Quote:
Originally Posted by austinla335d
Smoke em if you got em. :thump:
TDIwyse did a muffler delete a while back, and I got into the idea until I realized the gaping hole that would be left. He went through this elaborate aerodynamic installation, but I'm not so sure that's worth it considering there's zero power to gain and basically zero noise to gain. It's just dropping the weight of the muffler and then adding an aero thing that could be a headache.
edit: rushed the comment b/c my conference call started!
Let me elaborate in an effort to summarize... if that makes sense.
The 4 benefits of an exhaust system- and why they don't matter on the 335d (assuming OEM emissions are maintained, of course)
Let's assume you've already come to the conclusion that an exhaust system is almost literally not available anyway, and a muffler-delete is the only thing worth the $$ consideration.
1) Performance- You'll gain zero to minimal hp/tq, even with a "cat-back" style exhaust, custom or otherwise.
2) Sound- You'll gain zero to minimal db/throaty-ness/tone b/c anything happening downstream of the emissions stuff is already 95% muted, so much so that BMW essentially used straight pipes inside each muffler's shell for appearance only. In effect, removing the muffler for straight-thru piping is the equivalent of stripping away the muffler shell and packing material wrapped around it, hence zero to min. sound and power gain... you're just exposing what is already hidden underneath.
3) Weight- You'll save around 30lbs, according to TDIWyse, which in itself is good. It's the only argument to do it, really. If adding Meth, say a 3-5 gallon sump trunk-mount tank of very high quality (as I have- a 3 gallon unit), it installs against the back seat, just over the rear axle, this sort of helps to balance out weight distribution if the muffler is removed, but it doesn't matter... its small potatoes. Also, the methanol tank has a much higher center of gravity, above the axle instead of much lower, behind it. It would almost be better to have a meth tank mounted at muffler height... oh wait... that's what the geniuses on this forum are doing when the kill the DEF tank!
4) Appearance- You can weld on new tips for the same effect, since the rest is hidden. Appx. 4" fits perfectly in the cutout provided by BMW. After seeing quality Cyba tips in 4", in matte silver color, I felt like it could have come that way OEM as part of the M-Sport. It REALLY impacts the way an M-Sport rear diffusor ties the exhaust to the car. The OEM tips look almost like small wheels in big wheel arches and since seeing it, I've been thinking WANT WANT WANT when I see my car's booty.
Probably more info than you need, but maybe good for others perusing.
By the way, I love that you're going all out on the car. I was going to go with an LSD, but I don't track the car and would rather enjoy other things like further refining the appearance, and lighter wheels (hopefully my next mod, via ARC 8 in 19", but maybe 18"). TMI. Back to you in the studio!
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1.) Basically agree with that. But will add that your hp/weight ratio will improve.
2.) Disagree with this. Don't have any quantifiable data to share as to why, but based on before/after sound, I "liked" what I heard better with the delete. And it's throatier/deeper sounding to my ears with the deletes I'm running than it was with the muffler in place. I've posted some video's demonstrating the sound.
3.) Agree with the ~30 lb weight saving comment. Disagree with some of the weight estimates thrown around in the following part as to what is added with the methanol tank/pump. It doesn't need to be anywhere near that much... And if you're running methanol the fluid/pump weight has to be added some where. Better in the rear of the car than the front from my experience...
Also, putting on a functional rear diffuser to cover the gaping hole actually produced quantifiable benefits.