BLACKLINE PROFESSIONAL TRACTION SYSTEMS. Helical Gear Limited Slip Differential. Porsche 915 Transmission with 18 Spline Drive Shafts. Porsche 911 1972 – 1986 (18 Spline Models). Porsche 930 911 Turbo 1975 – 1988. Not suitable for models with 43 Spline Drive Shafts or G50 Transmission. Blackline Helical LSD’s – How They Work. The Blackline helical LSD’s are torque biasing, that is they distribute torque between the wheels, loading more torque towards the wheel with the best traction thus improving performance and driveabitily. Especially in low grip situations. The helical gearing manages the distribution of friction within the LSD. When torque is applied to the helical gear system it creates force that pushes the gear into the differential body, thus creating friction. Increases of torque, increases the thrust force directly proportional to the amount of torque. This allows the Blackline LSD to cope with considerable traction imbalance even under heavy power conditions, as would be the case on exiting a powered up corner. But at low torque conditions the LSD can differentiate quietly and smoothly, thus making the differential very suitable for normal road driving. The Blackline LSD uses the popular parallel axis helical geared configuration optimised for even load distribution. They are designed with a torque bias of 5:1 this means that if one wheel loses traction then the wheel with the most grip can receive five times as much torque as the wheel that is slipping. However, five times zero is still zero, so all these helical LSD’s work best when both wheels are’planted’ and some traction is still available on the slipping wheel. In practice this is rarely a problem as there is always some’drag’ on the slipping wheel, however some drivers expertly use left foot braking to partially lock the spinning wheel. Helical LSD’s work especially well when combined with modern anti-lock braking systems. Applies equal rotational speed to both wheels. Distributes torque according to available traction. Minimum servicing compared to plate type LSD’s. Controlled power on launches and drifting slides. Optimum gear tooth design and oil distribution. Gears and Body Manufactured from 8620 material. Direct replacement for stock differential. This is a Torque Biasing Helical Gear LSD. These are generally regarded as a nicer road LSD as they have little side effects during normal driving (unlike plate type LSD’s that constantly resist differing wheels speeds during cornering) They do not require a special oil. We recommend that the axle oil is changed after the first 500 miles as initially they can create swarf – this is normal and will reduce with use. (NOTE: This is NOT a plate type, viscous coupling or clutch pack LSD). Assembled Differential Unit ONLY. Bearings, gears, gaskets/seals etc are NOT included. No instructions are included. Questions: We are happy to do our best to answer sensible, genuine questions during our normal office hours (Mon-Fri 09:30-17:30), however please note we do not have intimate knowledge of all makes & models or have personal experience of fitting/using all our products. Products only fit models stated (if products fit other models its in our favour to say so)! Products listed as universal fitment are not designed for any one model.
