With the exhaust end of the emissions cleaned up [sic], there were now a few more engine sensors and control mechanisms that aren’t really being used or that aren’t necessary for a race car. So I removed the upper intake manifold (UIM) and throttle body and worked over all the pieces. First up was to remove the double throttle assembly. A small restriction in the intake path that is really only needed for cold start operation. The butterflies were removed and the dashpot and actuator removed. The butterfly shaft holes were plugged (bolt and JB weld) or capped (original double throttle cover plate).

With the UIM off I was able to remove the EGR valve and vacuum hoses and fabbed a blockoff plate to cover the exhaust holes. The EGR I removed was so clogged I doubt it was functioning at all. With the UIM off it was clear to see how brittle the original rubber fuel rail and coolant lines were. So these were also replaced with new hose. The throttle body coolant line was eliminated and the coolant being bypassed directly back to the block.

And then there was the dreaded S4 pulsation dampener. Sure enough the cap on my ancient dampener was cracked and rolling around inside was the loose screw. A fire waiting to happen. It was replaced with a brand new FPD that I found on a car in a junkyard! It must have been replaced days before the car blew it’s motor. Their loss my gain.

Back to the intake, which was the re-installed OE air box. I fabbed a REAL bracket to support the open intake and reinstalled the aftermarket $9 eBay filter and adapter. No real need for the x-over snorkel either so it was removed. With the intake now fully open the remainder of the air pump intake piping and baffle was removed too.

                                            ENGINE BAY CLEANUP:
                                            Manual Steering Rack (used)                                           $50.00
                                            Corksport SS oil cooler lines (new)                                $140.00 (incl. shipping)
                                            OE Mazda thermostat and gasket (new)                           $18.00
                                            Dual alternator pulley (new)                                            $20.00
                                            Water pump/alt belts (new) $10.99 ea. x 2                      $21.98
                                            Oil metering pump o-ring (new)                                      $5.49
                                            Oil metering pump copper gasket (new)                          $4.59
                                            Fiero electric fan (used)                                                  $20.00
                                            Electric fan relay/controller (new)                                  $30.00
                                            Fuel rail hoses and clamps (new)                                    $7.00
                                            Tube of JBWeld                                                               $3.99

                                                    MORE ENGINE BAY WEIGHT SAVINGS:
                                                    Air pump hoses and baffle tank                               2lbs
                                                    EGR valve                                                              0.5lbs
                                                    Double throttle assembly                                        1.4lbs
                                                    Switch from OE clutch fan to Fiero electric fan      4.5lbs
                                                    Switch from OE air box and intake to open filter    5.0lbs

 For now this pretty much takes care of the engine bay, time to work on the interior.