An update on this old thread:
I used to think that JPI changed their software at some point, to increase the amount of data which could be stored, and they did it by storing data only when it changes by at least 5F. This manifests itself in the large steps in the stored data:
JPI never replied when I asked them on multiple occassions. However a check of old EDM700 logs (from 2002) shows that the logged data is always at least 5F between consecutive samples, so nothing has been changed there
I cannot find a config for the data log resolution. There is a config for the display resolution.
Yes; I can read the new format with new software.
I was just wondering if - for the first time - they are using data compression to pack more data in there. It would make sense. One should be able to get almost 10:1 on numeric strings but they are getting maybe 2:1, at a guess.
Peter, obviously JPI has a new data download software as they also offer a new plotting feature by their EDM700 (seen in their new ad) and the data are compressed (see below)
https://www.jpinstruments.com/technical-support/software-downloads/
Windows 7.net version of EZTrends Plotting Software
This utility program will transfer compressed data from your EDM to your PC, for XP, Vista, or Win7, and decompress the data. It will plot the data on the screen and print the graph and allows great flexibility in how you display your data.
Does latest EDM700 firmware compress the data?
I tried to get an answer from JPI but entirely without success.
I have had mine rebuilt from the 2" to the 3" version (which they do for a very good price) and they put in new firmware at the same time.
The unit now seems to hold a lot more data, but they tell me the memory size is the same.
Also the old software can no longer open the downloaded files. It can download them but cannot unpack them. So something has changed.
I reckon they are using compression.
The EDM700's very limited data storage has been a constant irritation, in this day of dirt cheap memory, and I am glad they have done something...
So your MP/RPM gauges are faulty?
If you make POH speed at POH fuel flow with peak EGT, then your engine and your airframe are fine.
To get a certain fuel flow (= power setting), there are multiple MP/RPM combinations and generally the lower the RPM, the more efficient but in a normally aspirated aircraft that only helps you at very low levels because the MP drops off quickly with altitude so you end up flying WOT (wide open throttle).
Once you get GAMI injectors, you can use another technique: fly WOT and use a good cruise RPM and then use the mixer lever to adjust your fuel flow, the more LOP, the lower the fuel flow and thus power setting.
Much better!
You are now within 3kt of mine.
The rest is probably dead flies and instrument errors 
Also do fit GAMI injectors.
Checked today: at 2000' and 2400/23" EGTs peak at 44 LPH (11.6 GPH) making 135 KIAS.
The POH doesn't give the fuel flow at which the EGT should peak.
From memory, it merely contains a table of "best economy" power settings which are generally believed to mean peak-EGT but nobody AFAIK has ever got that confirmed by Socata. The present POH dates back to 1988.
At 23" / 2400 and say 2000ft the EGTs should peak at about 11.3-11.5 USG/hr. If they peak at a higher flow rate (say 12.5 USG/hr) there is something very weird going on and I suspect it is an instrument issue. This is nothing to do with the airframe.
it always peaks at lower fuel flow than shown in POH.
That is exactly the problem, you are comparing different power settings.
Let's assume everything is at peak EGT.
There are several combinations of MP/RPM to achieve a certain fuel flow. The speed should always be roughly the same. So find a setting that gives you the fuel flow of a POH entry and then compare your TAS. You can do it down low so IAS is roughly the same as TAS.
If you fuel flow is not the same as what you have in your POH, then you are not operating at the same power setting. Most likely your MP/RPM gauge are incorrect.
Have you determined your GAMI spread? There is a simple test to check how well balanced your injector nozzles are, i.e. whether your cylinders all reach peak EGT at the same time.
I use EDM800 for the leaning - and it always peaks at lower fuel flow than shown in POH.
