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      10-02-2021, 05:19 PM   #1
Slim415
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Will removing secondary cats cause the car to smoke?

I have catless DP's and bought Vibrant resonators to clean up to the sound. But I was curious if removing the secondary cats to put the resonators would cause smoking or exhaust fumes from my car. I live in SF California and last thing I need is a cop pulling me over and sending me straight to inspection.
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      10-03-2021, 02:33 AM   #2
whyzee125
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It won't smoke unless you're burning oil but you will definitely notice the smell.
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      10-03-2021, 12:01 PM   #3
Slim415
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Quote:
Originally Posted by whyzee125 View Post
It won't smoke unless you're burning oil but you will definitely notice the smell.
Even more then now with catless downpipes?
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      10-03-2021, 10:49 PM   #4
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Yes. The secondaries still do a lot to keep the smell at bay. My n54 with catless downpipes is not particularly noticeable whereas my old n55 with no cats smelled like a go kart track
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      10-04-2021, 06:49 AM   #5
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I get no smell and I am fully catless but I run full E85.
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      10-04-2021, 11:03 AM   #6
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Quote:
Originally Posted by NoGuru View Post
I get no smell and I am fully catless but I run full E85.
I really want to go the E85 route as well. But I'm not sure I would always be able to get it. Question- can your fuel system adjust to pump gas if you can't get E85? Would you also have to change tunes at the gas station?
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      10-04-2021, 11:58 AM   #7
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Quote:
Originally Posted by Slim415 View Post
I really want to go the E85 route as well. But I'm not sure I would always be able to get it. Question- can your fuel system adjust to pump gas if you can't get E85? Would you also have to change tunes at the gas station?
I have a custom tune designed to run on E80 but that can change by about 30% each direction and still run decent. To drop to say E30 I would have to flash a new tune and scaled down my Port Injection but its not a big deal.

You can do a flex tune that can very from say E10 to E60.
If you can get it and your fuel system can handle it, I highly recommend running at least an E30 tune. More power and less timing corrections means the motor is running more efficient.
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