Quote:
Originally Posted by Shorty45
What are some of the tuners seeing? I know some members have tuned them so I just wanted to know specifically; is it eLSD or timing or Traction Mgt.
|
I'm not a professional tuner, but I think I can provide some input. Maybe some pro tuners can fill in the gaps.
As you may already know most Camaro tuners use HP Tuners. HP Tuners is probably the best publicly available tuning software, but it's very limited compared to what GM has at their fingertips. HP Tuners is basically limited to the ECM and TCM, and within these modules only a small portion of the configuration tables are available for tweaking. The software within the modules, where most of the problem likely is, isn't [easily] configurable. Since tuners cannot adjust the code, they'll usually hack the settings to get a desired behavior.
The eLSD isn't part of the problem to my knowledge. I thought it was originally, which is why the thread is misnamed. (I'm not aware of any publicly available software to tune the eLSD module anyway.)
The ignition timing is altered dynamically by the ECM for lots of reasons... wheel slip, torque management, intake air temps, knock, etc.. For the launch problem, timing isn't the root issue. For the driveability problem, the timing tables could probably be tweaked for low-RPM and high airflow to help offset some of the timing loss when wheel slip occurs. I wouldn't bother though.
If you are looking to improve the launch via tuning, torque management is probably where you'll want to focus. The HP Tuners software exposes a lot of options here. There are torque management engine coefficients, but the tuning process for the coefficients isn't perfectly established (It's getting better though). Most tuners simply make small tweaks to maximum torque and driver demand tables until the car does what they want, as opposed to a more scientific and comprehensive approach.
I believe the torque management is likely where GM intends for it to be. It's the wheel slip % problem that I believe might be the oversight in the launching equation. My best launches have come from maximizing target wheel slip % and using a low launch RPM to avoid wheel slip. The wheel slip target % makes me very suspicious. Unless this setting is completely ignored at very low speeds, the setting doesn't make sense. At very low speeds a very high wheel slip % might be perfectly fine. A % metric only becomes meaningful after ~7 MPH.
Quote:
Originally Posted by Shorty45
Can someone tell me if the Corvette ever had the issue? I've looked on their forums but haven't seen it or I may have overlooked it..maybe there is something from CTSV. Just trying to get some other perspectives.
|
I don't know of any launching issues with the Corvettes or CTS-V. The C7s seem to launch fine from what I've seen. All of the new CTS-Vs are automatic, so I don't believe it suffers from the same issue. I work with a guy who has a '16 CTS-V and it launches hard compared to the manual transmission ZL1.
Everything above is just my opinion based on observations and testing. Unfortunately, I don't have access to the source code to confirm my theories. Hopefully GM will provide some overdue answers to us in the near future.