn
Kitfox IV-Jabiru 2200
N369LM

BARRY CHECK 6

Joined: 15 Mar 2011
Posts: 738

Posted: Wed Aug 22, 2012 5:26 pm Post subject: Newest GAMI lean test...probably off-topic for most

Doug:



It with tong in cheek, I have to laugh when you say "work your way through".  I joined the RATAX group to gain some insight.  But, instead I gained some track shoes to run away from RATAX as quick as possible.  They have so many problems it is amazing anyone would even consider that engine.  Yet, the they brag about the military using them on UAV's... Sure the military can... They have unlimited funds to keep them running.

 



Barry



On Wed, Aug 22, 2012 at 5:02 PM,  <kayberg(at)aol.com (kayberg(at)aol.com)> wrote:

[quote]  Glad to hear things are going well for you, Lynn.  Others have not been so lucky with the Rotec contraption.   At least two other people that I know have tried the Rotec and tossed it.  Granted, it was the 3300 Jab, but the engines never ran right and were not reliable enough to fly with.

     

   To others who are considering the Rotec, be prepared to work your way thought some disappointment.

    

   In my opinion.

    

   Doug Koenigsberg

 

 

 

   --

Lynn Matteson

Joined: 10 Jan 2006
Posts: 2778
Location: Grass Lake, Michigan

Posted: Thu Aug 23, 2012 6:30 am Post subject: 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)

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_________________
Lynn
Kitfox IV-Jabiru 2200
N369LM

BobsV35B(at)aol.com
Guest

Posted: Thu Aug 23, 2012 6:51 am Post subject: 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(at)jps.net writes:

  	  Quote: 	
		  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)

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Lynn Matteson

Joined: 10 Jan 2006
Posts: 2778
Location: Grass Lake, Michigan

Posted: Thu Aug 23, 2012 8:05 am Post subject: 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(at)aol.com wrote:



 	  Quote: 	
		   Good Morning Lynn,



 Both items look elegant to me!



 Any idea how much those tail pipes weigh?



 Happy Skies,



 Old Bob

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_________________
Lynn
Kitfox IV-Jabiru 2200
N369LM

BobsV35B(at)aol.com
Guest

Posted: Thu Aug 23, 2012 8:25 am Post subject: 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. <G>

  

 I love it!

  

 Happy Skies,

  

 Old Bob

  

  In a message dated 8/23/2012 11:06:25 A.M. Central Daylight Time,  lynnmatt(at)jps.net writes:

  	  Quote: 	
		  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(at)aol.com    wrote:



 	  Quote: 	
		   Good Morning Lynn,



 Both items look elegant    to me!



 Any idea how much those tail pipes    weigh?



 Happy Skies,



 Old  Bob

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marvinlnaz(at)yahoo.com
Guest

Posted: Thu Aug 23, 2012 8:33 am Post subject: Newest GAMI lean test...probably off-topic for most

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

        From: Lynn Matteson <lynnmatt(at)jps.net>

 To: jabiruengine-list(at)matronics.com 

 Sent: Wednesday, August 22, 2012 6:04 PM

 Subject: Re: Newest GAMI lean test...probably off-topic for most

 --> JabiruEngine-List message posted by: Lynn Matteson <lynnmatt(at)jps.net (lynnmatt(at)jps.net)>

The 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 more time for the mixture to atomize, and this makes for a smoother-running engine.

No, this is exactly the same test. All you are doing in this test is verifying that the fuel flow difference between when the first cylinder's EGT peaks, and the last cylinder's EGT peaks, is very, very close. That determines how well the engine's air/fuel mixture is distributed to the engine. If the first to peak is at say, 3.5 gph, and the last to peak does so when the flow meter reads 3.0 gph, that's a "GAMI spread" of a half-gallon per  hour, and that is not good distribution. If this were a direct-port injected engine, the injector nozzles would be changed to bring the flow closer together between the first, and the last, to reach peak EGT. This is what the folks at GAMI do. But my engine, using a Rotec TBI, is basically a carbureted engine, and you can't change individual nozzles like you can with the direct-port engines.

The EGT spread is still talked about, but not the actual numbers from what I've read. First you have to get the flow spread 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. some cylinders are too rich while others may be too lean, and the engine will 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 makes for longer-lived engines.

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 22, 2012, at 8:04 PM, Marvin Williams wrote:

 	  Quote: 	
		   Thanks Lynn and Barry.

 I assume 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 bigger also.  Am I wrong?

 I read the GAMI lean test article.  Seems to me that this test replaces the EGT spread criteria for proper cylinder balance.  Again, is that what you discern?

 The article talked about  an engine having a fuel flow spread of .7 gph after GAMIs are installed.  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 just 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?

 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 worth it.  I'll be quick to add that technology has changed (improved) more than I know since then, and perhaps I myself am a little (but not much) wiser now than I was then and it just might be that I would recognize the improvement more now than then.  All conjecture obviously.

 Fortunately, now that I have been  introduced to Fuel Spread tests, I can easily run the test on our Jabiru 3300 with the engine analysis and recording equipment we have, it should be a snap.  Fixing (or improving) the issues will be the challenge.

 Thanks again for the pictures and your post!

