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ITB's+Boost - Ign table input clarification

Practical Dyno Tuning

Discussion and questions related to the course Practical Dyno Tuning


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On your video for step 3 "base table config' you talk about using MAP for the load axis when setting up ign table, but then say that for multi TB plus boost you would use MAP for load axis. So you made no differentiation between multi tb + boost vs say single tb + boost. Did you mean to? I have it in my mind that (for multi tb +boost) you would need two axis(throttle position and MAP) and switch between them such that when vacuum no longer exists, you move from a throttle position input to a MAP signal. For reference, I have a N.A. v6 running 6 itb's. The input is throttle position. MAP sensor is connected but not used. Could you clarify for me?

Cheers

Mike

Sorry for the confusion - For any boosted application regardless of single or multi throttle, you would use MAP as the load axis since we need to vary the ignition timing predominantly based off manifold pressure. It's the fuel table where there are serious differences. With the fuel table we use TPS as the main load axis but then incorporate an overlay table which uses MAP as the load axis to compensate the AFR for boost pressure.

With your N/A engine with itb's you would useTPS for the load input for both fuel and ignition. If you have a MAP sensor connected to the ECU and it is reading from a balance bar post throttle bodies then you can also incorporate this into the ECU's background fuel calculation in some ECUs. This takes the principle of double MAP = double fuel into account