|
Agreed, also, if the reading of the post-cat O2 sensor is correct, regardless of what do you fit, you can leave the ECU alone. The auto-adaptive ability of the ECU will get the A/F ratio, spark advance etc right.
It's rare that a modern ECU of a NA engine is not able to compensate a full exhaust system.
You can have problem if the pre-cat O2 sensor position is very different, for example it happens when you fit a long tube header on a car which had short primary pipes and the original sensor plug very close to the engine. The delay of the reading of the sensor or the different wire lenght confuse the ECU. A good programmer can modify the target of the sensor or the delay of the reading.
This doesn't mean that a ECU remap can't improve the car, as there are also other characteristic of the management that are not subject to auto-adaptation, for example, throttle mapping, rev limiter, valve lift and timing if there is a variable system etc.
|