Disclaimer/disclosure:
I received this part for free, I believe because I helped it come into existence. That said, I have been a happy SuperSprint customer for years, on multiple cars. On my M3 coupe, I paid for my SuperSprint headers (V1 stepped), Section 1 (catted), previous section 2 (resonated), and muffler (street with race tips). I would have paid for this part, had they not offered it to me.
Onward…
Around 1-2 years ago, it became apparent to me that the section 2 becomes a restriction point on more heavily modified s54s. It was Nick’s car that first triggered my radar, follow by Hassan’s car, then reading up on some
exhaust theory. E.g. this:
SuperSprint’s original section 2 was developed in a time before people knew how to tune the S54. For the first ~10 years of the e46 M3’s existence, getting more than ~310 SAE rwhp out of a streetable/stock ecu/vanosed S54 was pretty unheard of. SuperSprint, reasonably, designed a section 2 that was optimized for that level of power, that matched the pipe diameter of most (non V1 stepped) headers. If you're doing a more mild build, this part still makes sense (and is probably superior to the new option).
In more recent history, s54 power modding has become much more effective. This has largely been the result of the ecu finally being understood (allowing real tuning), MAP based engine management making CSL airboxes more effective/viable, and attainable data logging solutions.
Combine a CSL style airbox, cams, SuperSprint V1 headers/section 1, and you have a setup that is flowing significantly more than stock.
Note: the SuperSprint V1 stepped headers and SuperSprint V1 section 1s use 2.5” tubing. This is not true of most other headers on the market, including eBay, OE Euro, and SSV2 headers. To take full advantage of this section 2, you need headers/section 1 that use 2.5” tubing.
Low end/mid range torque on the S54 can be completely gutted if the crossover/merge is not in the correct (RE: stock) location. That was something I was not willing to do. I also wanted a resonator in my setup, because I don’t like any significant level of rasp from my car.
So, I started to look around the market for a section 2 that met my criteria:
-2 x 2.5”
-Stock merge/crossover location
-Resonated
-Well made
… and it didn’t exist. Everyone running something along those lines was running a “custom” setup. So, I started pushing my desired setup both directly to my contacts at SuperSprint and to Turner/ECS (who is SuperSprint’s US importer). Unbeknownst to me at the time, Leighton was doing the same thing at the same time, though through his GB contact.
In April this year, SuperSprint posted this:
http://www.m3forum.net/m3forum/showthread.php?t=597650
And ~2 weeks ago, mine arrived
Clearly the shippers didn’t treat the box very well:
But Supersprint’s packaging was sufficient that it remained 100% undamaged:
Welds and build quality in general look excellent! As has been the case with all my previous SuperSprint products, as well.
I delayed installing it immediately because I had a track event, and at some point, with enough repetitions, I had it banged into my head that you should never install a new part before a track event. I needn't have worried-- I finally got around to installing it, and it went on perfectly and painlessly:
Side note: I am a big proponent of using different hardware than either BMW's stock mid pipe hardware or SuperSprint's hardware. The OE BMW exhaust bolts that attach the stock headers to the stock section 1 are inconel. This does mean that they're a bit pricey, but it also means they're FAR more corrosion resistant than any normal hardware. Normal exhaust hardware gets rusty quite quickly, which makes removal down the road for other projects a huge PITA, often snapping the bolts and requiring replacement. These are pricey up front, but rarely/never need to be replaced after that. They are a larger diameter, which means you have to slightly expand the exhaust gasket bolt holes, but the larger diameter also guarantees exact alignment between the exhaust sections, optimizing flow. I use these on the section 1 to section 2 joint and the section 2 to muffler joint:
bolt: 11621318568 nut: 18301317898. 6 of each required for section 1 to section 2, 4 of each required for section 2 to muffler. If you kept them when doing V1 headers, you already have 4. Nuts are one time use, so replace every time they're removed.
Results:
I've only had these on the car briefly, so the car has not been dynoed yet. I'll update this thread when it is. In the short term, take with as many grains as salt as are necessary. If that's what you're looking for, check out Paule claude's results-- much more obective data/dyno than I can provide, yet (though he can't take full benefit as his car is RHD and therefore can't run the V1 stepped headers).
But: the car feels significantly, noticeably FASTER. I would not be at all surprised if I have gained 20rwhp. I will be surprised if I gained less than 10rwhp. Low end/mid range power is completely uncompromised-- in fact, mid range power feels notably stronger.
Sound wise, the car is pretty unchanged vs the previous setup. It may be
slightly quieter than the SuperSprint single pipe section 2 I ran before, but if so it's only just so. Tone is completely unchanged. I'll update this with a video ASAP (maybe tonight).
Conclusion:
If you're doing a full S54 build, which pretty much always includes SuperSprint V1 headers/section 1, these are a no brainer option, IMO. They don't cost more than previous options, and they continue the 2.5" exhaust flow from the SuperSprint V1 Section 1.
If you're doing a more standard build, it probably makes sense to stick to a more traditional section 2.