Honda S2000 -- Transmission

9/15/2000 4:18:21 PM

6-SPEED MANUAL TRANSMISSION

OVERVIEW
Honda engineers designed an entirely new close-ratio, 6-speed manual transmission for the S2000. A limited-slip differential was chosen to ensure continuous application of power to the rear wheels, especially when cornering. The transmission and entire drivetrain are designed to be highly rigid and as compact and lightweight as possible, making the vehicle more responsive to driver input and increasing the driver's enjoyment and feel for the car.

LONGITUDINALLY MOUNTED 6-SPEED MANUAL TRANSMISSION
In the S2000 transmission, all six speeds and reverse are on two parallel shafts. Both transmission shafts are coupled at the output end, a design feature borrowed from Honda's front-wheel-drive transmissions. This reduces the load on the gear synchronizers by as much as 40 percent. Shift loads are also reduced, making shifting easier.

The use of double-cone synchronizers for first, third and fourth gears, and triple-cone synchronizers for second gear, helps reduce shift effort. Reverse gear uses single-cone synchronizers for smoother shifting and quieter operation.

TRANSMISSION GEAR RATIOS

First Gear:

3.133

Second Gear:

2.045

Third Gear:

1.481

Fourth Gear:

1.161

Fifth Gear:

0.970

Sixth Gear:

0.810

Reverse Gear:

2.800

Primary Gear Reduction:

1.160

Final Drive:

4.100

SHORT-STROKE, DIRECT SHIFT LINKAGE
The transmission shift linkage is mounted on the top of the transmission case, helping to eliminate play in the linkage and provide optimum feel when changing gears. Shift throws are short and direct. Shift detents and lateral-spring pressure are set so that the shift-lever neutral position lies on the 3rd-gear/4th-gear axis.

The shift lever is aluminum alloy and floats in a rubber mounting that absorbs vibration. Reverse-gear lockout is a mechanical type, which can be released by pressing the shift lever to the side.

SEPARATE LUBRICATION PUMP ENHANCES DURABILITY
Racing experience taught Honda engineers that high-performance transmissions need a separate lubrication system, so the S2000 manual transmission has its own lubrication pump, driven off the transmission secondary gear. The pump provides positive and reliable lubrication, regardless of G-loading, and helps to prolong gear and synchronizer life.

LOW-MASS POWERTRAIN
When cornering a high-performance, front-engine, rear-wheel-drive roadster, throttle input can be used as a means of fine-tuning vehicle control. For this reason, Honda engineers wanted to keep the S2000 powertrain's entire rotational mass to a minimum, thereby minimizing inertia, and the response time between driver input and vehicle reaction. In order to accomplish this, many components, such as the clutch, flywheel (20% lighter than the Accord engine's flywheel), propeller shaft, axle shafts and constant-velocity joints have had weight carefully removed.

COMPACT HEAVY-DUTY, PULL-TYPE CLUTCH
In addition to reducing the size and mass of the engine flywheel and transmission gears, Honda engineers adopted a pull-type clutch mechanism and reinforced friction materials better suited to the high-rpm nature of the powertrain.

LOW-VIBRATION PROPELLER SHAFT
The propeller shaft that takes power to the rear differential in the S2000 is a strong, one-piece design. To reduce noise and vibration from the shaft, which can turn up to 9000 rpm, Honda engineers specified sliding, constant-velocity joints at both ends, instead of the more common U-joints. Constant-velocity joints also transmit power more uniformly over a range of angles.

LIMITED-SLIP DIFFERENTIAL
The Torsen limited-slip differential (clutchless type) used in the S2000 is specifically adapted for high power output and automatically transmits drive torque to the wheel and tire with the most traction, thereby limiting wheel spin.

ONE-PIECE, HIGHLY RIGID AXLE SHAFTS
Power is transmitted from the differential to the rear wheels via a set of rigid, one-piece axle shafts. The shafts' increased level of rigidity improves the powertrain's response to throttle input.