Quote:
Originally Posted by Carbinebbq
Confused now. Many previous posts say it won't run right, and now you are saying it will run fine. Not trying to argue in any way, just needing clarification. Are you taking into consideration his car is AT?
I am asking because I am interested in catted headers, and I won't have a tune. Not looking for any magical gains because I will get a tune in the future. Just want to know if the car will run normal. Kinda in it for the rumble sound first, performance later. Not trying to be a pain in the ass asking what has been asked before. Just trying to be informed.
2017 WRB BRZ
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If you change the header even for a catted one their is still a possibility that you will throw a cel code P0420
Will I get a CEL code
If you go to catless header you will get a CEL code P0420 (cat efficiency) it may thak a while to show up though.
Even some catted headers will still cause a cel code
You can try O2 spacers or de-foulers but they will not always work 100%
The only 100% way is to disable the code in the ECU usually done in aftermarket tunes.
The Cel code P0420 will stop the cruise control on your car from working, it wont go into limp home or low power mode.
Can be reset by removing battery connection or using obd tool to reset. It going to keep coming back until you disable it though.
Why you get CEL Code when changing header
Integrated in header is a primary catalytic converter. Their is the primary 02 sensor before this cat and a secondary 02 sensor after it. The ECU compares the reading from both and works out if the primary cat (in header) is working efficiently. If it detects abnormal readings it will set CEL Code P0420.
a tune for headers will disable Cel code code P0420 as well as optomising parameters for a header.
Changing any other exhaust components other than the header will not trigger a CEL code. Its only the primary cat in the header that is monitored by ECU, secondary cat in front pipe is not monitored.
Ok CEL codes covered.
If the header is fitted correctly ie no leaks and o2 not damaged etc then the car should still run fine. (never put a 02 spacer on Front 02 sensor as you will get problems, always on rear 02 sensor) no spacer need if you have tune.
The spacer doesn't effect AFR it just tries to fool ECU that their is still a cat in system.
Changing header wont affect AFR.
If it flows more then the MAF sensor which meters air entering engine will detect this and correct AFR. The afr with or without an aftermarket header will be same
A tune will optimise cam timing to suit header and adjust AFR and ignition timing for better power and torque.
Intakes are the part that can effect AFR as they can throw off the MAF sensor calibration/scaling and this will effect AFR.