 * Rotec TBI-40-3, bing equivalent, includes regulator. |
Refine your Engine.
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Introduction
The Rotec TBI (throttle body injector), is the most compact and simple Throttle Body Injector on the market. Its unique fuel distribution system makes it easy to setup and operate. With excellent power per volumetric flow, smooth mixture control, and variety of models to suit any engine, this system is a must for any serious experimental pilot.
Fuel delivery and pressure are controlled by the “on demand” fuel pressure regulator, supplying the precise amount of fuel to the engine. This system is truly self regulating, and is not affected by fluctuating fuel levels or pressures.
Advantages
Greater performance and economy is a result of the ultra fine fuel atomization in comparison to regular carburetors. The superior air fuel mixture and no to mention the reduction of mixture temperature, put simply results in more efficient fuel combustion.
With the TBI’s use of a slide throttle, the total wetted area and drag is greatly reduced, resulting in more throat area for the same size bore.
Another advantage of the slide throttle control is that unlike the butterfly valve, the fuel mixture is not deflected into the side walls of the inlet track where the mixture tends to accumulate and loose the benefit of fuel atomization.
The TBI can run a wide range of fuel pressures, from 0.5 to 6.0 PSI. It can even run in gravity fed mode too. The TBI is not attitude sensitive having no float chamber so consequently is fully aerobatic!
Starting the engine from cold is simply a matter of pressing the diaphragm override button on the TBI regulator while cranking, this in effect gives the engine a squirt of fuel to start. Typical primer nozzles can also be utilized if the airframe has existing primer systems.
Idle speed is set via typical throttle aperture stop and bypass mixture screw which sets the idle fuel mixture.
The slide throttle and mixture levers are controlled via typical Bowden push pull cables. The air cleaner side of the TBI is of the standard aviation four bolt flange, designed to fit the standard range of aviation air intake ducting.
Rotec advise that carburetor heat is a mandatory requirement.
How the Rotec TBI Works
The Rotec throttle body injection uses a spray bar that is position into the intake air-stream. The venturi effect is utilized to draw fuel from the spray bar as required.
The simple yet incredibly effective fuel regulator is connected to the fuel inlet of the TBI. Fuel pump pressure on the inlet side of the regulator is blocked by a flow valve. This valve can only allow fuel to flow when the diaphragm experiences a drop in atmospheric pressure at the spray bar. The degree to which the valve opens depends on how much air passes the spray bar. The clever part is that the incoming fuel pressure at the regulator aids in the closure of the fuel flow valve. Consequently fuel pressure and the negative pressure created at the spray bar are always balanced. Altering the fuel pressure will have no effect as the balance will readjust automatically to match the exact fuel demand the engine requires for any given power setting. It is effectively a negative pressure regulator.
This principle is also used in scuba diving equipment. When a diver draws a breath, the respirator creates a small negative pressure on the diaphragm and the flow valve opens; but, on the other side of the flow valve is an Oxygen tank with very high pressure! Why does this pressurized air not blow up the diver’s lungs? Because as soon as the diver draws breath the diaphragm opens the flow valve. This in turn exposes the tank pressures to the diaphragm and instantly tries to close the flow valve. Therefore as the driver draws a breath and the diaphragm allows only the air required.
For more information, be sure to view the F.A.Q tab.
Product Range
There is Rotec TBI suitable for all engine types ranging from 40 – 250hp. While the TBI is designed with carbureted aircraft engines in mind, there is no reason it cannot be retrofitted to car or motorcycle engine, carbureted or EFI.
The Rotec TBI is offered as an option over the regular Bing supplied standard on the Rotec R2800 and R3600 radials. The TBI will attach to the typical Bing rubber coupling found on the Rotec Radials and Jabiru engines. The aviation flanges will also match directly to the their suited engine.
For Experimental Use Only. Fell free to contact us if you have any questions.
TBI Models
Model |
Image (Click to enlarge) |
Possible Applications |
Description |
Included Items |
Rotec TBI-34-R |
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Rotec TBI-34-S |
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Rotec TBI-34-2 |
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Rotec TBI-40-S |
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Rotec TBI-40-3 |
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Rotec TBI-40-4 |
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Rotec TBI-48-4/5 |
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TBI Accessories
| The Rotec Fuel Flow Meter provides the you with a wide variety of information such as achievable range and reserve flying time once you reach your destination. Calculated per second, this allows you to trim your throttle settings to optimize the fuel consumption with ease. |  |
Performance Testimonials & More:
Please contact Rotec Aerosport if you would like more testimonials.
