Boost Guage Installation

Ok this is a neccessary Item for anyone who wants a lot of performance out of their Supra.  First the decision is what brand to go with. The almost unanimous decision is the SPI boost guage with black face.  Why you may ask, because it looks like the stock guages and it comes in green color to match, and a added bonus is that it is in SPI and not bar so you can read it without having to convert numbers.  What size is recommended is 52mm for the clock location which is where 98% of the people install their boost guage.  So what is required to install the boost guage, not much but it is somewhat complicated and some hands on knowledge may be required, but anyone can do it required they have some patience.  The average billable hours if your having someone do the work for you is 2 hours.

Here is what is required, first get a 52mm SPI (or equivalent) boost guage with black face. 

Tools needed:  screwdriver == philips head, short preferred, wire cutters, wire strippers, some sort of wire connector like a but connector or spearker type terminals (both male and femal), wire coat hanger, little bit of duct tape or equivalent

**** Note This installation if for a 52mm boost guage to be installed in the clock location****

Here's how

remove the negative side of the Battery terminal

first remove the top panel of the supra dash, 5 screws in it all phillips head use the small screw driver to pull it out, unplug the 2 plugs in the odometer and hazard side, then unplug the 1 plug in the Trac control side

Remove the top panel it should slide out

Then remove the phillips head screw on the upper right panel, the same panel where the boost guage will be installed, there's only 1

2nd Pull the lower panel that goes over the speedometer, tachometer, fuel section, it has 4 snaps, remove it by prying (with hands) up kinda gently, it should just unsnap

3rd  Remove the shift Knob, if Standard it should just unscrew, if Automatice then it most likely undoes by some type of snap or some type of fastner

4th pull out the change or little ash tray in the same panel as the shifter, all that is needed is to open it and then pull it right out, Then begin to unpry the panel that it was housed in, it should just unpry easily and has about 5-8 snaps in it, again it comes out with moderate ease, I did not unplug the connecter here, instead I just laid the panel plugged in to the side

5th start to unsnap the main panel where the boost guage will be housed, it has 6-8 snaps and will take a min or two to unsnap, when finished start to remove the harness's there will be 2 harness's for the A/C, 1 for Trac button, 2 for the Cigarette lighter, and 1 for the clock

Remove the panel, now unscrew the 3 phillips screws for the clock, you will keep all these out,

5th:  Install the boost guage in the clock location and tighen the fasteners for the rear of the guage so that the guage never pops out or never moves around

6th:  Now you must splice into the wires for the dimmer section to light up the guage for night time driving, first you will want to cut some of the harness or cover section of the cigarette ligher dimmer section, this is the 2 wires with the grey snap on it that goes to the cigarret lighter, you will cut the loom back about 1-1.5" and then you will cut the wire appart, you will need to splice into the 2 sides of the wires and either use but connecters or femal speaker connecters, ***Note I recommend speaker terminals for easy removal in the future*** if using speaker terminals then basically strip back both sides of the same wire and connect them and crimp down with the connecter, do this for both wires, on the boost guage you will want to crimp down both terminals after stripping the wire with male ends of speaker terminals, IF you do not use speaker type terminals and only use butt connecters then you will splice the 2 stock wires to 1 end and the boost guage end to the other..

Now once you've got all your wiring ready to plug in, you will use the black (ground) from the boost guage to the white/green wire of the cigarrett lighter, and the green boost guage wire (positive) to the green/brown wire of the cigarette lighter, at this time you may want to reconnect the battery and test the dimmer by turning on the driving lights, ***Note do not plug the key into the ignition, just turn the light handle, otherwise you may get Airbag light*** it should work fine.