BorgWarner / KKK / Schwitzer Turbocharger Rebuild

BorgWarner
Turbo
Rebuild

Complete in-house rebuild service for the full BorgWarner turbocharger family. KKK K-series for European automotive. Schwitzer S-series for diesel performance. EFR ball bearing for racing. K03 through K31, S300 through S480, EFR6258 through EFR9180. In-house VSR balancing since 2008.

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KKK K03 to K31 European OEM
S-Series S300 to S480 Diesel
EFR Ball Bearing Racing
KKK / 3K
K03 K04 K06 K14 K16
KKK Large
K24 K26 K27 K28 K31
VNT / Variable
KP31 KP35 KP39 BV39
Schwitzer
S300 S400 SX SX-E SX3
EFR
EFR6258 to EFR9180
In Shop Since
2008 17+ years
KKK / 3K
Kühnle, Kopp & Kausch — Founded 1952
German turbocharger manufacturer founded as a Schwitzer operation in Frankenthal, Germany. Known today as KKK, KK&K, 3K, or Triple-K. Makes the K-series turbos (K03, K04, K14, K16, K24, K26, K27, K31) that appear as OEM equipment on virtually every European performance and diesel vehicle. Acquired by BorgWarner in the 1990s. Models carry the K prefix and 8-digit part numbers beginning in 53.
Schwitzer
S-Series — Founded Indianapolis, 1918
Despite the German-sounding name, Schwitzer was an American company founded by Louis Schwitzer -- the first winner of any race held at the Indianapolis Motor Speedway. Schwitzer pioneered heavy-duty and performance turbocharging and is the origin of the S-series models (S100 through S500) that dominate diesel performance builds. The S300 and S400 AirWerks line is the most widely used performance diesel turbo family in North America. Acquired by BorgWarner alongside KKK.
EFR
Engineered For Racing — BorgWarner Performance
The EFR (Engineered For Racing) line is BorgWarner's dedicated motorsport turbocharger series. Developed by a skunkworks team within BorgWarner's Advanced Aftermarket Product group, every EFR unit features a Gamma-Ti (titanium aluminide) turbine wheel, dual ceramic ball bearing assembly with metal cage, integrated compressor recirculation valve, boost control solenoid, and forged milled compressor wheel. Ranges from EFR6258 at 225-450 HP to EFR9180 at 800-1100 HP. The Gamma-Ti wheel is the EFR's greatest strength and its primary vulnerability -- it is brittle when cold and must be warmed up before any boost demand. The first two EFR development vehicles were a Porsche 911 and a Mazda Miata.
BorgWarner Part Number
Decoded

BorgWarner uses an 8-digit part number format across the KKK lineup that tells you exactly what frame, whether it is a complete turbo or just the CHRA, and which specific variant. Understanding this prevents ordering the wrong unit when a nameplate number is partially obscured or only partial numbers are available.

5303-970-0029
5303Turbo frame identifier. 5303 = K03 frame. The first four digits identify the turbo family (5304 = K04, 5314 = K14, 5326 = K26, 5327 = K27, etc.).
970Component type. 970 = complete turbocharger assembly. 988 = CHRA / center section only. Other codes indicate specific subassemblies.
0029Variant number. Identifies the specific compressor wheel, turbine wheel, and housing configuration within the frame family. Different variants are not interchangeable.

Frame Identifier Reference

PrefixFrameTypical Application
5303K03VW / Audi 1.8T gas small frame OEM
5304K04VW / Audi 1.8T upgrade / performance OEM
5306K06Small European gas/diesel OEM
5314K14VW Polo / small diesel OEM
5316K16European diesel OEM
5324K24Porsche 944 / performance / marine
5326K26Porsche 911 / marine / industrial
5327K27Commercial diesel / Cummins / Deutz
5328K28Performance / diesel
5431KP31VNT small diesel (Golf / Polo TDI)
5435KP35VNT medium diesel
5439KP39 / BV39VNT Mercedes Sprinter / VW TDI
5329K29Commercial diesel / Caterpillar
5331K31Detroit 12.7L S60 / heavy commercial

S-series (Schwitzer) and EFR turbos use a different numbering system. S-series use 5-6 digit part numbers (177281, etc.) and EFR use 6-digit part numbers (179150, etc.).

Series Coverage

Three Families,
One Shop

BorgWarner turbos span three distinct product families with different internals, applications, and rebuild requirements. We handle all of them. Select a family below to see series coverage.

