DFCO adjustments help

[mikz86ta]

I am relatively new to the tuning but not to working on cars. Honestly I never heard of DFCO until I got a tuning program and started reading threads. I dont have HPT yet but plan on it after tax return comes. I do have access to JET DST and have been learning some in general on it. I have read a ton of Stickies here, LS1 forums, LT1 Tuning forum, Monodax, Help guides and even bought the Greg Banish Adv Tuning book.
Yet I still want some clarity on a few things.

Concerning DFCO, Iwant to make some fine tuning there.
I have a 2003 4.3L 5sp S10. I realize the tuning relates more to the LS1 V8 since the 4.3 shares a similar PCM and setup. Honestly I think posting this in the V8 section might be a better option but I dont want to annoy the Mods by doing so.
One question I had is, what if anything is the focus of tuning DFCO when concerend with rear gear changes? Stock I had a 3.08 and now I have a 3.73 I never realized how changing that (gears) can alter DFCO, but seems to me that it does. Seems to me the MAP, Vaccum, RPM and given MPH is different with such a large ratio difference.

One question is what is the area to play with and how to do it concerning the 'harshness' of the DFCO? Like to me it comes on a bit too much. Like do I play with the Entry Rate?



I have std and Clutch Based settings under the Constants area.

Some changes I have made are as follows concerning 'WHEN' it comes in. I have not dialed it in perfectly tho.

I have upped the MPH from 20 to 45 (constants). I feel that I only want it to be applicable when I am cruising on the road...not driving in town or a parking low which it occured alot B4. I also have a MPH setting under Tables. I duplicated the MPH setting there (MPH vs. Baro)
I have changed the Temp from 40*c up to 83*c. My Temp based changes were because of the extreme 'pop pop' in the exh in the mornings when DFCO would engage and the engine is not up to operating temp. By the way, I have Headers, y-pipe, no cats, Hooker MaxFlo and a dump. Also a 180* thermostat
I also changed the RPM Enable to 2000


But theres a ton of Disable/Enable settings I dont understand yet like MAP, TPS, Delays, etc. I just played with what I understood for now.

BTW I have a AEM Wideband stand alone gauge so I see whats going on

Moving back to the 'How to adjust the harshness' question.....
In Tables/Spark:
DFCO Sp Adv vs RPM TPS high and seperate low tables.
DFCO Spark Adv Exit Ramp vs. TPS%
DFCO Net Sp Adv vs. RPM after ramp
DFCO Spark Adv Entry Ramp vs. RPM

In Tables/Fuel:
Enable RPM vs Gear
Disable RPM vs. Gear
Enable MAP vs Baro
Disable MAP vs Baro
Enable MPH vs Baro
Disable TPS vs RPM

I appreciate some help and what I should focus on in both dialing in the timing of the entry (warm CLoop/45MPH + / etc) and lowering the harshness it comes on, reducing the amount and maybe if once in and the vehicle speed reduces to a lower speed, then it turns off by itself.
Thx, Michel

[MMGT1]

With camed engines you want to raise both the entry and exit map by around 10% because of poor vac at lower rpm's. Maybe you could take this route with yours and see if the result is what you are looking for. Yes, DFCO is a PITA imo...lol

[mikz86ta]

Def good info to know but I run a stock cam. for now. And even if I do run a bigger cam it wont be too big because I will be supercharged by then
I doubt if going from 1.5 ratio rockers stock to 1.52's change much as far as vaccum.

I really want to know more concerning the gear ratio change. Since my RPM's in any gear vs. MPH are higher than they were stock. 3.08 vs 3.73 is a pretty good jump IMO

[MMGT1]

Nope, not much change in MAP at all.... but the gearing being so much shorter it may need the same changes to give the end result you are looking for. Raise the entry and exit MAP a little to compensate for the shorter gears. Shorter gears will equate to higher MAP reading doing the same speed as before with stock gears would it not? I may be missing something else, but give this a try.
The other would be to take a old scan that had origional gears and see what the rpm vs speed was in that set up. Take the difference between the old and new as a % error and apply that error to the enable and dissable tables. I say that will also get you pretty close. Obviously you have tuned the new gears in already as well?

[mikz86ta]

Ok I will try the entry/exit MAP idea.
The rpm vs. mph I will have to check on. The only thing I had changed was RPM vs. Gear which I raised hoping that would translate to reducing the DFCO entry until a much higher rpm. If I am driving in 1st in a parking lot (or2nd) and allow the rpms to be high, Id rather not have DFCO since it causes the open exh I have to 'pop pop' loudly. Annoying to me..scares others
Tuned the new gears? U mean changed the pcm so it knows I have 3.73s and corrected the speedo? Yes on that

[mikz86ta]

I read in the banish book about the 'Table of zones'. In zone7 its like the area where when u were on the throttle and let off (low tps, high rpm). Well in my Timing section, the area that would be Zone7, my timing advance settings are pretty high. Like 40's and up. Why should there be such a high timing in that area? Like I have higher timing there than any other zone