Want to add a testimonial? Please contact, or submit copy, to at testimonial@rotecaerosport.com.
Kitplanes Article by Steve Ells about Rotec’s TBI. To open the pdf click on:
Name: Derek Dyer
Origin: Australia
Engine: Rotec R2800
Fuel System: TBI-40-S
From: Derek Dyer [mailto:pleasant_hills@hotmail.com]
Sent: Monday, 24 January 2011 2:32 PM
To: Rotec Factory
Subject: TBI-40 / R2800 fuel burn
Hi Paul, Some fuel burn figures with the TBI on the R2800 radial. The leaning feature really cuts back on the fuel burn in cruise. Compared to the Bing which could not achieve this. The top end power is fantastic.
POWER RPM EGT Litres per hour Lean Cruise 3000 590 15.5 – 16 Full Rich Cruise 3000 480 22 Lean WOT 3350 650 26 Full rich WOT 3350 550 34 The whole system is so smooth. Very happy.
Regards, Derek
Name: Ron Shannon
Origin: USA
Engine: Jabiru 3300
Fuel System: TBI-40-S
From: Ron Shannon [mailto:rshannon@cruzcom.com]
Sent: Monday, 17 January 2011 10:27 AM
To: rotecengineering@bigpond.com
Subject: Re: TBI suggestions
Paul,
I am very happy to report that I have the TBI running on my 3300 and overall, it’s great and I’m very pleased with it.
After just a little bit of prime, it fired right up first time. After that, all I’ve had to adjust (so far) was the idle stop.
It runs great at idle as is so I’ve not bothered to fiddle with idle mixture. Interestingly, at static RPM, it puts out 130150 RPM more than the AeroCarb with the same prop! Yay!
Much thanks, Ron Shannon
KitFox Lane WA 89382 USA
Name: Bruce Knowles
Origin: Australia
Engine: Jabiru 3300
Fuel System: TBI-40-S
From: Bruce Knowles [mailto:knowlesbgla@westvic.com.au]
Sent: Thursday, 13 January 2011 4:22 PM
To: rotecengineering@bigpond.com
Subject: Bruce Knowles jabiru 3300 VH NZK
Hello Paul,
I fitted your TBI-40-S to my Jabiru 430 about 8 months ago and while at it I also fitted a new Sensenich prop to replace a damaged one. The replacement prop was identical to the previous. on first take off I was very surprised to observe the revs had increase dramatically to 3200 rpm when on the previous Bing set up would deliver about 2750rpm. That’s a big jump in performance, some 450rpm! At first I thought I had been supplied with the wrong prop but after careful examination, the prop checked out as having the same pitch and diameter as the previous. The increase in power had come directly from the addition of the TBI. It is advertised that a performance increase is to be expected but I did not expect to gain as much as I did. Full power performance and the resultant climb is much improved, and with the mixture control I simply lean off at cruise for best fuel burn. The increase in RPM has allowed me to add more prop and with that I dumped the Sensenich and purchased a bigger three Blade Bolly prop with more bite!
The Bolly Prop has allowed me to adjust it so that I can convert the new found HP in to usable performance. More power equals more fuel but the leaning capability of the TBI 40 design has allowed me to adjust the fuel flow back to a burn that the Bing simply could not offer.
I rang Paul at Rotec to tell him how impressed I was with the TBI. I am now looking very seriously at Rotec LCH liquid cooled cylinder heads as I believe the TBI fuel injection combined with LCH heads will make the ultimate Jabiru engine. As It stands now my heads temps do still tend to creep above acceptable limits on the warmer days. One step at a time so they say.
I would have no hesitation is recommending the TBI for the Jabiru engine, its brilliant.
Paul please feel free to forward my experiences to any potential customers you may have, you can also give them my email should they wish to discuss any aspect of the TBI.
Thanks again for wonderful product.
Regards Bruce Knowles
Name: Calvin Thorne
Origin: Canada
Engine: Jabiru 3300
Fuel System: TBI-40-S
From: Calvin Thorne
Sent: Thursday, 14 October 2010 11:55 AM
To: rotecengineering@bigpond.com
Subject: RE: Calvin Thorne – TBI Questions
Paul,
Thank you for the immediate response to my question.
You folks have the greatest customer service and this is hard to find these days.
Great doing business with you and will try to send more your way.