K03
150 to 180 HP — VW / Audi 1.8T Small Frame
The most common KKK turbo in the VW/Audi ecosystem. OEM on the 1.8T engine in multiple configurations across Audi A4, A6, VW Passat, and Golf. Part numbers typically begin 5303-970-XXXX (complete) or 5303-988-XXXX (CHRA). Water-cooled journal bearing. The K03 is frequently brought in worn from extended oil intervals or contaminated oil on high-mileage 1.8T engines.
Applications1996-2005 Audi A4 1.8T / 1998-2005 Audi A6 1.8T / 1996-2005 VW Passat 1.8T / VW Golf 1.8T / VW Jetta 1.8T / Seat Ibiza / Skoda Octavia 1.8T
K04
200 to 280 HP — VW / Audi Upgrade Frame
The K04 is a step up from the K03 in the same family. OEM on the Audi TT 225HP, S3, and Golf R32. Also the most common VW/Audi 1.8T upgrade path -- many K03-equipped platforms use the K04 as a direct upgrade. Part numbers 5304-XXXX. Same water-cooled journal bearing design. The K04-015 (53049700015) is one of the most-rebuilt KKK units we see.
ApplicationsAudi TT 225HP / Audi S3 / Audi A3 1.8T / VW Golf GTI 1.8T / K03 platform upgrades
K14 / K16
Small Diesel OEM
K14 is used on smaller European diesel applications including VW Polo 1.4 TDI and related platforms. K16 covers a range of European diesel OEM applications across the Volkswagen Group and other European makes. Both are journal bearing units. Common failure is sludge from extended diesel oil intervals which restricts the small oil passages in the compact CHRA.
ApplicationsVW Polo 1.4 TDI / various European small displacement diesel OEM
K24
200 to 300 HP — Porsche / Performance
The K24 was OEM on the Porsche 944 Turbo and 944 Turbo S, and has been used in various marine and industrial applications. Larger than the K03/K04 family. Journal bearing. The Porsche 944 Turbo K24 is a frequent rebuild unit given the age of these vehicles -- coking and oil contamination from decades of service are the typical findings at teardown.
ApplicationsPorsche 944 Turbo (1985-1988) / Porsche 944 Turbo S / marine / industrial
K26
150 to 350 HP — Porsche / Marine / Industrial
The K26 covers a wide range of configurations across automotive, marine, and industrial applications. Porsche 911 Turbo (930 series), various MAN bus applications, Mercruiser and Yanmar marine engines. Multiple compressor and turbine wheel combinations within the K26 frame. Contact us with your specific part number (5326-XXX-XXXX) to confirm the configuration for your rebuild.
ApplicationsPorsche 911 Turbo 930 / MAN Bus D0824 / Mercruiser Marine / Yanmar Marine 4LH-DTE / industrial diesel
K27
250 to 550 HP — Commercial Diesel
The K27 is a heavy-duty commercial diesel unit used across Deutz, Cummins, and various truck platforms. The K27-3072 configuration covers 250-550 HP and is listed in the BorgWarner AirWerks catalog. The K27 has also served as a Holset HX35W replacement in some Cummins applications. Journal bearing. Used extensively in European commercial truck and bus platforms.
ApplicationsDeutz commercial truck / Cummins diesel applications / European bus and truck / industrial
K28 / K29 / K31
350 to 500+ HP — Commercial / Performance
K28 covers performance and larger diesel applications. K31 is the large-frame unit used on the Detroit Diesel 12.7L Series 60 in truck and bus applications -- the K31 uses a Forged Milled Compressor Wheel (billet) as standard. K29 covers Caterpillar and various commercial applications. All journal bearing units in the traditional KKK architecture.
ApplicationsDetroit Diesel 12.7L Series 60 (K31) / Caterpillar diesel (K29) / performance and commercial diesel
KP31 / KP35 / KP39 / BV39
VNT Variable Geometry — European Diesel
The KP-series and BV39 are variable geometry (VNT) turbos used extensively across VW, Audi, Seat, Skoda, and Mercedes diesel platforms. KP31 for small engines, KP35 for medium, KP39 and BV39 for the popular 2.1D Mercedes Sprinter and various TDI applications. The variable nozzle vane system requires the same VGT service attention as Holset VGT units -- vane carbon buildup is the dominant failure mode. Part numbers begin 5431, 5435, 5439.
ApplicationsVW Golf TDI / Polo TDI / Passat TDI / Audi A3 TDI / Seat / Skoda TDI / Mercedes Sprinter 2.1D / various European diesel OEM
K33 / K34 / K36 / K37 / K42 / K44
Industrial / Commercial
Larger KKK frames used in industrial, agricultural, and commercial applications. K33 and K34 cover mid-range industrial engines. K36 and K37 are used in heavier commercial applications. K42 and K44 cover large industrial and marine diesel applications. Contact us with your nameplate part number (format 53XX-970-XXXX) and we will confirm what the rebuild involves.
ApplicationsIndustrial diesel / marine / agricultural / commercial truck platforms

The Schwitzer S-series is the dominant performance diesel turbocharger family in North America. All S-series turbos use twin hydrodynamic journal bearings and adjustable housing orientation (both compressor and turbine housings can be repositioned independently). The aftermarket shorthand "S366" or "S480" indicates the frame size (S300 or S400) and the compressor wheel inducer diameter in mm. Full BorgWarner nomenclature includes turbine wheel size and A/R (e.g., S300SX3 66/80 .91).

S300 / SX3
300 to 700 HP
The S300SX3 (cast wheel) is the workhorse of the AirWerks lineup. Available in S360 (60mm), S362 (62mm), S363 (63mm), S364 (64mm), S366 (66mm), and S369 (69mm) compressor wheel configurations. T3 and T4 turbine housing options. The S366 is the single most popular diesel performance turbo in North America -- capable of 500+ RWHP in the right application and widely used as both a single and the high-pressure charger in compound setups over an S400.
ApplicationsCummins 5.9L / 6.7L / Powerstroke 7.3L / 6.0L / 6.4L upgrade / Duramax LB7-L5P upgrade / universal T3 and T4 flange applications
S300 SX-E
350 to 700 HP — Forged Milled Wheel
The SX-E (Super eXtended) line upgrades the S300SX3 with a Forged Milled Compressor Wheel (FMW), 360-degree thrust bearing, integrated speed sensor port, and extended tip technology. Same frame and housing options as SX3 but significantly improved efficiency and airflow capacity. The S300SX-E is BorgWarner's current production performance line for the S300 frame and the preferred choice for serious street and track diesel builds.
ApplicationsSame as S300SX3 -- universal T3/T4 flange diesel performance applications
S400 / SX3
500 to 1000 HP
The S400 frame is BorgWarner's large-frame diesel performance unit. T4 and T6 turbine housing options. Common configurations include S464 (64mm), S467 (67mm), S472 (72mm), S476 (76mm), and S480 (80mm). The S467.7 is one of the most popular large-frame units for Cummins and Powerstroke builds supporting 600-800 RWHP. S400 units are frequently used as the low-pressure (atmospheric) charger in compound S300/S400 setups.
ApplicationsCummins 5.9L / 6.7L high-HP builds / Powerstroke 7.3L / 6.0L / 6.4L high-HP / Duramax high-HP / compound turbo setups (low-pressure)
S400 SX-E
600 to 1200 HP — Forged Milled Wheel
The S400SX-E applies the same FMW, 360-degree thrust bearing, and extended tip technology to the large S400 frame. T6 turbine housings are available for maximum exhaust flow on very high HP applications. The S488 SX-E (88mm compressor) is capable of supporting over 1,200 HP in extreme applications. Large-frame SX-E units are the choice for top-tier competition diesel builds.
ApplicationsExtreme HP diesel competition builds / Cummins / Powerstroke / Duramax large single or compound applications
S200 / S1 / S100
OEM Diesel / Commercial
The smaller Schwitzer frames used on OEM diesel applications in commercial and agricultural settings. S100 and S200 appear on Deutz, Volvo Penta, and various light-duty diesel platforms. While less common than S300/S400 in the performance market, these units are regularly rebuilt for commercial applications. Contact us with your specific part number and we will confirm rebuild availability.
ApplicationsDeutz diesel / Volvo Penta marine / agricultural and construction diesel / light commercial

Every EFR turbocharger uses a dual ceramic ball bearing assembly with metal cage, a Gamma-Ti (titanium aluminide) turbine wheel, an integrated compressor recirculation valve (CRV), a boost control solenoid valve (BCSV), and a Forged Milled Compressor Wheel (FMW). The Gamma-Ti turbine wheel is lighter and more heat-resistant than conventional Inconel, enabling higher shaft speeds and faster response than ball bearing turbos using conventional materials. However titanium aluminide is brittle when cold -- this is the most common EFR failure we see. The wheel must be fully up to operating temperature before any boost demand. Cold hard revs on an EFR are the fastest way to crack the turbine wheel. All EFR units require in-house VSR balancing at rebuild -- the ceramic ball bearing cartridge must be matched to the rebuilt assembly.

