Another JPI 830 Question

[Marauder]

So, I finally got a chance to fly and set up the HP setting in tthe unit following the instructions below: Section 7 - Programming Horsepower Constant For EDM’s equipped with FF, RPM, OAT and MAP, you will adjust the HP Constant once for your aircraft (NOTE: perform MAP adjustment prior to this process) Follow the steps below: 1. Prior to takeoff, with the engine running, enter Pilot Program Mode (hold STEP and LF until ‘PROGRAM’ is displayed). 2. Tap STEP until you see HP ADJUST. Hold both STEP and LF until you see HPC=108 (your value may be different). Try changing the constant by tapping/holding the LF button. Note that the %HP gauge value changes as you change the constant. This adjustment will be performed while airborne. 3. Once airborne, by reference to the Aircraft Flight Manual (AFM), not the EDM , setup a constant power setting of 70% in straight and level flight below 10,000 feet (be sure your mixture is Rich of Peak). If necessary, re-enter the HP constant mode (steps 1 & 2 above). Adjust the HP constant until the EDM’s %HP is as close as possible to 70%. Note: the reading is the percent of maximum HP, not actual HP. 4. Tap the STEP button to save and exit. After completing the setup, I flew around a bit at different and then went back to an altitude and set the power settings to mimic a 70% HP setting. I was surprised to see the JPI readout showing only 48%. Either I am misunderstanding how to set this up or I did it wrong. Should the JPI not be reporting 70% HP if I set the power up to duplicate 70%? What am I missing on this?

[Bob_Belville]

B26:

 

On my 930 I had to change the HP constant only from 120 to 125 to get the HP readout on the JPI to agree with the 70% I had set up by running @ 21" & 2600 RPM @ 7500' for my 200 HP '66E running well ROP. From that point on the JPI HP has looked very reasonable and I use to be sure I'm 65% or less before I lean for LOP operation.

 

What was your HP constant before and after you adjusted it?   

[Marauder]

Thanks Bob. The constant was 108. I see what I did wrong. In the words of Forrest Gump "Stupid is as stupid does"! I read the constant as the actual %HP and adjusted it to 70. I'm going back to being a shrimp boat captain...

[Marauder]

Forrest Gump back again. Bob -- I ended up with a constant of 128. Thanks for showing me where the shrimp were

[Bob_Belville]

B26, here's a couple of shots from yesterday showing 63 % power on the JPI @ 9000' @ 21.4" & 2440 RPM. LOP 8.5 GPH and 180.2 mpg. Is that sweet? 

[Cruiser]

there is a guy on the AOPA board with a M20E claiming he gets

 

TAS   gph    

165   9.5     
162   9.2     
155   8.2     

 

what do you think? I am not buying it. Maybe in MPH but not KTS. And this is ROP since he claims LOP is not efficient for 4 cylinder engines.

(sorry for the hijack  )

[Bob_Belville]

Cruiser: those ffs seem low for ROP. I was showing about 63% yesterday before I started leaning using the JPI LF function. @ 8.0 gph it was running a little rough and I moved it back to 8.5. (I don't have GAMI but my delta FF is only 0.2) That was 20-40 F LOP. For him to be 8.2 ROP he'd have to be running a pretty low power setting. Which doesn't seem to match the TAS he's getting. I think I could match the speeds or the fuel flows but not at the same time! But my 47 year old bird could certainly be cleaner: gear doors and antennae. And I fly with cowl flaps open this time of year except during descent to baby the temps.

 

OTOH, I had a different '66E years ago. (Owned by Tom Nalle now.) It was a relatively new plane back then. I had a few mods but the original windshield and cowl. I ran 25 ROP on the simple EGT we had back then and I remember 9.1 gph avg. and 180 mph (156k). I flew that Mooney almost 2500 hours in the '80s so the numbers stick in my old mind. Change out the w'shield and the guppy cowl and his 9.2 & 162 are very possible. Of course 25 ROP is no longer considered wise! It used to be called "best economy."  

[Bob_Belville]

Cruiser, ISTM an "E" with 201 type aerodynamic cleanup ought to be the fastest of all the 4 cylinder Mooneys. Short body & gross wt. only 2575 vs, 2740 for the F and more than that for Js using the same HP.  

[Marauder]

B26, here's a couple of shots from yesterday showing 63 % power on the JPI @ 9000' @ 21.4" & 2440 RPM. LOP 8.5 GPH and 180.2 mpg. Is that sweet?

Nice Bob! How does the 63% compare to your POH for those settings?

[Marauder]

there is a guy on the AOPA board with a M20E claiming he gets

TAS gph 165 9.5 162 9.2 155 8.2

what do you think? I am not buying it. Maybe in MPH but not KTS. And this is ROP since he claims LOP is not efficient for 4 cylinder engines.

(sorry for the hijack )

No worries over the hijack! That is the fun part of the forum -- see where things go! People often ask me why I dump money into an F model when I can "step up" to a J. When I bought my F she already had a 201 windshield and a number of the STC mods that were available. I added the lower cowl enclosure that got me another 4 knots. I true at 155 knots, ROP with whatever MP I can get at altitude, no ram air and the rpm set at 2,500.

I suppose you can get more out of an "E" because of the same powerplant and the lighter weights Bob mentions. Here is my proof

[Cruiser]

thanks Chris, 

Obviously less wt. at the same HP will increase speed but

 

what was the FF? 

[Marauder]

Hi Cruiser,

I flightplan 10 and see 9.5 to 9.8 on a regular basis (ROP). With the new JPI I am tempted to see what LOP will do for me. I'm sorry to say I'm old school. I never had the hardware on board to try it nor did I spend the time to do the GAMI spread. I'm not sure if my Mooney is an anomaly -- I have a couple of buddies who own Js and I'm in their performance envelope. That is until we compare me to my buddy with a late model J. He will will out pace me by 10 knots at the same burn.

[Marauder]

And another thing on the weight. When I met Mike (201er) and Alan (N74795) today we talked about weights. My F has a useful load of 960. Not exactly lighter than a J. Not sure how to explain my F's performance but I am not complaining.

[Bob_Belville]

B26,

Pretty close. My old Owners Manuel only lists 7500 and 10000. Ir has 21.0 & 2400 @ 66% at 10,000 @ std atmos.

I was @ 9000, 21.4 & 2440 with JPI showing 63% while at LOP. OAT was 12C and Baro was 30.24. Maybe Jetdriver can tell us if that's equiv. 

[ZuluZulu]

Bumping a very old thread to ask: those with the JPI EDM-730/830 and a 201, what HP CONSTANT setting do you use? What MAP ADJUSTMENT do you use? What high battery and low battery settings do you use? (Mine seem to be random guesses by some prior installer.) 

[ArtVandelay]

Bumping a very old thread to ask: those with the JPI EDM-730/830 and a 201, what HP CONSTANT setting do you use? What MAP ADJUSTMENT do you use? What high battery and low battery settings do you use? (Mine seem to be random guesses by some prior installer.) 

I compare static MAP to field barometer setting...adjust as necessary.