Custom exhaust ideas

[m3f_hardtosee]

I have a set of long tube Raceland headers that are currently installed with a Remus catback system. I love the sound, and while the dual exhaust tips are on the large side, I've come to like it. However, it's aging.



Now, while the car is dissassembled, I have access to an expert exhaust shop, and am considering the custom exhaust route.



Thoughts:



Racelands --> euro midpipe (if I can find it, or fabrication specs) --> x-pipe --> cats --> catback system



Is 2.25" piping sufficient for an OEM+ car? No engine tuning, maybe turner stage 2 down the road but not right now.



What are people's thoughts on the cats, is it better to go with dual cats or two Y pipes into a single?



I'm also considering getting the racelands coated by Swain Tech with their "white lightning" ceramic coating.. not pretty, but good for heat dissipation in the engine bay.



I'm open to options, suggest or flame away!

[m3f_NolliM3]

Three words...just do it. When you have completed your plan, get the car on the dyno and report back.

[m3f_tofunin]

You can just go the Supersprint euro exhaust route ~$1300. Milltek makes an exhaust for the euro M3. Or make a custom exhaust 2.25" is US spec 2.375/60mm is euro pipe diameter I went 2.5" but I am running the euro S50B32.

[m3f_matty.]

Three words...just do it. When you have completed your plan, get the car on the dyno and report back.

Agree with this, sort of.



1) I would not go bigger than the euro m3 piping. Really no need at all to do that, unless FI of course. Best option is the euro mid itself which will mate up nicely with the 60mm long tubes.



2) Find a good exhaust shop. It will cost you more but will be 100% worth it. Otherwise, all the power adders can be canceled out by shoddy workmanship and crappy pipe bending, etc.



3) Regarding cats, nothing beats OE. Even with climbing miles and age, I have always been able to pass, and have experience with people taking out new aftermarket cats failing then replacing with 'used' OE cats and passing.



4) Swaintech on the long tubes is actually a really good idea.



5) Long tubes really transformed the car for me. Everyone talks about them being a top end power mod. I experienced the opposite. I had a nasty torque dip in the 3800 rpm range with the stock tubular mani's that was cured with the long tubes meaning more torque coming on sooner and stronger. In that dip I picked up nearly 15 ft-lbs and 15 whp. At peak I picked up around 7 ft-lbs and whp. I really wanted to isolate the delta with this mod so EVERYTHING else was unchanged, including the dyno facility, and ambient conditions. People talk a lot of unfounded info about this mod but for me it was hands down one of the most effective mods on the s52.



Definitely do before/ after dynos and let us know how it goes.