Engine monitor with a GPS feature

[MooneyBob]

It's time to put an engine monitor in my J. I have narrowed my research to either EDM730 or EDM830.

If I understand it right the 830 comes with all the features that are optional for 730 plus it has the GPS feature. I still don't have a GPS but it will be next thing to get after the EDM.

My question is : Does any body use the GPS feature of the EDM? Is it a useful feature?

Any other recommendation?

[orionflt]

When we do the photo shoot you can look at my MVP-50

[ArtVandelay]

I believe the GPS interface works both ways:

It will give you mpg, fuel req to get to destination, etc on the 830

and the GPS will give you calculations as well depending on GPS(GTN-650, etc)

830 also includes fuel flow as standard obviously...

If not interested in fuel flow and resulting data, then go with 730.

[MooneyBob]

When we do the photo shoot you can look at my MVP-50

Very soon.

[carusoam]

Connecting GPS with FF is a nice modern feature. Fuel to destination is always good to know...

Best regards,

-a-

[jlunseth]

I have a 930 that was installed four or five years ago.  It has always provided fuel to destination information.  It is connected to the GPS but I am not sure exactly what information it gets, probably the 430's calculation of time remaining.  I have to say though, that fuel to destination is not particularly useful to me, for three reasons.  One is that when I am flying in the flight levels, there is going to be a protracted descent, 30-40 minutes at the end of the flight where the average fuel number that the 430 uses while at cruise, is going to become irrelevant.  It can tell me a reserve number when I am at cruise, but my actual reserve is going to be several gallons more.  Second, I almost never get anywhere near empty tanks, so I don't pay much attention to what reserve it is telling me.  Third, if I am going to get anywhere near empty tanks I use my own tracking of fuel flow so I know with precision how much is in each tank,, not what the GPS calculates.  So the fuel numbers the 930 provides are just readouts of what the 430 is computing, and not particularly of interest. 

 

The 930 is great for a lot of things, but its fuel reserve computations are not of particular interest to me.

[MooneyBob]

Connecting GPS with FF is a nice modern feature. Fuel to destination is always good to know...

Best regards,

-a-

Any good avionics shops in NJ?

[N601RX]

JPI usually has rebates. It looks like the one below just ended. They will very likely start a new one in a couple of weeks during the week of Sun In Fun. Most dealers will offer discounts on top of the rebates during the show. I got a 830 2 years ago at Oshkosh for $2600. That was a considerable savings over the best deal I could find the week before.

http://sarasotaavionics.com/whats-new-in-avionics/jp-instruments-rebates

[aaronk25]

Get the 830 or but the EI brand I bought my 830 2 years ago but I understand the EI might be a better bang for the buck.

Don't get the 730series JPI the orange display makes it look dated...its smaller, harder to read and most importantly won't get your attention should one of your predetermined thresholds such as cht oil temp exceed what you set the alarm at. The 730 flashes the one color it has....orange the 830 flashes red and it's larger screen gets your attention.

The post about the flight levels is mostly irrelevant because your 201 isn't a flight level machine. My gps and fuel at waypoint or destination is a AWESOME tool to help make good decisions. I use it all the time.

[aaronk25]

I have a 930 that was installed four or five years ago. It has always provided fuel to destination information. It is connected to the GPS but I am not sure exactly what information it gets, probably the 430's calculation of time remaining. I have to say though, that fuel to destination is not particularly useful to me, for three reasons. One is that when I am flying in the flight levels, there is going to be a protracted descent, 30-40 minutes at the end of the flight where the average fuel number that the 430 uses while at cruise, is going to become irrelevant. It can tell me a reserve number when I am at cruise, but my actual reserve is going to be several gallons more. Second, I almost never get anywhere near empty tanks, so I don't pay much attention to what reserve it is telling me. Third, if I am going to get anywhere near empty tanks I use my own tracking of fuel flow so I know with precision how much is in each tank,, not what the GPS calculates. So the fuel numbers the 930 provides are just readouts of what the 430 is computing, and not particularly of interest.

The 930 is great for a lot of things, but its fuel reserve computations are not of particular interest to me.