 Marvin

 From: Lynn Matteson <lynnmatt(at)jps.net (lynnmatt(at)jps.net)>

 To: jabiruengine-list(at)matronics.com (jabiruengine-list(at)matronics.com)

 Sent: Wednesday, August 22, 2012 10:46 AM

 Subject: Re: Newest GAMI lean test...probably off-topic for most

 Hi Marvin-

 I wish I had taken better pictures, but these two pretty much show what I did. When I was building it, I was thinking 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 the "oil box". In this picture, the box is still partly there. I would have had 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.

 <100_1055.jpg>

 <100_4853.jpg>

 This shot shows the basic tubes completed, and I'm just starting to build the plenum box around the tubes. >From looking at these shots, I can see that I need to take some better pictures of the final product.

 As far as the Gami lean test is concerned, you start with a rich mixture, and then start to lean the engine in small increments, according to the fuel flow meter, watching the EGT readouts. The temperatures 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 at 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 Jabiru manifold) the rear two cylinders peaked first, then one of the fronts, and finally the last one peaked. This was over the course of leaning that covered a 0.3 gph range. On a small engine like the Jabiru 4-cylinder, that shows that the fuel distribution in the intake manifold is not real good, but not terrible, either. But with the current manifold that I built, the EGT's will peak, and the next 0.1 gph reduction in flow (leaning), causes them all to start dropping right now. This shows excellent fuel distribution according to  the Gami method of lean testing. The writings of people that I have read...John Deakin, Mike Busch, to name a couple...say that most carbureted engines don't have very good fuel distribution, so I'm pretty tickled with my results.

 The address for the lean test is:  http://www.gami.com/gamijectors/leantest.php

 Some interesting reading about engine operation is found in John Deakin's writings. Here is the address for a complete index of his articles, Pelican's Perch:

 http://www.avweb.com/news/pelican/182146-1.html

 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 22, 2012, at 11:03 AM, Marvin Williams wrote:

 > OK Lynn, I'll bite.  Tell us 'dummies' exactly how you performed your GAMI Lean Tests.  Sounds interesting.  Also, how about some photos of your latest intake system.

 >

 > Nice to hear from you.

 >

 > Marvin

 >

&biruEngine-List"  target="_blank">http://www.matronics.com/Navigator?JabiruEngine-Lista href="http://forums.matronics.com/" target="_blank">http://forums.mat                     &nbs//www.matronics.com/contribution" target="_blank">http://www.matronics.co==================

 [quote][b]

Lynn Matteson

Joined: 10 Jan 2006
Posts: 2778
Location: Grass Lake, Michigan

Posted: Thu Aug 23, 2012 9:42 am Post subject: 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(at)aol.com wrote:



 	  Quote: 	
		   Good Morning Lynn,



 Both items look elegant to me!



 Any idea how much those tail pipes weigh?



 Happy Skies,



 Old Bob

_________________
Lynn
Kitfox IV-Jabiru 2200
N369LM

Lynn Matteson

Joined: 10 Jan 2006
Posts: 2778
Location: Grass Lake, Michigan

Posted: Thu Aug 23, 2012 9:42 am Post subject: 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(at)aol.com wrote:



 	  Quote: 	
		   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. <G>



 I love it!



 Happy Skies,



 Old Bob

_________________
Lynn
Kitfox IV-Jabiru 2200
N369LM

Lynn Matteson

Joined: 10 Jan 2006
Posts: 2778
Location: Grass Lake, Michigan

Posted: Thu Aug 23, 2012 9:48 am Post subject: 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:



 	  Quote: 	
		   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

_________________
Lynn
Kitfox IV-Jabiru 2200
N369LM

marvinlnaz(at)yahoo.com
Guest

Posted: Thu Aug 23, 2012 10:08 am Post subject: Newest GAMI lean test...probably off-topic for most

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 <lynnmatt(at)jps.net> wrote:



 	  Quote: 	
		   

 

 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

>

Lynn Matteson

Joined: 10 Jan 2006
Posts: 2778
Location: Grass Lake, Michigan

Posted: Fri Aug 24, 2012 2:14 am Post subject: Newest GAMI lean test...probably off-topic for most

Yup, output...I wanted to mix the air and fuel as much as possible.



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 2:08 PM, Marvin wrote:



 	  Quote: 	
		   



 Just a quick question Lynn. Do you swirl the TBI input or output  

 air?  I'm guessing output.



 Marvin

_________________
Lynn
Kitfox IV-Jabiru 2200
N369LM

BARRY CHECK 6

Joined: 15 Mar 2011
Posts: 738

Posted: Fri Aug 24, 2012 2:33 am Post subject: Newest GAMI lean test...probably off-topic for most

Lynn:



Which way is the swirl pattern in the carb throat, clockwise or counter clockwise?

And how did you determine it?

Barry



On Fri, Aug 24, 2012 at 6:13 AM, Lynn Matteson <lynnmatt(at)jps.net (lynnmatt(at)jps.net)> wrote:

 [quote]--> JabiruEngine-List message posted by: Lynn Matteson <lynnmatt(at)jps.net (lynnmatt(at)jps.net)>

  



 Yup, output...I wanted to mix the air and fuel as much as possible.

 

 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 2:08 PM, Marvin wrote:

 

  	  Quote: 	
		   --> JabiruEngine-List message posted by: Marvin <marvinlnaz(at)yahoo.com (marvinlnaz(at)yahoo.com)>

 

 Just a quick question Lynn. Do you swirl the TBI input or output air?  I'm guessing output.

 

 Marvin

 

 	
 



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