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Ellison throttle body carbs

rvaitor87

Well Known Member
Has anyone installed or is currently flying with a throttle body carb? I don't wnt to spend the big bucks for one not knowing what experiences people have had with them. Are there very many modifications that have to be made to install, how is the performance?, any fuel savings?. I have read all of the articles, but it helps to hear what real people have to say. I have a RV-3 with a O-320, and a cruise prop. any help willl be appreciated.
 
Ellison

Hi, I have an Ellison EFS-5 on my O-360-A1A powered RV-4 (an EFS-4-5 is recommened, but I got his one 2nd hand and thought I would try it). I've posted on it a couple of times if you know how to do a search you will find them. The Ellison does allow me to lean further than with the old carb, and works inverted great. Hand starts are also quite easy and reliable. I added a Van's solenoid primer kit when I changed to the Ellison, as I relied upon the throttle accelerator pump on the carb for cold starts before that.

I used the FAB airbox and filter I had on the carb. I made a new top plate for it though, with a bell-mouth extension that bolted up to the TBI inlet. This kept the air intake of the FAB in the same location as with carb and meant I didn't have to re-do the cowl air inlet. Read all the tips and FAQ from the Ellison 'site when planning the changeover.

I installed a vapour return line originally, but later removed it with no ill-effect (Ellison does not recommend one - I should have listened). When hot on the ground the engine will 'burp', due to vapour formation I presume, but it clears with power and I have never experienced it in flight. I have cool air blast tubes directed at my maggies and fuel pump, and no gascolator.

Setting up the TBI to begin with is easy enough, the instructions are clear, but some further adjustment is often required to get the balance between idle, idle cut off and inflight mixture is required.

I think they are a good thing, FI is also a good thing, but heavier and dearer.
 
Anyone else using the Ellison units? Sorry for the stupid question, but this just replaces the carb on a carbed engine, without replacing the intake, etc. I am looking at a 0-360 in a RV-8, but want the ability to fly inverted.
What are the total costs for a system, beyond the TB?

Thanks for the info!!
 
I read about an Ellison mounted ona Lyc. 320 in a RV-3 a number of years ago. He then replaced it with a carburator. He felt the Ellison only allowed about 90% power from the engine. Again, this was a couple decades ago.

A friend is building an RV-4 as an LSA aircraft. The largest engine that would be installed would be a Lycoming O-235. We were planning to use the Elllison to reduce the horsepower. We expect it to be difficult to keep the maximum speed on a RV-4 down to 120 knots.

I would be disappointed to find out that there is no power loss in going to the Ellison. I hope someone has more recent information.

Regards,
Jim Ayers
 
I would be disappointed to find out that there is no power loss in going to the Ellison. I hope someone has more recent information.

Regards,
Jim Ayers

I had an Ellison on a 0360 in the Cozy. There is no power loss, it will push as much fuel as you wish and go as fast as any other Lycoming.

I liked it, just a few moving parts and as stone simple as it could be. It is a single point injectiion system. It would dribble fuel shut down unless the fuel valve was off. A primer is necessary. It will ice up. It will work inverted. Inspection is clean a screen filter.

Direct cylinder head injection may be better, but Ellison definitely is better than the old float carb IMHO.
 
I have built two RV-6A's and an Rv-7A and had an Ellison TB on all three. I loved it. If I could build another one, I would use the Ellison. Unfortunately, I can't renew my medical and have to wait for the RV-12, which can't use the Ellison. The system is not prone to icing and will run upside down. It is very simple and will lean very aggressively. You will never save the cost of the Ellison with fuel savings, but it is still better than a carb.
 
Ellison

Hi, I have an Ellison EFS-5 on my O-360-A1A powered RV-4 (an EFS-4-5 is recommened, but I got his one 2nd hand and thought I would try it). I've posted on it a couple of times if you know how to do a search you will find them. The Ellison does allow me to lean further than with the old carb, and works inverted great. Hand starts are also quite easy and reliable. I added a Van's solenoid primer kit when I changed to the Ellison, as I relied upon the throttle accelerator pump on the carb for cold starts before that.

I used the FAB airbox and filter I had on the carb. I made a new top plate for it though, with a bell-mouth extension that bolted up to the TBI inlet. This kept the air intake of the FAB in the same location as with carb and meant I didn't have to re-do the cowl air inlet. Read all the tips and FAQ from the Ellison 'site when planning the changeover.

I installed a vapour return line originally, but later removed it with no ill-effect (Ellison does not recommend one - I should have listened). When hot on the ground the engine will 'burp', due to vapour formation I presume, but it clears with power and I have never experienced it in flight. I have cool air blast tubes directed at my maggies and fuel pump, and no gascolator.

Setting up the TBI to begin with is easy enough, the instructions are clear, but some further adjustment is often required to get the balance between idle, idle cut off and inflight mixture is required.

I think they are a good thing, FI is also a good thing, but heavier and dearer.

