Expectation can be a dangerous thing, especially with tuning. We admit we had high expectations for Project Mazdaspeed Proteg, as we had it serviced at Mazda's Tech Center. The service included the usual checks, a new windshield and a reflashing of the ECU. A factory authorized reflash was designed to correct a wide-open throttle (WOT) hesitation and address the air/fuel ratio.
We heard the reflash was good for anywhere between 4 and 6 hp, so we're expecting to see a 170-hp curve on our next dyno chart. We were dismayed, however, to see power drop to the 162-whp range. Furthermore, while providing a better air/fuel ratio up to about 5300, the reflashed curve dropped off the graph where we had been able to keep the curve on the chart, which explains the drop in peak power. The news was a little better with the torque, as it jumped a bit from 172.6 to 173.8.
There are procedures that require a shop to handle the wrenches and some that can be pulled off at home. Wiring up a boost gauge falls into the latter. Installing our GReddy electronic boost gauge was a simple matter of locating a boost source, grafting a T-fitting into the vacuum line and running it to the supplied signal processor. Then we ran GReddy's three-wire harness into the cabin and sourced power from the ignition and headlights and found a ground.
From there, it was a matter of where and how to mount the gauge in the cockpit. We kept it simple and used a GReddy mounting base and positioned the gauge to the left of the main cluster. Only after installing the gauge did we come to fully appreciate how quickly the ball-bearing T25 spools up. Moderate throttle input sends the needle toward the .5-bar point on the gauge.
Overall, we're a bit befuddled. We'll leave the engine alone for a while and redirect our attention elsewhere. Currently we're focusing on upgrading stopping power and bumping up to 18-inch wheels. Then we'll add an exhaust and a boost controller and put the wood to the T25. Stay tuned.