How do I know if I need the Coarse Spline LSD for Porsche 915?

Porsche built the 915 and 930 gearboxes with two side-gear splines, fine and coarse, and the model year alone does not settle it. Choose the Coarse Spline LSD for Porsche 915 only after confirming the spline in your gearbox, and contact our team if you are unsure.

Does it fit the 930 Turbo?

OS Giken Japan lists the coarse-spline unit for the 911 five-speed only, and lists the 930 Turbo four-speed under the fine-spline unit. Turn 14 shows some 930 Turbo fitment for this part, so confirm the spline in your gearbox before ordering.

Will it make the car harder to drive on the road?

No. OS Giken designed the Porsche Super Lock to suit both circuit and street use, moving smoothly from open to full lock, with pressure ring springs set to reduce drag at low speed. Expect some noise in tight parking maneuvers.

Can OS Giken tune it for my car?

Yes. OS Giken retunes Super Lock units in-house. Cone springs set initial torque, pressure ring springs set how quickly full lock arrives, and the pressure ring and iron cross set the ramp angles, so the unit can be matched to weight, power and use.

Does it fit Tiptronic or PTV Plus cars?

No. OS Giken Japan states that Tiptronic cars are not compatible, that cars with a factory LSD other than PDK cars are not compatible, and that cars with Porsche Torque Vectoring Plus cannot be fitted. Check the options on your car before ordering.

What oil should be used?

Use a gear oil suited to clutch-type limited-slip differentials, and change it more often than with an open differential, especially after track use. OS Giken lists a transaxle oil capacity of 3.7 liters for 911 applications. Fresh oil keeps the friction plates working consistently between rebuilds.

Description

Additional Info

Shipping policy

BP PRICING DIFFERENCE

Reviews

Product Inquiry

Description

OS Giken Super Lock Coarse Spline LSD for Porsche 915 911 Manual

OS Giken’s Coarse Spline LSD for Porsche 915 gearboxes is a Super Lock plate-type limited-slip differential for G-series 911s with the 915 five-speed manual and coarse-spline side gears. OS Giken Japan lists it for 1974-1989 911 five-speed cars. Turn 14 records the part as 28/25-456-12-10S. With the engine hung behind the rear axle, a 911 loads its rear tires hard on corner exit, and an open differential lets the inside wheel spin away that drive. The Super Lock builds lock smoothly and progressively, putting power down evenly and keeping the rear settled on and off throttle, on the road or at the track.

Coarse or Fine Spline

The 915 and 930 gearboxes were built with two different side-gear splines. This unit is the coarse-spline version. A fine-spline version is listed separately and also covers the 930 Turbo four-speed. OS Giken asks buyers to confirm the spline before ordering.

Features

Patented OS Giken pressure ring for smooth, progressive lock
Moves smoothly from open to full lock without extra slip on throttle
Pressure ring springs tuned against low-speed drag
Large-capacity friction plates and OS Giken side gear shape
Chemically heat-treated, high-grade steel alloy components
Coarse-spline side gears for 915 gearboxes

Applications

Porsche 911 (G-series): 915 five-speed manual, coarse spline, listed 1974-1989

Notes

This Coarse Spline LSD for Porsche 915 gearboxes requires coarse-spline side gears; confirm the spline before ordering
Turn 14 also lists 1978-1979 930 Turbo fitment; OS Giken Japan lists the 930 Turbo under the fine-spline unit, so confirm before ordering
1987-1989 Carrera models with the G50 gearbox take a different unit
OS Giken Japan lists Tiptronic cars, PTV Plus cars and cars with a factory LSD (other than PDK) as not compatible
Installation labor is not included

Frequently Asked Questions

How do I know if I need the Coarse Spline LSD for Porsche 915? Porsche built the 915 and 930 gearboxes with two side-gear splines, fine and coarse, and the model year alone does not settle it. Choose the Coarse Spline LSD for Porsche 915 only after confirming the spline in your gearbox, and contact our team if you are unsure.
Does it fit the 930 Turbo? OS Giken Japan lists the coarse-spline unit for the 911 five-speed only, and lists the 930 Turbo four-speed under the fine-spline unit. Turn 14 shows some 930 Turbo fitment for this part, so confirm the spline in your gearbox before ordering.
Will it make the car harder to drive on the road? No. OS Giken designed the Porsche Super Lock to suit both circuit and street use, moving smoothly from open to full lock, with pressure ring springs set to reduce drag at low speed. Expect some noise in tight parking maneuvers.
Can OS Giken tune it for my car? Yes. OS Giken retunes Super Lock units in-house. Cone springs set initial torque, pressure ring springs set how quickly full lock arrives, and the pressure ring and iron cross set the ramp angles, so the unit can be matched to weight, power and use.
Does it fit Tiptronic or PTV Plus cars? No. OS Giken Japan states that Tiptronic cars are not compatible, that cars with a factory LSD other than PDK cars are not compatible, and that cars with Porsche Torque Vectoring Plus cannot be fitted. Check the options on your car before ordering.
What oil should be used? Use a gear oil suited to clutch-type limited-slip differentials, and change it more often than with an open differential, especially after track use. OS Giken lists a transaxle oil capacity of 3.7 liters for 911 applications. Fresh oil keeps the friction plates working consistently between rebuilds.

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.

Reviews

There are no reviews yet.

Only logged in customers who have purchased this product may leave a review.

Product Inquiry

First Name (*required)

Last Name (*required)

Your E-Mail (*required)

Telephone Number (*required)

Country (*required)

Vehicle Year / Make / Model (*required)

Please Explain What do you want to do with your vehicle

Additional Information (optional)

I agree to the terms & conditions and privacy policy and to have Bulletproof Automotive LLC contact me for promotion, marketing and other purposes via email, phone or SMS message.

OS Giken Super Lock Coarse Spline LSD for Porsche 915 911 Manual [PR014-HA]

Guaranteed Safe Checkout

OS Giken Super Lock Coarse Spline LSD for Porsche 915 911 Manual

Coarse or Fine Spline

Features

Applications

Notes

Frequently Asked Questions

About OS Giken

Reviews