Hi glad to hear you had good success with you Ellison -5. I am looking for an Ellison 4-5 to have overhauled by EFS and go on my 0360. As Ellison is not currently manufactering do you on of any available .

Thanks ,
Mich
 
Ellison

Hi, I have an Ellison EFS-5 on my O-360-A1A powered RV-4 (an EFS-4-5 is recommened, but I got his one 2nd hand and thought I would try it). I've posted on it a couple of times if you know how to do a search you will find them. The Ellison does allow me to lean further than with the old carb, and works inverted great. Hand starts are also quite easy and reliable. I added a Van's solenoid primer kit when I changed to the Ellison, as I relied upon the throttle accelerator pump on the carb for cold starts before that.

I used the FAB airbox and filter I had on the carb. I made a new top plate for it though, with a bell-mouth extension that bolted up to the TBI inlet. This kept the air intake of the FAB in the same location as with carb and meant I didn't have to re-do the cowl air inlet. Read all the tips and FAQ from the Ellison 'site when planning the changeover.

I installed a vapour return line originally, but later removed it with no ill-effect (Ellison does not recommend one - I should have listened). When hot on the ground the engine will 'burp', due to vapour formation I presume, but it clears with power and I have never experienced it in flight. I have cool air blast tubes directed at my maggies and fuel pump, and no gascolator.

Setting up the TBI to begin with is easy enough, the instructions are clear, but some further adjustment is often required to get the balance between idle, idle cut off and inflight mixture is required.

I think they are a good thing, FI is also a good thing, but heavier and dearer.

Hi Grant, glad to hear you had good success with you Ellison -5. I am looking for an Ellison 4-5 to have overhauled by EFS and go on my 0360. As Ellison is not currently manufactering do you on of any available .

Thanks ,
Mich
 
Your mileage may vary

Mike,
I ran an Ellison TBI on my 0-320 powered RVX for 50 hours and removed it. The main reason was inconsistent idle mixture adjustment. At full throttle it matched my MA4SPA carbs performance. LOP operations, max power and simplicity all previously mentioned are valid. A very good system as long as you follow the instructions and are conscious of the sensitivity of intake airflow requirements. The Van's FAB helps. Below 1000 RPM however, mine had issues with idle mixture I never resolved.

I really like the idea of the TBI. The Rotec TBI for the 0-320 slightly improves the Ellison's idle mixture bar design and has an in-line fuel pressure regulator. It is also less expensive :) http://www.rotectbi.com/
For what it's worth.

Smokey
 
Last edited:
I bought the ellison from smokey rar i had problems until i sent it in to ellison about 200 bucks for overhaul as i remember execlent teck support and has run flalwless ever sence
 
The Rotec TBI does it for me.

Mike,
I ran an Ellison TBI on my 0-320 powered RVX for 50 hours and removed it. The main reason was inconsistent idle mixture adjustment. At full throttle it matched my MA4SPA carbs performance. LOP operations, max power and simplicity all previously mentioned are valid. A very good system as long as you follow the instructions and are conscious of the sensitivity of intake airflow requirements. The Van's FAB helps. Below 1000 RPM however, mine had issues with idle mixture I never resolved.

I really like the idea of the TBI. The Rotec TBI for the 0-320 slightly improves the Ellison's idle mixture bar design and has an in-line fuel pressure regulator. It is also less expensive :) http://www.rotectbi.com/
For what it's worth.

Smokey

There are a couple of issues in adapting the ROTEC TBI in fitment. But they are easily overcome.

Like the Ellison it does require the the "air straightener grid" developed for the Ellison. This evened out the temp's in the cylinders (and dropped them as well). Which also increased the power some. My Rotec TBI also had the inconsistent idle problem that Smokey describes and also the hot start "burp" that someone else mentioned. I cured both of these problems by fitting a blast tube to the fuel inlet on the TBI. I fitted the blast tube trying to solve the hot start hick-up and was surprised that it not only soled the hot start hick-up but also solved the idle problem.

The ROTEC has a separate in line fuel pressure regulator (as Smokey mentioned), that also has a primer incorporated into it.
 
TBI

My "purchased RV-4 W/ 0-360" had an Ellison TBI on it. It has worked well under all conditions. The only thing I did to it was open up the holes in the fuel rail .002". This was when I installed the 11.5 CR pistons and had the head opened up. More HP needed a little more fuel. That was about 500 hours ago.

I do lean it about 50% or so for ground operations. I have also had other certified Turbo charged A/C that required this as well as N/A engines. Prior to TO power I go to 100% on the mixture, and then run LOP for X country. The little O-360 engine runs fine showing LOP on the EGT.

Unlike a carb, adding throttle it will not enrich unless you add fuel with the mixture control. A good understanding of how the TBI works helps in operation.

The fuel rail is just a tube with many holes across it. The throttle slides from one side to the other side uncovering the holes. The mixture control rotates the rod. Idle cut off has the holes facing FWD. Full rich has the rod rotated 90'. The air passing by sucks the fuel out of the rod.

It is quite simple and mine has been trouble free.
 