EFR6258
225 to 450 HP — Small Frame Fast Spool
The smallest and fastest-spooling EFR unit. 62mm compressor / 58mm turbine. The EFR6258 is the go-to upgrade for 4-cylinder applications where response is the priority -- Mazda MX-5, Honda K-series, Subaru EJ, and smaller displacement builds. Part numbers 179140 (supercore) and 179150 (with 0.64 A/R housing). Integrated CRV and BCSV are standard on all EFR units.
ApplicationsMazda MX-5 / Miata / Honda K20 / K24 / Subaru EJ20 / 4-cylinder builds 1.6L-2.0L up to 450 HP
EFR6758
300 to 550 HP
67mm compressor / 58mm turbine. Steps up from the 6258 in flow capacity while retaining the small turbine for fast response. Popular on 2.0L-2.5L 4-cylinder builds and smaller 6-cylinder applications where 300-550 HP is the target range. A balance of response and peak power that suits most aggressive street builds on 4-cylinder platforms.
Applications2.0L-2.5L 4-cylinder builds / Subaru STI EJ257 / EVO 4G63 / Honda / Toyota / 300-550 HP target
EFR7163
400 to 650 HP
71mm compressor / 63mm turbine. One of the most popular EFR units for medium-frame 4-cylinder and small 6-cylinder applications. Capable of 400-650 HP depending on application. The 7163 is frequently used on 2.0L-3.0L 6-cylinder builds where the 6758 has been outgrown. Available in multiple A/R turbine housing configurations. Part number reference: 11711013004 (compressor cover).
Applications2.0L-3.0L 4-6 cylinder / Subaru EJ / EVO / Supra 2JZ / RB25 / SR20 builds at 400-650 HP
EFR7670
500 to 750 HP
76mm compressor / 70mm turbine. Steps into the mid-large frame range. Used on 2.5L-4.0L engines targeting 500-750 HP. Suitable for single-turbo 2JZ builds that have outgrown the factory twin setup, larger 4G63 builds, and RB26 upgrades. The 7670 is where the EFR line transitions from 4-cylinder-focused to genuinely capable on 6-cylinder platforms. Part number reference: 12761013034.
Applications2JZ-GTE single builds / RB26DETT / 4G63 / 4B11 / 2.5L-4.0L 6-cylinder 500-750 HP
EFR8374
500 to 900 HP
83mm compressor / 74mm turbine. One of the largest practical single-turbo EFR units for gasoline performance applications. 500-900 HP capable. Popular for large-displacement single-turbo builds on 3.0L-5.0L engines. The 8374 pushes the limits of what can be achieved with a gasoline-fueled single turbocharger while maintaining ball bearing response characteristics. Part number reference: 12831013012.
ApplicationsLarge displacement 6-8 cylinder / 2JZ / LS / Barra / Supra / single turbo builds at 500-900 HP
EFR9174 / EFR9180
700 to 1100 HP — Largest EFR
The largest EFR units. 91mm compressor with 74mm (9174) or 80mm (9180) turbine. 700-1100 HP capable on gasoline. The EFR9174 and EFR9180 are serious race units -- at this size the ball bearing advantage in spool time is most apparent versus comparably-sized journal bearing turbos. Contact us before shipping -- large-frame EFR rebuilds are assessed individually based on configuration and ball bearing cartridge condition. Part numbers shared: 12911013005.
ApplicationsExtreme HP circuit race / large displacement single or compound / 700-1100 HP gasoline applications
Part Number Reference

Find Your Part Number

Search by BorgWarner part number, KKK model, Schwitzer number, EFR model, or application. BorgWarner uses multiple part numbers for the same turbo across complete assemblies (970) and CHRA-only units (988). Vehicle OEM part numbers are also cross-referenced where known.

