Background: I am tuning the fuel/ignition timing on my Roe GTS. The previous owner was at higher altitude and only had 91 octane available. The timing was way retarded and the AFRs were pig rich high 10s, low 11s. Now I'm leaning it out to 11.8-12.2 as recommended by Sean Roe and advancing the timing. The timing is a trickier subject. I am planning to try out the ignition maps from viperacr.com. Here's a link: SOME TIPS AND INFORMATION ABOUT VIPER TUNING I am concerned about tuning into audible knock and causing engine damage. Is this how you get to the edge of the tune and then back off? Car specs: 96 GTS Roe w/ 5psi pulley, VEC 3 93 octane 50/50 water/meth injection with stock jets (325 mL included with Roe kit) AEM wideband on after bank 1 collector before cat B&B headers, RT hi-flow cats, Bellanger exhaust Mobil 1 15w50 (included this because someone mentioned this may be too thick - feedback?) Log conditions: 80s ambient 70F dew point Night Sea level 114 IAT Log graph: See attached for a recent log. The AFR is still rich and I'm leaning it out. The timing is set at the values provided on '96-02-Viper-SC-L53-9D-A3-S108.cbc' from the VEC cd. Ignition timing: I also attached a graph showing the piggyback timing alterations for different tunes. I'm currently using the ROE timing and am considering moving to ACR91 then ACR93. Legend: PAT - Previous owner's ROE - from VEC CD ACR91 - From viperacr.com 91 octane tune ACR93 - From viperacr.com 93 octane tune ACR94 - From viperacr.com 94 octane tune Path forward: Set AFR to 11.5 Advance timing to ACR91 Advance timing to ACR93 Lean AFR to 11.8 or 12.2 Each step will be checked with runs to check for knock-free operation. I will advance the timing while in the mid 11s AFR because advancing the ignition will increase the AFR due to a longer combustion time in the cylinder. Feedback on the plan? I also may have access to a dyno this Saturday. Others have mentioned that a dyno tune will vary from a road tune. I have access to both to get the best results. I also have the complete log and tune files. Where is a good place to post them?