Quote:
Originally Posted by kianf22
This is interesting to hear. I'm in the same boat with warranty. Was thinking of going jb4 honestly. My understanding is that flash and piggy are both detectable but a flash is MORE detectable. i.e. they would have to do some more digging to find the jb4 whereas flash would be instantly detected. Is this true? I've been debating between keep it stock, piggy, and flash for some time now.
Also sorry to hear you couldn't live with the cold start. It is pretty loud with the non resonated midpipe but imo sounds rly good and I haven't gotten any complaints from my older neighbors and I live in the suburbs lol. I will admit there is sometimes some vibrating at certain rpms but It's not annoying enough for me to call it drone and the way it sounds all other times makes up for it.
Is it safe to turn off cold start on a catted downpipe? Isn't the cold start needed to warm the cat?
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That is my understanding regarding warranty as well, flash is easily (if not instantly) detectable even if you re-lock the DME. JB4 requires a bit more digging. My thinking is that anything worth worrying about replacing under warranty would be something BMW would do that extra digging for anyway, so the result would be the same.
Maybe your catted downpipe muffles the cold start just enough to make it livable which is good to know. I'm very happy with the sound and volume level any other time but the cold start, it's more than quiet enough when cruising and roars when you go WOT. I agree there is some drone when under light load like going up an incline on the highway but it's not enough to bother me (and I am picky).
I'm no expert by any means but my understanding is that the cold start heats the cat for emissions only as the cat is not effective until it reaches operating temp, so I can't see why turning it off would hurt anything.