My 830 on my 201 is within 1gallon or less of actual fuel on board at time of landing. Yes a decent from flight levels uses less fuel with all the stored energy in terms of altitude but I don't think this applies to his N.A. IO-360, at least not to the degree your seeing with your turbo bird and in most cases huge upper level tail winds (or your wouldn't be up that high right?)

[Hector]

OK. The 730 series does not have an orange display, in fact, it is virtually identical to the 830 except it does not have capability for MAP. Fuel flow is optional as is RPM. I have the 730 with fuel flow connected to my GPS and it's a great unit. I already had fuel flow in my plane (JPI FS 450) so I just replaced it with a 730. If I had to buy the 730 with the fuel flow option it might be best just to go with the 830. My only mistake is that the only hole in my panel was on the copilot side (see picture) and neither the 730 nor 830 has a wide viewing angle which means I have to lean over a bit to see it. I'll probably end up fabricating a 20 degree angle bracket to aim it my way a bit. Amazingly enough I have not been able to find one for sale anywhere. Spruce makes them for the smaller 2 inch holes but not for the 3 inch

Sent from my iPad using Tapatalk HD

[bnicolette]

If you can swing it go for the 830.  I had my 396 (portable) plugged into my 830 and it gave me all the pertinent fuel information.  Awesome unit.

[Ned Gravel]

If you can swing it go for the 830.  I had my 396 (portable) plugged into my 830 and it gave me all the pertinent fuel information.  Awesome unit.

 

Or perhaps the 900 because it is certified as "primary" and you can replace a hockeysock full of instruments.

[AmigOne]

JPI for sure will have a rebate for the Sun & Fun convention next month and you do not have to attend to claim it.  If you buy from one of their dealers (say Gulf Coast) during the rebate period (well beyond the duration of the Convention) they'll send you a coupon with the unit, send it to JPI with a copy of your receipt and they'll send you the rebate for that product.  JPI engine monitors and the 450 fuel totalizer have had a GPS output for a long time now.  Because I got a great price at the time I have the totalizer and the engine monitor in two separate instruments which in a way I like better because I do not have to scroll and chose either engine or ff display like in a single instrument (say EDM 700).

Connected to the GPS, the fuel information in terms of used, required to destination and reserve is updated constantly if you adjust the power, the winds change impacting your ground speed or if you deviate for weather.   I'm surprised that some do not find this information useful.  Flying in the flight levels does not apply to most of us.

[Marauder]

I'm happy with the 830 I own. If I were in the market today, I would definitely check out the EI CGR-30P since it is considered primary and is priced in the 830 range.

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[carusoam]

The round dial unit may have a better chance of fitting in the panel in front of the pilot....

Something to keep in mind while looking...

Best regards,

-a-

[Bob_Belville]

I have the 930. It is "primary" and replaces tach, MAP, Fuel qty, OilP, OilT, EGT, CHT. I would think it is worth the price diff if you're going to get something. It uses GPS input to display MPG, Est time to empty, etc.

 

 

[mikesalman]

Does anyone know how I should expect to pay for installation of a JPI 930 when I already have a JPI 800. Here is what my panel looks like. I'm just asking for a rough idea from you guys that had it done.

http://mooneyspace.com/gallery/image/35096-/

[M016576]

Get the 830 or but the EI brand I bought my 830 2 years ago but I understand the EI might be a better bang for the buck.Don't get the 730series JPI the orange display makes it look dated...its smaller, harder to read and most importantly won't get your attention should one of your predetermined thresholds such as cht oil temp exceed what you set the alarm at. The 730 flashes the one color it has....orange the 830 flashes red and it's larger screen gets your attention.The post about the flight levels is mostly irrelevant because your 201 isn't a flight level machine. My gps and fuel at waypoint or destination is a AWESOME tool to help make good decisions. I use it all the time.

You're describing the 700/800, not the 730.

The 700/730/800/830 all share a common pinout and harness- the 700/800 have a monochromatic display, the 730/830 have a full color display.

[N601RX]

I received this last night from chief. There should be jpi rebates in addition to this.

http://chiefaircraftinc.com/1OM5-29YWG-6F9FP6Z580/cr.aspx

[aaronk25]

You're describing the 700/800, not the 730.