Showing -- results
Part Number Model Engine / Application Vehicle Notes
5303-970-0029K03-0291.8T 20V APU / ARK1998-1999 Audi A4 / A6 / VW Passat 1.8TComplete Turbo
5303-988-0029K03-029 CHRA1.8T 20V APU / ARKAudi A4 / A6 / VW Passat 1.8TCHRA Only
53039700029K03-0291.8T AMG / AWM / ATW / AUG2000-2005 Audi A4 / VW Passat 1.8TComplete Turbo
53039880029K03-029 CHRA1.8T AMG / AWM / ATW / AUG2000-2005 Audi A4 / VW Passat 1.8TCHRA Only
058145703JK031.8T 20VAudi A4 B5 / A6 C5 / VW Passat B5Audi OEM
058145703NK031.8T 20VAudi A4 B5 / VW Passat 1.8TAudi OEM
5303-970-0005K03-0051.8T 150HPAudi A4 / A6 VW Golf / Passat 1.8T 150HPComplete Turbo
5303-988-0005K03-005 CHRA1.8T 150HPAudi A4 / VW Golf 1.8T 150HPCHRA Only
5304-970-0022K04-0221.8T 225HP BAM / APXAudi TT 225HP / Audi S3 1.8TComplete Turbo
5304-988-0022K04-022 CHRA1.8T 225HP BAM / APXAudi TT 225HP / S3CHRA Only
5304-970-0023K04-0231.8T 225HPAudi TT 225HP / S3 upgradeComplete Turbo
5304-988-0023K04-023 CHRA1.8T 225HPAudi TT 225HP / S3CHRA Only
53049700022K04-0221.8T BAM / APX2000-2006 Audi TT / S3Complete Turbo
53049880022K04-022 CHRA1.8T BAM / APXAudi TT / S3 CHRACHRA Only
53049700015K04-0151.8TAudi A3 / VW Golf GTI 1.8TComplete Turbo
53049880015K04-015 CHRA1.8TAudi A3 / VW Golf GTI 1.8TCHRA Only
54399700049KP39-0492.1D 95/110KW OM646Mercedes Sprinter / Vito 2.1DVNT Complete
54399880049KP39-049 CHRA2.1D 95/110KW OM646Mercedes Sprinter 2.1DVNT CHRA
5439-970-0049KP39 / BV392.1D CDIMercedes Sprinter 2.1D / E220 / C220VNT Complete
A6460900280KP39 / BV392.1D OM646Mercedes Sprinter / E-Class CDIMercedes OEM
038253016GKP39 VNT1.9 TDI 130HPVW Golf IV / Bora / Passat 1.9 TDI 130HPVW OEM
53279706445K27Deutz diesel 330HPDeutz commercial truckComplete Turbo
53279886445K27 CHRADeutz dieselDeutz commercialCHRA Only
53269706202K26D0824LFL01 117KWMAN BusComplete Turbo
53269706491K26HR692 4.2L 95KW MarineMercruiser MarineComplete Turbo
53269706292K264LH-DTE 125KW MarineYanmar MarineComplete Turbo
172743K31Detroit 12.7L S60 350-500HPClass 8 truck / busFMW Billet Wheel
714789-0001K31Detroit 12.7L S60Class 8 truck / busComplete Turbo
714789-0002K31Detroit 12.7L S60Class 8 truck / busComplete Turbo
177272S300SX3 S360/68/.91Universal diesel performanceCummins / Duramax / Powerstroke upgrade60mm S300
177275S300SX3 S366/73/.91Universal diesel performanceCummins / Duramax / Powerstroke upgrade66mm S300
177281S300SX3 S366/74/.88Universal diesel performanceCummins / Duramax / Powerstroke single or compound HP66mm S300 T4
177283S300SX3 S363/68/.88Universal diesel performanceCummins / Duramax / Powerstroke upgrade63mm S300
177284S300SX3 S366/74/.91Universal diesel performanceCummins / Duramax / Powerstroke upgrade66mm S300 T4
177208S300SX S362Universal diesel performanceCummins 5.9L / Powerstroke 7.3L upgrade62mm S300
177210S300SX S364Universal diesel performanceCummins 5.9L / 6.7L upgrade64mm S300
169012S300 John DeereJohn Deere diesel OEMJohn Deere agriculturalOEM Application
179180S400SX S480/87/1.25Universal diesel competitionCummins / Duramax high-HP single or atmospheric compound80mm S400
14009097014S400SX-EUniversal diesel performanceS400 SX-E series large frameFMW S400
13009097049S300SX-EUniversal diesel performanceS300 SX-E seriesFMW S300
13009095091S300SX-EUniversal diesel performanceS300 SX-E seriesFMW S300
14879880082S400SX-EUniversal diesel competitionS400 SX-E large frameFMW S400
179140EFR6258 Supercore4-cylinder 225-450HPMazda MX-5 / Honda K / Subaru EJBall Bearing Supercore
179150EFR6258 0.64 A/R4-cylinder 225-450HPMazda MX-5 / Honda K / Subaru EJBall Bearing Complete
11621013032EFR6258 Comp CoverEFR6258 compressor housingEFR6258 applicationsComponent
11671013004EFR6758 Comp CoverEFR6758 compressor housingEFR6758 applicationsComponent
11711013004EFR7163 Comp CoverEFR7163 compressor housingEFR7163 applicationsComponent
12701013022EFR7064 Comp CoverEFR7064 compressor housingEFR7064 applicationsComponent
12761013034EFR7670 Comp CoverEFR7670 compressor housingEFR7670 applicationsComponent
12831013012EFR8374 Comp CoverEFR8374 compressor housingEFR8374 applicationsComponent
12911013005EFR9174 / EFR9180EFR9174 / EFR9180 comp housingLargest EFR applicationsComponent
179140EFR6258 Iron Supercore225-450 HP / 4-cylMazda MX-5 / Honda K / Subaru EJ / universalIron CHRA Supercore
179150EFR6258-A T25 0.64 A/R225-450 HP / 4-cylMazda MX-5 / Honda K / Subaru EJ / universalComplete w/ T25 IWG Housing
11587105002EFR6258 Alu Supercore225-450 HP / 4-cylEFR6258 aluminum CHRA supercoreAluminum CHRA Supercore
11581009006EFR6258 T25 0.64 A/R HousingEFR6258 turbine housingT25 flange 0.64 A/R -- A-TypeTurbine Housing
11581008000EFR6258 T4 0.85 A/R HousingEFR6258 turbine housingT4 flange 0.85 A/R -- F-TypeTurbine Housing
11581008001EFR6258 T4 0.85 A/R F(v) HousingEFR6258 turbine housingT4 flange 0.85 A/R F(v)-TypeTurbine Housing
11581008002EFR6258 V-Band 0.80 A/R HousingEFR6258 turbine housingV-Band 0.80 A/R -- G-TypeTurbine Housing
11581008003EFR6258 V-Band 0.85 A/R HousingEFR6258 turbine housingV-Band 0.85 A/R -- I-TypeTurbine Housing
11589880036EFR6258 G-Type Complete225-450 HP / 4-cylEFR6258 complete with G-Type V-Band housingComplete Turbo
11621013032EFR6258 Compressor CoverEFR6258 compressor housingEFR6258 SX-E style compressor coverComponent
11671013004EFR6758 Compressor Cover300-550 HPEFR6758 compressor housingComponent
11637105000EFR7163-F Supercore300-600 HP2.0L-3.0L builds / EJ / 4G63 / SR20 / K-seriesSupercore Assembly
11711013004EFR7163 Compressor Cover300-600 HPEFR7163 compressor housingComponent
12701013022EFR7064 Compressor Cover400-650 HPEFR7064 compressor housingComponent
