EFII boost pump for the RV-8

When my used Airborne boost pump went belly-up at about 140 hours and attempts to revive it were fruitless, I decided to bite the bullet and just buy a new fuel pump. My choices were the one that Van's sells, the Andair or the EFII pump.

I read most of the info and reviews here on VAF before making my decision, and decided to buy the EFII. When it arrived, I had immediate concerns about mounting it where my old Airborne pump was located, between the front of the gear leg tower and the firewall.

There is only 15" of room there (sorry for the dirt -- remnants of trying to resuscitate the old pump) ...


I made a bracket from some heavy aluminum plate and used the existing mounts in the longeron where I had previously mounted the old pump ...


But, when I made minimum-radius bends in tubing to attach to the straight AN fittings that come attached to the pump module, it used up 14.75" of the available space ...


That meant that I needed to either make a real spaghetti-mess of tubing with a bunch of bends, or turn the pump around and run tubing from the fuel selector valve to the FORE end of the module, and loop another long run from the module to the fitting on the firewall.

I wasn't too happy with that prospect, but couldn't think of any other way to do it, and I'd used up a lot of aluminum tubing trying to make shorter bends and make it work.

Finally, an e-mail to Robert Paisley at EFII did the trick. I suggested swapping the straight fittings for a couple of 90-degree fittings, which freed up a LOT of room. The overall length of the module with straight fittings and 90-degree bent tubing went from 14.75" to only 11" with the 90-degree fittings ...




Here's a picture of the 90-degree fitting -- note that it has an O-ring seal and a lock nut, so it can be clocked in any direction ...


Once mounted with the new 90-degree fittings, plumbing it was a comparative breeze. I did still have to make a loop to connect to the firewall fitting, but the line to the valve was straightforward ...


I'm sure that someone making a new installation could design a better way to install the EFII boost pump module, but since crawling through the baggage door was somewhat limiting, I was happy with the compromise.

Robert was a gem to work with, responding immediately to my queries for help. The pump seems to work as advertised, once I got it primed by starting the engine and letting the engine-driven pump do the hard work.

I checked the fuel flow and it pumped out 46 gallons/hr, plenty for my IO-360. Fuel pressure is solid, and the unit is relatively quiet.

Oh, and if anyone is wondering where the supplied fuel filter is ... I have filters mounted in the wing roots, prior to fuel reaching the selector valve.

Hope that helps.

Nice looking installation Don! I am looking forward to you getting a hundred or so hours on the new pump before we fly it in the -3....

Paul

Let me start with "I'm a buyer not a builder" so this may be a VERY stupid question / idea ...

given you needed a loop anyway, could you have mounted the pump in reverse so the tank feed came over the top and did a 180 degree minimum bend down. Then the out feed would do something that looked like a half Cuban 8 to connect up to the firewall?

Like i said, sorry if I'm suggesting a stupid idea. However, if it is a stupid idea, can you explain it to me as a "teachable moment"

Thanks.

Nice solution!

Hi Don,
That looks like a great outcome.
(And thanks for the good words

Glen,
That would certainly work just fine. Teflon hoses with 90 deg ends would make it really easy to connect the parts.

Robert

Am I Crazy?

I am also not a builder (yet). Looking at your pump couldn't you have mounted the pump vertically with the power side being on the bottom and the flow through being on top. From the looks of it - it seems that this might have made the install a little slicker - but again, I am not a builder, and I am not sure what the requirements for mounting are. I like what you did - looks clean.

One thing I see in the photo has me a little concerned.

Of course I know photos can misrepresent how things look in real life, so I may be off base here, but as I see it, if the mounting bracket below is the only thing holding the pump assembly, I would put some kind of additional support on the inboard edge----down to the floorboard.

In your installed photo, it looks like the bracket is not attached to the floor, and may even be floating above it. Too much chance of vibration, and possibly cracking of a fuel line.



Hope this makes sense as I have stated it.

Another item of concern is the ability for a field replacement.
Is this pump available over the counter in any application that will allow you to service and replace when on the road?

One reason the AFP pump is attractive is that its a Carter fuel pump part number P74015 that has many field applications and is likely to be availible in most locations you might be trapped in.

Having had to place a few of these in the field, and never at home base, it becomes important.

Is your available over the counter?

humptybump said:

Let me start with "I'm a buyer not a builder" so this may be a VERY stupid question / idea ...

given you needed a loop anyway, could you have mounted the pump in reverse so the tank feed came over the top and did a 180 degree minimum bend down. Then the out feed would do something that looked like a half Cuban 8 to connect up to the firewall?

Like i said, sorry if I'm suggesting a stupid idea. However, if it is a stupid idea, can you explain it to me as a "teachable moment"

Thanks.

Click to expand...

If I'm understanding what you're asking, Glen, that's exactly what I was planning to do before I swapped the straight fittings for the 90-degree ones. I turned the pump module around so that the arrow (flow) was facing aft, and was going to loop the supply line to the fore end of the pump (inflow) and then loop the line from the aft end (outflow) back to the firewall. That's the orientation of the pump in the picture where it takes up all 15" of room, but I doubt you can tell that from the picture. Perhaps that wasn't clear in my write-up. Sorry.

