Quaife FWD/AWD Limited Slip Differential for K Series

Quaife ATB Helical LSD - Honda/Acura K Series FWD/AWD

You're running a K series and you're spinning one wheel. You're launching and the inside wheel's just lighting up while the outside wheel sits there doing nothing. You're coming out of a corner hard and the power's going to the wheel that's in the air instead of the wheel that's on the ground. That's what an open differential does. It sends power to the wheel with the least resistance. It's garbage for performance driving. Quaife's ATB helical LSD replaces your stock open differential with a gear-type limited slip that automatically sends torque to the wheel with traction. No clutch packs. No preload. No maintenance. Just helical gears that bias torque away from the spinning wheel and send it to the wheel that can use it. You're launching and both wheels are hooking. You're coming out of corners and the power's going where it's supposed to go. This is a direct bolt-in for K series FWD and AWD transmissions. It's what you install when you're done lighting up one tire and you're ready to actually put the power down.

Here's Why Your Stock Open Differential Is Killing Your Performance

The stock K series differential is an open diff. It's designed to let the wheels turn at different speeds when you're going around corners. That's fine for driving to the grocery store. It's terrible for performance driving. Here's what happens when you've got power and you're trying to use it. You launch hard. The inside wheel breaks loose because there's less weight on it. The open diff sends all the power to that wheel because it's got less resistance. Now you're sitting there spinning one wheel and going nowhere. Or you're coming out of a corner on the throttle. The inside wheel lifts slightly. The open diff dumps all the power to that wheel. It spins. You get wheelspin. You get torque steer. You get the car pulling to one side. You're fighting the steering wheel instead of driving the car. Quaife's helical LSD fixes that. It's a gear-type differential that uses helical gears to transfer torque from the wheel that's slipping to the wheel that's gripping. You launch and both wheels are putting power down. You're coming out of corners and the power's going to the wheel with traction. The car goes straight. The steering feels connected. You're actually using the power you're making instead of spinning it away on one tire.

Helical Gears Instead of Clutch Packs - No Maintenance, No Preload

Most aftermarket LSDs use clutch packs. They work but they've got problems. Clutch-type LSDs have a preload. That's a set amount of resistance before the diff lets the wheels slip. The preload's there all the time. It makes the car feel tight in parking lots. It makes the steering feel heavy at low speeds. The clutch packs wear out. You're rebuilding the diff every 20,000-30,000 miles and replacing the clutch packs and shimming the preload back to spec. Quaife's ATB helical LSD doesn't use clutch packs. It uses helical-cut gears. The gears mesh together at an angle. When one wheel starts to spin, the helical gears create a force that pushes torque to the other wheel. The amount of torque transfer varies constantly based on how much the wheels are slipping. There's no set preload. There's no harsh locking like a clutch-type LSD. The diff feels like an open diff in parking lots and at low speeds. Then when you're on the throttle hard and one wheel's trying to spin, the helical gears automatically send the torque to the wheel with grip. It's seamless. It's progressive. It just works. And because there's no clutch packs, there's no maintenance. You're running your stock transmission fluid. You're not rebuilding the diff. You're just driving it.

Works in FWD and AWD K Series Transmissions

Quaife's ATB helical LSD is part number QDF21U and it fits both FWD and AWD K series transmissions. If you're running an RSX, an EP3, an FA5, an FG2, an FK8, an FL5, or any other FWD K series car, this diff bolts right in. If you're running an AWD setup with a CR-V or Element transmission, this diff bolts right in. It's a direct replacement for the stock open differential. You're pulling the transmission, opening it up, pulling the stock diff, installing the Quaife, and reassembling the trans. The Quaife uses the stock ring gear. It bolts to the stock case. It uses the stock bearings. Everything fits like OEM. Installation's straightforward if you've done transmission work before. The diff's been proven in everything from street cars to road race cars to drag cars. We've seen Quaife diffs run in 500+ whp FWD cars running 10-second passes. We've seen them in AWD drag cars making 800+ whp. They work. They last. They don't require rebuilds.

Built from Billet Steel and Machined to Tight Tolerances

Quaife machines this diff from Corus steel billets. That's not cast iron like some cheap LSDs. That's billet steel. The gears are CAD-designed and CNC-machined. Every gear's cut to tight tolerances. The diff's inspected to ISO 9001 standards before it ships. Quaife's been building helical LSDs since the 1960s. They know what they're doing. This isn't some no-name LSD that's going to break when you launch hard. This is a Quaife. It's proven in circuit racing, drag racing, rally, and street use. The diff's been tortured in every possible application and it holds up. You're not worrying about the LSD anymore. You're worrying about other parts of the car because the Quaife's just working.

What You Get

• Quaife ATB helical LSD - part number QDF21U
• Direct replacement for stock K series open differential (FWD and AWD)
• Helical gear-type LSD (no clutch packs, no preload, no maintenance)
• Automatically biases torque to the wheel with traction
• Progressive torque transfer (never locks harshly like clutch-type LSDs)
• Eliminates one-wheel wheelspin and torque steer
• Uses stock transmission fluid (no special LSD fluid required)
• Machined from Corus steel billets (CAD-designed, CNC-machined)
• ISO 9001 certified manufacturing
• Proven in circuit racing, drag racing, rally, and street use
• Made by Quaife

Fits These Cars

• 2002-2006 Acura RSX (all trims, FWD K series)
• 2002-2005 Honda Civic Si (EP3, FWD K series)
• 2006-2011 Honda Civic Si (FG2/FA5, FWD K series)
• 2012-2015 Honda Civic Si (FB6/FG4, FWD K series)
• 2017-2021 Honda Civic Type R (FK8, FWD K series)
• 2023-2024 Honda Civic Type R (FL5, FWD K series)
• 2023-2024 Acura Integra (FWD K series)
• 2002-2006 Honda CR-V (AWD K series)
• 2003-2011 Honda Element (AWD K series)
• K series swaps (FWD and AWD)

Note: Direct bolt-in replacement for stock K series open differential (FWD and AWD applications). Helical gear-type LSD with no clutch packs (no preload, no maintenance, no rebuilds). Uses stock transmission fluid. Automatically transfers torque from spinning wheel to wheel with traction (progressive engagement, never locks harshly). Eliminates one-wheel wheelspin, reduces torque steer in FWD applications. Machined from Corus steel billets with CAD design and CNC machining. ISO 9001 certified. Proven in 500+ whp FWD builds and 800+ whp AWD builds. Requires transmission removal and disassembly for installation. Uses stock ring gear and bearings. Professional installation recommended. Made by Quaife. Part number QDF21U. Fits all K series FWD transmissions (RSX, EP3, FA5, FG2, FB6, FK8, FL5, Integra) and AWD transmissions (CR-V, Element).