Calvin Thorne
Cochrane Alberta Canada
Name: Lynn Matteson
Origin: Australia
Engine: Jabiru 2200
Fuel System: TBI-34-S
From: Lynn Matteson [mailto:lynnmatt@jps.net]
Sent: Tuesday, 10 November 2009 1:19 AM
To: Rotec Factory
Subject: Engine stoppage during takeoff
Hi Paul-
The TBI that I bought from you at Oshkosh has been running great on my Jabiru 2200 engine………
Thanks again for the suggestions, and keep up the good work. Several people have mentioned to me that they got good advice from you regarding their installations. Good show, mate!
Lynn
Name: Dana Thurston
Origin: USA
Engine: Jabiru 3300
Fuel System: TBI-40-S
From:runningmancourier@comcast.net [mailto:runningmancourier@comcast.net]
Sent: Tuesday, 12 October 2010 5:36 AM
To: Factory, Rotec
Subject: Jab 3300 with TBI!!
RIGHT ON!!
First flight of my Sonex with a jabiru 3300 and a Rotec TBI went off great!!! This engine NEVER ran like this!!! Having had some near deaths with the “brand A” throttle body and forever trying to get it to run sort of alright…the Rotec was awesome right from first start and gives me a solid 100 rpm gain on climbout with lower EGT (1100 tops)! I’m making significantly more HP and its smooth in every rpm range. I couldn’t be happier with the choice I’ve made. I’ll send some pics when the cowl comes off and till then enjoy a brief walk around!!
Dana Thurston
USA
Dana also included this video of his Sonex:
Name: David Mccandless
Origin: Australia
Engine: Rotec R2800
Fuel System: TBI-40-S
From: david mccandless [mailto:daval@iprimus.com.au]
Sent: Tuesday, 20 July 2010 11:00 AM
To: rotec factory
Subject: Funk R2800 installation
To the Rotec Team
I now have my 1946 Funk flying with the Rotec R2800 fueled with the Rotec TBI. It performs better that I ever imagined.
The whole installation turned out to be a very pleasing exercise in aircraft home engineering. There were minor glitches along the way and the Rotec factory support in solving those glitches was most appreciated.
When I got myself into a hole (almost literally!) with the lubrication system due to my own stupidity, the factory came up with a positive ‘can do, can fix’ solution that has culminated in a vast increase in my knowledge of, and confidence in, my R2800.
The TBI is not a complicated piece of equipment, but it still must be installed and tuned correctly for satisfactory performance. The fact that Paul was always available on email or at the end of the phone for advice made the whole installation a simple series of steps.
Timely backup with improved components, supplied free of charge along the way has left me with a feeling that Rotec were interested seeing my Funk project through to a successful conclusion and that it was not just ‘another engine sale’.
Please feel free to refer any potential customers to me should they wish to discuss any aspects of my engine fit experience.
With my best regards and thanks,
Dave McCandless
email : daval@iprimus.com.au
08 9295 0685
Name: Martin Hone
Origin: Australia
Engine: Rotec R3600
Fuel System: TBI-40-S
From: Martin Hone [mailto:aerobiz1@gmail.com]
Sent: Wednesday, 23 June 2010 11:45 AM
To: rotecengineering@bigpond.com
Subject: Re: TBI working great.
Paul, I spoke with one of the local flyers on the weekend that is looking at putting one on his
Lycoming O-320 powered BD4, so I can just say pretty much what I told him…………..
When I fitted the Rotec R3600 into the prototype Spacewalker II – RR, I was originally going to
keep things simple and use the supplied Bing carb. As it turned out, I had a tuning issue with the
Bing, so it justified ordering the TBI unit before the first flight. While I therefore cannot make a
direct comparison between the Bing and the TBI, I have found the TBI to be very simple to
maintain and tune, with the very real advantage of being able to adjust the mixture in-flight. This
feature alone makes the TBI a worthwhile purchase, allowing optimum engine performance at
various altitudes, and saving fuel. On a recent cross country flight over 14 hours duration, The
R3600 was consistently taking on less fuel at each fuel stop than a friend’s Rotax 912-powered
J6 Karatoo. We were travelling at the same speed, so the R3600 was loafing, but we were both
amazed at is economy of 18.1 litres per hour (4.8 US gallon per hour). As soon as the carb on
my Lycoming O-320 powered RV gives trouble , it will be replaced by a Rotec TBI immediately.
Martin Hone.