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Mike, I considered movement when I made that bracket, and was prepared to either add a couple of lock nuts to the mounting bolts and adjust them to rest against the floor, or to support the plate with some rubber bumpers to passively rest against the floor. Neither seems to be needed -- that bracket is ROCK SOLID. Keep in mind that the module -- the pump and manifold assembly -- is rigid. When bolted to the bracket, any vibration is certainly less than I had with the old Airborne pump mounting bracket. I suppose it wouldn't hurt anything to support the edge away from the longeron with a couple of rubber bumpers.

In a normal installation, when installation occurs during the building, it would be a grand idea to install nutplates in the floor prior to closing it up. Once the floor is built, however, I can't see how that could be done.

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As for field replacement, Kahuna, I guess I'd put this in the same category as other equipment -- from avionics to servos to canopies. If it breaks "in the field", chances are slim that anyone will have a replacement handy. If my canopy cracks in the field, nobody is going to have one handy either. Same for an autopilot servo. I would have to call the company and have one overnighted, the same as with lots of our flight-critical pieces of equipment.

FWIW, the pump portion of the module is a Walbro pump, so the liklihood of finding a field replacement is probably much higher than finding an RV-8 canopy.

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Good questions and comments all. Thanks for the feedback.

I'm sure Robert can chime in on the parts availability in the field, as well as any vibration concerns. In fact, were I doing it over again, I might consider using flexible fuel lines to eliminate any worries about vibration.

parts

Hi Kahuna,
We use an extremely reliable pump from Walbro. I have never heard of one going out. I have a whole box of dead pumps of the same variety that is in the AFP unit (notice they don't warranty the pump). We used to use two of them on every Subaru installation. Everyone ended up taking them off, due to very short lifespan. Never a problem after replacing with the Walbro pump.

That being said, we machine the Walbro pump to a precision length. So in the unlikely event that one needs to be replaced, it should come from us. You could have a local machine shop size the part if it came down to it.

Robert

N8RV said:

In a normal installation, when installation occurs during the building, it would be a grand idea to install nutplates in the floor prior to closing it up. Once the floor is built, however, I can't see how that could be done.

Click to expand...

http://www.aircraftspruce.com/catalog/hapages/nutserts.php

Mike S said:

http://www.aircraftspruce.com/catalog/hapages/nutserts.php

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Dang. Nutserts. Why didn't I think of that?? I have a whole bunch of 'em, too. Of course, they're for #6 screws, so probably not really strong enough.

On the other hand, how secure does it need to be? It's not like it's really going anywhere. At some point, it becomes an exercise in futility -- killing a fly with a sledge hammer instead of using a fly swatter.

Still if someone really wants it solidly mounted, installing some nut plates -- or even nutserts, for that matter -- would be the best. No need to attach to the longeron at all.

Leave it to me to make something much more complicated than it needs to be.

mkjprice said:

I am also not a builder (yet). Looking at your pump couldn't you have mounted the pump vertically with the power side being on the bottom and the flow through being on top. From the looks of it - it seems that this might have made the install a little slicker - but again, I am not a builder, and I am not sure what the requirements for mounting are. I like what you did - looks clean.

Click to expand...

Mike, maybe I'm misunderstanding your question, but the module must be mounted horizontally -- parallel with the fuselage floor. If, by "vertically", you meant mounted against the side of the fuse instead of the floor, then yes, that is possible. I thought about that, but because I had already made the mounting bracket and it was such a work of art , I stayed with the orientation. Also, it would still take up 14.75", so I didn't think it was worth the trouble.

Were this an initial installation, and I had direct access from above (before riveting on the upper skin), there are MANY better ways to mount the module. Regardless, shortening the module by using 90-degree AN fittings seemed the smart thing to do.

I started this thread to show a potential pitfall specific to the RV-8 to help other builders who may be looking at various boost pumps, not to showcase some innovative installation. I don't think the overall length of the module is an issue with any other RV model.

While it's really very solid as it is, I like Mike's suggestion about further isolating it from ANY vibration, and can easily accomplish that with the addition of a couple of rubber bumpers on the bottom of the mounting plate. Other than that, I have no concerns about the functionality of the installation -- it's solid, it fits into the space, it doesn't leak, it's out of the way and, best of all, IT WORKS!

Hope that helps.

Update

One benefit of this forum is being able to follow up on product purchases and installations.

So far, I've had zero issues with the EFII pump as installed. It seems to do what it's designed to do, quietly and efficiently. I'll be sure to post if it ever ceases to work as advertised.

That is all.

N8RV said:

One benefit of this forum is being able to follow up on product purchases and installations.

So far, I've had zero issues with the EFII pump as installed. It seems to do what it's designed to do, quietly and efficiently. I'll be sure to post if it ever ceases to work as advertised.

That is all.

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Good to hear Don - ours is installed and patiently awaiting our getting the airframe finished for an engine start....someday!

Self-Priming?

N8RV said:

Robert was a gem to work with, responding immediately to my queries for help. The pump seems to work as advertised, once I got it primed by starting the engine and letting the engine-driven pump do the hard work.
Hope that helps.

Click to expand...

Does this mean that this pump is not self-priming?

prime

Hi Mike,
The pumps prime nicely after they get fuel in them once. The first time they are run it is best to pour some fuel into the pump to get the components wet.
After that they will prime nicely and run smoothly and quietly.
Robert

Experimental Chaos said:

Does this mean that this pump is not self-priming?

Click to expand...

Just FYI. I ran my pump today for the first time and it primed itself no problem. There was no fuel between the selector valve and the engine driven fuel pump where the fuel pressure taps off of. Hit the boost pump switch and within about five seconds had 30 or so psi on the gauge.