12641008007EFR7064 C-Type T4 0.92 A/R IWG HousingB2 frame / T4 flangeEFR7064 twin scroll IWG turbine housingTurbine Housing
12641019016EFR7064 D-Type T4 1.05 A/R EWG HousingB2 frame / T4 flangeEFR7064 twin scroll EWG turbine housingTurbine Housing
12761013034EFR7670 Compressor Cover500-800 HPEFR7670 compressor housingComponent
12701008016EFR7670 C-Type T4 0.92 A/R IWG HousingB2 frame / T4 flangeEFR7670 twin scroll IWG turbine housingTurbine Housing
12701019047EFR7670 D-Type T4 1.05 A/R EWG HousingB2 frame / T4 flangeEFR7670 twin scroll EWG turbine housingTurbine Housing
12831013012EFR8374 Compressor Cover500-900 HPEFR8374 compressor housingComponent
12741008001EFR8374/8474 C-Type T4 0.92 A/R IWG HousingB2 frame / T4 flangeEFR8374 and EFR8474 twin scroll IWG turbine housingTurbine Housing
12911013005EFR9174 / EFR9180 Compressor Cover700-1100 HPEFR9174 and EFR9180 compressor housingComponent
12801008009EFR9180/9280 C-Type T4 0.92 A/R IWG HousingB2 frame / T4 flangeEFR9180 and EFR9280 twin scroll IWG turbine housingTurbine Housing
177208S300SX S362 62/76 .91Diesel performance 350-500 HPCummins 5.9L / Powerstroke 7.3L single upgradeS300 Cast Wheel
177210S300SX S364 64/76 .91Diesel performance 350-550 HPCummins 5.9L / 6.7L upgradeS300 Cast Wheel
177272S300SX3 S360 60/68 .91Diesel performance 300-500 HPUniversal T4 / compound LP or HPS300SX3
177275S300SX3 S366 66/73 .91Diesel performance 400-700 HPCummins / Duramax / Powerstroke single or HP compoundS300SX3 T4
177281S300SX3 S366 66/74 .88Diesel performance 400-700 HPCummins / Duramax / Powerstroke single or HP compoundS300SX3 T4
177283S300SX3 S363 63/68 .88Diesel performance 350-600 HPUniversal diesel single or compound HPS300SX3 T4
177284S300SX3 S366 66/74 .91Diesel performance 400-700 HPCummins / Duramax / Powerstroke singleS300SX3 T4
169012S300 John Deere OEMJohn Deere diesel agriculturalJohn Deere OEM applicationS300 OEM
13009097049S300SX-E 66/74 SupercoreDiesel performance 400-750 HPCummins / Duramax / Powerstroke SX-E upgradeS300SX-E FMW 360 Thrust
13009095091S300SX-E 63/80 SupercoreDiesel performance 400-700 HPCummins / Duramax / Powerstroke SX-ES300SX-E FMW 360 Thrust
179180S400SX S480 80/87 1.25Diesel competition 700-1100 HPCummins / Duramax / Powerstroke large single or LP compoundS400SX T6
178855S400SX3 S467 67/83 1.10Diesel performance 500-900 HPCummins / Duramax / Powerstroke SX3S400SX3 T4
178856S400SX3 S467 FMW SupercoreDiesel performance 500-900 HPCummins / Duramax SX3 supercoreS400SX3 FMW Supercore
177248S400SX3 S471 71/83 1.10Diesel performance 500-1050 HPCummins / Duramax / Powerstroke large single or LP compoundS400SX3 T4 Twin Scroll
177287S400SX4 S480 80/96 1.32Diesel competition 700-1100 HPCummins / Duramax extreme HP single or LP compoundS400SX4 T6
14009097014S400SX-E S476 76/82 SupercoreDiesel competition 800-1200+ HPCummins / Duramax / Powerstroke SX-E extreme HPS400SX-E FMW 360 Thrust T4
14879880082S400SX-E SupercoreDiesel competition 800-1200+ HPCummins / Duramax SX-E large frameS400SX-E FMW Supercore
178787S400SX-E T4 .90 A/R HousingS400SX-E 87mm turbine housingS476SX-E / S480SX-E T4 0.90 A/R V-Band outletTurbine Housing
178788S400SX-E T4 1.00 A/R HousingS400SX-E 87mm turbine housingS476SX-E / S480SX-E T4 1.00 A/R V-Band outletTurbine Housing
178789S400SX-E T4 1.10 A/R HousingS400SX-E 87mm turbine housingS476SX-E / S480SX-E T4 1.10 A/R V-Band outletTurbine Housing
178790S400SX-E T4 1.25 A/R HousingS400SX-E 87mm turbine housingS476SX-E / S480SX-E T4 1.25 A/R V-Band outletTurbine Housing
11587105001EFR6758 Supercore -- B1 6758300-550 HPEFR6758 supercore assemblySupercore
11589880034EFR6758 Turbo -- B1 6758F 0.85 A/R VOF WG300-550 HPEFR6758 complete 0.85 A/R T25 WGComplete Turbo
11589880035EFR6758 Turbo -- B1 6758F 0.85 A/R VOF WG V-Band300-550 HPEFR6758 complete 0.85 A/R V-Band inlet WGComplete Turbo
11589880037EFR6758 Turbo -- B1 6758G 0.80 A/R VTF WG300-550 HPEFR6758 complete 0.80 A/R T4 twin scroll WGComplete Turbo
11639880002EFR7163 Turbo -- B1 7163G 0.80 A/R VTF WG300-600 HPEFR7163 complete 0.80 A/R T4 twin scroll WGComplete Turbo
11639880005EFR7163 Turbo -- B1 7163F 0.85 A/R VOF WG300-600 HPEFR7163 complete 0.85 A/R T25 WGComplete Turbo
11639880006EFR7163 Turbo -- B1 7163F 0.85 A/R VOF WG V-Band300-600 HPEFR7163 complete 0.85 A/R V-Band inlet WGComplete Turbo
12709097006EFR7064 Supercore -- B2 7064 Aluminum BH400-650 HPEFR7064 aluminum bearing housing supercoreSupercore
12769097001EFR7670 Supercore -- B2 7670 Aluminum BH500-800 HPEFR7670 aluminum bearing housing supercoreSupercore
12809880000EFR9180 Complete Turbo -- B2 9180 0.92 A/R VTF T4 WG700-1100 HPEFR9180 complete 0.92 A/R T4 WGComplete Turbo
12839097000EFR8374 Supercore -- B2 8374 Aluminum BH500-900 HPEFR8374 aluminum bearing housing supercoreSupercore
12919097000EFR9174 Supercore -- B2 9174 Aluminum BH700-1000 HPEFR9174 aluminum bearing housing supercoreSupercore
12919097001EFR9180 Supercore -- B2 9180 Aluminum BH700-1100 HPEFR9180 aluminum bearing housing supercoreSupercore
12919097002EFR9174 Supercore -- B2 9174 Iron BH700-1000 HPEFR9174 iron bearing housing supercoreSupercore
179257EFR8374 Iron Supercore -- B2 8374500-900 HPEFR8374 iron CHRA supercoreIron Supercore
179258EFR8374 Turbo -- B2 8374 0.83 A/R VO WG500-900 HPEFR8374 complete turbo 0.83 A/R V-BandComplete Turbo
179350EFR7670 Supercore -- B2 7670500-800 HPEFR7670 supercore assemblySupercore
179351EFR7670 Turbo -- B2 7670 0.83 A/R VO WG500-800 HPEFR7670 complete turbo 0.83 A/R V-BandComplete Turbo
179354EFR7064 Supercore -- B2 7064400-650 HPEFR7064 supercore assemblySupercore
179355EFR7064 Turbo -- B2 7064 0.83 A/R VO WG400-650 HPEFR7064 complete turbo 0.83 A/R V-BandComplete Turbo