Name: Martin Hone
Origin: Australia
Engine: Rotec R3600
Fuel System: TBI-40-S
From: Mike Custard [mailto:mike@advancedaviationinc.com]
Sent: Saturday, 10 April 2010 2:54 PM
To: ‘Rotec Factory’
Subject: Rotec TBI Vs Marvel-Schebler
Hi Paul,
I finally got the chance to fly with the TBI (0-200) and I have attached the comparison sheet. Idle, throttle response and overall engine performance was very good.
Tables:
Marvel-Schebler Carburetor VS. Rotec TBI-40-3 Throttle Body
Injection on a Continental 0-200 powered Kitfox
With Marvel-Schebler Carburetor
RPM MP GPH EGT1 EGT2 EGT3 EGT4 2400 16.9 5.1 1082 1120 1283 1229 2500 17.7 5.6 1079 1119 1309 1262 2600 18.2 6.2 1084 1117 1288 1266
With Rotec TBI-40-3 Throttle Body Injection
RPM MP GPH EGT1 EGT2 EGT3 EGT4 2500 17.5 4.5 1210 1285 1236 1265 2600 18.2 6.2 1218 1300 1261 1279 @5000MSL, 45F OAT, Dynon D-180 EFIS/EMS
Thanks,
Mike Custard
Name: Nick Coleman
Origin:
Engine: Lycoming O-320
Fuel System: TBI-40-4
From: Nick Coleman [mailto:herkpileit@hotmail.com]
Sent: Tuesday, 6 October 2009 9:38 AM
To: rotecengineering@bigpond.com
Subject: TBI Install on O-320 Swick-T pictures
G’day Paul,
As promised here is some pictures of my TBI install on my O-320 powered Swick-T.
When I first got the TBI out of the box I thought there is no way this thing can work very well. It is too small, too light, it did not cost me an arm and a leg, and there is only two moving parts.
However, on a leap of faith I pulled off the piece of #$@$%* PS-5C pressure carb that I have run for years and set about installing your TBI. I was completely shocked when the engine started on the fourth blade on the initial start.
I have about five hours flying it now and I cannot be more pleased. It starts right up every time, hot or cold. My engine runs smoother and quieter than it ever has. I do not have the specific numbers yet, but I am using a significant less amount of fuel per hour.
While doing aerobatics in a practice box my ground observer even noticed that my engine seemed to running be much quieter and smoother than it had in the past.
I cannot tell you thanks enough, it just works great.
If you have any customers looking for recommendations please feel free to have them contact me.
Thanks again,
Nick Coleman
Photos of Nick’s Installation
Please click on each thumbnail to enlarge, when done click on the photo to return.
Name: Lynn Mattison
Origin: Australia
Engine: Jabiru 2200
Fuel System: TBI-40-S
Lynn’s Comments are posted on the Matronics Forum.
Lynn Matteson
Kitfox IV Speedster, tail dragger
Jabiru 2200, #2062, 727.5 hrs
Sensenich 62″x46″ Wood prop
Electroair direct-fire ignition system
Rotec TBI-40 injection
Extract #1: On Mon Aug 03, 2009
Status: Rotec TBI success story underway
http://forums.matronics.com/viewtopic.php?t=60924&sid=d9652d1274cf0c12345c9f2e385d2fde
I bought a Rotec TBI-40 mechanical fuel injection system while at Oshkosh, and spent the last 3 1/2 days making the throttle control bellcrank, the air intake tube adapter, and the fuel line, and after all checks and double-checks, I fired her up.
The TBI performed as advertised….right out of the box.
The first flight will come tomorrow. As advertised, this thing will not drip fuel like the other well-known Bing replacement on the market. Nothing against them, but I am VERY happy I made the decision…so far, anyway. Flying might be another thing, but so far, so good.
Extract #2: On Aug 10, 2009
Status: TBI installation done…tests flights underway
http://www.matronics.com/forums/viewtopic.php?t=61142&sid=3416128505bf5a4e9e493f561619fe58
… the addition of the Rotec TBI-40 mechanical fuel injection system will enable the pilot to control the EGT’s rather well. I’ve been test flying mine over the last several days, and I’ve seen EGT’s as close together as (today’s flight) 41 degrees F., and CHT’s as close together as 7 degrees F. It’s nice to be able to adjust the mixture with this device, and also to see the fuel flow read down as low as 2.9 gph at about 80 mph ground speed into a 12 mph wind at 2700 rpm.
I’ve been playing with “lean off peak” with this device, which is one reason that I bought it. It amazed me that you can see the EGT’s go down after reaching peak temperature….I was a skeptic as first, but if the engine lives, I’ll be a believer. Even without the ability to go lean of peak, just being able to adjust the mixture on the fly is worth the added workload on this pilot during takeoff and landing.
