Shadin vs. EDM 900

[Flash]

I'm getting an EDM 900 (although its delivery has been delayed, but that hardly makes mine unique) for my 1993 M20J. My avionics installer tells me that I have to choose: Either keep my Shadin and don't input fuel flow information to my EDM 900, or get rid of my Shadin. Here's how I see it:

--Advantage to keeping the Shadin is that my fuel flow information is always staring back at me in the familiar red numbers. It doesn't get lost in everything the EDM 900 is displaying. And I can easily read out hours of endurance and expected gallons reserve at destination. I like that a lot.

--Another advantage to keeping the Shadin is that if something goes wrong with my EDM 900 (which displays the gallons remaining in each tank), I retain an independent source of total fuel remaining. Maybe this isn't a huge deal, since I also have the sight gauges on top of the wings.

--Advantage to feeding the fuel flow information to the EDM 900 and dumping the Shadin is that the EDM 900 records the data, so I can go back later and analyze fuel flow and CHTs and EGTs at different times during the flight.

Am I missing anything here? Is the data from the EDM 900 worth the tradeoffs from losing my Shadin?

Edited August 31, 2022 by Flash

[Flash]

I notice that the EDM also shows endurance and fuel used, and although it doesn't show reserve at destination I should be able to calculate that pretty easily by subtracting fuel used from 64. So maybe all I'm losing by losing the Shadin is the redundancy of having a separate instrument for gallons remaining in each tank and total gallons remaining. That still seems like I'm losing something, though.

[ArtVandelay]

I notice that the EDM also shows endurance and fuel used, and although it doesn't show reserve at destination I should be able to calculate that pretty easily by subtracting fuel used from 64. So maybe all I'm losing by losing the Shadin is the redundancy of having a separate instrument for gallons remaining in each tank and total gallons remaining. That still seems like I'm losing something, though.

It gives you time till empty, so you know your time to destination (subtract time for reserves) and you know if you need to stop for fuel.
You can make similar arguments for other factory gauges, especially required ones like oil pressure, temperature.

[wishboneash]

I'd probably let go of the Shadin if I were you. You will not have the LOP/ROP functionality without fuel flow in the EDM 900. The logging features are always nice to have such as to keep track of trends as you can download and study them later (also check GAMI spreads using the EDM software).

[Aerodon]

You can probably piggy back them, and get both.  Only one device powers the transducer, but both read the same signal (signal and ground). Sometimes sides are required on the JPI, send me an email and I'll shoot you a drawing.

Aerodon supercub180@gmail.com

 

 

 

[kortopates]

Like Aerodon said, that's not true. It's common practice to wire the Shadin FF transducer in parallel with the EDM. You can contact JPI tech support for details too. But with all that said, IMO, there is no need to keep the Shadin, which only provides FF and Used, while the EDM also provides Used, Remaining, endurance time, fuel Gal remaining at your destination (or next waypoint depending on how you set it up), and nmpg. 

[Fly Boomer]

34 minutes ago, kortopates said:

EDM also provides Used, Remaining, endurance time, fuel Gal remaining at your destination (or next waypoint depending on how you set it up), and nmpg. 

And I assume the top-end 900 also gives FF?

[kortopates]

43 minutes ago, Fly Boomer said:

And I assume the top-end 900 also gives FF?

Yes, all of the current JPI products offer it or include it standard.

[Marauder]

I have a JPI and an EI FP-5L. They each provide fuel flow and pressure. I’ll have to look at the installation again but I know I have at least two flow transducers and perhaps two pressure transducers.

Don’t know much about the Shadin capabilities but I wanted to have redundancy.


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[ArtVandelay]

You can probably piggy back them, and get both.  Only one device powers the transducer, but both read the same signal (signal and ground). Sometimes sides are required on the JPI, send me an email and I'll shoot you a drawing.
Aerodon supercub180@gmail.com
 
 
 

Given the JPI is certified, I’m not sure you can piggyback the shadin as that’s not in the installation manual/drawings of the JPI?