My "purchased RV-4 W/ 0-360" had an Ellison TBI on it. It has worked well under all conditions. The only thing I did to it was open up the holes in the fuel rail .002". This was when I installed the 11.5 CR pistons and had the head opened up. More HP needed a little more fuel. That was about 500 hours ago.

How did you open them up?
 
TBI

I just purchased a set of number drills amd used them fo find out the hole size. I then opened the holes up .002". I did it in .001" steps I had a small hand arbor and it was easy.
There was a place in Alliance, OH that handles the ultra small sizes.
 
Micro drill bits

Here is the place I purchased the small bits:

Ohio Drill & Tool
23255 Georgetown Rd.
Post office Box 154
Homeworth, Ohio 44634

330-525-7717
Toll Free 800-826-5237

I purchased these in 2007, I'm not sure they are still there. I had to search through about 4 LBS of invoices.

I purchased this little RV-4 in 2003, about $60,000 ago in mods. That was close to what I paid for it with about 200 hours on it. The market sure changed. I now have over $100K in a much used -4 that I still like. One of the mods was 9 Gal. tip tanks


It did have what I wanted, 0-360, SC prop, inverted systems, and was a slider.

I never claimed to be the sharpest knife in the drawer.
 
Throttle Body Injector

I had an Ellsion 4-5 TBI on my RV6 Lyc 0-360 for 18 years and it has worked well. Unfortunately trying to get the company to overhaul it, or even to acknowledge my emails became to dang hard, as many can attest to. So I bought a Rotec TBI (Austrailia) last Dec and only after quite a bit of delicate modification did I get the performance I needed. Now I get plenty of power for the sometimes intense form flying that we do. Still, the mods nec could have been made easier by the company and they seem unwilling to help out as much as I could wish.
 
What mods?

What mods did you do to the Rotec? I’m worried about my Ellison since support is zero.
 
Ellison support

We have the same problem, Ellison is running ok now but worried about support in the future. What happened to the person that bought out Ben? Any help would be greatly appreciated.
Roger
 
TBI

I have a Ellison TBI on my O-235-F2B (125hp) powered RV3
It came with the aircraft, idles just above 500, runs well, no problem with the power, excellent exhaust pipe colours.
Very happy with it.

Rob
RV3 G-BVDC
 
What mods did you do to the Rotec? I’m worried about my Ellison since support is zero.

Rick, the Rotec (4-5 for my 0-360) is similar to the Ellsion and hookup changes were minor. As I said, I get more power, a better idle, and it has a nice primer mechanism which obviates my old primer lines to the cylinders. I needed to fabricate a 1" think spacer so the same air filter box would work.
The hardest part was having to take the TBI apart (many times) and enlarge many of the holes in the metering tube, with tiny drill bits; It took several tries to get the power I needed along with a good (less lean) mixture (all by suggestion from Rotec). Again, it's all working good now but too many learning curves and effort in my opinion. If I could go back 20 years, I probably would install a carb and save myself tons of headache. After I sold my Ellsion, I found out there is a guy in my area that works on them.... go figure.
 
Thanks….

I have a carb ready for OH just in case too. I have noticed my Ellison seems to run smoother when I run a little MMO. Smoother slide feel, less appearance of slide seal fuel seepage or staining, less post running drippage, if that’s a word.
 
Me too !

I have 18 years on my EFS4-5 and would like to replace the diaphragm for piece of mind. Anybody have any info on this ?

Gary

I have a carb ready for OH just in case too. I have noticed my Ellison seems to run smoother when I run a little MMO. Smoother slide feel, less appearance of slide seal fuel seepage or staining, less post running drippage, if that’s a word.
 
Why where the mods necessary ?

Was there a lean condition at full power / full rich ? or a transition issue ?

If I get a Rotec to replace my EFS4-5 will I have to go through the same trials and tribulations as you. I have been happy with the Ellison for the last 18 years, but had a note in my log to replace the diaphragm every 10 years, It's been 18 now.
G

Rick, the Rotec (4-5 for my 0-360) is similar to the Ellsion and hookup changes were minor. As I said, I get more power, a better idle, and it has a nice primer mechanism which obviates my old primer lines to the cylinders. I needed to fabricate a 1" think spacer so the same air filter box would work.
The hardest part was having to take the TBI apart (many times) and enlarge many of the holes in the metering tube, with tiny drill bits; It took several tries to get the power I needed along with a good (less lean) mixture (all by suggestion from Rotec). Again, it's all working good now but too many learning curves and effort in my opinion. If I could go back 20 years, I probably would install a carb and save myself tons of headache. After I sold my Ellsion, I found out there is a guy in my area that works on them.... go figure.
 
I have 18 years on my EFS4-5 and would like to replace the diaphragm for piece of mind. Anybody have any info on this ?

Gary

...just for the record...35 years now with 2 Ellisons on the Defiant.

Other than just superficial occasional cleaning / inspection up to 2021, no failure and terrific service. One DG1-HD diaphragm was needed in 2021, and the other gave up late 2022.
 
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