Overkill's transmission settings I'm putting this out in the open so others might see this and find the help they need. This was posted to me over at NAIOA and intrigued me, so I wanted to talk to you about it.
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Just a FYI Hopefully ZZP is aware of the trans pressure limit that is needed for the 04 and up vehicles. Apparently the original (and current) DHP tunes contain a max trans pressure of 96 PSI and is not very good for the 04 and up vehicles (according to "Overkill"). The 1.5 BIN I received from DHP contained a max trans pressure of 96 PSI and I had to lower the trans pressures. I have the article on my laptop so I'll post some excerps when I get home tonight. **edit** Found it on the web again. I will only post the known pressure / slip issues and not the fixes due to the fact that they are proprietary of the creator (Overkill). There are a few settings within the 04s that are very different than 97-03s that need to be dealt with. There are also some coding changes in DHP's coding vs stock that I think leads to an increase of the problem and needs fixing. No offence DHP! Transmission slip: This can be caused by a few things.. 1) 96 line pressure corresponds to a very aggressive force motor control setting. You can't see this table in the PT, but every 04 I've seen has very aggressive settings compared to pre-04. 2) DHP 04 computers have a greatly reduced torque abuse spark control table. This is the lookup table for torque reduction. At a certain percentage of torque reduction, it removes the corresponding degrees of timing advance as listed on this table. I don't know why this was reduced, but reduced timing removed on this table means less engine power cut means transmission slippage on some cars and obviously 04s have difficulty here. Hard shifts: 1) referring to #1, if the transmission doesn't slip, this high value can definitely cause some firm shifting, overly firm. But the main thing is #2. 2) To combat the slippage, some people have raised the torque reduction upshift % greatly to try and cut power on shifts. I tried this too, and this really causes the firm shifting to become apparent. I don't know precisely why but obviously the PCM is trying to do drastic things to cut power output by that large percentage so the transmission can shift. |
I recently installed a ZZP PCM. I did put in there that I have an 04 Impala. But, my 1->2 shift seems sluggish most of the time, and before long on a drive all of my shifts are hard as a rock. Is this what is happening to my trans (slippage)? And is it trying to save itself by going to extreme shifts? I'll put my original PCM back in if that's the case, and I plan on sending it to you for adjustments anyway. I just want to know if my ZZP PCM is hurting my trans by causing slip.
Thanks.
Linear Mode
