Quote:
Originally Posted by Jason@Nameless
We're going to see how the header behaves after a pile of dyno runs regarding thermal expansion and determine if the flex couplings are necessary. Our thought for the most part is that the flex couplings were added to the factory exhaust for manufacturability and insurance of fitment, but including flex couplings in our exhaust is completely do-able. At this point we just don't think it's a necessary component for a jig-fit and handbuilt system to fit properly. Additionally, if you look at the other headers in the Subaru market that do include the flex couplings (both in turbocharged and naturally aspirated configurations), they're almost always the first item that fails on those designs. Likewise, the factory flex coupling fails in the WRX & STi up-pipes and they are of a design which is radically different than the flexible couplings available on the market as they have a full internal hard sleeve inside of them. The closest analog that is available off the shelf is an externally braided, internally spiral-wound design which is similar to the ones that we use on our WRX & STi exhausts.
As far as catted vs. catless, we certainly have plans to develop a catless design as well, rest assured. We'll do it! :-D
I have not weighed the factory heat shields, but they are not included in that 15.0lb weight, that is just the weight of the manifold shown in the photo above.
J
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But what about all of the header designs on subaru's without flex joints, they always crack at the flanges.. Borla, gt spec, perrin, all of them seem to do it. The only exhaust manifolds I have not seen crack, are the ones with the flex joints.
Its honestly the only reason I never switched from the factory manifolds on my STi.