Client to Rotec Interface/Dealings
Don and Dianne Have been Rotec clients since 2004 purchasing a Rotec engine and accessories.
From: Donna Warner [mailto:donlusc1979@earthlink.net]
Sent: Tuesday, 8 September 2009 5:32 AM
To: Rotec
Cc: rotecengineering@bigpond.com
Subject: Rotec Factory – Product, Management & Support
Don & Dianne Usher
Hi – Our name is Don & Donna Warner
We manage “Team Luscombe” ( ATC-694 Holder ). We Restore, Repair and Custom build Luscombes. Currently we are replicating a 1938 Luscombe model 4. You can view our project on the Rotec web site, Home page / Warner model 4.
We started this project because of Rotec’s new R2800 engine, and after talking with Paul at “Sun-N-Fun” and seeing their demo aircraft, a Kit Fox, We were sold on the engine and the people that produce it.
We ordered the engine and included their exhaust system and propeller. Factory designed equipment saves many hours in production and evaluation. Rotec has already engineered everything to work together. No trial and error.
The Factory support we have received from Paul and Jim has been excellant. They are quick to respond to our technical questions and any problems that came-up they have resolved fairly and to our satisfaction.
Our parent company, Luscombe Silvaire who build the new LSA Luscombe’s, has just completed a Rotec R2800 installation also, its called the Phantom II. It performes perfectly and has already appeared in Plane & Pilot, June 2009 issue.
As business managers, We appreciate working with other business people that have a good product, present it with pride and are always willing to take care of any problems that may arrise.
Rotec is a great company. They have a teriffic aviation product, conduct their business professionally and treat their customers friendly, fairly and above all with respect.
Respectfully,
Don & Donna Warner
Team Luscombe
Donna Warner
Bill Pokes has been dealing with Rotec since 2004 purchasing an engine and accessories…
From: bill [mailto:bill@tilesignsandgraphics.com]
Sent: Wednesday, 9 September 2009 3:39 AM
To: rotecengineering@bigpond.com; denver7@xplornet.com; RotecAdmin@bigpond.com
Subject: RE: Rotec Factory support
All,
I am flying the Rotec 2800 on my Kitfox. I am beyond happy with the engine and the support provided by The Rotec Staff. I was fortunate to have been at this years Airventure at Oshkosh and met Paul Chernikeeff.
I was great to put a face with a name.
Regarding support:
When I have had a question, the Rotec staff has responded in less than 24 hours. I sure wish all suppliers were as responsive.
This engine is a Contemporary Radial Engine which Starts immediately, runs smooth, has incredible sound, great looks and draws a crowd wherever I go. I have flown a number of Kitfox aircraft and the performance with this engine is astounding. The acceleration on takeoff pushes you back into the seat cushions. I gave a ride to a long time Kitfox owner last week and his comment after takeoff was “ WOW”. I am swinging a 76” x 55” prop- which was what Paul suggested – and the performance is just what we were looking for.
At Gross with 4500’ density altitude ( the ride previously mentioned) we were climbing at around 1200 FPM. The long prop required longer landing gear legs, but I understand a 3 blade prop is available. If anyone has any questions please feel free to call or email. The Kitfox is at Chandler Arizona Airport ( KCHD). I will be glad to show it to you.
Best Regards and Thank You Paul for all of your continuing help and support.
Bill William Prokes
From Jake Shultz – please see the link to Jake’s page.
.
My interaction with ROTEC has been a stellar experience…
My engine has only recently arrived so I have not yet mounted or ran it, however the interaction and support from ROTEC has been wonderful.
From the very first call to the arrival of my engine, they have answered all my questions and have been very professional. The passion and pride that they hold for their product is evident to me.
The engine sits on my shop floor looking like a piece of fine sculpture.
http://www.rotecengines.com/Projects/JakeSchultz.html
I would have no hesitation in recommending a purchase…
Jake
Francis (Joe) Meyeres – Client since 2004 purchasing and engine and accessories.
From: Francis L Meyeres [mailto:meyeres3e@sbcglobal.net]
Sent: Wednesday, 9 September 2009 11:24 AM
To: Rotec
Cc: rotecengineering@bigpond.com
Subject: Re: Rotec Factory support Comments
I have a Kitfox Classic IV with a Rotec R2800 on the nose. I can’t tell you how much I have enjoyed that engine since I first got it.
