I ended up doing a full conversion to speedhut gauges, and thought I would share my process. The stock FD gauges are capable of reading the LS signals but extra conversion boxes are needed, and new sensors. I decided to go through and update the gauges to speedhut programmable versions. I was able to retain all the factory housings and bezels for a complete stealth look. I used these sizes:
4.5" Tachometer
4" Speedometer
2-1/16" Oil pressure
2-1/16" Water temp
2-1/16" Fuel gauge
I actually measured the holes, and the 4.5" tach and 4" speedo work perfect. They actually measure out almost identical to the diameter of factory gauges.
So for those of you that dont know, the speedhut gauges include their own bezel (usually aluminum) and their own rings to mount them. They also have a button (if programmable) and their own plexi-glass window. I ditched the plexi-glass window and aluminum bezel in order to make the factory mazda pieces work.
So here is how the speedhut gauges look compared to the stock ones:
I went with the Revolution style gauge with white font. I also had the custom lettering put on to say "RX-7" ($10 option)
I uncliped the clear lense cover and the black plastic backing from the cluster assembly and was left with this:
The stock gauges themselves unbolt from the back. There are about 3 bolts per each of the gauges, and some excess bulbs I removed since the speedhut gauges are pre-lit.
You will notice that these holes are way to small for the larger gauges. I used some side cuts and started making cuts into the edges of the housing. This effectively opens up the holes for the larger gauges. Then I literally threaded the gauge body into the housing.
Made it so the gauge will "press/thread" in:
Tach installed: notice the alumium bezel is removed and the slider ring on the back is also ditched.
Run the wires through the (now) un-used bulb holes:
Once all the gauges are pressed in, I noticed that there are stubs on the edges of each gauge. I will need to drill out the clear lens to accept these protrusions. I put a bit of toothpaste on the tip of edge stub and then lined up the lens so I could see where I needed to drill:
The "drill here" mark it made on the lense:
At this point I re-installed the lens and see that everything fits and lines up like OE
But quickly realized you can't push buttons on the programming for each gauge. I marked "eye-balled" where each of the buttons were with a sharpie, then removed the bezel and drilled it out to accept the speedhut rubber buttons and standoffs.
Drill slowwlllyyyyyy:
Buttons installed:
Standoffs put in place to reach the button on the gauge:
Screwed all the items back together and I now have a fancy factory looking gauge setup with programmable shift lights and alarms:
