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Headers w/out a tune

wasserott

wasserott

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Anyone on the forum running headers without a tune. Kooks advertises green cats and no CEL.

Feedback welcome.
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Arpa

Arpa

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I'm doing the full Kooks header, offroad pipes, X-pipe and catback, but with a custom dyno tune. Highly recommended to ensure proper configuration. You don't want the car to run too rich or lean.
 
AlphaCoyote

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On Bama Performance's website they give this answer :

"Long tube headers constitute as a major change for the exhaust aspiration of your vehicle's engine.To compensate for the added air flow, and the relocation of the oxygen sensors, a new or updated tune is required."
 
Brostang

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Its correct that you dont want to run lean, but a header install will not directly cause a lean condition. The upstream (pre-cat) O2 sensors are the wideband sensors which measure lambda (a facotr of stoich combustion). Then actual AFR is calculated based on the specific stoich value for a given fuel.

Downstream (post-cat) O2s are for emissions readiness. They just say if the cats are working or not and do not affect injector duty cycle.

In conclusion, you wont run lean if you run catless headers with O2 spacers/restrictors. You just wont make as much power as you would with a tune optimized for the headers.
 
firestarter2

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Brostang said:
Its correct that you dont want to run lean, but a header install will not directly cause a lean condition. The upstream (pre-cat) O2 sensors are the wideband sensors which measure lambda (a facotr of stoich combustion). Then actual AFR is calculated based on the specific stoich value for a given fuel.

Downstream (post-cat) O2s are for emissions readiness. They just say if the cats are working or not and do not affect injector duty cycle.

In conclusion, you wont run lean if you run catless headers with O2 spacers/restrictors. You just wont make as much power as you would with a tune optimized for the headers.
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