The folks at Rotec have been absolutely outstanding to work with any time there has been any questions or issues that have arose.
If you are thinking about purchasing a Rotec and are concerned about their support… put your mind at ease. These guys have a great product that runs smoothe, sounds outstanding, has plenty of power and absoulety has all the asthetic qualities the others wish they had.
Guarenteed you will not draw a crowd to look at your new “Brand X” motor like you will with the Rotec Radial!
Joe Meyeres
Throttle Body Injection FAQ
Are there any advantages in setting the Rotec TBI to run “lean of peak”?
Absolutely, there is a saving on fuel and engine life.
Contrary to what most think this is where the lowest temperature is, so it is easier on hot engine components. On the Bing Carburetor no one has any idea where it really is so you could in fact be running rich of peak, which would raise cruise head temps, also burn more fuel, and potentially shorten engine life, through excessive and unnecessary heat.
TBI and turbocharging?
| Turbo Configuration | Works with TBI | Comments |
| Pull (Suck) through | YES | Has no problem operating under this configuration. |
| Push (Blow) through | NO | Does not work as a differential pressure is required between the regulator and the spray bar. |
TBI and Rotax installations?
Single TBI Approach
Rotec Aerosport recommend Rotex owners simplify their engine by replacing the 2x standard Bing carburetors with a single TBI-40-3. Instead of having 2x fuel lines, 2x throttle controls, 2x chokes, 2x air filters, and all the cables and hoses to accommodate dual units. All that is required is a bridge manifold to converge both intakes. Please see the thumbnails of the Ion Aircraft. Click here for more details.
The following is an unmodified email questionnaire to Steve Schultz at Ion Aviation.
From: Steve Schultz [mailto:Steve@ionaircraft.com]
Sent: Tuesday, 21 February 2012 6:37 AM
To: rotecengineering@bigpond.com
Subject: Re: Rotec TBI some info about your installationHowdy Paul;
The TBI was one of the best decisions we’ve made. From the first day we had the Rotax we were frustrated with the dual carbs. Two fuel lines, two throttle controls, two chokes, two air filters, cables and hoses everywhere, etc. And although we got proficient at the Rotax carb-sync procedure, we never liked it. It was just another hoop to jump through.
1. What was involved when installing the TBI to your Rotax, was the installation overly difficult?
It was not overly difficult at all. I will send you a drawing shortly, but the short version is we fabricated a single plenum with two runners feeding the existing one-into-two induction castings. We spent more time figuring out the cable routing than we did making the actual induction.
2. What have been the main advantages when using the TBI compared to the Bing set up?
The engine runs much more smoothly across the RPM band, the ability to lean the engine, slight reduction in weight, VASTLY reduced parts count (especially moving parts) much simplified fuel and control cable routing.
3. Was any gain in power found?
No, but for the same power we are burning a little bit less fuel.
4. With the leaning feature have you established an optimum fuel burn for the Rotax?
Well, we have established that we can run LOP without trouble. We have not tried to find a particular optimum as we tend to run the throttle and mixture as the need dictates. We have found that the the engine burns much cleaner and we have seen fuel consumption reduced by approx 3L/hour for equivalent RPMs.
5. Why did you opt for one single TBI-40 when two TBI-34’s could have be used?
Single point of fuel/air induction. Two -34′s in many regards would have been similar to the Bings, i.e. two of everything, etc. We were very intent on having one body of air/fuel feeding both sides of the engine, one fuel line, one throttle cable . . . etc.
6. In regards to mixture control how have you found this in operation?
Very smooth, very simple, pain-free. We have EGT’s on all 4 cylinders, which I would recommend for best results and peace of mind.
7. Once the TBI unit was physically installed, how much did it take to dial it in?
About one half-day of farting around with the throttle stops and the idle mixture screw. No drama.
We did find that we needed to move the pressure regulator. The original location allowed the reg to pick up too much heat and was boiling the fuel in the reg (auto gas, not avgas). In a traditional airplane–not a pusher like ours–this probably would not have been a problem because we could have routed cooling air over the reg. As it was we moved it and it has been fine since. Since then, no problems.
8. Is the engine easy to start when using the TBI, what is your start procedure?
With our set up it is slightly harder to start than with the Bings, but we strongly suspect that this is specific to our installation and not indicative of a problem. Our system has a relatively large internal volume for the fuel/air mix. We think that’s why the engine rarely catches on the first try by always starts on the second try–it’s just taking a moment longer to fill the volume. Once the engine has been run, even for a moment, subsequent starts are immediate.
