Quote:
Originally Posted by BoostedBMW
+1... we are talking about an exhaust that would most likely weigh less than 15lbs (dual mufflers for the 335) if it were made out of titanium. This car is a pig to begin with so to have to go through all of the trouble of making a custom CF exhaust (I have never heard of this to be honest) seems like it wouldn't be worth the trouble. BTW, what happens when a rock hits the undersite of your CF exhaust? I know that the CF diffuser on my s2000 took a whole month to crack. 
In any case, does anyone even produce a full Ti exhaust yet for this car? I can't remember if it was JIC or some other JDM brand that I think produced one. |
Quote:
Originally Posted by thegeneral101
i agree with you, the cost would not "outweigh" the benefits |
+1
carbon fiber is strong but brittle, hence the reason it cracks so easily. and the cost for sure would outweigh the benefit. think about it - suppose someone brings the weight of his 335i's cat-back exhaust from 70-lbs down to 20-lbs by going from the stock cat-back to a full titanium cat-back. it is expensive enough to go to titanium, but it would cost far more to do it with carbon fiber b/c 1) its never been done before (and so you'll have to spend quite a bit of $ on R&D, not just production), and 2) there's more labor involved in producing a full carbon fiber exhaust (assuming the general procedure you proposed is possible in the first place). so what's the point in further reducing the weight of your cat-back exhaust if it already only weighs 20-lbs?..especially if it can't be done for cheap?
while Al is lighter than Ti according to the periodic table, i never see aluminum exhaust systems. why? my guess is that it bends, creases, and pinches too easily - and so a minor bump or large rock might pinch off the exhaust to the point where flow is dangerously low. i don't think it has anything to do with temperatures since blocks are sometimes made of aluminum, and the highest temperatures occur inside the block. regardless, your answer for the lightest exhaust systems are going to be made of titanium.
BoostedBMW: i'm not aware if JIC offers any products for the 335i, but i can tell you that their quality is second to none. i replaced the stock exhaust on my Supra with a JIC Bullet full titanium cat-back exhaust, and while i don't recall how much the stock system weighed (probably in the neighborhood of 50+ lbs), the JIC only weighed 11-lbs. (that includes everything after the downpipe). the welds are flawless...in fact you can see them here (i took the pic a few weeks after the install):
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