To TBI or not to TBI?

I am thinking of installing a Rotec TBI in my -4.
Lyc O-360 with a MA4-5 (Carb. in need of overhaul)

The question is where to put the real effort, rebuild MA4-5 or go on with the TBI installation.

Any experience, comments and thoughts are welcome.

Your call.

We have a T.B.I. engine, but it is an E.C.I. system from the start that is matched to the Van's intake snorkel and air filter box. So it was not that hard to fit it to the hardware from the factory. If you have an MA-4 or 5 already on and all the hardware hooked up to it. I would think about if it is going to take a lot of time and adaptation to change over. To rebuild the carb. is the more reasonable in that case. But you are the driving force in this problem and to save 1/10 of a gallon or less of fuel per hour and hold those Acro. angles a little longer is what you want. Go for it. The carb. is still a very dependable device and will serve you well down through the years.. Hope this helps. Yours. R.E.A. III # 80888

Do you inverted oil? I have personally never run a TBI but I've never heard good things about them. Some Pitts guys run them because the are cheap but go to fuel injection as soon as they can.

Regardless of cost, and it would not be a massive amount more, buy a Bendix RSA servo system or one of the Airflow Performance systems from Don Rivera.

Don't muck around. You will not regret it

I have experience with TBI with Lycoming 0235 and 0360. It worked well for me.

Take a look at

http://www.ellison-fluid-systems.com

They have been around for a while and I was pleasantly surprised to see the web sight is still up and running. Ben Ellison was a first call guy when I dealt with him.

David-aviator said:

I have experience with TBI with Lycoming 0235 and 0360. It worked well for me.

Take a look at

http://www.ellison-fluid-systems.com

They have been around for a while and I was pleasantly surprised to see the web sight is still up and running. Ben Ellison was a first call guy when I dealt with him.

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They no longer manufacturer new units. They have a few still in stock and still provide service. The only issues I have ever heard about the Ellison units, and experience myself, is the dye from the 100LL can build up over time and muck up the small orifice that allows the unit to draw fuel on starting. (I would be lying if I told you I knew exactly how that part of the unit works)
Not sure if the Rotac is the same design or not.
Other than that, TBI's are very simple, effective, and reliable. The Ellison is going back on my newly rebuilt engine for the Bucker.

The TBI is very cheap and works better than the MS carb' in that you can lean it further without rough running. It will cost probably the same to buy a Rotec than o'haul your MS carb'. You can buy a new Rotec for what it costs to o'haul an old Ellison (sadly).
The issues with the TBI are the installation, it will not tolerate turbulent airflow at its entry/exit, but an airflow straightener will sort that out. Too much ram air is not not good, it needs to suck.
Keep the TBI cool, they don't like being hot.
Rotec will tolerate Autofuel, but you need to make sure all your flexible pipes, fuel pump etc will.
I have just received clearance to operate on Mogas (autofuel) on my RV4 in the UK. In order to do so I had to remove the mech' pump and use dual electric pumps (one with its own small 4ah battery charged off of the main buss) & change any hoses that are not Ethanol compliant.
I fitted a fuel return system to vent any vapor locks.
The bonus with the TBI against the MS carb' is that it will work inverted
Neil

Depends on why...are the inverted capabilities of the TBI important to you? I just finished converting my O-320 to Ellison TBI, but only because I wanted the inverted capabilities. If that wasn't important to me, I would have rebuilt the Carb everyday of the week and twice on Sunday - just not worth the effort.

As an aside, I think the TBI is great, it was just a lot of work and doesn't provide significant upgrade to positive G flying...

I am an A&P and there are many SAFETY reasons why a TBI Ellison or Rotec is a bad idea. Support, especially from Rotec is HORRIBLE! They will talk a good story till you buy it then good luck exchanging e-mails on technical issues over days trying to resolve an item 2 minutes over the phone would resolve. From a safety stand point there is no source for known problems and you ain't gunna get an AD--ever if there is one. They will not tell you or play down known problems nor will they notify you regarding them since it could hurt sales. The FAA isn't going to do much to help since they are protected behind the "experimental" disclaimer when you left the reservation. Marvel Schibler has 40-50 years of proven reliability and there is a reliable history of documented issues. Be smart on this one, if not for yourself the mom and kids.

bentlr said:

I am an A&P and there are many SAFETY reasons why a TBI Ellison or Rotec is a bad idea.

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Care to back up your SAFETY claim with some statistics? Or is this just one mans opinion? I am certainly no expert, but I cannot recall even one accident where a Rotec TBI was shown to have been a causal factor.

