Finding MBT timing without the live tuning feature.

I was wondering how you find the MBT ignition timing for cars that don’t support live tuning? A friend of mine wants me to tune his CL9 Honda, which has upgrades including pistons, camshafts, VTC gears, and cylinder head work. Unfortunately, Hondata doesn’t support his model, and I assume the MBT timing is going to be significantly different with these mods.

My current plan is to create a new ignition table with a flat 25 degrees across all cells, then add 2 degrees at a time in the cells I’m testing during ramp runs. As you can imagine, this is going to be extremely time-consuming and inefficient. Does anyone have a better approach to this?

As a supplement, I am using the Honda Tuning Suite software to tune his car which only supports the K-line flashing for this certain model. This will be much slower than the CAN bus flashing so if there isn't a efficient way for the tune I might just turn down his request.

Some people get multiple ECUs and bench flash them with different values, then just swap ECUs. Still takes a lot of time, and one reason that stand-alone ECU are typically chosen for modified vehicles.

One approach might be to start with the stock maps, and only remove timing if knock is detected. Changes that increase performance (ie. put more fuel/air mass into the cylinder) will most certainly need less timing than optimized timing for the stock configuration.

Perhaps you can get timing information from someone with a similar configuration (offer to pay for it -- it will be saving your customer money), even if they are using a stand-alone ECU.