- Throttle to idle, mixture full rich
- Electric boost pump on, wait for fuel pressure (about 3 seconds)
- Actuate primer plunger on the pressure regulator (3 seconds again)
- Immediately engage starter
- “Blip” the primer 1-2 times while cranking
9. Have there been any down sides to using the TBI over the Bing?
None. We are very glad we did it and we would do it again. Some folks may fuss that they have to manage the mixture instead of leaving it to the Bings, but that is a short-sighted view.
http://www.ionaircraft.com/
Dual TBI Approach
Alternatively a Rotax TBI-34-S twin system as used by Fabio from Italy worked very well at all attitudes. See comments on inverted test below.
From: fausto.tongiorgi@enel.com
Sent: Wednesday, 2 February 2011 12:01 AM
To: ‘rotecengineering@bigpond.com’
Subject: Inverted flight with TBIHello Paul,
I have installed a my own kit for inverted flight on COMET with Rotax 912s
I am using two Rotec TBI-34-S in place of the dual Bings.The performance is a big improvement.
The engine you can see the running tests in some photos. The engine is running perfectly up side down!!! The engine does not know where are up or
down!!
Best Regards, Fausto
All 2 strokes Rotax also easily accept dual TBI’s as seen on this powered paraglider.
___________________________________________________________________________________________________________________________________
Why does the TBI-34 have more holes in the spray bar than the TBI-40?
The TBI-34 has less airflow relative to the TBI-40 due to its smaller diameter inlet. Less airflow means less fuel drawn from the spray bar. This mean more holes are needed for even fuel mixture for the smaller TBI unit.
In the advent of an emergency can the primer override button be used, if I suspect the engine has suffered from vapor lock and or fuel starvation?
100% Yes! If you suspect you have vapor lock and or a failure of the fuel delivery system, by all means try introducing fuel by employing diaphragm override button. Tests have shown that at full power most engines will continue to run albeit extremely rich with the diaphragm button employed. Definitely something to understand, and keep in mind during flight.
What if I accidentally lean the engine to the point the engine quits while in flight, to bring the engine back to life do I just go full rich?
NO! If you lean the engine to the point where it has actually stopped firing, to richen the mixture will probably do nothing, as the air speed over the injector spray bar has now become too slow to help; even if you go to the full rich position. The best way to bring the engine back to life is to promptly pull the throttle back to idle, (if the prop is still wind milling this will immediately restart the engine), then apply full rich, and increase power to desired levels. The engine will give plenty of warning that it is getting towards an excessively lean state. It will start to run very rough when too lean. Leaning any further will see the engine starve of fuel and stop firing.
What sort of fuels can the TBI run on?
The TBI can run on both Avgas and auto gas. However it should be noted that vapor lock is far more prevalent with auto fuels than with Avgas. In both cases and in particular use with auto fuels, great care must be taken to shield the fuel hoses in fireproof sleeve and keep all fuel items such as fuel pumps and the regulator as cool as possible. Air blasting these items is recommended. In the case of using auto fuel, a restricted return fuel line back to the main fuel tank is recommended. This will allow any air bubbles that are formed by vapor lock to bleed off back to the fuel tank.
What about carburetor heat? I hear that slide throttle bodies don’t ever suffer from ice?
No, any carburetor or throttle body that restricts manifold pressure to control power output, will by nature greatly reduce the local temperature at the throttle opening. A traditional exhaust heated carb heat system is mandatory.
Does a TBI system require air cleaners?
Yes, the TBI relies on fine air filtration as unwanted debris and dirt are not only bad for your engine but also can impeded the movement of the slide throttle.
Does the TBI system need fuel filters?
The TBI comes standard with a “last chance filter”, which is located inside the main fuel fitting. It consists of a very fine gauze mesh that is designed to stop debris from blocking the many fine jets. The airframe is still required to have its own filtration up stream. The TBI in built filter should be inspected and cleaned every 100 hours.
What attitude should I mount the TBI to the engine? Is the fuel system aerobatic?
The TBI can be mounted at any attitude and at any angle. The system has no float so can fly at any attitude. Even upside down. Making the TBI the perfect aerobatic fuel systems.
The best spot for mounting the TBI & fuel regulator?
The TBI can be mounted vertically, in fact any attitude make no difference.
When attaching scat hose you must be very careful not to have sharp 90 deg bends, as the airflow across the spray bar is then biased and the TBI performance cab be adversely affected.