179356EFR9180 Supercore -- B2 9180700-1100 HPEFR9180 supercore assemblySupercore
179357EFR8374 Turbo -- B2 8374 0.92 A/R VTF WG500-900 HPEFR8374 complete 0.92 A/R T4 twin scrollComplete Turbo
179358EFR9180 Turbo -- B2 9180 0.83 A/R VO WG700-1100 HPEFR9180 complete 0.83 A/R V-BandComplete Turbo
179375EFR6758 Supercore -- B1 6758300-550 HPEFR6758 supercore assemblySupercore
179388EFR6758 Turbo -- B1 6758 0.64 A/R VO WG300-550 HPEFR6758 complete 0.64 A/R T25 WGComplete Turbo
179389EFR7064 Turbo -- B2 7064 0.92 A/R VTF WG400-650 HPEFR7064 complete 0.92 A/R T4 twin scroll WGComplete Turbo
179390EFR7670 Turbo -- B2 7670 0.92 A/R VTF WG500-800 HPEFR7670 complete 0.92 A/R T4 twin scroll WGComplete Turbo
179391EFR7064 Turbo -- B2 7064 1.05 A/R VTF400-650 HPEFR7064 complete 1.05 A/R T4 twin scrollComplete Turbo
179392EFR7670 Turbo -- B2 7670 1.05 A/R VTF500-800 HPEFR7670 complete 1.05 A/R T4 twin scrollComplete Turbo
179393EFR8374 Turbo -- B2 8374 1.05 A/R VTF500-900 HPEFR8374 complete 1.05 A/R T4 twin scrollComplete Turbo
179394EFR9180 Turbo -- B2 9180 1.05 A/R VTF700-1100 HPEFR9180 complete 1.05 A/R T4 twin scrollComplete Turbo
11581009007EFR6258 Turbine Housing -- B1 58mm 0.83 T3 Twin Scroll WGEFR6258 turbine housingEFR6258 T3 twin scroll WG assemblyTurbine Housing
11631008000EFR7163 Turbine Housing -- B1 63mm 0.85 T25 VOF WGEFR7163 turbine housingEFR7163 T25 flange 0.85 A/R WGTurbine Housing
11631008001EFR7163 Turbine Housing -- B1 63mm 0.85 V-Band WGEFR7163 turbine housingEFR7163 V-Band inlet 0.85 A/R WGTurbine Housing
11631008002EFR7163 Turbine Housing -- B1 63mm 0.80 T4 Twin Scroll WGEFR7163 turbine housingEFR7163 T4 twin scroll 0.80 A/R WGTurbine Housing
11631008003EFR7163 Turbine Housing -- B1 63mm 0.85 V-Band Non-WGEFR7163 turbine housingEFR7163 V-Band inlet 0.85 A/R Non-WGTurbine Housing
12641008006EFR7064 Turbine Housing -- B2 64mm 0.83 T3 Single Scroll WGEFR7064 turbine housingEFR7064 T3 single scroll 0.83 A/R WGTurbine Housing
12701008014EFR7670 Turbine Housing -- B2 70mm 0.83 T3 Single Scroll WGEFR7670 turbine housingEFR7670 T3 single scroll 0.83 A/R WGTurbine Housing
12741008000EFR8374 Turbine Housing -- B2 74mm 0.83 T3 Single Scroll WGEFR8374 turbine housingEFR8374 T3 single scroll 0.83 A/R WGTurbine Housing
12741008003EFR8374 Turbine Housing -- B2 74mm 1.45 T4 Twin Scroll H-TypeEFR8374 turbine housingEFR8374 T4 1.45 A/R H-Type twin scrollTurbine Housing
12741019002EFR8374 Turbine Housing -- B2 74mm 1.05 T4 Twin ScrollEFR8374 turbine housingEFR8374 T4 twin scroll 1.05 A/RTurbine Housing
12801008002EFR9180 Turbine Housing -- B2 80mm 0.83 T3 Single Scroll WGEFR9180 turbine housingEFR9180 T3 single scroll 0.83 A/R WGTurbine Housing
12801008006EFR9180 Turbine Housing -- B2 80mm 1.45 T4 Twin Scroll H-TypeEFR9180 turbine housingEFR9180 T4 1.45 A/R H-Type twin scrollTurbine Housing
12801019001EFR9180 Turbine Housing -- B2 80mm 1.05 T4 Twin ScrollEFR9180 turbine housingEFR9180 T4 twin scroll 1.05 A/RTurbine Housing
179282EFR Actuator -- Low Boost 55-58mm TW 0.64 THEFR actuatorEFR IWG actuator low boost -- 55/58mm turbine 0.64 housingActuator
179283EFR Actuator -- Med Boost 55-58mm TW 0.64 THEFR actuatorEFR IWG actuator medium boost -- 55/58mm turbine 0.64 housingActuator
179284EFR Actuator -- High Boost 55-58mm TW 0.64 THEFR actuatorEFR IWG actuator high boost -- 55/58mm turbine 0.64 housingActuator
179285EFR Actuator -- Low Boost 64-80mm TW 0.83 THEFR actuatorEFR IWG actuator low boost -- 64-80mm turbine 0.83 housingActuator
179286EFR Actuator -- Med Boost 64-80mm TW 0.83 THEFR actuatorEFR IWG actuator medium boost -- 64-80mm turbine 0.83 housingActuator
179287EFR Actuator -- High Boost 64-80mm TW 0.83 THEFR actuatorEFR IWG actuator high boost -- 64-80mm turbine 0.83 housingActuator
179420EFR Actuator -- Low Boost 55-58mm TW 0.92 THEFR actuatorEFR IWG actuator low boost -- 55/58mm turbine 0.92 housingActuator
179421EFR Actuator -- Med Boost 55-58mm TW 0.92 THEFR actuatorEFR IWG actuator medium boost -- 55/58mm turbine 0.92 housingActuator
179422EFR Actuator -- High Boost 55-58mm TW 0.92 THEFR actuatorEFR IWG actuator high boost -- 55/58mm turbine 0.92 housingActuator
14009097006S400SX-E Supercore -- S400SX-E 72mm 96/87Diesel competition 700-1100 HPS400SX-E 72mm compressor supercoreS400SX-E Supercore
14009097007S400SX-E Cartridge -- S400SX-E 72mm 96/87Diesel competition 700-1100 HPS400SX-E 72mm cartridge/CHRAS400SX-E CHRA
14009097008S400SX-E Supercore -- S400SX-E 88mm 110/96Diesel competition 1000-1500+ HPS400SX-E 88mm compressor supercoreS400SX-E Supercore
14009097009S400SX-E Cartridge -- S400SX-E 88mm 110/96Diesel competition 1000-1500+ HPS400SX-E 88mm cartridge/CHRAS400SX-E CHRA
14009097010S400SX-E Supercore -- S400SX-E 80mm 110/96Diesel competition 900-1400+ HPS400SX-E 80mm compressor supercoreS400SX-E Supercore
14009097011S400SX-E Cartridge -- S400SX-E 80mm 110/96Diesel competition 900-1400+ HPS400SX-E 80mm cartridge/CHRAS400SX-E CHRA
14009097012S400SX-E Cartridge -- S400SX-E 76mm 100/96Diesel competition 800-1200 HPS400SX-E 76mm 100/96 cartridge/CHRAS400SX-E CHRA
14009097013S400SX-E Supercore -- S400SX-E 76mm 100/96Diesel competition 800-1200 HPS400SX-E 76mm 100/96 supercoreS400SX-E Supercore
14009097015S400SX-E Cartridge -- S400SX-E 76mm 100/87Diesel competition 800-1200+ HPS400SX-E 76mm 100/87 cartridge/CHRAS400SX-E CHRA
15007105015S500SX-E Cartridge -- S500SX-E 88mm 120/110Diesel extreme 1200-2000+ HPS500SX-E 88mm cartridge/CHRAS500SX-E CHRA
15007105016S500SX-E Cartridge -- S500SX-E 94mm 120/110Diesel extreme 1500-2500+ HPS500SX-E 94mm cartridge/CHRAS500SX-E CHRA
