Gearbox Upgrades

Crunchy Gears? Require more drive out of corners? We have all the answers for your gearbox requirements.

Gearbox upgrades can often be overlooked for Suspension and Performance upgrades, but what you gain from your gearbox can be a real world performance benefit like no other.

Different Types of Differentials


Open Differential (Normal differential found in most standard cars)

The open differential always applies the same amount of torque to each wheel. There are two factors that determine how much torque can be applied to the wheels: equipment and traction. In dry conditions, when there is plenty of traction, the amount of torque applied to the wheels is limited by the engine and gearing; in a low traction situation, such as when driving on ice, the amount of torque is limited to the greatest amount that will not cause a wheel to slip under those conditions. So, even though a car may be able to produce more torque, there needs to be enough traction to transmit that torque to the ground. If you give the car more gas after the wheels start to slip, the wheels will just spin faster.

Helical / Gear Differentials LSD

All gear LSDs (including Torsen®, Truetrac®, Quaife®, Peloquin, OBX, etc.) work in basically the same manner: they divide the drive torque between the two axles, applying drive to each side, up to the available grip of each tire. The amount of drive torque one wheel can get over the other is described as the bias ratio, a measure of the torque split across the axle.

Standard, open differentials have a bias ratio of 1:1. They can only apply as much drive torque as there is available traction at one wheel. When one wheel loses grip, the total available drive is lost as well (at a 1:1 ratio). All your power goes out the slipping wheel – along the path of least resistance.

Torque biasing differentials offer increased bias ratios over open differentials. For example, if a diff has a bias ratio of 2.5:1, then it can apply drive torque to the wheel with the most traction (gripping wheel) at 2.5 times the traction limit of the wheel with the least traction (slipping wheel). This is a significant improvement over an open diff.

The problem is that when one tire has LITTLE or NO grip (zero axle-load), the other wheel gets ZERO DRIVE, because (basic math here): 2.5 x 0 = 0.

Lift a wheel (or substantially unload a wheel) and you get zero axle-load on that side – that means that during the time the wheel is unloaded, the typical diff will NOT power the wheel that’s still on the ground. No matter how high the bias ratio, you get no power to the ground.

Plate / Clutch Differential LSD

The clutch type has a stack of thin clutch-discs, half of which are coupled to one of the drive shafts, the other half of which are coupled to the spider gear carrier. The clutch stacks may be present on both drive shafts, or on only one. If on only one, the remaining drive shaft is linked to the clutched drive shaft through the spider gears. In a cone type the clutches are replaced by a pair of cones which are pressed together achieving the same effect.

There are three input torque states your car will be subjected to. These are load, no load, and overrun.

  • A 2-way differential will have the same limiting torque in both the forward and reverse directions. This means the differential will provide some level of limiting under engine braking helping to slow the car.
  • A 1-way differential will provide its limiting action in only one direction. When torque is applied in the opposite direction it behaves like an open differential. In the case of a FWD car it is argued to be safer than a 2-way differential.[5] The argument is if there is no additional coupling on overrun, i.e. a 1-way LSD as soon as the driver lifts the throttle, the LSD unlocks and behaves somewhat like a conventional open differential. This is also the best for FWD cars, as it allows the car to turn in on throttle release, instead of ploughing forward.[5]
  • A 1.5-way differential refers to one where the forward and reverse limiting torques, Trq d_fwd, d_rev , are different but neither is zero as in the case of the 1-way LSD. This type of differential is common in racing cars where a strong limiting torque can aid stability under engine braking.

Cost = Helical LSD for EP3 / DC5 £525.00
Cost = Plate LSD for EP3 / DC5 £695.00

Gear Upgrades Final Drives and Shorter Gear Sets


MFactory Final Drives

By changing your final gear ratios, you can experience a dramatic increase in acceleration, giving you on average, a 10-15% increase in torque throughout the entire rev-range over the OEM Final Drive.

We could talk about the benefits of gearing till we’re blue in the face, so to keep this simple for the non-technical customers out there, or for those who just want to know the numbers, here are some examples of just how much power you can gain.

Cost = 5.08, 5.46, 5.83, 6.33 for K20 applications = £580.00

Vehicle: USDM Integra Type-R
Gear Ratio Peak Engine Torque ETE Power Gain Cruising (5th Gear)
OEM 4.4 Final Drive 122lbft 122lbft 0% 70mph @ 3600rpm
MFactory 4.785 Final Drive 122lbft 133lbft 9% 70mph @ 3900rpm
MFactory 4.928 Final Drive 122lbft 137lbft 12% 70mph @ 4100rpm


Vehicle: UKDM 01-06 Type R
Gear Ratio Peak Engine Torque ETE Power Gain Cruising (6th Gear)
OEM 4.388 Final Drive 142lbft 142lbft 0% 70mph @ 2900rpm
MFactory 5.46 Final Drive 142lbft 176lbft 24% 70mph @ 3700rpm
MFactory 5.84 Final Drive 142lbft 189lbft 33% 70mph @ 3900rpm
MFactory 6.33 Final Drive 142lbft 204lbft 44% 70mph @ 4300rpm


Vehicle: USDM 92-96 Prelude VTEC
Gear Ratio Peak Engine Torque ETE Power Gain Cruising (5th Gear)
OEM 4.266 Final Drive 158lbft 158lbft 0% 70mph @ 3500rpm
MFactory 4.64 Final Drive 158lbft 172lbft 9% 70mph @ 3900rpm
MFactory 5.15 Final Drive 158lbft 191lbft 21% 70mph @ 4300rpm

ETE: Engine Torque Equivalent (How much torque an engine with a stock transmission will need in order to accelerate at the same rate)
%: The percentage of Torque Increase between the Stock Transmission and the Custom Transmission

Synchro Upgrades and Replacement


MFactory Carbon-Lined Synrchos. Improve shifting response with the MFactory Carbon-Lined Synchros. Utilizing a carbon fiber lining technology which acts as braking material during gear engagement, this allows for quicker and more precise shifting and prolongs the life of your gear set.

– Made from high strength Japanese brass.
– Synchros are carbon fiber lined for increased durability.
– 100% larger surface contact area for increase performance.
– More aggressive lock angle for effortless high rpm shifting.

After several years of research & development on our championship winning race cars, we are proud to offer the most technologically advanced synchros on the market for the Honda transmission.

Will fit all K-series gearboxes.

Cost = 1/2/3/4 Gear Synchros K20 = £244.00
Cost = 1/2/3/4/5/6 Gear Synchros K20 = £299.00

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