The 700/730/800/830 all share a common pinout and harness- the 700/800 have a monochromatic display, the 730/830 have a full color display.

Lol.... You caught me!

[jlunseth]

I am responding to Aaron's post (actually two of them), responding to my post about long descents and why the fuel remaining number is not very useful, and first, Aaron is correct, if you don't have a long descent to do, then my point about the reduced fuel flow during a long descent is not important.  However, there are a couple of other reasons why the fuel remaining number that the 930 displays is not particularly useful to me, and maybe it would be helpful to explain what I do and why I do it.

 

The 930, and for that matter all the JPI's that I am aware of that display fuel calculations, do not use actual measured fuel on board to display fuel remaining.  My 930 has fuel gauges that display, with variable accuracy, how much is in the tanks.  But the fuel remaining is calculated based on measured fuel flow subtracted from an assumed number.  My aircraft, for example, has a usable fuel capacity of 75.6 gals. usable.  At the beginning of every flight the 930 asks if I have refueled, and if I say yes it resets to fuel to 75.6 gals.  It has no idea how much fuel I have actually put in the aircraft.  There is a function for reducing or even increasing that number, if for example I know I only have 50 gals. on board I can use one of the buttons to reduce the starting number.  It is quite a lot of screwing around to do that if the number is much different from 75.6 .  But the bigger issue is that whatever number it starts with, is not an accurate measured number, it is either 75.6 or the number I tell the JPI to use.  That puts a premium on making sure the tanks are actually full to the top when I am going to fly a trip where full capacity is important.  On those occasions, I either fill the tanks myself or supervise, and it is necessary to rock the wings to get all the trapped air out.  On shorter flights where fuel is not going to be critical I don't bother with that, I know that even if I am 5 gals. short in each tank, I am going to have lots of fuel left over at the end of the trip, that is one reason why the JPI's reported number is not very useful to me.

 

My aircraft has anti-siphon valves, which are just flappers that come from inside the tank and cover the filling hole.  They are there so that if the seal on the fuel cap fails, the fuel won't get sucked out of the tank.  That is nice, but they make it impossible to stick a measuring tube or stick in the tank, so in my case I can't really measure how much is there if the tanks are only partly full, most of the time I just fill them to the rim and that is 75.6 gals.

 

The other and probably more important reason that the JPI's fuel remaining number is not very useful, is that the JPI does not have a way of knowing how much is taken from each tank.  It starts with the number that is given, usually 75.6 gals., and then subtracts measured fuel flow.  So it provides a total fuel remaining, but can tell you nothing about where the fuel is.  So even if it calculates that I have 37.8 gals. left, which is about three hours of fuel, it cannot tell me which tank it is in.  Gauges, at least in my aircraft, are mediocre for this task because regardless of how new and up to date the readout is (i.e. a 930 instead of the factory strip gauge), most of us still have the factory senders in our tanks, they are old and not very accurate in most cases.  They have a habit of sticking in spots, and then freeing up, so you may fly for two hours with the display showing 37.8 gals. in the tank, and then suddenly there are only 10 gals.  In my aircraft the gauges show zero fuel when I have somewhere between 6 and 8 gals. left in the tank, and that is a total of around one hour's worth of fuel that the gauges are not going to tell me is there.

 

What I have done is to test out the fuel flow meter.  I did this by following the instructions in the JPI manual, filling the tank to full capacity (filling it myself), flying three flights of about 2 hours each, refilling to the same place each time (to the brim) and noting the fuel used, then comparing the fuel used from the gas pumps over those flights, to the number the JPI gave me.  It was accurate to a tenth of a gallon over 50 gallons, and I did this twice just to be sure. 

 

So I have confidence that the one reading in my aircraft that will be accurate is fuel flow (which reads as "USD" on the JPI). 

 

The one piece of paper I use in the cockpit is a blank sheet on which I write a chart, starting with 37.8 in each tank and then subtracting what I have used from that tank each time I switch.  I will typically ascend to cruise and then cruise for awhile on one tank, then switch when I have reached a "USD" number that is around 20 gal., and just for luck I like it to end with a .8.  So lets say I switch at 18.8 USD.  My chart shows me that I now have 19 gals. in that tank (I usually start with the left tank).  I have now been in the air somewhere around an hour to an hour and a half.  When I make the switch, I will cruise on the new tank until it is time to start the descent (which from the flight levels is usually quite a ways out).  At that point I will switch over, knowing that I have about an hour and a half on the descent tank, which is about twice what I need.  Better yet, I am dead certain it is 19 gals. in that tank, I am not guessing where it is and how much there might be in that tank.

