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Ellison TB

Jimzim

Well Known Member
I can't seem to find much specific info thru searching...has anyone installed an Ellison Throttle Body on their RV7, 0-360 Lyc? I have one and am trying to determine feasability. I'm not sure about an airbox for carb heat, will the lower cowl fit, a priming system, etc... Is it readily do-able or should I just go with a carb or fuel injection. I don't want to complicate the build and slow things down too much as I am anxious to fly, but I also have heard great things about the performance/reliability of the ETB. Any experiences would be really helpful!
Thanks very much, Jim
 
Jim,

Altough we are using a Rotec TBI on a O-360 A1A, the Ellsion unit is similar. If you do not like to make too many changes to your installation, I would stay with the Ellision. The Rotec unit has a lower price but needs more "engineering" and adaptions to complete the installation. I can not speek for any behaviour and performance data, because our's not running yet.

You might consider to use a spacer between the TBI and the FAB for intake alignement, because the TBI is smaller in height than the Marvin Schebler carb. At least it is like this for the Rotec. But I have seen that the Ellsion is almost 1 inch higher and I do not have the data of the carb at hand. So the Ellison might be almost the same dimension as the carb.

Another point you might have to take into account is the different control cable routing. You might best see it on the homepage of Thomas, a German RV-4 builder: http://www.rv-4.de/
 
-5

Hey Jim,

Shoot me a PM.

I've been running an Ellison EFS-4-5 since 2003 (and 1000 hours), and would not go that route again.
 
Pros:

It's a very simple thing, with few moving parts.

When it works good, it works good.

Cons:

Can't run WOT at high airspeeds due to the turbulent airflow generated in Van's FAB causing problems with even fuel distribution. That is, you'll give up the ram-air MP benefit of the Van's setup. Van tried to make the Ellison TBI work years ago, and gave up (as I recall). I've tried various (internal) changes to the FAB with little/no improvement.

Very susceptible to vapor lock / fuel vaporization, on the ground and in the air. I live in Maine... (multiple iterations of fuel line routing / shielding).

Fussy with mixture settings...too rich is way too rich...too lean is way too lean...hardly any paint left on the red knob...

Personal Observations:

The Ellison people haven't been very friendly or helpful, a characteristic that some other (non RV) TBI users have also experienced. (Not that I'm all sweetness and light)

If they worked so well, how come more of the RV nation don't run 'em? They've been pretty popular in the Canard-community, but, as you know, the air induction system is very different.

I don't believe there's anything wrong specifically with the Ellison TBI, it's just not well-suited to the RV design.

Does anyone else remember when Van tried to give them a go?
 
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They've been pretty popular in the Canard-community, but, as you know, the air induction system is very different.

That is the key and I believe Van's airbox design is inferior compared to a staight-on induction system design that uses a cone-type filter.
 
Mine works fine!

I didn't build it. But I fly an RV-6, O-360, CS, and Ellison TBI. I don't have any hot start troubles, no vapor lock, runs great at WOT. I seem to have more leaning capability than carbs typically do, though carbs vary in that aspect, too. The guy that built the plane and the engine has a lot of experience with RVs and others. Possibly it's the overall setup that's the difference?
 
@rocketbob:

I have a buddy of mine (well known on the airshow circuit) who has an MX derivative with a radically different induction setup (straight-on into a cold-air sump type rig), and with whole different set of issues (I can't go WOT, and he can't do anything less)...all this with multiple calls to Ellison.

Just my experience. I guess I'm just not enough of an experimenter to make it work. I'm sure that someone (the likes of many of the guys I admire on VAF) would be able to make it work...I just don't have that kind of attention span...
 
Sometimes the fix is something absurdly simple. There was a guy on our field that had a Sonex with an Aerocarb that had two cyls running way lean and hot. He tried a bunch of things then one day decided to change the orientation of the carb slightly and that did the trick.
 
Sometimes the fix is something absurdly simple. There was a guy on our field that had a Sonex with an Aerocarb that had two cyls running way lean and hot. He tried a bunch of things then one day decided to change the orientation of the carb slightly and that did the trick.

Just curious: How do you change the "orientation" of the carb slightly.:confused:

My carb just bolts on to the intake port. Can't figure out how to adjust that?? I realize that an Aerocarb on a Sonex is different from a Marvel-Schebler "tractor" carb, but still curious.

Thanks,
 
My installation was right out of the book. Ellison is very specific about how to orient the unit in relation to the cylinders, that is, the slide operating perpendicularly to the thrust line.

Short Story: If they worked so great, wouldn't everybody have one?
 
There seem to be 2 camps, love 'em or hate'em. I wonder how much has to do with installation specifics. The WOT issue seems to center around getting air into the thing smoothly at all throttle settings which, in turn, depends on air box styles, mounting orientation, etc... I'm going to try and make the Van's banjo box work with a vertical induction set up and maybe the "grid" tube to straighten the incoming air. I think it will all fit up OK. Not sure yet about how I'll provide for carb heat, though. Seems I should give the ETB a real shot since I own it and still hear good things from many. Any further experiences or installation tips much appreciated!
Thanks, Jim
 
I've got one on my -4 w/ O-320-D1A 160HP and have been very pleased with its operation. As mentioned earlier, it is a little finnicky to get set up and I found that the key is to follow the instructions to the letter. It appears possible to skip a step in the adjustment but don't, I tried and it was not quite right. But since taking the time to follow the instructions, I have not had any problems what so ever. I can lean much more than any carb. As you lean you need to use the EGT to find peak, you'll feel the engine very slightly stumble and then smooth out as power output falls and the engine will continue to run smoothly to a surprisingly lean setting.
I have found I have about a .5 in increase in MAP from the TBI plus with a pseudo ram air intake another .5 in and have consistantly produced one inch MAP than a friend's o-360 powered -8.

My performance numbers are an exact match of Van's numbers.

I can't speak to anyone else's experience but mine has been very good.

Glenn Wilkinson

P.S. I believe the finnicky-ness (new word) is based in the ability to so finely adjust the settings that the difference between being perfect for one day's conditions will cause it to be off some on another if leaned to the absolute limit.
 
Well, if I hated the thing, I'm pretty sure I would have unbolted it by now (1000 hours) and heaved over the bank behind the hangar.

I just said I wouldn't go that route again, and may take a deep breath and convert it to FI depending on how much coal I get this holiday season.

A Joyous Apocalypse to all...

PS - I don't run LOP, FWIW.
 
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