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      12-04-2018, 02:18 PM   #5
nothingman
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Drives: 2021 GT4
Join Date: May 2017
Location: Mason Dixon Line

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Steamspeed

STX67
Manufacturers Description:
The Steam STX 67 for BMW N55 is a direct replacement stock-location turbo for BMW owners with BMW's new TwinPower (twin scroll) 3.0 l inline 6 direct injection motors (BMW engine code N55). The N55 is motor is used extensively throughout the BMW lineup, but includes: M135i (E82/E88/F20), 335i (E90/E92/F30), etc.

The Steam STX 67 for BWM TwinPower N55 engines provides turnkey stock location replacement of the OEM turbo. This means your turbo will appear stock, and can utilize exhaust, intercoolers, and intakes designed for the stock turbo.

Made from all brand new components, so there are no core deposits, and you don't have to return your factory turbo. The turbo is brand new instead of a rebuilt used OEM turbo.

The STX 67 compressor wheel is 5-axis CNC milled billet aluminum and flows ~25-30% more than the stock turbo.

STX78R
Manufacturers Description:
The STX 78R is quite a bit larger than the STX 67, about +11mm on the exducer side. Based strictly on the comp wheel, this turbo should be able to make between 500-600 whp, but the OEM turbine housing should limit that to some degree. Initial dyno testing will show to what degree.

Base purely on inductive reasoning, this turbo should perform somewhat better than the currently popular Pure Stage 2 turbo: their turbo has wheels somewhat larger than a GTX3076R, our 78R is somewhat larger than a GTX3076R, they remachine the OEM housings, so do we, but the main difference is that our turbo has a BB center section, and Pure reuses the OEM JB CHRA. Given that the only main difference that impacts performance is that our has a BB CHRA, what does that impact?

BB CHRAs have some standard advantages over JB: it is more responsive especially with transient boost, it is more efficient, it is more durable, etc. In this case, the biggest difference, I think, will be the fact that BB CHRAs can be stay efficient in spite of backpressure much better that a JB CHRA. Normally JB is fine up to 2:1, but BB can still be efficient at much higher ratios. This matters a lot in this case, because the OEM manifold/turbine housing is going to generate a lot of backpressure when you try to make over 500 whp.

Specs:
Bearing System: custom ceramic BB
Custom Compressor wheel In:59 / Ex:78 (the size is between GTX3076 and GT3582)
Custom Turbine wheel In:60 / Ex:57 (The size slightly bigger than GT3076 - In:60 / Ex:55).
Flow capacity: 70 lbs/min (est.)
Estimated WHP: ~550+ whp

Source:
STX67: http://http://steamturbochargers.com...r-upgrade.html
STX78R: http://steamturbochargers.com/index....r-bmw-n55.html
Steamspeed Blog: https://blog.steamspeed.com/2018/03/...w-n55-install/
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Last edited by nothingman; 12-21-2018 at 09:56 AM..
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