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      12-05-2012, 05:50 AM   #3
GTHAUS's Avatar

Drives: F80 M3
Join Date: Jun 2011
Location: Chicago

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Originally Posted by Used2be View Post
Very impressive results, congratulations. I know you have no business interest in doing this, but perhaps a few of your potential customers would like to test your catless downpipes with the rest of the exhaust stock. Is this possible and do you think your stage one tune would work with the stock center pipes and rear mufflers? I'd be curious to see if removing the cats and adding a mild tune would bring more benefit than replacing the system from the cats back and no tune. Also interesting to judge the sound quality of the stock mufflers with the added flow from deleting the cats. Might be a whole new sounding beast!

Secondly, from your experience with BMW, do you think the engine warranty is pretty much gone with the deletion of the cats? And I suppose the same can be said with any tuning of the engine ECU? When any ECU tuning has proved itself reliable over time, I suppose many will not worry and proceed, but at first it is a concern for me at least.
1. TYR TECH (Stage 1) tune with Cat-delete software can work with stock/OE exhaust system + catless Down Pipe set up. However the Maximum (optimal) performance result and Agressive sound note (realized with Meisterschaft exhaust) will not be there.

2. Depending on your dealer.
Some don't really care, but some are very strict about it.
It is pretty common that ECU upgrade will not cause much of an issues with dealer vehicle warranties, but catless downpipe alone can
since it can trigger check engine light when you don't have a proper ECU tune.
Catless down pipes with proper (TYR TECH) ECU tune (so it doesn't trigger CEL) usually does not have any issues with dealers.