GrimmSpeed Chase JB400 Turbocharger

$1,350.00 $1,147.50
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Introducing the JB400 Turbo:

The GrimmSpeed Turbocharger Program started by recognizing a need in the market for a robust, quick-spooling and high-performing turbo. Design began from the ground up and took over 3 years of hard work, testing and development to introduce a product that we're proud to have carry The GrimmSpeed Name. The focus of this project was to offer a stock location OE replacement turbo, which when paired with GrimmSpeed supporting mods, allows enthusiasts to take full advantage of their EJ series turbo engine.

Both of our new turbocharger options feature state of the art proprietary compressors, turbines, CHRA's and wheel designs which maximize the power made on your EJ engine at two different price points. The overall design went through tedious gas flow test analysis, strenuous failure testing and engine pounding dyno/road testing, all to create the new standard for EJ engines: The GrimmSpeed Chase JB400 and Overtake BB500 Turbochargers!

The Chase JB400 Turbo is the smaller of our two offerings, this journal bearing unit is a perfect bolt-on to any stage 3 car, with which you are able to maximize the car’s power potential with instant results through installation/tuning. The Chase JB400 features a robust 49lb compressor wheel, with a 53mm turbine wheel to offer quick response and power in the mid-range where you need it. The Chase Version was able to hit 440WHP and 460WTQ on The GrimmSpeed Stage 3-equipped 2020 STI with the addition of only tuning and fuel mods. The impressive bit is that the vehicle was able to hold over 400WTQ from 4150RPM, an RPM range where the stock turbo begins to lose power. Compared to a tuned stock turbo STI, the Chase 400 is able to produce 70 more horsepower and 66 more ft/lbs of torque.


  • Compressor Wheel Size (Inducer/Exducer): 51.2mm / 73.8mm Extended tip48 Trim
  • Turbine Wheel Size (Inducer/Exducer)53.8mm / 47mm, 76 Trim
  • Compressor Flow49 lb-min
  • Compressor Inlet Diameter: 2.4"
  • Compressor Wheel Type Material/Alloy: Billet 2618
  • Compressor Housing AlloyA356
  • Turbine Housing AlloyD5S
  • Bearing Type: Journal 
    • Severe duty 360 degree thrust bearing and twin hydrodynamic bearings –very robust for this size of turbocharger, to ensure reliability at high boost levels and in race applications
    • Dual piston rings and advance oil flinger design to combat oil leakage and CHRA pressurization 
  • Compressor A/R: 0.65
  • Turbine A/R: 0.88
  • Adjustable Wastegate: Pre-set at 15Psi base pressure

Now that you’re familiar with the Chase JB400, it’s time to get to know the big daddy. Introducing The GrimmSpeed Overtake BB500. This turbocharger features world class power delivery and quick spool characteristics. It remains a stock location EJ turbo, but features a larger 55lb compressor wheel and massive 60mm turbine wheel to allow the engine to really breathe at high RPM. Just like with the Chase JB400, drivability was our #1 goal and by combining slick aero wheel designs with a dual ceramic ball bearing center housing rotating assembly, we were able to achieve superior spool results. This allowed us to hit 20PSI BEFORE 4100RPM and out-spool our well-performing Chase turbo by an impressive 150 RPM! When bolted onto our 2020 STI Shop Car, we were able to produce 488WHP and 515WTQ. However, the most impressive part is that the Overtake Turbocharger is able to hold 400WTQ+ from 4000RPM and hold over 400WHP from 4250RPM all the way to Redline! The design philosophy was to keep the turbo in its powerband after shifts and to hold substantially more power than the stock turbo to redline. The Overtake produces 129 horsepower and 109 ft/lbs of torque over a tuned stock STI turbo. This is all accomplished on a vehicle with only simple bolts-on, cars with additional engine work such as cams, intake manifolds, etc will be able to produce even higher gains!


  • 04-21 Subaru STI
  • 02-07 Subaru WRX [Other modifications required]
  • 04-08 Subaru FXT/Baja [Other modifications required]
  • 08-14 Subaru WRX/FXT [Equipped with GrimmSpeed Intercooler, STI-Style Conversion Hose, etc]
  • 05-09 Subaru LGT/OBXT [Equipped with GrimmSpeed Intercooler, STI-Style Conversion Hose, etc]