Following the 4 HPT trans modules we've already explored, we'll proceed to tune the trans, using the Auto Shift Speed to affect the WOT shift points, The Auto Shift Properties to make the trans a tad faster and firm, the Auto tcc to make some adjustments to the stock verter/aftermarket verters, and the Torque Management module to remove some TM.
Making the trans shift faster
Please use common sense here, the 6L80e trans can be set to shift faster, we can decrease the times it takes for the trans to perform the shift. With a decrease in time, an increase in shift pressure is also desirable so the clutches have what they need to get applied. how much can you decrease time from the shift and increase pressure to the shift is the million dollar question, i wish we had some sort of formula we could use to say, decrease xx ms from the shifts and increase xx psi so the clutches get what they need, and the trans react this way or that way. Unfortunately this is not the case, i'm sure somebody at GM must know, but this information has yet to be made public
, so we have to resort to trial an error.
Per Chris notes :
"The inertia torque is "factored" into a number between 1 and 9 which is then used later to modify the base shift time and other things. From what i can tell this is the primary thing calibrators use to control the shift "feel" once the main things are calibrated. You'll notice in the Shift Inertia Factor Profile tables, higher numbers are used at higher torque and RPM. Further on in the Shift Time Inertia Adders you'll notice that these higher numbers equate to smaller additions to the shift times (ie. shorter shift times, which equate to higher pressures and firmer shifts). The basic idea here is that the shift is all about managing the rotating inertia change in a certain time between the shafts and clutches as some speed up and slow down during various shifts.
You will also notice that the shift times have two primary type "Normal" and "Special". This is selected by the Pressure Pattern Mode options ie. each of pattern X, Y & Z can be set to shift times Normal or Special.
So you end up with a base shift time + some adders based on inertia torque and other stuff. This shift time is then used to setup the desired torque profile.
The Shift Time Transition Initial controls when during the shift completion (% of shift time) the torque based model starts, then the Shift Time Transition Final controls when it ends - kind of the ramp in time and ramp out time as far as i can tell. Probably used as a way to wait for things to stabilize enough for the torque based model to be accurate, then ramp out once the shift is basically complete. Again, at higher torque and RPM the numbers get smaller.
The desired output torque factors and multipliers control the torque profile itself and experimentation will be required to see exactly what these do, from what i make of it they control the shape of the torque profile as the shift complete's. ie. more torque in the initial shift and less later or the other way around depending on probably a million other things that maybe one person in GM fully understands!
If you have understood anything so far you will realize at this point there are two ways to change the shift feel. Either go in an change the shift times themselves *or* mod the inertia factor profile so that the smaller adders are selected at lower torque/RPM. If you aren't getting good shifts at full throttle then you probably want to change the shift times themselves to be shorter, since you are already at Profile Factor = 9 in most cases. If you just want firmer part throttle shifts and are happy with everything else then maybe just increase the Profile factor from say 3 to 4 or 5 in the mid range torque/RPM areas"
Here are the base shift times, you have tables for normal and special, as i said in post#2, normal in the tables apply to normal mode in the trans, and special apply to your Sport mode. you can increase or decrease shift time and pressure to Normal and Sport mode, and increase/decrease pressure from manual mode only.
Normal and Especial refer to shift times, inertia profiles intertia adders, etc, etc, are all time referenced in ms (miliseconds), you have tables that affect upshift and downshift, and this can also be setup per gear, 1-2,2-3, 3-4 4-5,5-6, then 2-1, 3-2,4-3 etc, etc.
Then you have tables that control shift pressure (pressure pattern) defined as X Y and Z
As i said in post#2
Pattern X control pressure for Normal mode
Pattern Y control pressures for Sport mode
Pattern Z control pressures for Manual mode or TUTD
Pattern Y and Z share the same pressure pattern mode, this means pressure patterns Y and Z applied to shift pattern Especial. Pattern X applies to shift pattern Normal.
So how can we mix all this info together ?
Note, i don't change anything here, but for the purposes of general knowledge, in case you decided to change things in this table, here is the table that Chris is referring to in his Quote, Inertia Factor profile, if you look at this table, it has those values from 1thorugh 9, from 0 to 6400 rpm, and -30 through 413 ft.lb, (engine requested torque), so the higher the rpm and requested tq, the numbers move from 1 to 9, once you look at the next print screen, you'll understand why.
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How can i translate all those numbers from 1 through 9, if you look on the shift time tab, you'll find your answer, applying to Normal or Especial shift pattern, per gear, upshift or downshift. this are the tables i modify, i leave the ^ stock, but i modify the base shift time, and the inertia adders to effectively remove shift time and affect trans feeling.
The lower the numbers, the fastest she'll shift, and also the firmer the shift would get, the trans can be too jerky if it made to shift to quick, so jerky that some people like me would hate the feeling, some others would love it, up to the tuner really and what you want out of the car, the feel can be adjusted to suite your needs. as a rule of thumb, lower the numbers from the profile 7,8 and 9 (this is WOT if you look at the inertia profile tables, at high-max engine requested torque)
Keep in mind i don't touch the inertia adders for downshift tables, nor i modify the inertia factor profile for downshift, if you do so, please be aware than making this tables faster can actually cause a big delay from your downshift, or make it stupid bad jerky, cluncky or worst, i simple lower the base power downshift values a little, splashing your fingers all over the place around here is what confuses the shiat out of your trans, be gentle to her, start small, test and observe, you don't have to change everything here to zero because the new Camaros or vettes have all zeros, or change every little table for upshift or downshift, Look at the tables to the right of the base shift tables, i've enclosed them in blue or green as an example to make the whole thing make more sense, that's how they add/remove time from the base shift tables, per gear, upshift or downshift.
Below you'll find an example, base shift time for Normal mode 1-2, inertia adder normal 1-2, and Output torque normal 1-2, there are other things like the shift time transition intial and final for normal and sport that also add/remove time from the shift. I've modified those in mine, but you'll have to experiment, only after you've set your base and inertia adders. they modify shift feel, so change them at the end so you'll realize what they'll do do the shift feeling, it's hard d to tell, but changing this values would change the moment the clutches are about to get applied/release.
In the G8's, GM used the base tables, plus the inertia adders, and output torque factor tables, to have the shift/feel coordinated. splashing your fingers in this tables would upset the timing balance
, or zeroing the base when the others tables are adding/removing time from the base, would make for a very discoordinated trans, you might now about it because she WILL shift like complete shiat. A good tuner is not the one that can make her shift fast, but one that can accomplish that and make the trans last.
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In a general way, this is what i did in my application
Removed more or less 5 ms from the base shift time table for normal and a couple from the inertia adders in normal, and some more for Especial, (normal is almost Normal, special is way faster), and made them more or less all the same values, (from input from a guy in HPT who rebuild trans for a living and gave us that advise
) only for the single upshift gears (1-2,2,3,3-4 etc, leave the 1-3, 1-4, 2-6 etc alone, she would shift crappy if you touch those, ask me how i know), this reflects some of the changes i did for the upshift normal and especial, you do as you want since you're learning how easy this is.
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More to come...