I've seen some call it EGR but that is where you actually flow x amount of exhaust gas back through the intake.

CDE on the other hand I understand is the flow dynamics (reversion and pressure waves etc) of the exhaust gasses simply getting out the chamber, up the exhaust, and out to the world.

So camshaft and exhaust design obviously play major parts in this, and there are CDE tables in the Delphi so the EMU obviously cares about such things (or at the very least, takes them into account).

OK so I've changed my camshafts so lift and timings are obviously different, and I've gone from the stock 2-2 with a crossover pipe to a 2-1 ...things are obviously going to be different. A look at stock maps show quite different CDE tables for different bikes so Harley aren't using some plucked out the air table shipped by Delphi.

I see that the latest TTS has some CDE tuning within its auto tune, but I've got a PV and my VE tables are far from gently undulating, they go from 60 at one side up to 110 at the other (which, fair enough, I know works, but...)

One other thing to note is that when I first changed my cams I noticed that the MAP at idle went from 35 or whatever is stock up to 42, and I'm at sea level. I did some testing of CDE values and got as far as noticing that raising the values lowered MAP back down a bit to 37.

...so, how do you tune CDE properly

any discussion?
cheers

 

mmm, I take that back, I'm not sure if stock maps change per exhaust, maybe it's just camshafts??

 

That is the reason that camshaft selection is one of the first things you should look at. When you pick a map with a very different cam timing, the actual cam timing is way off from what the ECM thinks it should be and it's actually reading MAP at the "wrong" time. Biggest tell tales are VE's that swing wildly - to the point you'd look at them and say "Hmmm, i really don't think the engine breathes like that..." and an idle map reading that changed from the mid 30's into the 40's or even approaching 50. I've seen people put the completely wrong map in at it's trying to idle and the MAP is 50kPa. Its delivering fuel and timing like it's at cruise, but it's at idle...

 

Good point and I suspect there must be a setting for that in there somewhere.

You can put cam settings into the TTS and FP3 but I don't see that feature in the Power Vision ...so what or how do PV users set it correctly? ...DynoVision don't have any softail maps for different cams!!

Or rather than having a setting called IVO/IVC, is this where the CDE tables really come in?



EDIT: quick note - changing the cam settings on the FP3 did not make any difference to the MAP reading at idle, I tried with various different manual settings

 

What calibration level are you working with? Are you working with MAP based or throttle position VE tables?


Map based tables are much easier to work with when dealing with CDE. (Which is the same as the EGR tables in TTS. DJ just changed the name.) 60 kpa is the magic break point for CDE. With MAP based tables it is easy to see this 60 kpa limit by just looking at the calibration. TPS based VE tables need logged data in order to tell at what TP in the VE table did 60 kpa happens at. As for as I know. DJ has no tools for this and their instructions are kind of lacking in this department. The TTS manual and help files have a decent explanation of how to use this table.


IVO/IVC is something completely different. Vision has something like IVO but you need to get the code so it will appear, and then. DJ has no tools for this or explanation about what to do with it. It is a change it, and see what it did type of adjustment.


If you are dealing with a cable driven bike, and your idle kpa is way high. Another way to approach it is throttle blade stop screw, but IAC position needs to be verified from cold to hot idle to make sure it isn't tapped out.

 

cheers hrdtail78

Instructions are kind of lacking in general, hence the question. There is actually more information (or hints of) if you read up on exhaust design and the likes of Megasquirt tuning.

In my case I have a 2014 Softail, calibration level 358, which is TPS/RPM VE tables.

I've read the TTS info on CDE a few times but to me it only seems to describe what it does, but not what to do with it. We know CDE affects MAP below 60kpa and something about smoothing the VE tables

I have run logs and extracted and graphed the 58-60 MAP/RPM and can get the same graph and trend line the TTS manual shows ...but the question becomes, so what? what's next? ...if you see what I mean

Not to get too side tracked, I only mentioned cam timing as being linked to or at least a factor in the CDE tables and their tuning - the Stock maps have different CDE tables between the 103HO engine and the older 103 for example so I'm expecting different tables again would be more ideal for my 57H

 

As a quick dirty test (to see what happens) I changed the tables to what is in the stock 103HO map

What I did see was the MAP at idle dropped from floating around the 42 mark to jumping around between 36 and 39 ...idle is smooth 1000 + or - 20 or so

 

Great. I didn't know how for along you were, but this info is a must for the cal level you are dealing with.


