Non M exhaust 3rd times a charm

[Steeler]

Well after 2 failed attempts to get the sound I wanted, I broke the bank and went all out with a Magnaflow dual cat s-pipe, Supersprint Y-pipe and Supersprint "race" muffler(now listed as a sport muffler)
The bimmerbrakes header has been on for a while now and the motor is supercharged.
The sound in person is bassy and almost V8 sounding.
I was so stoked when I started the motor for the fist time I had to put on video.
I will give a full review of how it sounds and feels in terms of drone rasp etc. once I get the car on the street for the season.
In the meantime here's a short clip in the garage.

[inTgr8r]

I know the feeling about going through various systems.

Glad that you found exhaust nirvana.

[E86Z]

Sounds good, get us a rolling clip!

[Steeler]

Originally Posted by inTgr8r

I know the feeling about going through various systems.

Glad that you found exhaust nirvana.

Thanks Ian.

Originally Posted by E86Z

Sounds good, get us a rolling clip!

Will do, still sorting some minor issues before first drive of the season.

[pokeybritches]

Sounds good Dave! I need to film mine too, now that I have the cats in. I'm sure it's similar.

What are the specs of the cats again? Cell count / dimensions?

The Schmiedmann cats I bought are 300 cell and larger than I expected. They wouldn't fit without modifying the spacing of the pipes. I had the s-pipe and y-pipe welded into a single piece to get rid of the exhaust clamps and possibility of leaks. I will take pictures next time I get it up on the rack.

So far I've had four different s-pipe setups, combined with catless SS headers, y-pipe, and race muffler:

1. OEM pipes / resonator - moderate volume, lots of crackles/pops and occasional flames when abruptly letting off the throttle.

2. OEM pipes / resonator / tiny Magnaflow 400 cell cats mounted just after the headers - almost no change with the cats. Still sounded catless, but reduced exhaust fumes.

3. Supersprint s-pipe (no cats or resonators) - huge volume increase. The car sounded as loud as my ESS Z4M (the M has SS race mufflers, catless headers, and tiny 100 cell DKF cats). Everyone tried to race me when I drove the car, I guess because they assumed I was flooring it everywhere, until I actually got on the throttle and it got twice as loud. The car was obnoxious, and fumes were ever present. It sounded good with surprisingly little rasp, but was way too loud. Sound echoed off concrete barriers, overpasses, tractor trailers... pretty much anything. The SS pipes were larger than OEM, and the SS y-pipe originally had inserts to mate to OEM. These had to be removed by an exhaust shop to mate to the SS s-pipe.

4. SS s-pipe / Schmiedmann cats mounted far back near the y-pipe - volume calmed down significantly, but the car is still loud. Crackles/pops are maybe 20% of what they were, so the car no longer sounds catless. Volume is similar to a Z4M with catless headers, OEM U.S. s-pipe cats, and a sport muffler... or OEM U.S. headers with a race muffler. IMHO, this is perfect for daily driving. I can tell the cats take a little longer to heat up, because there are more crackles and pops when I first start driving. If mounted closer to the headers, I expect they would pass emissions with no CEL. My setup will utilize O2 sensors mounted in the headers with a separate fix. Fumes are almost non-existent.

The sound is throaty and powerful, but not obnoxious. There is "drone", in that you hear the engine while you're driving down the highway, but the car is silent with light throttle. The sound is bassy, and some of the midrange and high notes are muffled with the addition of the cats. The sound is right for the car. Some enthusiasts may like the echo and howl of the catless system, but I hated tip-toeing around the neighborhood in the morning when leaving for work. Other drivers no longer think I'm challenging them every time I downshift. The sound balances well with the rush of boost from the supercharger.

It took a total of 6 different setups before I got the one I wanted, counting the original OEM setup. For those curious, MSRP as follows (plus shipping, but you should be able to find the parts cheaper if you shop around):

1. SS headers, P/N 022 787 401 - $1735
2. Jet Hot ceramic coating - $300
3. SS s-pipe, P/N 788 112 - $370
4. Schmiedmann cats - $297 shipped
5. Cat install - $350
6. SS y-pipe, P/N 022 788 113 - $377
7. SS race muffler, P/N 022 044 125 - $979

Total - $4408

If you don't care about emissions/CEL, or have a tune, you can get 90% of the sound for a lot less:

1. Bimmerbrakes headers (used) - $300
2. Buy my OEM/Magnaflow catted s-pipe - $150
3. SS y-pipe - $377
4. SS race muffler (PM me for vendor) - $673

Total - $1500... for 15-20 hp NA, or 20-35 hp FI... and some glorious sound!