[Flash]

1 hour ago, ArtVandelay said:

Given the JPI is certified, I’m not sure you can piggyback the shadin as that’s not in the installation manual/drawings of the JPI?

This is exactly the issue my shop raised. 

[Will.iam]

It was far cheaper to add a connector cable to the ff transducer the shadin was using than get another one from JPI. It was also cheaper labor as not to have to open fuellines etc. plus with both of them i have the shadin always showing where as my jpi-700 i have to goto that page. Much easier to change k-factor in jpi than shadin and while shadin is close on 5 gal run out test, i was able to tweak jpi k-factor to be exact. Now i plan with the shadin but if i no kidding want to know when the engine will start sputtering i look at the jpi. 

[Fly Boomer]

1 minute ago, Will.iam said:

It was far cheaper to add a connector cable to the ff transducer the shadin was using than get another one from JPI. It was also cheaper labor as not to have to open fuellines etc. plus with both of them i have the shadin always showing where as my jpi-700 i have to goto that page. Much easier to change k-factor in jpi than shadin and while shadin is close on 5 gal run out test, i was able to tweak jpi k-factor to be exact. Now i plan with the shadin but if i no kidding want to know when the engine will start sputtering i look at the jpi. 

Sounds like you use the pair for cross-check.

[Aerodon]

Not all the features on a JPI replace an OEM display.  For example - amps.  I am probably going to keep my OEM ammeter gauges on my 252, but I have not finished researching. And not all measurements are even required.  C172's don't have CHT standard, but the EDM900 now has a CHT that is certified for primary.  

And then sometimes the FF is written up as a fuel pressure instrument with limitations.  JPI will add fuel pressure with redlines, and suddenly you have a new parameter to look at.

I think an installer needs to have the airplane POH, type certificate and the JPI STC in hand and do a careful side by side comparison to make sure nothing is lost.

And when it comes to piggy backing the FF on the OEM fuel flow, the JPI is isolated with diodes and does not power the transducer.  If you  had two oil pressure gauges in one oil pressure line, why can you not have two electric counters on the same OEM transducer?

I looked at my 252 POH, and fuel flow is not required equipment.  MP, RPM, Amps, yes.     

Then look at the JPI documentation:  FF is primary.  OAT and Amps are not.  How many glass cockpits out there that use the JPI OAT and amps, without the OEM equipment?

 

Aerodon

 

[Fly Boomer]

4 minutes ago, Aerodon said:

an installer needs to have the airplane POH, type certificate and the JPI STC in hand and do a careful side by side comparison to make sure nothing is lost.

^^^somebody needs to do this^^^
After the installer gets done, and everything works, is not the time to discover you lost something.

[Will.iam]

1 hour ago, Aerodon said:

Not all the features on a JPI replace an OEM display.  For example - amps.  I am probably going to keep my OEM ammeter gauges on my 252, but I have not finished researching. And not all measurements are even required.  C172's don't have CHT standard, but the EDM900 now has a CHT that is certified for primary.  

And then sometimes the FF is written up as a fuel pressure instrument with limitations.  JPI will add fuel pressure with redlines, and suddenly you have a new parameter to look at.

I think an installer needs to have the airplane POH, type certificate and the JPI STC in hand and do a careful side by side comparison to make sure nothing is lost.

And when it comes to piggy backing the FF on the OEM fuel flow, the JPI is isolated with diodes and does not power the transducer.  If you  had two oil pressure gauges in one oil pressure line, why can you not have two electric counters on the same OEM transducer?

I looked at my 252 POH, and fuel flow is not required equipment.  MP, RPM, Amps, yes.     

Then look at the JPI documentation:  FF is primary.  OAT and Amps are not.  How many glass cockpits out there that use the JPI OAT and amps, without the OEM equipment?

 

Aerodon

 

My JPI is a 700 and is primary for tit but nothing else so i have voltage but still also have the original analog volt load meter the 252 came with. It’s easier to check alternator output with the jpi than the original. I have heard that you do not want 2 ff on the line as it’s not as accurate? But my main reason was why pay $500 extra for a ff transducer when I didn’t have to. At some point I’ll switch to a 900 or 930 but it’s hard to put money into functions i already have compared to something like increasing my useful load that an encore conversion would do. Or putting in a LHS. 