Lets assume some things. 2500 rpm row and 60 kpa happens at 10% throttle. The VE value is 65. The VE value of 15% throttle is 75. That means that there is about 14% change between the two. I would add 14% to the 2400 cell in EGR table, and remap VE's to see outcome. This will get things in the ball park and moving in the correct direction.


What it is doing and why? Basically we are setting up the ECM to calculate PW faster and more accurate in it's predictions. We see the break points of 10 and 15. When the ECM is concerned with the positions in-between as well. 10, 11, 12, 13, 14, 15. ( Yes, I understand it is really 10.3, 10.8, 11.2..... I am keeping it simple. anyway....) Take the same 2500 rpm row and 10, 15% columns. 10 is 65 and 15 is 75. The EGR value is your constant in this row. The ECM is going to treat 12.5% throttle of a VE value of 70. This is the best case assumption performed by the ECM. While you are jockeying around in this area. This is how the math is performed. Now lets raise the constant in the EGR table. Which puts the 10% cell at 2500 rpms at 74. 15% throttle stays at 75. Now when we hold 12.5% throttle. ECM is going to calculate the VE as 74.5. A lot less tolerance for the ECM to make a mistake if it is only figuring out the VE from moving between 74 to 75 than from 65 to 75. Remember the ECM is constantly trying to figure out the PW 4-5 firing cycles out in the future.


Another benefit from the EGR table is VE ceiling and floor or the limits that are set of 127.5 on top and 20 or 40 depending on cal level. On cable driven/ TPS VE tables. The higher VE numbers are usually in the 10-20% 3500-5000 rpm. KPA VE tables the high VE's are usually around 40-60kpa. Same RPM. We can see that this area will be affected by EGR table, and there is an opportunity to reduce these VE's of 127 with out jacking up cubic inch or shrinking injector size. In other cases like a 120 cubic inch engine with a blower and 60lbs injectors. We can also use the EGR table to raise the floor of the lower VE cells around the idle area and still have the headroom on the right side when boost in produced. This last scenario is less common. But like I have stated before. The features in these tuning programs and the more tables that are exposed to us. Really shine the further away from stock you get or when and if problems arise.


This table exposure in TTS is a direct result of running into the scenarios I mentioned above, and bringing it up to the tuning manufacture. The manufactures response was to expose the EGR tables. The others just continue to play follow the leader. Pure monkey see, monkey do.


HTH's
Jason

 

Easier to calculate, smoother VE tables, giving smoother engine transitions ...that makes lots of sense and explains the task at hand, cheers.

I like your example there, clear and concise ...let me get my head around that and see if I can apply it to my 3-5% TPS cells that are down in the mid 60's

I didn't think I had to worry about the 127.5 ceiling but I just had my heads ported and see some starting to push up towards the 120 mark.

 

hmm, that didn't seem to work, I seemed to get negligible change to anything?

So I have collected and charted TPS/RPM for data where MAP is between 58 and 60.

I've produced the trend line where we expect everything to the left is less than 60kpa and therefore likely to be affected by CDE

I transposed the trend line to my VE/TPS tables (the yellow highlights in the pic)

I tried comparing the yellow value with the next one up (e.g. 10% vs 15%) and worked out the %age difference

I then added the %age difference of the original CDE to produce a new CDE value
(repeat for all lines in the CDE tables

and retuned ...not much difference at all??

so I tried using percentage difference between the two cells either side of the yellow value (e.g. 7% vs 15%)

and retuned ...a noticeable difference but not particularly significant


What I'm looking at is trying to flatten the huge dip in low TPS ...am I barking up the wrong tree here?





Orig VE table, hello highlights represent the 60kpa trend line





Calculated change to CDE table