I'm interested in seeing who and how someone will tackle upgrading the downpipes on the 335, I read that a BMW designer said that one of the problem points of a 335 with more power would be that the DP (downpipe) is more prone to overheating and cracking as a result of the greater heat.
From my experience with a turbo car, having a 3" DP is very beneficial, even if it feeds into a 2.5" system. I'd say the DP is a greater priority worrying who's is bigger.
I'd also be interested in seeing an upgraded TIP (turbo inlet pipe) and LIP (lower-intercooler pipe) from the pictures I saw it looks like the stock ones are pretty nice, doesn't seem like there are any "pancake pipes" like there was on the 1.8T. But it's always nice to get the most that you can out of what you have.
From the pix off the thread:
How the N54 works
You can see in this one, that the air traveling to the turboes from the intercooler encounters a hard turn which probably drastically affects the flow of air in the pipe. Now BMW probably did this because of the limit on available space under the hood of the 335. But I haven't seen pictures up close of the engine actually in the car to see how much room there actually is to play with... Theoretically if there was space for a slightly larger pipe with less of an aggressive bend, it would surely free up hidden ponies, allow faster spooling, and improve flow efficiency into the turbo (maybe allowing more boost to be run?).
Another view of the piping. Also when you look at how the pipe hooks up with the intercooler one would think that there could be a better way of doing it? Once again BMW is probably working against available space. But I'm just throwing it out there. You can see the pipe pointed out by #8 is somewhat pancaked...
Now in this picture you can see why the downpipe would have problems overheating... There is an aggressive bend right after the turbo, all that hot gas is slamming against that wall. On top of that it leads almost straight into the cat. converter... I really am no expert but would it be better to position the cats further down along the way?
In this picture I couldn't help but notice how similar the stock DV's on the N54 look just like the Bosch diverters found on 1.8T's (wooooo).
Forge Motorsport makes great upgrades that are widely used in the VW/Audi/Porsche community. Just thought someone should look into whether or not they have thought about applications for the N54.
Maybe someone will come out with a silicone hose kit for the turbo piping on the 335. That would be great. I believe Samco makes them for VW/Audi/Porsche.
Haha, I just realized that I haven't fully read that thread on how the N54 works, so I'm guessing that when I come back to my computer later and read it I'm going to have alot of my previously stated ponderings answered.
Just thought I'd kick of a downpipe/LIP/TIP/DV discussion because I haven't seen any good ones so far on here. I'll be doing research about this stuff in my free time.
Please feel free to correct me on anything stated above. I'm in no way a pro/expert on the matter, I just have some experience with turbo cars and thought I came up with some interesting points.