Yes that is true about mapping. Ideally any modification to the breathing of the car and it needs a remap.

 

You don't need a remap for an exhaust system - it doesn't release enough back pressure to cause the car to run lean. It's not the same effect as a trubo car (even on a turbo the exhaust won't affect it much)

If you do the intake and manifold then you should get the AFR checked. it's more a combination thing.

 

An exhaust alone wont alter the AFR that much, well it will 'slightly' but nothing to be worried about.

When you add a combination of bolt on's, thats when the stock ECU map wont do as your operating outside its hardcoded parameters.

Its also worth noting, partial throttle and WOT. Dyno runs are done in WOT and this is where you will see if the AFR is out or not, during partial throttle the ECU can adjust/learn for bolt on's to a large extent.

 

I think your decat will have had quite a contribution as well.

Chris.

 

Spot On!!

In an ideal world, it would be done after every little mod, but its not an ideal world!

 

Decat / high flow cat makes THE most significant change in A/F ratio.
Toda manifold did not change things much
and J's racing single 60mm exhaust made the car run more rich in comparison to the stock one.
All these measured with Inovate Wideband sensor and gauge.

Edit: Also CAIs instantly lean the A/F ratio at their resonance point.

 

So, is it myth or fact that the MY00-01's run richer than the later models

 

I know for sure that MY03 ECU runs ritcher than MY04 and MY05, measured with the same method...