Turbo spool & Ignition Timing

It seems that ignition advance affects how a turbo spools. We were tuning an 2.3L Evo 9, and we noticed that the turbo spooled 250rpms earlier during 3rd gear ramp runs from 2000 rpm all the way to redline, due to low ignition advance during spool up (9*@2200rpm tapering to 1-3*@29 psi peak boost).

The other ramp run had, 250rpm slower spool with greater ignition advance (16*@2200rpm tapering to 1-2*@29 psi peak boost).

We don’t have access to a dyno so we are doing road tuning. The car runs on pump fuel (90-93 RON) with 10% toluene in the fuel tank. How do we determine what timing advance we should run during spool up? Do we keep adding timing till it knocks and back off a few degrees of ignition advance or do we retard the timing to spool the turbo faster even though we might be losing some torque with less timing advance?

You just need to make some time recording done and it will tell you which one makes the best timing as it depends on grip available.

Hello, Andre. I would really appreciate your knowledge and feedback on this matter. Thanks a lot. I love the content you guys are providing.