View Full Version : INSTALL: DEFI boost gauge

10-08-2007, 11:45 AM


This is a how-to on a Defi boost gauge install that was done on Villan's EVO. The install was done in a garage with basic hand tools in a few hours working really slow and really carefully. Please refer to other how-tos on how to remove the glovebox and steering column cover.
Note: Please use your best judgement when trying to do the install. I will not be held responsible for damages done to your vehicle by using these instructions. You assume all liability. Know your limitations. With that said, on we go...

Here is the Defi white faced boost gauge. (note the sexy car in the background)

Start out by removing the glove box. Please refer to the how-to posted by other users. It should take no more than a minute to remove the glove box out. It's really easy.

Once the glove box is removed, go back to the engine bay. Behind the passenger shock tower you should see a black rubber grommet. Carefully manipulate your hand in the limited amount of space and push the grommet through the firewall. It should pop out inside the car. Have someone keep an eye out on the inside to track the grommet as it pops out. This is what you should see when after the grommet is pushed into the car.

Get the grommet from inside the car and prep it for the vacuum line. The Defi vac line is pretty thick in diameter so you will need a large drill bit to make and enlarge the hole. Work slow and increase the bit size until the proper clearance is made.

Here's the line slid into the grommet.

Once the hole is made into the grommet, I suggest you route the vacuum line for the boost gauge.
Have someone inside the car feed the line through this hole.

The other person should grasp the line from the engine bay and pull out some line.
Here's the line through the firewall with the grommet put back in.

The grommet will take some force from the inside of the car to be put back into it's spot. You might need the help of something long to push on the grommet. We used an ASP baton. You can use your hands to push on it some more.

Once the line is routed into the engine bay, give yourself enough slack to be able to connect to the FPR line. Make sure the inside has enough slack also to be routed towards the steering column.

Once vacuum line length was confirmed and all was well, we went ahead and tapped into the appropriate FPR line.
Cut and put your "T" into this line here. I removed the plastic coil wrap.

The line is cut in half and the "T" connected. Here's the finished product. I went ahead and ziptied the connections and also wrapped conduit/wire loom around the vacuum line to give it a presentable look. The line was ziptied to the strut bar to tidy things up a bit.

That pretty much takes care of the engine part of the install.

You should be able to see the vacuum line inside the car now. You will need to route it to the driver's side. We routed the line from the passenger side underneath and went where the arrow is pointing.

It comes out to the driver side like this. I taped a bicycle spoke to the end of the vac line to help feed it through.

Next feed it up into the steering column and pull it out.

This should take care of the vacuum line for now. Next you will need to make the electrical connections to your gauge.

NOTE: Before removing the steering column, make sure you mark the area where you want to mount your pod. An autometer pod was used in this install. Take the column cover off using already posted instructions and drill pilot holes for the screws on the pod bracket.


Mount the bracket with the supplied screws. We went ahead and masked the cover and spray painted the bolts to blend them in a little. We used Satin Black spray paint. Any brand should work.

Set that aside to dry. Now it's time to wire the gauge.
We went ahead and tapped into the harness that is attached to the rheostat/cluster dimmer switch. We used the green wire with the white stripe from the blue harness connector.

First, pop out the dimmer switch assembly. Use something thin the pry out the assembly. I used a thin feeler gauge. You can use a screw driver but be really careful.

After that is done, carefully unplug the harnesses and pushed them out through the side so there is easier access to the wires.

You will need to tap into the green/white stripe now. If you use this wire, the boost gauge will light up when the headlight switch is turned on. HOWEVER, you will not be able to dim the boost gauge. It's either on or off. A simple wire tap will do the job.

I grounded the black wire from the boost gauge on the bolt pictured using a spade connector.

With the connections made, you can test out the gauge to see if it lights up. Don't start the car but rather just turn on the accessories because the vac line is not attached yet. Plug the dimmer switch up and hit the headlight switch. The light should come on if everything was connected properly.

Next trim the necessary amount of vac line and install the line in the back of the gauge. Get your painted column cover and mount the remainder of the gauge pod and gauge. You can used more wire loom to dress up the electrical wires of the gauge. Put everything back together in reverse order. Here's the final pic of the install. I probably skipped some steps but the install is very straight forward.