[BoogeyMan'sBMW]

Originally Posted by jlE90

Unless you have a muffler delete or aftermarket muffler theres gonna be no sound. Im currently running secondary cat delete and resonator delete and it sounds stock. Performance wise, no difference

Originally Posted by redlinedbimmer

Well I have a eurocharged tune now, but I would get it retuned by them after getting the cat delete. I don't want to delete my muffler, which from reading sounds like I might get more overall gains if I deleted the cat but left the muffler on because I wouldn't lose the back pressure right? I'm not trying to make it super loud, just want more power, but I wouldn't mind a little sound. I just don't want it to smell like an uncatted car, I didn't think it would considering we have the primary cats still in the headers. Also curious how just deleting the cats would change the overall sound, leaving the rest of the exhaust stock, everyone else seems to delete the cats and resonator or muffler.

so you e90 guys who cut ur secondary cats out had no problems in terms of SES lights and inspection, correct? Every time i find what I think is the answer, someone tells me otherwise.

[R.G.]

I cut my secondaries out and ran high flows before I went stage 2 catless dps.
I was getting hidden exhaust codes but no SES

[Rival]

Originally Posted by BoogeyMan'sBMW

so you e90 guys who cut ur secondary cats out had no problems in terms of SES lights and inspection, correct? Every time i find what I think is the answer, someone tells me otherwise.

yes the 2nd cats are past 02's, they wont throw codes or turn on a light for service.

tons of n52 guys have dropped them.

[BoogeyMan'sBMW]

Originally Posted by Rival

yes the 2nd cats are past 02's, they wont throw codes or turn on a light for service.

tons of n52 guys have dropped them.

thanks for confirming!

[ZSP.3R]

Had my car up on the lift awhile back and decided to remove the secondary cats into the stock muffler.

No gains, maybe little at higher end of the torque band.
Slightly louder stock rumble..
However, louder "slighty louder stock rumble" under load.. (4 people in the car - extra added weight)

I'm also running an AFE intake, which sounds much louder.

No issues.

[STR8-6IX]

i have an f10 528i, 2011 model with N52 engine.. the stock piping is quite good for our cars so I decided to delete the secondary cats. i was very pleased with the results, the engine growls and makes a delicious inline 6 engine note from underneath the car, although the exhaust sound did not get much louder. anyway, 4000rpm+ pulls very strong all the way to redline, im feeling at least a 5hp gain from deleting them. one thing to keep in mind is that you should not go full throttle for the first 150km to let your ecu fully adjust. after 150km, you should subject your car to as many different driving scenarios as you can. (highway, city, full throttle, etc.)
tl'dr, do it. sounds great. good gains for a reasonable price.