Straight line
Both wheels turn at the same speed. The gears are locked to each other and the case turns as one piece, so each wheel gets half the torque.
Torsen differential · BMW 188K
Have fun for real this winter.
Throw out your open diff and swap it for a Torsen diff. A gear-driven, torque-sensing limited slip differential. No clutch packs to wear out, no rebuilds, no welded-diff problems. Just more fun behind the wheel.
Not sure? Find out which diff you haveYou swap the outer races in the diff housing yourself. It is done with a drift, no press needed.
€1,200
Approx. price
Before discount. Exact price when the batch is confirmed.
Your discount€50
To pay today0
- No payment, no obligation
- First in line when the batch is ready
- Price and delivery time are sent to you when the batch is confirmed. You decide then.
Specifications
| Fits | |
|---|---|
| Does not fit | |
| Type | |
| Ratio | Keeps your own ratio (the ring gear moves over) |
- All gearsNo clutch plates or springs that wear out.
- Fit it yourselfTutorials walk you through it step by step.
- Bearings pressed onAs an option, ready to fit.
- No payment nowRegister your interest with no commitment.
What diff do I have?
Choose your car, and we show which rear diff it has and whether we have a Torsen for it.
The list covers common rear-wheel drive cars and is a guide. Diffs can differ between years and markets, so check on the car before you order parts.
A differential that senses torque.
Every car needs a differential so the outer wheel can turn faster than the inner wheel in a corner. A standard open differential does this well, but it has a weakness: it always sends the same torque to both wheels. When one wheel loses grip, the torque to the other wheel drops with it, and the power disappears as wheelspin. That makes a drift hard to initiate, and even harder to hold.
A Torsen (short for torque sensing) differential uses gears that resist being driven backwards. When one wheel starts to spin, that friction inside the gear set sends more torque to the wheel that has grip. So drifts are easier to initiate, and you can hold them with confidence. Tip: if a wheel loses grip completely, touch the brake lightly. That gives the wheel some resistance, and the Torsen sends the torque across again.
- All gearsNo clutch plates or springs that wear out.
- InstantReacts to torque the moment it changes. No lag.
- SmoothQuiet and predictable on the street. No chatter in tight turns.
- Low upkeepRuns on regular gear oil. No special friction modifier.
- Bearings pressed onAs an option, with new carrier bearings fitted. No bearing press needed.
Three situations, one set of gears.
Cornering
The outer wheel travels further and has to turn faster. The gears inside rotate against each other and let the wheel speeds differ, just like an open diff.
One wheel loses grip
The slipping wheel tries to speed up, but the gears resist being driven that way. The internal friction transfers torque across, so the wheel with grip keeps driving the car.
Inside the housing
The ring gear bolts to the flange and turns the housing. Each pinion meshes with one side gear and with its partner, which meshes with the other side. When the wheels want to turn at different speeds, the pinions spin in their pockets, and their helical teeth push them against the housing walls.
That push creates friction in proportion to the torque going through. More torque means more locking, automatically.
Why it holds a slide.
In a drift the weight moves to the outside of the car, and the inside rear wheel goes light. That is where an open diff gives up. Our Torsen has a 5:1 torque bias ratio, so it keeps feeding the loaded outside wheel.
Open diff
The light inside wheel spins up and takes all the drive. The outside wheel stops pushing and the car straightens up.
Torsen 5:1
Both rear wheels keep spinning together. You hold the angle on the throttle and leave two black lines.
Rear wheel spinning Tyre mark
Simplified illustration. If the inside wheel lifts completely off the ground, a light pull on the handbrake gives the Torsen something to push against again.
How it stacks up.
WeldedCheapest. Locked all the time, scrubs tyres and hops in tight turns.
TorsenThe middle ground. Holds a slide, but drives like a normal car on the way to work.
Clutch LSDMost locking. Highest price, and plates that wear out and need rebuilding.
| Open | Torsen | Clutch LSD | Welded | |
|---|---|---|---|---|
| Price | Stock | Mid | High | Lowest |
| Drive out of corners | Poor | Very good | Very good | Maximum |
| Street manners | Perfect | Perfect | Good, some chatter | Poor, tyre scrub |
| Wear parts | None | None | Clutch plates | None |
| Locks under braking / lift-off | No | Mildly | Yes (1.5 / 2-way) | Always |
| One wheel in the air | No drive | No drive* | Drive | Drive |
| Best for | Commuting | Street drift, track, daily driver | Competition drift, track | Drift on a budget |
* On its own it gives no drive, since a wheel in the air has no resistance. Use the brake trick: touch the brake lightly, the free wheel gets some resistance, and the Torsen sends the torque across again.
Tell us which one you want.
We are planning the first batch now. Register your interest with no commitment, and we will contact you with price and delivery time when the batch is confirmed.
€50 off a diff for everyone who registers.
- No payment, no obligation
- First in line when the batch is ready
Good to know.
Is this a drop-in replacement?
It replaces the carrier inside your existing diff. If you choose the carrier bearings pressed on, you only move the ring gear over from the old carrier. You can fit it yourself, and we have tutorials that walk you through it step by step. If you feel unsure, leave it to a workshop.
Is it good for drifting?
Yes. It keeps both rear wheels driving on the throttle, so it holds a slide well, and it costs less than a clutch LSD while still being easy to live with every day. For top-level competition, where you want the diff locked on lift-off and handbrake too, a clutch-type 1.5 or 2-way LSD is still the stronger choice.
What oil does it need?
Regular hypoid gear oil of the grade your axle calls for. No friction modifier is needed since there are no clutch plates.
Does registering cost anything?
No. It is only an interest list. We send price and delivery time first, and you decide then.
How does the discount work?
Everyone who registers interest gets €50 off a differential, with or without bearings. It does not apply to bearings bought on their own. The discount is linked to the email address you register with and is taken off the price when you order from us.