Project S2000 With the increased horsepower we plan to produce with the Full-Race turbo setup, we want to make sure our driveline is bulletproof and can handle any power we throw at it. To accomplish this, we've purchased a Quaife QBE60G sequentially shifted 6-speed gearbox along with a set of Innovative 85A durometer engine/transmission mounts.
Before ordering the gearbox, we had to select our gearing. Quaife offers a variety of available gear ratios, and with the help of its gear calculator, we picked the QBE60G gearset and have listed the AP1/AP2 gearing for reference (we have multiplied through by the primary gear reduction to show the effective gear reduction). We can adjust top speed with the use of different final drives, depending on the track configuration. The 3.63 setup is good for 178 mph at 8500 rpm and the 4.10 will top out at 157 mph. By effectively making first gear just a bit shorter than the OEM second gear, we've made first gear usable on track, and consequently, are able to tighten up the spacing between the remaining gears. This will ensure that engine rpm can always be kept close to peak power.
With the Quaife, you have the option of helical- or straight-cut gears. We've opted for straight cut, which are more efficient (there's no axial thrust force caused by helical-cut gears) and make that great high-pitch whine. We've also fitted the gearbox with the optional gear position indicator and the standard/short shift lever. Finally, we selected the Burton-type short input shaft that's designed to work with a hydraulic release bearing and push-type clutch. With the reduced power loss from the straight-cut gears, closer spaced gearing and shortened shift times, the QBE60G should translate to improved lap times. Quaife rates the gearbox conservatively at 450 hp, but we're confident it will hold up to our planned 550 whp. Avoiding standing starts/launches will certainly help increase its lifespan.
Next up, we fitted an S2000-to-Quaife bellhousing adapter from DMRR. This let us bolt the gearbox to the engine, which allowed us to install the Innovative engine mounts and drop in the engine/trans. The Innovative mounts are a perfect fit, feature an attractive/durable crinkle coat black finish and they'll certainly improve engine response and minimize engine movement. Depending on your application, Innovative offers a wide range of bushing durometers from 60A for street, 75A for street/track, 85A for race and 95A for extreme applications. We opted for the 85A to provide a good balance between response/limited movement and vibration isolation. The mounts are CAD-designed, stress-analyzed and come backed with a lifetime warranty.
Once in the bay, we quickly realized that something wasn't adding up. It turns out the DMRR bellhousing is designed for a 12-degree engine rotation as opposed to the factory 15-degree position. We're the first to actually use the DMRR S2000 bellhousing adapter in an S2000, as most of these end up in Ford Escorts/Cortinas with F20C engine swaps. This meant the gear lever was pointing toward the passenger side and positioned farther forward than we had anticipated. After some careful investigation and planning, we mounted up the engine exactly how we wanted and were happy to find we had room to move the engine back 1.25 inches and down approximately 1 inch. We set the engine to 12 degrees to properly orient the gearbox and fabricated new engine/gearbox mounts designed to use the Innovative bushing carriers and 85A durometer bushings. We made up a set of delrin bushings to ensure the engine location remained correct as we fabricated the new mounts.
With the new mounts complete, the gearbox shift lever is centered in the original location and is at a comfortable height. With the engine located closer to the vehicle's center, we should see improvements in handling response. We were careful to keep the oil pan just above the bottom of the framerails and low points on the subframe so it won't interfere with the underbody and should be safe if the car were to end up off track. By lowering the engine we've also served to lower the vehicle's center of gravity, which will certainly translate to improved cornering force.
While the gearbox installation hasn't been a straight-forward bolt-on affair, it should provide the ultimate in performance. The Innovative mounts are a great option for any standard S2000 engine/gearbox combination offering factory fit and guaranteed reliability. We're currently working on a custom twin-plate clutch setup and The Driveshaft Shop is making custom aluminum prop shaft to complete the installation. Stay tuned for the next installment!
