[BMWrush17]

Has anyone tried the AR catless downpipe with resonator?

http://www.ardesign.info/store/select-your-vehicle/bmw/e9x-335i-335xi/exhaust/ar-design-135i-335i-335xi-hi-flotm-catless-downpipe-w-resonator-n55-2011.html

[abhishriv]

thinking about taking out the 2nd cats but do the resonators make the setup less loud? i have ar dp with bmw performance exhaust right now.

[nitehawk]

Originally Posted by abhishriv

thinking about taking out the 2nd cats but do the resonators make the setup less loud? i have ar dp with bmw performance exhaust right now.

That will make it even louder and it will drone some, but will kill the rasp.

[sebasupreme]

Originally Posted by tscdennab

So I removed my secondary cats a few weeks ago (I already had the primaries removed) and Oh My God...the exhaust became loud as hell and it had a mad rasp, you cannot imagine how bad it sounded. Between 1800 and 2000RPM, in neutral or under load, it sounded like a lot of metal parts were grinding very loudly against each other. Basically like running open headers. Drone was not existent though thanks to the BMW Performance Exhaust.

First I replaced my OEM catless downpipes (cats replaced with pipe) with Macht Schnell 3" coated downpipes. I couldn't feel any improvement in performance or in sound, although maybe the rasp moved a couple hundred RPMs lower in the rev range. The downpipes fitted absolutely perfectly and the ceramic coating looks extremely good. The welds are also perfectly done, I am very happy with them. For $610 coated (I got a deal but it's not hard to get such a deal from MS), I think these downpipes have the highest quality/price ratio. I highly recommend them.

But what about the rasp ? I immediately ordered a pair of Vibrant 1792 resonators, and I welded them where the secondary cats used to be. I honestly didn't expect a big improvement because they are quite short (12") and straight-through inside and they couldn't possibly improve such a bad rasp and such a loud sound. Wrong ! The rasp is 100% gone and the exhaust is much quieter, identical or less loud than when I had all the cats installed ! It's absolutely incredible how a pair of $45 straight-through resonators have such an enormous effect on the exhaust note and loudness.

Conclusion: I am extremely happy with my setup. The BMW Performance Exhaust + Macht Schnell catless downpipes + Vibrant 1792 resonators produces deep, drone-free, rasp-free and not too loud sound while maintaining the performance of a fully catless setup.

Below you can find some pictures and a video of the sound.

Sorry to bring up an old thread, but how would this work with an N55?

From what I've read my understanding is that the N55's don't have secondary cats so how would I get rid of the rasp?
Remove primary cats and install Resonators?