Bentley said:

Support, especially from Rotec is HORRIBLE! They will talk a good story till you buy it then good luck exchanging e-mails on technical issues over days trying to resolve an item 2 minutes over the phone would resolve.

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So they have lousy customer service? Is this your personal experience, or information you got from your wife's brothers second cousin? FWIW, I got a fast reply to the one and only email I have sent them, and any other "support" questions I have needed have already been answered on their website, ie height, diaphragm hole diameter & screw type and idle mixture adjustment.

Bentley said:

From a safety stand point there is no source for known problems and you ain't gunna get an AD--ever if there is one. They will not tell you or play down known problems nor will they notify you regarding them since it could hurt sales.

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So no auto makers in the U.S. have ever done the same thing? And you may well find that there WILL be AD's issued against experimental aircraft, or their components if you bother to look, by the same token that a certified component installed in an experimental must comply with any AD's issued against it. Reference the recent Jabiru debacle in Australia if you want confirmation - even experimental aircraft with Jab 2200/3300's were barred from overflight of populated areas due to engine reliability concerns. If CASA convinces themselves something has a problem, they will take action.

Now, on a positive note: I installed a Rotec on my -9 and I love it. The -9 is ready for its final inspection, but even in testing, the Rotec starts instantly, every time. I did install a diaphragm-override lever though , and I use it, even though it may not be necessary long-term. It (the TBI unit itself) is beautiful to look at and apparently dead-simple in operation.

The Rotec is shorter than a typical MA4-SPA carb, so you will need to alter your airbox and probably carb heat attachments, but that is nothing major. The mixture control arm operates left-right, so you will need to fabricate a bracket to terminate the mixture cable as well as a bellcrank to translate the fore-aft motion left-right.

One thing I have seen reported is the need to keep the pressure regulator cool. Mine is a little closer to the exhaust than I would like and I will probably end up installing a blast-cooled enclosure around it following flight testing results, but it is one thing to be aware of.

Other than that, I am glad I bought it, and hope it'll prove itself long-term.

I used to fly with a guy that had an Ellison TBI on a 360. It ran OK once he got it started. Every time he started it cold he had to use quick start to light up the engine. Reliable proven injection is best, either Precision (Bendix) or Air Flow Perfomance makes and nice system based on Bendix.

there is a thread already going on this site for rotec TB's that has some good info on the trial and error we have gone through already on getting a 0360 running well with a rotec, (0320 seem to work well out of box with an MA4, not so with a 0360 and an MA 4/5)
My 0360 in an Mustang II works well but took some messing around to get just right, had to drill out some fuel tube wide open throttle holes, adjust regulator spring and clean out some casting material out of the idle passage to get there.
must have cool fuel or regulator will vapour lock, I added a closed bottom fuel pump shroud, regulator shroud with blast tube and a selectable fuel bypass circuit on the fuel pump switch in order to use 50% MO gas, works well now even in high ambient temps, it leans well and has been trouble free once set up correctly. but will say again, it must have cool fuel.
not much fun watching fuel pressure drop to 4 psi and feel the engine surge when in the rocks

Jay

TBI

I am just passing 200 hrs on my RV4. Ellison 4/5 on a O 360 A1A 9:1's. I bought the TBI used and sent it back to Ellison for inspection and anything else it needed. It has operated flawlessly from the first engine start to present. No issues with cold start or hot starts. Fuel injection was not in my budget and the simplicity of the TBI compared to a carb was important to me. I have the after market intake grid installed. Too bad Ellison is no more so for my next project I will go with a Rotec.

blackbeard10 said:

Too bad Ellison is no more so for my next project I will go with a Rotec.

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They are still around. They just serviced mine for the Bucker restoration. They even have some new units still in stock (or did) although they are no longer manufacturing new ones.

I've been running an Ellison TBI for about 1,200 hours since first flight in 2003.

Pros:

1. Better leaning.
2. Lightweight.
3. Uncomplicated.
4. Inverted Flight.
5. Low Cost.

Cons:

1. Heat intolerant. Took me a while to get the shrouds / blast tubes / heat sinks figured out. Even now a long climb-out on a hot day requires fuel boost all the way up and until the hot decreases under the hood...
2. Ram Air Intolerant. Can't run WOT at high airspeeds.
3. So So Customer Service. Not very helpful when you have a question (YMMV).

I'm considering converting to FI for improved mixture balance between cylinders and WOT efficiency. Not sure what that would really get me in the real world, but it sounds good...

No experience with the Rotec TBI, but they make a **** sexy looking engine...