LNF- Torque Management Inj Disable kills DFCO- WTF?

[CDNITE]

Let me try to explain... stop thinking and forget everything you think you figured out...



The number values in the chart (1,2,3,4,7,8,12,13,14,15) are groups/sets of cylinders

so 0=0000 where the cylinder order is 4,3,2,1 means no cut on that 720* cycle

1=0001 where the cylinder order is 4,3,2,1 means cylinder 1 is cut on that 720* cycle

3=0011 so that cylinder 2 and 1
12=1100 so thats cylinder 4 and 3

7=0111 so thats cylinder 3,2, and 1
14=1110 so thats cylinder 4,3, and 2

15=1111 so thats 4,3,2, and 1

with four cylinders in the LNF the vertical (Y) value is for the cycle number

the horizontal (X) is the cylinder cut mode or "intensity" so to speak

thats why 0s in column 4 is bad... the other tables expect this to be total cylinder cut, and with a 0=0000 then no cylinders cut (injectors stop firing).

Thus column 0 is normal running state (default) injector sprays fuel as requested.

Got it? Does that explaination make any sense? Any more questions?

--Christian

[Pandion]

Okay. That really breaks it down for me lol. I get it now. Thank you for the explanation, I really appreciate it.

[gmtech16450yz]

Didn't read all this but it looks like what I figured out way back when I was looking at this is still valid?

Common practice was zeroing the entire table, but I found it disabled DFCO. I figured the horz axis was the "mode" or "intensity" (actually I think Chris told us that), and it made sense to me that when you're in DFCO, it would be a full "intensity" type of fuel cut so it made sense that the stock table had 15's there. I figured there would be no time you would want to only cut certain cylinders in DFCO so I zeroed everything that wasn't a 15 to enable DFCO and disable all other cyl cut situations. It did seem to help on NLS misfire problems people were having, but I ended up finding weak valve springs to be the biggest cause for me and have since been running a stock table with no problems for quite a while now.

Is there any way you could get that info to Chris? If it's stuff he hasn't seen I would think it would have to help him figure this stuff out?

[CDNITE]

GMTech, I assume you're referring to me... I read your post and yes you had the right idea I just thought I would clarify it since I had this new info.

I'll though I agree that it seems weird at first to only cut some cylinders I read a 12 section chapter on this and the methodology is actually very sound. Bosch spent a lot of money and time with really good engineers testing this. I'll paraphrase the logic they came to.

Because of the high compression and boost levels and higher octane requirements there is a very narrow thermal range where the GDI system operates best. Mostly it is for proper fuel atomization but also for preventing "hot spotting" and expansion variances on component surfaces. Having multiple modes of cycling the cylinders through their "cool down" preserves this even and constant thermal range during different driving conditions. There is even a reference to using oil to coolant heat exchangers and specific coolant formulas to reach this temp and maintain it better.

Now how significant is it... thats hard to say... I've worked with many German engineers in many industries and they have a tendency to over think and engineer unusual (I'd say unnecessary) systems. This could be one of them, but they did a lot of work. Hell, just the compiling the data and writing this chapter is a feat on it's own. But unless you want to spit flames and get that throttle pop I'd leave it alone and/or do some testing.

I haven't checked, is this table the same on all the LNF tunes? I wouldn't be surprised if the FWD and RWD tables are different to get even cooling with that layouts packaging.

Lastly another chapter on power management says that systems (other operator groups) use this injection cut table, a "ignition angle" (thats a direct translation) table and a ETC (Electronic Throttle Control) table to decide how to cut torque and manage power.

I'm no Tuning genius and expert like some of the members here, in fact I'm even greener than a rookie, so my understanding and translation of this information could be very wrong.

I left Germany today and headed to Denmark so I'll have very limited access to the web, but I'm excited that I and this info could further "our" cause! PM me or ask questions on the LNF threads and I'll do my best to share what I have.

--Christian

[BigDaddyCool]

I've been reading over your thead here guys, a run a NA V6 in Australia with the same sort of ECU.

I have this same table but with 5 axes each way. Now I thought I'd give your idea's a go and so far so good. I left my far right axes as stock and zero'd out the remainder of the table. Works good.

Mines set to 63 for that area. My DFCO still works and powers better then before. So it would seem even with the exact lack of understanding on this area...... doing the trick of leaving the far right side and zeroing out the rest works fine.

[metroplex]

I just read through CDNITE's explanation and it sounds like I just need to keep that table stock. Is that the consensus?
With Fords, you can adjust the delay for DFCO, min/max load, etc... so you can either make it harder to get into DFCO or make it easier. I don't see that capability on the LNF or am I wrong? I am getting 2-3 mpg better on my 2014 SHO by making it go into DFCO almost as soon as I let off the throttle.

[CDNITE]

DFCO does increase fuel economy, Bosch designed the stratified DFCO table for cylinder cooling and help maintain turbine speed.

Spraying fuel in alternating cylinders very 720* cycle cools the piston head and cylinder, some of this fuel air mix will burn on the turbine blades and help maintain boost. (No Lift Shift feature uses this and cam phasing)

I run all 0s, as the maintenance of cylinder temperature is more important than a few hundredths or tenth of an MPG.

Notice on using all 0s, if you do, its important to send out you oil for testing every oil change. A large increase of gasoline in the oil can be a sign of "cylinder wall washing" or "piston ring washing". This is when the gasoline acts as a solvent and strips the surfaces of lubricating oil and can be a sign of increase ring ware or wall scoring.

--Christian

[Balento]

I have read all pages of this thread and 1st a BIG thank you for all this! I am about to recalibrate my MAF sensor so i can re-tune everything else. Should I put the stock values for the recalibration and then make changes once I finish recalibration? I care about driveabilitya lot but I care more about being safe. I am making a tune for dily driving (I installed a 57/57 .63ar turbo) so I have my sights for around 360whp to maintain the turbo at a decent efficincy.

[CDNITE]

Yes calibrate with this table set to stock, then change it after your happy with the calibration.

--Christian