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Yah still waiting for the exhaust system to come but I'm thinking 馃挱 of cutting out the cat's and installing a pip from the header to the cat back exhaust
 

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On my dash I've got the two buttons for defrost and ac

On my dash I've got the two buttons for defrost and ac the ac will not turn off and the defrost will not turn on well thay will but I've got to tap the button's and hold em watt is up with that can anyone relate or explain what I need to do to fix it
 

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I wouldnt cut the cats out unless you are genna retune for it. As for the buttons just try swaping them out. It seams they are messed up (and only them) but Iam guessing.
 

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For max gains, cut the 2nd cat. Before the cat the piping is about 2 1/8" after the cat it drops down to 1 7/8" . I cut my secondary cat and went 2 14" from there back. So in essence its 2 1/4 from header back now. Best way to do it.
 

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No need to retune for such a small change (besides, there is no real running available at a reasonable cost) yes UpRev is available, but for 6-800 dollars for a retune and very little gain, not worth it if you ask me.
 

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Honest question. Does cutting the cat out make a difference? I have been told that the ecu doesnt really know what happened so it makes almost no difference other than sounds and maby a 1-3 hp gain.
 

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You said it, HP and TQ gain. It's not crazy power on the versa, but when you have 109HP every 2-3 does help and makes the car more enjoyable to drive. The removal does add noise, but that can be fixed by adding a resonator such as magna flow, vibrant or any good brand straight thru one with out affecting the gains.
 

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The OEM software is set in open loop for WFO throttle with the exhaust the way it comes from the factory. If you mod that and the exhaust does flow better to create more power you are then likely too lean as the fuel map was set for the amount of flow the car had before and not after. While the engine likely won't destroy quickly it CAN wear out faster if you stay in the throttle a lot. You may not be able to tell the lacking fuel at all but the engine can.

The injectors only reset for variable fuel a/f in closed loop not open, the latter fuel map is set in stone and does not change for mods. ECM picks up on it instantly, the O2 sensor reports leaner than before, but ONLY in open loop and why the unlearned think nothing has changed. The closed loop map likely has enough fuel to cover the slight difference, the injectors then readjust and driver goes on thinking things are fine.

Why they say to tune the software.

Some cars may not even run as well as they did before with cat gone, some about the same. Others depending on different design issues can really run better catless, and those are the ones that will give the most trouble if the software is not updated to reflect the missing cat. Some few can burn pistons pretty quick or shell them out from detonation due to missing fuel.

So beware.
 
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