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      03-23-2011, 10:55 PM   #27
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Drives: 2014 550i Space Gray/Black
Join Date: Mar 2011
Location: SW Florida

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Pointless to do delete secondary cats

Originally Posted by alpine92m3 View Post
hey thanks a lot ! one more question i'm having an exhaust shop do this mod .. do you think it will make any difference in sound or anything thing in that nature if i just replace the cats with straight pipe.. ? once again thanks!
You have to spend a little money for a tune if you want to see big power from this motor, along with deleting primary cats. Only reason for ONLY deleting secondary cats is boredom or tiny budget? It makes no hp...

This mod is actually quite pointless and does more harm than good in the long run, since the primary cats are the most restrictive, and you should retain your secondary cats to deal with the smell. The proper mod would be to delete the primary cats with TMS test pipes (cat delete kit ) and leave the secondary cats to take care of the smell that's common with deleting them. TMS test pipes are perfect, they slip over the stock exhaust and come with flanges and premium clamps to finish the job. You have 2 cuts and no welding. Then you get your tune from OETuning or ESS or AA, to take care of the CEL, you get 50-60hp. TMS sells them for $399. If you wanted to, you could retain the rest of the stock exhaust and it will be slightly louder than stock.

No problems with warranty and any company that I know of will always reflash your car for free in the event the dealer kills your tune.
2014 550i M-Sport
2010 E92 M3 6 speed