 

The number that the JPI reads out for "fuel remaining" is a total fuel number.  When it tells me I have three hours remaining, I know that the fuel flow it has subtracted is very accurate, but I also know that the starting number was an assumption, not a measurement, so the ending number is based on an assumption.  What the fuel remaining number cannot tell me, is where that three hours of fuel is.  Nothing the JPI has on it, whether hooked to a GPS or not, is going to be able to tell me that with any degree of accuracy.  The gauges are just a "best guess."  

 

When I installed the JPI I looked at ways to get a better measured fuel number.  EI has a different type of fuel sensor that is supposed to be much more accurate than the old style float sensors.  EI's rep. was on this site for awhile and I asked whether the EI senders would work with the JPI.  He could not tell me and said that was a judgment my A&P would have to make.  The installation of all new sensors was also a very pricey thing, there are two sensors on each side, so I stuck with the factory senders.  The EI engine monitor, obviously, would work with the EI sensors.  But when I was looking at the MVP-50 a few years ago, its fuel remaining calculation was done in the same way as the JPI calculation, that is, it was based on an assumed starting number and not on measured fuel in the tank. 

 

So the bottom line is that I don't find myself using the fuel remaining number that the 930 displays very much at all.  It is a secondary verification for the actual, accurate, fuel flow numbers I have on my little paper chart.  And by the way, that chart is a scrap, sometimes I write it on the back of a fuel invoice folded up.  I just want it to be permanent and not subject to change under any circumstances. 

 

I am not saying it is not fun to have that "fuel remaining" number, just that, when I need something I can count on, like exactly how much fuel is in which tank at the end of a long cross country of several hours, that "total fuel" number is not very useful.

[carusoam]

JL,

Good to see your method.

The engineering and accuracy is very agreeable.

The human error portion of the aging brain is what let's me say a connected GPS and fuel flow is a good idea.

Setting/knowing the starting volume is critical. Document as I go on my scrap paper.

I typically burn 10 gal per side, then change. If everything goes as planned. The instruments tell me I have more fuel than I have distance to go.

If I screw up the engineering part, there is a solid plan set in advance. At the moment the JPI says I don't have enough fuel to go the distance I have been notified that I have made a mistake or headwinds are tougher, an I still have time to do something about it.

The next notification comes with a series of yellow lights on the instrument panel. Low fuel L and Low fuel R. When they come alive they come with an uncomfortable feeling.

There are many airplane accidents related to fuel exhaustion. This is my belt and suspenders method of keeping it from being the reason for my last flight.

Somebody can take this out of context. They enter the tanks to be filled, when they are not. Follow that with using the JPI as a key decision maker, it cannot be relied upon in this manner.

Best regards,

-a-

[Bob_Belville]

Good grief! The fuel flow meter, once calibrated, is extremely accurate. Mine is this accurate: 420.2 actual gallons vs. 421.6 FF calculated. That's 0.33% or 0.14 gallons difference in a 4 hour flight.

 

What the JPI calls "Remaining" is as accurate (or inaccurate) as the starting amount. If you can't be bothered to make sure you set that correctly don't blame the device. BTW, when you add fuel to less than full you do not want to reset the USD value to zero, you want to simple add the gallons added to the tanks to avoid introducing errors.

 

If you do not fill the tanks to a consistent level it will average out over several flights but any given flight will be off by the inconsistent filling.  

 

The more practical issue is managing fuel so that if we're still flying with less than 1 hour fuel on board we know where the fuel is... which tank has how much. All the FF device can tell you is total remaining, it's up to you to log how much you've burned from each tank.

 

My fuel gauges informed by tank floats seem to be pretty accurate when the fuel levels get down to single digits in a tank but no one should ever trust an airplane fuel gauge no matter how many decimals are displayed.