Arc Eye

13 Sep Arc Eye

Photokeratitis, otherwise known as arc eye, is basically a sunburnt cornea that results from exposure to the intense UV rays coming off welding arcs.

Now, your humble blogger came with some pretty substandard optics from the factory, but his obsession with in-the-moment welding shots are undoubtedly causing some degree of additional wear-and-tear on the ol’ vision-balls. And then there’s the Nikon’s image sensor to take into account, as well. But, as the Buddha says, “life is suffering, so quit being such a namby-pamby,” or something similar. Either way, we’re once again putting ourselves and our equipment at risk today to bring you some of the best in-process fabrication pictures on the series of tubes known as the internet (which Microsoft Word INSISTS on capitalizing, even though it’s not 1996 anymore).

With the Y-pipes, tips and everything in-between all finished up, it’s time to focus our attention on the last pieces of pipe to fall into place — the arms that connect the Vibrant pass-through resonators to whatever system the rear section will be bolted to. As with almost every other pipe that gets welded in this shop, we’ve got the argon backpurging all set up as we put down the final welds in the arms.

As one may expect from reading this blog previously, when there’s welding take place, we’re grabbing pictures to show you lovely folks. The standard welds along the arms are much easier than the part that connects the arm to the Y-pipe; for the former, both pipes are exactly the same size, whereas there’s a bit of ovalesque-versus-circular matching up taking place with the latter. That’s why it’s important to go slowly and make sure everything’s being done right the first time. But for now, screw that, let’s look at some welds.

With the first arm completed, we moved over to the second. After all, it’d be a pretty terrible system if we didn’t finish it before installing it.

And with that, we’re finished — except we’re not. There’s still the matter of the mounts, which we’re finishing up as we speak. The install is taking place at the shop later this week, as well, so hopefully we’ll be around to snap a few shots during that, as well.

Moving over to the 540i M-Sport that’s receiving a single-sided FMU rear section, we’ve continued tacking together the pipes leading from the existing exhaust to the new resonators behind the bumper. It’s going through the final welding now, so that should be coming up in a blog post in the near future.

As we were getting the tips aligned on the back end of the 540i’s rear bumper, we realized that there’s just a bit too much real estate in that cutout for the two tips to look appropriate. Thoughts were shot back and forth between various members of the crew; upsizing the dual tips was an option, but even an extra half inch in diameter for both tips would put them dangerously close together, risking vibration and touching issues. The idea of a single pipe out back was tossed around, but the mockups left it looking a bit awkward. So we took a bit of an angle on the single pipe idea, and came up with the solution that looks the best to us, and makes good use of the bumper’s cutout — it’s going to be a turndown.

Now, the turndown itself is larger than the diameter of the old tips, and there’s only one of them, so the airflow through both pass-through resonators will need to be merged back into a single exit that has a neck-up at the end of it. This will keep the sound characteristics that we want (as the dual resonators play a major role in this) while affording us the aesthetics as well. Plus, with the turndown, you won’t be able to look into the exhaust and see the Y-pipe’s innards, creating a cleaner look as well. Benefits all around! Seeing as how the old tips were already welded onto the dual resonator setup, we put that aside for use in a future E39 M5 setup, and fashioned a whole new dual resonator setup sans tips. Since it’ll merge into two, then back into one, we’ve also got two Y-pipes to utilize, meaning we’ll be delivering even more welding content to you very soon, so stick around if you’re into that sort of thing, and we certainly hope you are.