Many make a simple spigot out of fiber glass, it’s a good idea to make the ID of the spigot flare so it matched the full radius of the TBI trumpet.
A plenum box attached to the 30mm stand off would be a good idea. Plenums act as a static air reservoir for the TBI to draw from, rather than pulling from a length of scat hose which can often have dynamic air fluffing about its length.
The remote fuel regulator can suffer from the effects of G forces, because these forces will alter the weight of the fuel in the delivery lines. For this reason it is recommended to mount the TBI regulator no further than 6 inches from the fuel fitting on the TBI’s main body, closer is even better. On the Horizontal plain, the regulator must be mounted level with the same fuel fitting, or even slightly above +2” -0”. This is important. Do not position the TBI regulator lower than the throttle body.
Note: All installations need to be thoroughly ground tested on the ground before flying. The ground tests will tell all.
How does the TBI work? It appears to be just like any of the other slide type carburetor?
No, the Rotec TBI is not a carburetor, it is in fact a mechanical fuel injection system. It self meters fuel supply by use of a cleverly calibrated negative pressure fuel regulator. This in effect continuously compensates for any variations in fuel pressure and or power requirement. Other slide type carburetors do not do this!
How do I adjust the idle mixture? How does the TBI unit allow the pilot to adjust mixture in flight? Does it use a flow valve like most other fuel systems?
The TBI has the most efficient means of adjusting fuel mixture. Rather that just closing or opening a crude fuel flow tap, the TBI works completely differently, in that it rotates the fuel delivery spray bar through 90°.
The spray bar has many tiny holes along its length. When the holes are rotated to directly face the incoming airstream the engine is at full lean. When the holes are rotated so they are at right angles to the air flow the TBI is at full rich. The action is smooth and consistent.
The idle mixture screw found on the rear side of the unit. This will need to be adjusted for setting the correct fuel mixture for idle only. The idle speed is then set using the throttle stop. Please see the installation guide for detail instructions.
Do I have to keep adjusting the mixture if I change power settings, or as the fuel tanks get low?
No, unlike many other fuel systems you do not have to keep adjusting the mixture in flight. You would typically fly at full rich for the entire flight and at all throttle settings and only lean the mixture in instances where fuel economy is required, (cross country for example). For any given throttle position the air fuel ratio will be maintained. This ratio is set by the allocation of the many tiny holes and where they are located in relationship to the power setting used.
How do you start an engine with a Rotec TBI? Do you have to use a primer?
To start the engine you simply depress the diaphragm override button, and this injects fuel into the engine. This can be operated from the cock pit with a simple cable and rocker arm mechanism. After starting the engine subsequent restarts should not require priming. If the aircraft is already fitted with an existing primer system this can be used too.
What sort of fuel pump do I need to use, can it run on a gravity fed fuel system?
The TBI can run at a fuel pressure ranging from 0.05 – 6 psi. This includes gravity fed fuel systems. In most cases the typical fuel pumps used on most piston aircraft engine will fall within the correct specifications.
Will including a TBI with my LCH installation, further increase the performance of my Jabiru engine?
Yes. Adding a Rotec Throttle Body Injection system to your engine, along with the the Rotec Liquid Cooled Heads will further increase engine performance. Along with a cooler running, and therefor more reliable engine, the TBI will increase the performance of the fuel system, and as a result increase power output.
There’s some additional comments by Lynn Mattison (Jabiru 2200 + Rotec TBI-40-S on a Kitfox) who relays practical results and observations on the Matronics Forum. Scroll down to find Lynn’s post; its well worth reading.
File |
Description |
| Installation Manual | Installation overview, including some FAQ and troubleshooting. |
| All TBI models – Basic Dimensions | External dimensions for all TBI models and regulator. View this drawing to select the best TBI for your installation. |
| Rotec TBI-34-R Dimensions | External dimensions for TBI-34-R and regulator. |
| Rotec TBI-34-S Dimensions | External dimensions for TBI-34-S and regulator. |
| Rotec TBI-34-2 Dimensions | External dimensions for TBI-34-2 and regulator. |
| Rotec TBI-40-S Dimensions | External dimensions for TBI-40-S and regulator. |
| Rotec TBI-40-3 Dimensions | External dimensions for TBI-40-3 and regulator. |
| Rotec TBI-40-4 Dimensions | External dimensions for TBI-40-4 and regulator. |
| Rotec TBI-48-4/5 Dimensions | External dimensions for TBI-48-4/5 and regulator. |