15009097001S500SX-E Supercore -- S500SX-E 88mm 120/110Diesel extreme 1200-2000+ HPS500SX-E 88mm supercoreS500SX-E Supercore
15009097002S500SX-E Supercore -- S500SX-E 94mm 120/110Diesel extreme 1500-2500+ HPS500SX-E 94mm supercoreS500SX-E Supercore
178781S400SX Supercore -- S400SX 76mm 105/87Diesel competition 800-1100 HPS400SX 76mm compressor supercoreS400SX Supercore
178782S400SX Cartridge -- S400SX 76mm 105/87Diesel competition 800-1100 HPS400SX 76mm cartridge/CHRAS400SX CHRA
179171S400SX Turbo -- S400SX 71mm 100/83Diesel performance 600-900 HPS400SX 71mm complete turboS400SX
179172S400SX Supercore -- S400SX 71mm 100/83Diesel performance 600-900 HPS400SX 71mm supercoreS400SX Supercore
179174S400SX Turbo -- S400SX 74.5mm 100/83Diesel performance 600-1000 HPS400SX 74.5mm complete turboS400SX
179175S400SX Supercore -- S400SX 74.5mm 100/83Diesel performance 600-1000 HPS400SX 74.5mm supercoreS400SX Supercore
179176S400SX Turbo -- S400SX 76mm 105/87Diesel competition 800-1100 HPS400SX 76mm complete turboS400SX
179179S400SX Supercore -- S400SX 80mm 110/87Diesel competition 900-1200+ HPS400SX 80mm supercoreS400SX Supercore
179182S400SX Turbo -- S400SX 82mm 110/87Diesel competition 900-1200+ HPS400SX 82mm complete turboS400SX
179183S400SX Cartridge -- S400SX 82mm 110/87Diesel competition 900-1200+ HPS400SX 82mm cartridge/CHRAS400SX CHRA
179184S400SX Supercore -- S400SX 82mm 110/87Diesel competition 900-1200+ HPS400SX 82mm supercoreS400SX Supercore
179186S500SX Supercore -- S500SX 88mm 120/110Diesel extreme 1000-1500+ HPS500SX 88mm supercoreS500SX Supercore
179187S500SX Cartridge -- S500SX 88mm 120/110Diesel extreme 1000-1500+ HPS500SX 88mm cartridge/CHRAS500SX CHRA
179188S500SX Turbo -- S500SX 88mm 120/110Diesel extreme 1000-1500+ HPS500SX 88mm complete turboS500SX
179189S500SX Cartridge -- S500SX 91mm 120/110Diesel extreme 1200-1800+ HPS500SX 91mm cartridge/CHRAS500SX CHRA
179190S500SX Supercore -- S500SX 91mm 120/110Diesel extreme 1200-1800+ HPS500SX 91mm supercoreS500SX Supercore
179191S500SX Turbo -- S500SX 91mm 120/110Diesel extreme 1200-1800+ HPS500SX 91mm complete turboS500SX
179352S400SX Supercore -- S400SX 67.7mm 91/83Diesel performance 500-900 HPS400SX 67.7mm supercoreS400SX Supercore
12709095019S200SX-E Supercore -- S200SX-E 7070S200 frame SX-E dieselS200SX-E 70mm supercoreS200SX-E Supercore
12769095003S200SX-E Supercore -- S200SX-E 7670S200 frame SX-E dieselS200SX-E 76mm supercoreS200SX-E Supercore
13009097005S300SX-E Cartridge -- S300SX-E 63mm 87/76Diesel performance 400-700 HPS300SX-E 63mm cartridge/CHRAS300SX-E CHRA
13009097006S300SX-E Supercore -- S300SX-E 63mm 87/76Diesel performance 400-700 HPS300SX-E 63mm compressor supercoreS300SX-E Supercore
13009097007S300SX-E Cartridge -- S300SX-E 64.5mm 87/76Diesel performance 400-700 HPS300SX-E 64.5mm cartridge/CHRAS300SX-E CHRA
13009097008S300SX-E Supercore -- S300SX-E 64.5mm 87/76Diesel performance 400-700 HPS300SX-E 64.5mm compressor supercoreS300SX-E Supercore
13009097047S300SX-E Supercore -- S300SX-E 8780Diesel performance 500-800 HPS300SX-E 87mm compressor 80mm turbine supercoreS300SX-E Supercore
13009097051S300SX-E Supercore -- S300SX-E 9180Diesel performance 500-800 HPS300SX-E 91mm compressor 80mm turbine supercoreS300SX-E Supercore
13009097053S300SX-E Supercore -- S300SX-E 8380Diesel performance 450-750 HPS300SX-E 83mm compressor 80mm turbine supercoreS300SX-E Supercore
13009097055S300SX-E Supercore -- S300SX-E 8780Diesel performance 500-800 HPS300SX-E 87mm compressor 80mm turbine supercoreS300SX-E Supercore
13009097056S300SX-E Supercore -- S300SX-E 8376Diesel performance 450-700 HPS300SX-E 83mm compressor 76mm turbine supercoreS300SX-E Supercore
14009097006S400SX-E Supercore -- S400SX-E 72mm 96/87Diesel competition 700-1100 HPS400SX-E 72mm compressor supercoreS400SX-E Supercore
14009097007S400SX-E Cartridge -- S400SX-E 72mm 96/87Diesel competition 700-1100 HPS400SX-E 72mm cartridge/CHRAS400SX-E CHRA
14009097008S400SX-E Supercore -- S400SX-E 88mm 110/96Diesel competition 1000-1500+ HPS400SX-E 88mm compressor supercoreS400SX-E Supercore
14009097009S400SX-E Cartridge -- S400SX-E 88mm 110/96Diesel competition 1000-1500+ HPS400SX-E 88mm cartridge/CHRAS400SX-E CHRA
14009097010S400SX-E Supercore -- S400SX-E 80mm 110/96Diesel competition 900-1400+ HPS400SX-E 80mm compressor supercoreS400SX-E Supercore
14009097011S400SX-E Cartridge -- S400SX-E 80mm 110/96Diesel competition 900-1400+ HPS400SX-E 80mm cartridge/CHRAS400SX-E CHRA
14009097012S400SX-E Cartridge -- S400SX-E 76mm 100/96Diesel competition 800-1200 HPS400SX-E 76mm 100/96 cartridge/CHRAS400SX-E CHRA
14009097013S400SX-E Supercore -- S400SX-E 76mm 100/96Diesel competition 800-1200 HPS400SX-E 76mm 100/96 supercoreS400SX-E Supercore
14009097015S400SX-E Cartridge -- S400SX-E 76mm 100/87Diesel competition 800-1200+ HPS400SX-E 76mm 100/87 cartridge/CHRAS400SX-E CHRA
15007105015S500SX-E Cartridge -- S500SX-E 88mm 120/110Diesel extreme 1200-2000+ HPS500SX-E 88mm cartridge/CHRAS500SX-E CHRA
15007105016S500SX-E Cartridge -- S500SX-E 94mm 120/110Diesel extreme 1500-2500+ HPS500SX-E 94mm cartridge/CHRAS500SX-E CHRA
15009097001S500SX-E Supercore -- S500SX-E 88mm 120/110Diesel extreme 1200-2000+ HPS500SX-E 88mm supercoreS500SX-E Supercore
15009097002S500SX-E Supercore -- S500SX-E 94mm 120/110Diesel extreme 1500-2500+ HPS500SX-E 94mm supercoreS500SX-E Supercore
12709095019S200SX-E Supercore -- S200SX-E 7070S200 frame SX-E dieselS200SX-E 70mm supercoreS200SX-E Supercore
12769095003S200SX-E Supercore -- S200SX-E 7670S200 frame SX-E dieselS200SX-E 76mm supercoreS200SX-E Supercore
Common Failure Modes

