Ignition Table Retard/ Advance: which table?

Hi Andre,

I know that you are demonstrating tuning changes in the High Octane Ignition Table. What if I have Basic Ignition Table and High Octane Ignition Tables , provided that I am using High Octane Fuel, Is it enough to retard/advance timing in the Basic map only (given that both maps have different ignition degrees at different RPM and Maf scalings), OR, both maps?

Appreciate your feedback.

Thank you

It would help if I knew what ECU you were tuning. Often if you have a high octane and low octane ignition table the ECU will move between the two tables based on the feedback from the knock control system. Generally if you aren't suffering from knock the ECU 'should' be taking the ignition timing from the high octane table - You can usually tell by logging the actual delivered ignition timing and compare this to the two tables (often there may be other modifier tables just to confuse matters though).

The important part is to make sure that there is a decent timing split between the high and low timing tables, otherwise the knock control system can't function properly.

Thanks Andre. It makes sense. Yes, in fact, I have High and low octane tables in addition to the basic table. It is Siemens MS43 ECU, and a modified FI car. I focused on the basic ignition table for retarding the timing in the areas I has consecutive knock and I did take off 2 degrees only from high and low octane tables. In other words, I am only changing the basic ignition table timing and not bothering with the octane tables.

I noticed in the course that you worked on the high octane table and that is why I was concerned about it. Here, we have fuel 95 and 98 octane. This is why I ignored the low octane table as well.

So, in this case, with three ignition timing tables: basic, RON 91 and RON 98, should I perform a change in the three of them (given that the timing among the three is different)?

The course is great and I really learned a lot from it. I started reflashing prior to the course, and it helped clarify things more thoroughly.

Appreciate your feedback.