Air and Fuel› Superchargers, Turbochargers and Components

KRATOS

KRAS55Bi-EVO Turbocharger Upgrade System

$7,895.00

SKU: KRAS55Bi-1

Special Order
Special Order
Ships in 4–6 weeks
Free Shipping over $200
$100 Minimum Order
30 Days Return
INSTALL DIFFICULTY
DIY PRO SHOP

Advanced — 4+ hours

Overview

The KRATOS KRAS55Bi-EVO is a turbocharger upgrade system designed for BMW S55 engines. It features a one-piece turbo-fold crafted from investment-cast 316 stainless steel for reduced heat and increased efficiency. The system utilizes proprietary ceramic ball bearing technology for enhanced reliability and transient response, offering five times the service life of steel bearings.
Show original supplier description
The KRATOS KRAS55Bi-EVO is a high-performance turbocharger upgrade system engineered for BMW M3, M4, and M2 Competition models equipped with the S55 engine. At its core is a one-piece turbo-fold, a feat of engineering combining manifolds and turbine housings into a single investment-cast 316 stainless steel unit. This design contributes to a mathematically matched A/R ratio, reduced heat, increased turbine efficiency, and smoother internal transitions, all validated by Computational Fluid Dynamics modeling. A key innovation is the proprietary silicon nitride ceramic ball bearing technology. The bearing cartridges are built to withstand extreme abuse and are endurance race tested for reliability. The compressor wheels are sculpted from forged billet aluminum, featuring third-order geometry designs achieved through point milling. For even greater performance, an optional Ti6Al4V titanium compressor wheel is available, offering superior strength for more aggressive designs and suitability for road race or endurance applications. The KRAS55Bi is capable of supporting up to 850+ wheel horsepower on a stock engine with supporting modifications, and up to 900+ whp with a built engine and cylinder head. To complement the increased compressor diameter, the S55 system includes custom-designed four-ply silicone inlets with a match-ported, polished billet aluminum elbow. These inlets offer direct fitment to OEM crankcase ventilation and intakes.

Product descriptions are provided by our supplier partners and may not always be perfectly accurate. Not sure this fits? or call (760) 282-4645 and we’ll verify before you order.

Fitment

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Specifications

BrandKRATOS
Part NumberKRAS55Bi-1
CategoryAir and Fuel
5,000+ Trusted brands
1M+ Enthusiasts
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(760) 282-4645 hello@motormia.co

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Returns & Fitment

Built for enthusiasts. Every order is backed by our 30 day return window on eligible items. Unused and uninstalled products may be returned with approved RMA and no restocking fees when received in new condition. Orders placed through the MOTORMIA app with a complete build qualify for our Fitment Guarantee — free return shipping if the part doesn’t fit your exact setup. The guarantee covers fit only; installation must follow manufacturer instructions, and we recommend a qualified shop for parts marked Difficulty 4–5.

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Shipping

Orders are processed in 1–3 business days. In stock parts ship promptly from our partner network. Special-order items either aren’t currently stocked or are built to your spec — expect 4–6 weeks. If a part goes on backorder while your order is in the queue, we’ll reach out and work through discounted alternatives together.

Free shipping over $200 in the continental US. Alaska, Hawaii, U.S. territories (Puerto Rico, U.S. Virgin Islands, Guam, American Samoa, and the Northern Mariana Islands), and international orders carry surcharges — most appear at checkout. Some exceptions (LTL freight, or suppliers who quote freight only after we place the order) won’t. In those cases we’ll reach out with the exact charge before your order moves forward.

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