[Steeler]

Not sure on the make up of the cats Josh.
It is a Magnaflow s-pipe and cats sold as 1 unit.
Did not really care what the cell count or materials were after the previous failed attempts, just wanted a completed system that would pass emissions. MF says it is C.A.R.B approved on their website. It is not an exact fit for the 3.0i M54 but some simple fab made it an OEM looking system.
Your suggestion of the SS Y-pipe and can worked out nicely and as you say gives the car the "right" sound.
I have added j-pipes to screw my post cat sensors into but do not know the results yet as far as emissions readiness goes.
Still a bit of trial and error methinks before it is 100% emissions proofed but the sound is there finally.

[SaltyNC]

Sounds awesome.

[deemo319]

That sounds really good. I am currently trying to figure out the sound profile I want for my car.

My first attempt actually made it worse than stock, so still lots of work to do.

[pokeybritches]

Originally Posted by dbarton62

Not sure on the make up of the cats Josh.
It is a Magnaflow s-pipe and cats sold as 1 unit.
Did not really care what the cell count or materials were after the previous failed attempts, just wanted a completed system that would pass emissions. MF says it is C.A.R.B approved on their website. It is not an exact fit for the 3.0i M54 but some simple fab made it an OEM looking system.
Your suggestion of the SS Y-pipe and can worked out nicely and as you say gives the car the "right" sound.
I have added j-pipes to screw my post cat sensors into but do not know the results yet as far as emissions readiness goes.
Still a bit of trial and error methinks before it is 100% emissions proofed but the sound is there finally.

Very nice! Worst case, there's still the O2 sensor mod via catsim, but I would think any CARB approved mod would be emissions legal.

Supersprint did a great job with their setup for our non-M's. I think it sounds a lot like modified Supras, minus the turbo, but with more rumble and bass. I'd agree that although the car is undeniably a straight 6, there are definitely hints of a V8 with the rumble. Even when I had no resonators or cats, and only straight pipes into a muffler, the car never sounded farty or raspy.

[Steeler]

Originally Posted by pokeybritches

Very nice! Worst case, there's still the O2 sensor mod via catsim.

Josh, how did the a r e a 74 sim work out.

[dc_wright]

Did the muffler delete on my 3.0si. Sound pretty good! Not too loud, no drone. Has a nice rumble to it under load and not much more interior noise level cruising on the highway. $250 at the exhaust shop plus $60 for the BMW band clamps.
Could have done it a bit cheaper but I wanted a set up where I could install the OEM muffler with relative ease if I so choose.

[wdb]

Originally Posted by dc_wright

Did the muffler delete on my 3.0si. Sound pretty good! Not too loud, no drone. Has a nice rumble to it under load and not much more interior noise level cruising on the highway. $250 at the exhaust shop plus $60 for the BMW band clamps.
Could have done it a bit cheaper but I wanted a set up where I could install the OEM muffler with relative ease if I so choose.

This is a very appealing option! I may have to give it a go on the zed.

[dc_wright]

Originally Posted by wdb

This is a very appealing option! I may have to give it a go on the zed.

It's definitely a way to go with a 3.0si. I've done several road trips and when cruising you can't tell the sound level from stock and I haven't experienced any drone issues. I've done a couple autocross events with the one this past weekend at a sound level monitored site with no complaints.

[inTgr8r]

dc_wright do you happen to recall dimensions of the band clamps?

[dc_wright]

Originally Posted by inTgr8r

dc_wright do you happen to recall dimensions of the band clamps?

Yep! They're BMW part number 18307560777 and they're 50mm. One little surprise was the tubing between the resonator box and the muffler was smaller diameter (approx. 45mm/1.75") than the tubing between the secondary CATs and the resonator box. The muffler shop was able to roll the end of some 2" tube down to match and weld it onto the tubes coming from forward to adapt it to the band clamps and the 2" tube used to straight pipe where the muffler was.