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View Full Version : Torque and speed units: what are they?



Supercharged111
March 19th, 2009, 02:59 PM
D1143 for example, Abuse mode speed enable value 412. Is that 412 RPM's out the tailshaft or what? D1065, torque limiting in 1st gear 2032.4. What are the units? I have no idea what it's limited to right now and thus no idea what stands to be gained by altering these values.

Aloicious
March 20th, 2009, 04:51 PM
D1143 for example, Abuse mode speed enable value 412. Is that 412 RPM's out the tailshaft or what? D1065, torque limiting in 1st gear 2032.4. What are the units? I have no idea what it's limited to right now and thus no idea what stands to be gained by altering these values.

I always seem to not have my tuning laptop around when I need it, but there is a place (on mine its the upper right side of the screen, just right of the graphs, and above the table explaination), that shows what units a table is in.

Supercharged111
March 21st, 2009, 02:39 AM
I noticed on the torque that I'm retarded, they are in nM, but the limits are 2032nM which is like 1500ft/lb. Is that 1500ft/lb at the crank or after gear reduction? Either way, I fail to see how the torque reduction in D1065-1079 could possibly hold me back. Even the upshifts are only withholding 20-25% of available engine torque, but I don't see how long that lasts. Almost makes me wanna leave TM intact as, from what I can see, it appears largely unintrusive on this PCM.

hog
March 21st, 2009, 02:50 AM
I would assume that 1500 lb/ft limit would be after the torque converter and possibly some gear reduction.

If an L31 out puts 330 lb/ft torque, then the TC has an STR of 1.8 that makes the 330, 594 lb/ft, add on the 4l60e's 3.06:1 1st gear that 594 lb/ft becomes 1782 lb/ft coming out of the trans.

The 1996-97 Vortec TM is less agressive than the 1998-2000 GMT 400 trucks using the blackbox PCM.

Disabling TM does make a difference on the 96-97 trucks even with stock engines, I would think this holds true for the 98-00 trucks as well.

peace
Hog

Supercharged111
March 21st, 2009, 02:59 AM
6646 after the rear end, not counting driveline losses, so I wonder where it calculates from? Because the torque limit values are 2032 for all gears, and not just 1st. I've heard of people rave after TM is disabled, but just looking at it in the tune I don't see what the big holdup is. I'll raise the torque limit values to the moon and see what happens, but I'm thinking of leaving some intact for the shifts unless someone can confirm for how long the timing is pulled? If it gives it right back as soon as the shift is done then that's OK, but if it's gonna hang for a couple seconds after the shift then that shit can just go.

hog
March 21st, 2009, 03:53 AM
I do know that in a Vortec V6 the timing that is pulled during a WOT upshift is in great enough quantity and duration to give the truck a nose over feeling. This wasnt as bad in the V8 trucks.

If the torque values are the same through all gears the values in 2nd, 3rd and OD should be OK, because the max torque value wont ever be reached, not even close.

Also timing isnt just retarded during WOT upshifts, it can retarded during launches from a dead stop for instance.

In Tunercats 2 simply raising the TM Enable coolant temp will disable all TM in the black box PCM's.
If you are flow a bunch of power through a 4l60e, its a good idea to leave some TM in effect.

The actual torque calculations would probably be calculated by MAF, temp and injector PW's to name just a few.

peace
Hog

Supercharged111
March 21st, 2009, 04:51 AM
The only things I'm going to do to this truck right now are long tubes w/single 3" Magnaflow and volant CAI. Further down the road, I've got an extra set of Vortecs that I want to port and install with my LT1 cam and 1.6's, but even that doesn't count as a great deal of power to me. The 4L60E might not agree though. . . That being said I'd like to leave some semblance of torque management in place, but I want to remove that feeling of castration the truck currently has. I plan on disabling abuse mode right off the bat. Other than that, disable torque limiting by upping the allowable values in 1st and that's about all I can see to do. I plan on shortening the shift times and initially leaving the pressure values as they are stock, but I'm not sure about cutting TM on the upshifts for the sake of longevity. I suppose I could log some runs and figure out for how long TM lingers on the upshifts?

Supercharged111
March 21st, 2009, 08:19 AM
The 2032 is apparently the max value, so that would point toward the truck not really having any torque reduction at all, at least not in 2wd. 4wd low there are some lower values in 1st gear. I cut the upshift TM in half, entered 0kmh for abuse mode (if above this speed, abuse mode is disabled), and entered .25 second shift times across the board and noticed that the truck shifted a little quicker, but was otherwise the same. I also noticed that the truck idled really rich after I did this and started missing, so I went for a drive and all seemed well. I then later loaded a different timing table into the main spark advance and changed PE commanded AFR's a little and this seemed to make it a bit more responsive, particularly at lower RPM's and in OD. It seemd like it bucked a little a time or 2 so I'm going to get the scan software working so I can monitor knock and some other good stuff. I just took the EFI Live out of the wrapper right after making my previous post.