MFactory Helical Limited Slip Differential for B Series

MFactory Helical Limited Slip Differential - Honda/Acura B Series

Running a B series Integra or Civic at the track and you're spinning one wheel coming out of corners? Your open differential's sending all the power to the wheel with less traction. The MFactory helical LSD splits power between both wheels so you're actually putting power down instead of lighting up one tire. Your stock open diff sends 100% of the power to whichever wheel has less grip. That's why you're spinning the inside wheel coming out of corners. The helical LSD can transfer up to 75% of the torque to the wheel with more grip. You're getting way better corner exit traction and you're not one-wheel-pegging it everywhere.

Here's Why Open Diffs Suck for Track Use

Your stock B series diff is an open differential. When you're cornering hard and one wheel lifts or loses traction, all the power goes to that wheel. The wheel with traction gets nothing. You're spinning the inside wheel and going nowhere. An open diff works fine for street driving where you're not pushing the car, but on track it's garbage. Every time you're trying to put power down coming out of a corner, you're spinning one wheel. The MFactory helical LSD uses gear geometry to split power between both wheels based on which wheel has more traction. When one wheel starts to slip, the diff transfers torque to the other wheel automatically. No clutch packs, no preload springs, just gears doing their thing. You get predictable power delivery and way better corner exit speed.

Helical LSD vs. Clutch-Type LSD

Most aftermarket LSDs are clutch-type (like Cusco or OBX). They use clutch packs that wear out and need rebuilds every few years. You're also supposed to run special diff fluid with friction modifiers. The MFactory helical LSD uses gears instead of clutches. There's nothing to wear out and you don't need special fluids. Just run regular gear oil and forget about it. I've got 5+ years and probably 100+ track days on my MFactory diff and it still works like new. Clutch-type diffs also change your steering feel because they bind up under certain conditions. The helical diff doesn't bind, so your steering feels normal.

Forged Steel, Not Cast

The MFactory diff's made from forged Japanese SAE 4320 and SAE 9310 steel. That's way stronger than cast steel or cheap Chinese forgings. The gears are double-tempered and cryogenically treated (super sub-zero treatment) for extra toughness. MFactory also shot-peens the gears to increase surface hardness. The diff's designed to handle drag racing shock loads, so it'll survive anything you throw at it on a road course or autocross. The gear geometry's designed to minimize parasitic drivetrain losses. MFactory claims their diffs transfer 1-2% more power to the wheels than competitors' diffs. That's not a huge number, but every bit helps.

Three Variants - Make Sure You Order the Right One

MFactory makes three different B series diffs: **B16A/B18A/B18B** - Fits 1990-1993 Integra (B18A), 1999-2000 Civic Si (B16A2), 1994-1997 Del Sol VTEC (B16A), 1994-2001 Integra GS/LS/RS (B18B) **B18C1/B18C5** - Fits 1994-2001 Integra GS-R (B18C1), 1997-2001 Integra Type R (B18C5) **B Series AWD** - Fits 1997-2001 CR-V (manual transmission). Works with standard FWD B series axles or AWD CR-V axles. The diffs aren't interchangeable. The ring gear bolt patterns and case sizes are different. Order the correct one for your transmission or it won't fit.

What You Get

• MFactory helical limited slip differential
• Forged Japanese SAE 4320/9310 steel construction
• Double-tempered and super sub-zero treated
• Shot-peened gears for increased surface hardness
• Up to 75% torque transfer to one wheel
• No clutch packs (maintenance-free)
• Works with standard gear oil (no special fluids)
• No steering bind or adverse effects
• Lifetime globally transferable warranty
• Available in three variants (see fitment below)

Fits Your Car (Choose Correct Variant)

• 1990-1993 Acura Integra (B18A)
• 1999-2000 Honda Civic Si EM1 (B16A2)
• 1994-1997 Honda Del Sol VTEC (B16A)
• 1994-2001 Acura Integra GS/LS/RS (B18B)

• 1994-2001 Acura Integra GS-R (B18C1)
• 1997-2001 Acura Integra Type R (B18C5)

• 1997-2001 Honda CR-V (manual transmission)
• Works with standard FWD B series axles or AWD CR-V axles

Note: Order the correct variant for your car or it won't fit. If your B16A2 Civic Si came with a factory viscous LSD, this diff won't bolt in without changing the ring gear. Installation requires pulling your transmission and opening the diff. If you've never done diff work, get a shop to install it.