It takes a fierce competitor to keep up with the competition. Add talent and consistency to the mix and you’ve got the makings of a champion. In the case of Chris Forsberg, this formula yielded three championship titles and the most podium finishes in the Formula Drift Pro Championship series. If you’ve ever watched Forsberg drive, it would be no wonder that he’s often referred to as “Mr. Consistent”. A fan of the Nissan Z chassis we get an inside look into his latest competition machine, a twin Garrett G Series G25-660 turbocharged Nissan 370Z making over 800whp.

Z Specialist

Forsberg has drifted Nissan’s Z chassis (Z33, Z34) for over 12 years. Unlike some of the other competitors in the field, his experience with the Z has contributed to his expertise with the platform. He has long been a fan of the Nissan VQ-series V6 engine that powers the Z, but a lack of development for the engine made using it in competition prohibitive and unreliable. Of course, the aftermarket offered basic bolt-on turbo and supercharger kits for the VQ engine, but it was still not enough to be competitive in a field dominated by Chevy LS V8 engine swaps, Toyota 2JZ-GTE engine swaps and output levels in excess of 1,000 horsepower. To be competitive, Forsberg followed suit, using LS engines and Nissan’s V8 engine, the 5.6-liter VK56DE.

Off Season, New Partners, New Turbos

Forsberg saw the opportunity to further improve his Z34 when Garrett unveiled its new flagship turbochargers, the G-Series. In the case of Forsberg’s new Alpha VQ engine, the larger Garrett G25-660 and G25-660 Reverse Rotation turbochargers proved the best fit for his target output. Fast Intentions supplied a pair of prototype low-mount exhaust manifolds that channel high enthalpy gasses from the exhaust ports into the G25-660 turbochargers. Fast Intentions then fashioned 3-inch turbo-back exhausts to channel the exhausts gasses from the turbochargers to the rear of the chassis. Fast Intentions also fabricated piping to join the compressor discharge ports of the G-Series turbochargers to a custom front-mount intercooler. According to Forsberg, this new setup shed 200-pounds plus an additional 50-pound weight loss compared to the VK56 setup with further improved weight distribution.

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Leaner and Meaner

Forsberg’s Z34 put down 850 horsepower and 700 lb-ft torque to the rollers of a Dynojet dynamo-meter with twin Garrett G25-660 turbochargers on .72 V-band turbine housings. Forsberg stated, “In the 2018 setup, we chose the GTX3071R Gen II turbochargers. We had a good experience with them, especially with nitrous oxide injection to help improve bottom end response. On this new setup, the G-Series turbochargers offer excellent tip in with the same air flow at the top. It’s amazing how much air these turbochargers flow with only a 3-inch inducer. In addition, the G-Series turbochargers’ compact design makes it a good choice for builds with tight spaces. The CHRA features water ports that make routing the lines much easier.”

Forsberg’s Z34 put down 850 horsepower and 700 lb-ft torque to the rollers of a Dynojet dynamometer with twin Garrett G25-660 turbochargers on .72 V-band turbine housings.

G-Series Turbos

Garrett designed its G-Series turbochargers from a clean sheet, incorporating cutting edge technologies and manufacturing techniques to make a compact and efficient turbocharger designed for high-performance applications. These turbochargers feature forged billet aluminum compressor wheels, CNC machined with Garrett’s latest aerodynamics. On the hot side, the G-Series turbos feature Mar-M alloy turbine wheels with improved aerodynamics and heat resistance up to 1,922-degrees Fahrenheit (1,050-degrees Celsius). The G-Series CHRA design incorporates dual ceramic ball bearings for reduced friction and increased longevity. All new compressor housings and stainless-steel turbine housings complement the new wheel designs to deliver quicker response, greater airflow and improved performance. The initial release models include two sizes, the G25-550 and G25-660, along with the G25-550 Reverse Rotation and G25-660 Reverse Rotation. These small yet capable turbochargers offer an ideal balance of response with enough airflow to support lofty horsepower targets. The Reverse Rotation options also make the G-Series turbochargers ideal for V-engine configurations that could benefit from forced induction in a compact package.

 

 

Vehicle Spec Sheet:

Company/ Team: Chris Forsberg Racing
Social Media Handles and Hashtags: @chrisforsberg64, facebook: chrisforsbergracing

VEHICLE INFORMATION-
Year / Make / Model: 2009 Nissan 370Z
Chassis Code: Z34
Competition Class: Formula Drift Pro 1
Fuel: VP Import
ENGINE INFORMATION-
Engine Code: VQ35HR
Bore & Stroke (mm) / Displacement (cc): 96mm x 92mm / 3,996cc
Peak Horsepower / Torque(@ RPM): 850whp / 700 lb-ft @ 7,000 RPM
Dyno Type: Dynojet
Engine Builder: AMS Performance
Block Modifications: RJM Closed Deck Block
Pistons / Compression Ratio: JE Pistons, 12.0:1 Compression
Connecting Rods / Crank: BC Brian Crower Pro H-Beam Rods
BC Brian Crower 4340 Forged Stroker Crank
Cylinder Head Modifications: Jim Wolf C9 Cams
Factory Throttle Bodies
Exhaust Manifold(s): Fast Intentions Turbo Manifolds
Exhaust System / Downpipe: Fast Intentions 3-inch Custom Downpipes
Fast Intentions 3-inch Exhaust
Wastegate(s): Turbosmart 40mm Wastegates (x2)
Intercooler: Fast Intentions Custom Front-mount Intercooler
Fuel Injectors: Deatschwerks 1,500cc/min (x6)
Fuel Pump(s): Deatschwerks DW400 Fuel Pump
Additional Fuel Delivery: Deatschwerks DWR2000 Regulator, DWFF110 Filter, Lines and Fittings
Engine Management System: MoTeC M150 Engine Management System
Boost Controller: MoTeC
Nitrous Oxide: 120-Shot Nitrous Oxide Injection

TURBOCHARGERS
Turbocharger(s): Garrett G25-660 (x2)
Frame: G25
Compressor Wheel Specs: 54mm Inducer, 67mm Exducer, 65 Trim
Turbine Wheel Specs: 54mm Inducer, 49mm Exducer, 84 Trim
Turbine Housing: .72 A/R
Peak Boost: 30psi