Car Tuning ECU Remapping and Calibration 3

Question 1

What is the primary risk of advancing ignition timing too aggressively during a tune?

Accepted Answer

Engine knock or detonation that can destroy pistons and bearings

Answer

Too much ignition advance causes the air-fuel mixture to detonate before the piston reaches TDC, generating destructive pressure spikes.

Question 2

What does 'target AFR' (Air-Fuel Ratio) mean during a WOT (wide-open throttle) tune on a naturally aspirated engine?

Accepted Answer

A slightly richer mixture, typically 12.5–13.2:1, for peak power and cooling

Answer

At WOT, tuners target a rich AFR around 12.5–13.2:1 to maximize power and provide charge cooling while avoiding lean detonation.

Question 3

What is an 'injector dead time' (or latency) correction in ECU calibration?

Accepted Answer

A time compensation added to injector pulse width to account for the delay before fuel actually flows

Answer

Injector dead time compensates for the mechanical delay between the ECU signal and actual fuel flow, which varies with battery voltage and fuel pressure.

Question 4

Why is it important to calibrate the MAP (Manifold Absolute Pressure) sensor when fitting a larger turbocharger?

Accepted Answer

Because the stock MAP sensor may not have the pressure range to read elevated boost levels

Answer

A stock MAP sensor rated to ~1.5 bar absolute will clip and provide incorrect readings if boost levels exceed its measurement range.

Question 5

What is the function of the 'enrichment table' or 'acceleration enrichment' in fuel mapping?

Accepted Answer

It temporarily adds extra fuel during rapid throttle opening to prevent a lean stumble

Answer

Acceleration enrichment adds a brief fuel shot when the throttle opens quickly, compensating for the lag in airflow measurement and preventing a lean hesitation.

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Car Tuning ECU Remapping and Calibration 3