[1Quick545]

I tried searching the F10 forums for this already and it looks to not be discussed. So maybe this is a dumb question / inquiry?

Back in the day we took our WRX turbos to get ported and polished to improve the flow. This was a couple hundred dollars to do at a local shop and had a pretty good impact for the money.

Why isn't this being done to the N55?

Just over here trying to plan for my future mods….

[Unspec]

Not much gain for the money.

[95blkmax]

Originally Posted by 1Quick545

I tried searching the F10 forums for this already and it looks to not be discussed. So maybe this is a dumb question / inquiry?

Back in the day we took our WRX turbos to get ported and polished to improve the flow. This was a couple hundred dollars to do at a local shop and had a pretty good impact for the money.

Why isn't this being done to the N55?

Just over here trying to plan for my future mods….

Unlike the WRX turbos that can be bolted off, the N55 turbo is one-piece with the manifold (a "turbofold" per say), and so it is much more difficult to get into lathes for this sort of milling. Certainly not impossible but just a lot less companies have the equipment to do it.

Having said that, if you have seen Pure turbos, be it their stage1 or stage 2... they are essentially what you are asking about- bored out stock units with matched impeller and turbine wheels to go with it (along with a full rebuild and balancing, of course).

[1Quick545]

Originally Posted by 95blkmax

Unlike the WRX turbos that can be bolted off, the N55 turbo is one-piece with the manifold (a "turbofold" per say), and so it is much more difficult to get into lathes for this sort of milling. Certainly not impossible but just a lot less companies have the equipment to do it.

Having said that, if you have seen Pure turbos, be it their stage1 or stage 2... they are essentially what you are asking about- bored out stock units with matched impeller and turbine wheels to go with it (along with a full rebuild and balancing, of course).

Originally Posted by 95blkmax

Unlike the WRX turbos that can be bolted off, the N55 turbo is one-piece with the manifold (a "turbofold" per say), and so it is much more difficult to get into lathes for this sort of milling. Certainly not impossible but just a lot less companies have the equipment to do it.

Having said that, if you have seen Pure turbos, be it their stage1 or stage 2... they are essentially what you are asking about- bored out stock units with matched impeller and turbine wheels to go with it (along with a full rebuild and balancing, of course).

That makes sense. I wonder why the engineers decided to build it this way. Has anyone attempted to build a custom manifold that a turbo can "bolt" on?

So essentially if I can find a shop that can port and polish the turbo/manifold it may make sense. Then also have the shop also upgrade the turbine. The trade off is pure can do it for $4k and it is proven.

[95blkmax]

Originally Posted by 1Quick545

That makes sense. I wonder why the engineers decided to build it this way. Has anyone attempted to build a custom manifold that a turbo can "bolt" on?

So essentially if I can find a shop that can port and polish the turbo/manifold it may make sense. Then also have the shop also upgrade the turbine. The trade off is pure can do it for $4k and it is proven.

There is that tradeoff, and also keep in mind that depending on your power goals, the turbofold itself becomes a choke point due to its narrow design. Works fine up to the low to mid 500s but above that it struggles. Thats why companies like Vargas Turbo Technologies or Big Boost run a proper cast manifold with smooth runners to the turbo. If you want reliable 500 or under, the PS2 is perfectly capable of that (with the supporting mods of course). If you're gunning for 600+ then you gotta look elsewhere.

Also, JPWorkz and a handful of others make custom tubular SS manifolds for N55s, but they are $$$. Some are bottom mount, some top mount. But this gives you the opportunity of picking your own turbo and bolting it on as you wish

[Unspec]

I believe showtime did a custom top mount turbo. Unsure what kind of power he eventually made though

[Surly73]

Just something I like to keep in mind whenever discussing any "potential power gains" of a particular mod. You didn't mention the starting point of the vehicle you're thinking of, but...

Considering that even on my PWG (less capable) N55 535, I can flash some software like MHD stage 1 and get immediate and substantial performance gains without changing anything else - whatever else we're talking about has limited impact on performance based on a factory starting point.

Swapping the stock exhaust? See above. Thinking a new air intake or K&N filter insert will help? See above. Port and polish the stock turbo? See above. How could the intake have been the limiting factor if I can get what might be a bump of 60+hp from a flash?

Now, if you're already at Stage 2+ software and you're actually reaching limits of other components or surpassing the ability to keep everything cool enough, then the other conversations can take over. In stock form, it's all software limited (in many cases with complete validity for the long term protection of various components).

[BimmerHausPerformance]

The manifold part of the turbofold itself is stamped steel and cannot be honed out, as was mentioned it is the Achilles heel of the n55…

[1Quick545]

Originally Posted by BrowBMW

The manifold part of the turbofold itself is stamped steel and cannot be honed out, as was mentioned it is the Achilles heel of the n55…

Originally Posted by BrowBMW

The manifold part of the turbofold itself is stamped steel and cannot be honed out, as was mentioned it is the Achilles heel of the n55…

Okay. Thanks! Just trying to game plan here…

Once I get back from the beach I am going to post a better response to everybody with my thoughts.. not that my thoughts matter but someone in the future might be thinking the same as I am and might save them some time.