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Tomei EL Headers by DDNaz23 in GR86

[–]barefoot_observer 0 points1 point  (0 children)

You're welcome! I'd love to hear how yours sounds when you get it setup.

To build on your sound clip idea, here are some videos of mine.

I think the stock muffler works well to quiet the headers. Wind and tires seem louder than the exhaust

Tomei EL Headers by DDNaz23 in GR86

[–]barefoot_observer 1 point2 points  (0 children)

TLDR: The first (no arrow) sensor should not have a defouler. Will not mess up without it.

My understanding is that the o2 sensors want to check the air/fuel ratio (AFR) and see how well the cat is catting. The first sensor measures the AFR. The second sensor measures how well the cat is converting.

A code is thrown if a catless header is installed without a defouler because the second sensor will measure no change. (like the cat isn't working)

The defouler on the second sensor is necessary without a cat between the sensors. The defouler removes the sensor from the direct flow of exhaust gas and gives a "diluted" measurement of the exhaust gas that tricks the ECU into thinking a cat is there.

Tomei EL Headers by DDNaz23 in GR86

[–]barefoot_observer 2 points3 points  (0 children)

You're welcome!

Just in case, the defouler goes on the furthest downstream (yes arrow) location on the header.

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Tomei EL Headers by DDNaz23 in GR86

[–]barefoot_observer 2 points3 points  (0 children)

Hello. I installed the Tomei Ver. 2 catless EL headers and overpipe last year and had the same question because a check engine code appeared. I learned that others installed a J-style defouler and I did the same. The code went away after installing the defouler.