Project NSX: Part 18 – DBW Conversion with Motec

This rear engine sensor bulkhead connector takes all of the signals from the engine bay and brings it into the cockpit to the ECU.  This harness has everything from multiple pressure sensors, multiple temperature sensors, O2 sensors, Drive-By-Wire control, turbo speed, exhaust gas temperatures, crank position sensor, etc…

Here is the original cable-actuated NSX throttle pedal assembly used on 1991-1994 NSXs.  As the throttle pedal is depressed, it pulls on the (red) cable to open the throttle body.  The cruise control module is located under the hood and an electric motor that pulls on the (orange) cable that goes through the front bulkhead to the throttle pedal assembly.  To maintain vehicle speed, the cruise control pulls on this (orange) cable which causes the throttle pedal to physically move which pulls on the (red) cable to open the throttle body.  I’m not aware of many cars that have a throttle pedal that moves like this when controlled by the cruise control system.

Comparing the original 1991-1994 cable-actuated pedal (left) to the 95+ DBW pedal (center), and the RHD NA2 NSX-R pedal (right), they look very similar but are not interchangeable.  The 91-94 pedal has an extra lower pivot that the cruise control arm rotates on.  The upper pivot on the 91-94 pedal is for the vertically-mounted throttle cable.  The upper pivot on the 95+ DBW cars is where the “L”-shaped throttle bracket pivots to pull on the horizontal upper throttle cable.

Interestingly, the RHD NA2 NSX-R pedal uses a bushing and has a straight upper throttle bracket which does not work in LHD pedal assemblies.  For this conversion, NA1 NSXs need throttle pedal assembly part number 17010-SL0-A02.

From a frontal view, compared to the 95+ DBW pedal (left), the RHD NA2 NSX-R pedal (right) is offset too far to the right, in addition to the cable geometry that will not work.  Needless to say, this RHD pedal cannot be used.