Is the Rear Super Lock LSD for GD and GR cars the same as the front unit?

No. This Super Lock LSD for GD and GR STI cars is the rear differential, part number SB041-HA. OS Giken sells the front unit for the same cars separately as SB041-HA01. Owners fitting both get a clutch-type locking differential at each axle of the STI.

How does it work with the DCCD center differential?

The driver-controlled center differential decides how torque is split between the axles. The rear Super Lock then decides how the rear share is split between the two rear tires, keeping both driving when the inside wheel unloads. The two work together, and the DCCD setting still governs front-to-rear balance.

What do STI owners gain on track?

Stronger drive out of slow corners and more willingness to rotate under power. With a clutch-type rear unit the car can be steered with the throttle more readily, which suits time attack and rallycross. On public roads the difference is small.

Does it suit the 2011-2014 sedan?

OS Giken USA lists the unit for GDB and GRB cars. The GV sedan shares the GR platform, but it is not named in the listing, so Bulletproof Automotive recommends confirming fitment for a sedan before ordering. The VIN will settle it.

Can the setting be changed later?

Yes. OS Giken retunes Super Lock units in-house. Cone springs set initial torque, pressure ring springs set the speed of lock-up, and the pressure ring and iron cross set the ramp angles. TCD spec discs can be added for better oil cooling on long events.

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Description

OS Giken Rear Super Lock LSD for GD / GR Subaru Impreza WRX STI

OS Giken’s Rear Super Lock LSD for GD / GR Subaru Impreza WRX STI puts a clutch-type differential at the back of the EJ257 car’s all-wheel-drive system, where it decides how much of the center differential’s rear torque actually reaches the road. The STI’s driver-controlled center diff can send more drive rearward, but the factory rear unit only biases torque while both tires carry load, and a rally-style car on stiff springs unloads its inside rear constantly. The Super Lock keeps both tires driving through OS Giken’s patented pressure ring. It is the upgrade for an STI used for time attack, rallycross or track days.

Design and Performance

The friction plates run on splines through the side gears, which lets OS Giken fit up to twice the plates of competing designs. With that much plate area the differential can run a light preload for street use and still progress smoothly to full lock under power. The case is machined from one billet and every part is chemically heat treated.

Features

Clutch-type rear differential for the STI all-wheel-drive system
Patented pressure ring for progressive, predictable lock
Up to twice the friction plates of competing designs
Light preload suited to a road car
Billet case and raw-forged gears
Retunable by OS Giken for initial torque and lock timing

Applications

Subaru Impreza WRX STI: GD | 2004-2007 | 2.5L EJ257 turbo
Subaru Impreza WRX STI: GR | 2008-2014 | 2.5L EJ257 turbo

Notes

This is the rear unit; the front Super Lock LSD for GD and GR STI cars is part number SB041-HA01
Installation labor is not included

Frequently Asked Questions

Is the Rear Super Lock LSD for GD and GR cars the same as the front unit? No. This Super Lock LSD for GD and GR STI cars is the rear differential, part number SB041-HA. OS Giken sells the front unit for the same cars separately as SB041-HA01. Owners fitting both get a clutch-type locking differential at each axle of the STI.
How does it work with the DCCD center differential? The driver-controlled center differential decides how torque is split between the axles. The rear Super Lock then decides how the rear share is split between the two rear tires, keeping both driving when the inside wheel unloads. The two work together, and the DCCD setting still governs front-to-rear balance.
What do STI owners gain on track? Stronger drive out of slow corners and more willingness to rotate under power. With a clutch-type rear unit the car can be steered with the throttle more readily, which suits time attack and rallycross. On public roads the difference is small.
Does it suit the 2011-2014 sedan? OS Giken USA lists the unit for GDB and GRB cars. The GV sedan shares the GR platform, but it is not named in the listing, so Bulletproof Automotive recommends confirming fitment for a sedan before ordering. The VIN will settle it.
Can the setting be changed later? Yes. OS Giken retunes Super Lock units in-house. Cone springs set initial torque, pressure ring springs set the speed of lock-up, and the pressure ring and iron cross set the ramp angles. TCD spec discs can be added for better oil cooling on long events.