Why They
Fail

01
K03 / K04 Oil Coking (VW / Audi 1.8T)
The VW/Audi 1.8T K03 and K04 are compact water-cooled units that are highly sensitive to oil quality and change intervals. Extended intervals with conventional oil allow deposits to build up in the compact CHRA passages. The result is bearing starvation on startup and progressive wear. VW/Audi 1.8T engines are also known for oil consumption issues that accelerate CHRA contamination. Every K03 and K04 rebuild includes full passage cleaning and inspection before new bearings go in.
02
KP39 / BV39 VNT Vane Sticking
The variable geometry KP39 and BV39 units found on Mercedes Sprinter, VW TDI, and Audi diesel platforms develop the same vane carbon buildup seen in all VNT turbos. Soot from the EGR system accumulates on the nozzle ring and vane pivots. Power loss, boost lag, P0299 under-boost codes, and limp mode follow. Vane assembly disassembly, cleaning, and inspection are part of every KP39 and BV39 rebuild. Damaged or seized vane pivots are replaced before reassembly.
03
S300 / S400 Bearing Wear from Oil Contamination
Performance diesel builds running the S300 and S400 often push oil temperatures and change intervals further than the journal bearings prefer. Contaminated oil from extended intervals, biodiesel blends that degrade oil faster, or coolant intrusion from failing head gaskets (common on 5.9L and 7.3L platforms) all accelerate bearing wear. The adjustable housing orientation on S-series turbos also means installation errors -- improper drain angle causing pooling -- are a frequent root cause that gets overlooked when only the CHRA is replaced.
04
EFR Gamma-Ti Turbine Wheel Fracture
The most common EFR failure we see in the shop. BorgWarner uses a Gamma-Ti (titanium aluminide) turbine wheel in every EFR unit. Titanium aluminide is exceptionally light and heat-resistant at operating temperature, which is why it enables the fast spool and high shaft speeds the EFR is known for. The problem is cold brittleness -- titanium aluminide is significantly more brittle at low temperatures than at operating temperature. On a cold start, especially in cold climates or after the car has sat overnight, the turbine wheel is at its most vulnerable. Revving hard before the turbo has reached operating temperature, or any boost demand on a cold engine, puts stress on a wheel that has not yet warmed into its ductile range. The wheel cracks or fractures. Fragments can be ingested into the engine. This is the single most preventable EFR failure -- let the engine warm up fully before any boost demand, every time.
05
K26 / K24 Age-Related Wear
The Porsche 944 Turbo K24 and Porsche 911 Turbo 930 K26 are increasingly coming in simply due to age -- these are 30 to 40 year old turbos with decades of heat cycling and varying maintenance histories. Oil coking from years of accumulated deposits, dried and cracked seals, and shaft play from long-term bearing wear are typical findings. The good news is that the KKK journal bearing design on these units is robust and most can be rebuilt to full specification with new components.
06
Compressor Surge on K-Series Small Frame
K03 and K04 units on modified VW/Audi 1.8T engines are commonly pushed beyond their compressor maps with aggressive boost targets and poorly tuned maps. Compressor surge on a small-frame KKK turbo is audible and damaging -- the reverse airflow loads the thrust bearing with reverse axial force. Thrust bearing and washer wear is a diagnostic indicator at teardown. Boost maps that stay within the compressor map boundary and a properly sized blow-off valve prevent this.
Common Questions

Frequently Asked

In BorgWarner's KKK part number system the three digits after the frame identifier tell you what the part is. 970 means it is a complete turbocharger assembly including the housings. 988 means it is a CHRA only -- the center rotating assembly without the compressor or turbine housings. For a rebuild where your housings are in good condition, a 988 CHRA number is the reference. For a full replacement, 970 is the complete unit. The variant number at the end (0029, 0022, etc.) is the same regardless of whether it is a 970 or 988.
S366 is shorthand that only tells you the frame is S300 and the compressor wheel inducer is 66mm. It tells you nothing about the turbine wheel size, turbine housing A/R, whether it is an SX3 or SX-E, or what turbine flange is on it. The full BorgWarner nomenclature for the most common "S366" is S300SX3 66/80 .91 or S300SX3 66/74 .88, where 66 is the compressor inducer, 80 or 74 is the turbine inducer, and .91 or .88 is the A/R. When shipping a Schwitzer unit for rebuild, the 6-digit part number on the tag (like 177281) tells us exactly what you have. If that tag is missing, measuring both wheel inducers and the turbine housing gives us the same information.
The EFR uses a dual ceramic ball bearing assembly with metal cage. The cartridge itself is not individually rebuilt -- if the ceramic balls or races show wear the cartridge is replaced as a unit. In many EFR rebuilds where the failure cause is oil contamination or heat soak and the balls are caught early, the cartridge can sometimes be retained. We inspect the ball surfaces and races at teardown and quote replacement only when needed. The turbo is then VSR balanced after assembly regardless of whether the cartridge was replaced.
Rebuild it now. Noise on a K03 or K04 while still building boost almost always means bearing wear that has progressed enough to allow shaft movement. The shaft movement causes the compressor and turbine wheels to run closer to their housings than they should. At some point one of them contacts. When that happens on a running engine the turbo fails suddenly and debris can be ingested into the intake and exhaust. Catching it at the noise stage costs you a bearing replacement and VSR balance. Catching it after contact costs you housing replacement or a new turbo and potentially engine damage. Come in now.
Drain any residual oil from the inlet and outlet ports. Plug all ports to prevent contamination. Double-box with foam or bubble wrap padding on all sides. Ship via UPS or FedEx to 37833 Pineapple Ave Unit A, Dade City, FL 33523. Contact us before shipping and we will send a receiving confirmation. For S300 and S400 units please note if the compressor or turbine housings have been repositioned from factory orientation so we can return it in the same configuration.
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sales@theboostlab.com theboostlab.com Dade City, FL