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Fuel flow transducer mounting location

blahphish

blahphish

Well Known Member
Recently it came to my attention that there have been some people that experienced unstable indications from their fuel flow transducer if mounted in the default location. I read a few threads on Matronics and there seems to be lots of variations of success rates and device types.

Anyone have any feedback on whether the 'red cube' transducer with standard vans fuel pumps will work reliably in the normal location or should I go ahead and plan to move the transducer forward of the firewall?
 
I have a Floscan in the tunnel (stock location). Almost dead on at both low & high power settings.
 
Brian here is a photo of how I mounted my fuel flow transducer. It works great here and was very easy. Just need to have youe hose split and new ends put on.


Geoff
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blahphish said:
Recently it came to my attention that there have been some people that experienced unstable indications from their fuel flow transducer if mounted in the default location. I read a few threads on Matronics and there seems to be lots of variations of success rates and device types.

Anyone have any feedback on whether the 'red cube' transducer with standard vans fuel pumps will work reliably in the normal location or should I go ahead and plan to move the transducer forward of the firewall?
Click to expand...


Define reliability? :D

I would argue that it works realibly in either location, although a fair number of people have flow variations in the factory location. Since it's only a factor when the boost pump in on, it's probably not a big issue.

With that said, and the fact that I'm kind of anal, when it comes to measure fuel, I moved my. It's now located between my FM-200 fuel controller and the distribution spider.

Depending on where you got your engine from there are several good mounting places FWF. Since I have the Rod Bower ram air mod, mine is probably not in a typical location. Photos are on mykitlog site. If you search the AFS forum, you should be able to find a photo of where Rob Hickman mounted his. Geoff Combs has a similiar photo on his Phanfare site. There are seveal others out there too.

bob
 
I run a carbonated O-320 and the documentation for FuelScan was pretty specific that it goes between the engine driven fuel pump and the carburetor. Not being an engine designer, I decided to RTFM and do as I wa told, so my transducer is definitely foreword of the firewall :)
 
I have a stock setup (IO-540 and a red cube in the location per plans) and have no issues with it. Fuel quantities are very reliable (just a few tenths of a gallon difference between the fuel put in and what the computer says I used). My thinking is that it's slightly inaccurate when the boost pump is on, but that difference is negligible given the pump is not on very often.

-Rob
 
Me Too

Almost the exact results as Rob has above.

Flow sensor in tunnel, very close to the numbers from filling the tanks, and reads high with the boost pump on.
 
Aerosport1 said:
Brian here is a photo of how I mounted my fuel flow transducer. It works great here and was very easy. Just need to have youe hose split and new ends put on.


Geoff
0_0_b508044d4bd8c2d5d479155b0dd69607_1
Click to expand...

Geoff, is that your flying configuration? I thought the Flo-Scan documentation said the cube has to be fire-sleeved when mounted Forward of the Firewall.
 
And....

I know this is an old thread, but along with Mark's (Charliewaffles) question about firesleeving, I thought EI also recommends you don't mount the red cube FT60 on the engine due to excessive vibration. Has it been successful in this location Geoff?

Does anyone have other pics of mounting locations or info to share?

David
 
I have the Floscan (not red cube) mounted in the standard location. There's no question it reads high with the boost pump on.

I was being particularly anal during the first 50 hours and desperately wanted to fix it. 150 hours later it is a complete non-issue. I prefer having that bit of plumbing where it is. The high reading is not really detectable in fuel planning given the amount of time the boost pump is on.

Bill
 
Thanks

Good to know gents. Given that I've already fabricated the fuel lines in the tunnel without the red cube (since I planned to place it FWF), I think I'll continue with my plans. I've dug up 7 installation photos and everyone seems pleased with the FWF location (except the gentleman who installed it with rigid aluminum tubing and had a fuel line failure leading to an engine failure).

Thanks again,
David
 
Me too

Same as Wayne, works as advertised.
My goal was to keep as many of the fuel system components as cool as possible.
Only 108 hours so far and no hick ups at all.
 
on the lower left firewall

Here is where I did mine and it works great! I copied someone else. Brantel I think.

FinishKit%20243.jpg
 
Strasnuts said:
My instructions stated to firesleeve the red cube so I did.
Click to expand...
I thought my instructions said not to mount it rigidly to the engine... The vibration will be very hard on the bearings inside it. I just finished working out the permutations of hose and mounting that would let me add one to my -6, i'll try to take photos tomorrow to show the location. [edit - just noticed this was the -10 forum... My mounting may give others ideas though, so i'll still post pictures when I get them.]
 
Snowflake you are right.

Here is some notes from the installation manual.



Fuel Flow Transducer Notes
? NEVER blow through the transducer. Keep the yellow caps on until it is installed.
? The fuel flow transducer(s) should be installed in a straight section of your fuel line. (6 straight inches on each side is desirable).
? The fuel line should not drop down after exiting the transducer.
? The wires MUST NOT come out of the bottom of transducer. Wires pointing up is the best .
? When assembling fittings into the 1/4? NPT inlet and outlet ports do not exceed a torque value of 25 ft.-lbs.
? Do not use Teflon tape in an aircraft fuel system. Use ?Fuel Lube/Ez Turn Lubricant?
? The transducer should be mounted down stream of a fuel filter.
? Do not attach the transducer directly to the engine to avoid excessive vibration.
? Do not mount the transducer near the exhaust systems or other hot engine components.
? If the transducer is in the engine compartment, it should be covered in fire sleeve to protect it from excessive heat.
? The transducer wires may be trimmed any desired length
Possible Transducer Placement Locations:
1. Between the auxiliary electric boost pump and the engines mechanical fuel pump.
2. Between fuel injection servo and the distribution block.
3. Between the Engine driven pump and the Carburetor
Note: If your engine is equipped with a fuel return line from the carburetor back to the fuel tank you will need to install two flow transducers.
One in the feed line from the fuel pump to the carburetor and one in the return line from the carburetor back to the fuel tank. This applies to
certain Continental engines and Rotax 912(ULS) and 914 engines.
 
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