About OS Giken

OS Giken was founded in Okayama, Japan in 1973 by Masaharu Okazaki. It built the TC16 and TC24-B1 DOHC cylinder heads for Nissan L-series engines, began making multi-plate racing clutches in 1982 and started supplying OEM limited-slip differentials in 1983. Development of the Super Lock LSD began in 1997, and of the OS-88 sequential gearbox for the Skyline GT-R in 1998.

Additional Information

The Bulletproof Automotive website contains many thousands of products purchased in multiple different currencies. All of the prices are entered manually and accurately at the time of entry. Due to the consistently fluctuating international exchange rates, at times prices may not be able to be honored at their original intended rate. We apologize for any inconvenience this may cause, unfortunately our website is unable to compensate dynamically for what can at times be volatile changes in the cost of items due to currency values fluctuating, changes in prices from suppliers, changes in shipping and import duties, and other factors. Rest assured that any order you place on line will be at zero risk to you in this area. If in the event your order cannot be fulfilled at the original intended website price we will offer you a 100% refund, no questions asked. We will continue to do our best to maintain updated prices and we will always continue to offer our price match guarantees as well to ensure our prices are always the best for you. In short, prices may change without notice. It is always advised to give us a call prior to placing your order online to confirm availability and to confirm current pricing.

Shipping Policy

Items that are in stock in the US, either at Bulletproof’s warehouse or at a supplier’s warehouse, are generally delivered within 7-10 days. Special order items from overseas take considerably longer. As a courtesy Bulletproof offers delivery estimates to our customers which take into consideration manufacturer availability and shipping schedule. These estimates represent our best guess based on previous orders from the manufacturer and do not in any way imply a guaranteed delivery window. Many manufacturers work in a “just in time” inventory system and often take 2-20+ weeks to produce an item once an order is submitted. All deliverable items are then sent to our Japanese warehouse. Bulletproof ships a minimum of one full ocean freight container every month from Japan, oftentimes more than one a month. Ocean freight takes an average of 4 weeks. Typically it breaks down to one week in Japan for paperwork and customs, two weeks by boat and one week in US customs/clearance. Due to the wide number of variables between manufacturer and shipping schedules, delivery estimates are simply just that – estimates. We attempt to estimate conservatively and we usually deliver faster than our estimates suggest. It is not Bulletproof’s policy to guarantee delivery time of any special order item, this is impossible for us to do. By ordering you acknowledge that there is no required delivery ETA and an order may not be canceled or altered due to manufacturing or shipping delays, all ETA’s are provided as a best guess only. Please review the full Terms & Conditions here.

BP Pricing Difference

We do pricing a little differently on our JDM brands and we believe in making things simple and clear. No hidden fees or surcharges. Every price you see includes the shipping cost to our office in Los Angeles, California and all the associated taxes/duties/fees for bringing the products into the US. The only shipping you ever pay is from our facility in the US to your location. Be wary of resellers that don’t include the cost of international shipping in their pricing on JDM parts. While we believe we’ll always have the lowest all-in price on JDM products, we offer a price match guarantee for all authentic parts purchased from authorized dealers as well. For many international customers, it’s much more affordable to ship from the USA than from Japan directly, as the air freight and ocean freight costs are typically much less. However, for customers looking to ship directly from Japan outside of North America, or domestically in Japan, we can provide pricing specifically for that scenario. Please do not hesitate to contact us with any pricing questions or concerns. Please email us at sales@bulletproofautomotive.com with any inquiries.

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OS Giken Rear Super Lock LSD for GD / GR Subaru Impreza WRX STI [SB041-HA]

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OS Giken Rear Super Lock LSD for GD / GR Subaru Impreza WRX STI

Design and Performance

Features

Applications

Notes

Frequently Asked Questions

About OS Giken

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