[carusoam]

FF sensors are interesting…

They have a spinning wheel, and generate a signal each time a specific piece of plastic breaks a light beam….

Essentially it generates 1s and 0s, by outputting a high and a low voltage….

The engine monitor and FF display do the counting…. And calculating…. And displaying….

 

Unlike OilT, and EGTs… this signal can be split and shared….

Doing it properly… is the responsibility of the avionics guru….

 

Now…. If you elected yourself to be the avionics guru…

It isn’t very hard to read the list of sensors that the JPI is considered primary for… it is very clearly written in the docs… this is true for all manufacturers of instruments…. Not all of the functions are rated as primary…

Oddly… the JPI doesn’t measure vaccuum…  they were so forward looking decades ago…. They knew we were going away from vac driven instruments…   

 

Or….. to make it really easy…

Ask our EI guy…. He explains this stuff all the time for his collection of instruments…

We don’t need to be the guru…   But, then you may want the EI family of instruments…

 

Soooo….

Plan on keeping both because you want to…  See if the Shadin makes it easy to share data with the JPI…

Then have the FF data, and GPS data, shared with the JPI…. And se how much fuel is required to get to the final destination….

JPI has been doing this since the mid 90s… with their 700 series… (their marketing doesn’t tell you this, They don’t have much customer service, and they aren’t very friendly to work with when you need their help… especially when you are bringing an issue they have and don’t want to recognize it…)

Best regards,

-a-

 

 

 

[kortopates]

Not all the features on a JPI replace an OEM display.  For example - amps.  I am probably going to keep my OEM ammeter gauges on my 252, but I have not finished researching. And not all measurements are even required.  C172's don't have CHT standard, but the EDM900 now has a CHT that is certified for primary.  
And then sometimes the FF is written up as a fuel pressure instrument with limitations.  JPI will add fuel pressure with redlines, and suddenly you have a new parameter to look at.
I think an installer needs to have the airplane POH, type certificate and the JPI STC in hand and do a careful side by side comparison to make sure nothing is lost.
And when it comes to piggy backing the FF on the OEM fuel flow, the JPI is isolated with diodes and does not power the transducer.  If you  had two oil pressure gauges in one oil pressure line, why can you not have two electric counters on the same OEM transducer?
I looked at my 252 POH, and fuel flow is not required equipment.  MP, RPM, Amps, yes.     
Then look at the JPI documentation:  FF is primary.  OAT and Amps are not.  How many glass cockpits out there that use the JPI OAT and amps, without the OEM equipment?
 
Aerodon
 

I kept my Mooney dual ammeter/load meter/volt meter because it makes it easy to verify both alternators in a glance. Plus it doesn’t really take up valuable panel space.

I also added a dual port differential fuel pressure to monitor metered fuel pressure; because i could.
And for redundancy i have backup
EI Map and RPM instruments where the OEM ones were and kept the factory TIT.
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[LANCECASPER]

On 8/31/2022 at 9:04 PM, Will.iam said:

My JPI is a 700 and is primary for tit but nothing else so i have voltage but still also have the original analog volt load meter the 252 came with. It’s easier to check alternator output with the jpi than the original. I have heard that you do not want 2 ff on the line as it’s not as accurate? But my main reason was why pay $500 extra for a ff transducer when I didn’t have to. At some point I’ll switch to a 900 or 930 but it’s hard to put money into functions i already have compared to something like increasing my useful load that an encore conversion would do. Or putting in a LHS. 

From what I understand, I don't think a JPI700 can replace any factory instrument for primary, including TIT. @Aerodon will know though since he's a JPI dealer and has installed many.

[Will.iam]

30 minutes ago, LANCECASPER said:

From what I understand, I don't think a JPI700 can replace any factory instrument for primary, including TIT. @Aerodon will know though since he's a JPI dealer and has installed many.

Mine is actually a jpi 711 not a 700 which as you pointed out the 700 is not certified as primary. But the 711 is.