VW Golf LED Boost Gauge

VW Golf  GTI "In-Dash" 0 - 30psi Boost Gauge

Before and especially after additional performance modifications have been completed and installed, it is imperative we know whether the Electronic Control Unit/Module (ECM/ECU) is providing the engine with enough fuel under high boost and/or load. You will want to know how much boost your turbo chargers are providing you with. For a start all the cash you spent on the ECU can be quantified if it lives up to the boost specs. Optionally, if you have gone the electronic boost controller route, you will want to see the boost information at eye level. Boost must be monitored closely when doing turbo upgrades and other inlet manifold pressure related performance modifications. Now, you can go and buy an "off the shelf" boost meter from your favorite after market parts store, and install it somewhere in the car where it is guaranteed to look like an "afterthought" and join the "Rice Rocket" & "Boy Racer" brigade (not my terminology). You could spend copious quantities of cash on an integrated system  in your instrument cluster, or you can do a proper job, with the satisfaction that you did it all yourself.  And hey, that is half the fun, isn't it?.  We chose to build and design our own Integrated 1 - 30 psi Boost Gauge integrated into the Tachometer of the stock instrument cluster. It uses either the car's stock MAP sensor readings (in this case we use an external sensor as the stock unit is limited to 20 psi) to give real time boost pressure readings on 20 1.8mm LEDs. LED number 1 is 1.5 psi (30/20) and so on up to 30. It is accurate to +/- .250 psi when calibrated correctly. It can be easily adapted to read virtually any boost pressure, the only limitation is that of the selected pressure sensor. It can use any 5v pressure sensor. This article focuses on utilization of the MSD 2313 MAP sensor we purchased separately. The parts we provide are for sea level operation but can easily be calibrated for other altitudes. Our Boost Gauge integrates into the Dash (Check out this page for a kit of component parts or a complete unit) so it looked as if it was there from the factory. This takes a lot of planning and measuring, in the long run it will look perfectly acceptable to the most discriminating connoisseur.

Disclaimer (Please Read it Thoroughly)

By connecting and using this Custom Gauge you agree that the designer and author of this document and gauge is in no way responsible for damage to persons, a vehicle or vehicles as a result of installing meter.

Liabilities: The author and designer assume no responsibility for the modifications you do on your car. Although to our knowledge these instructions are accurate, this includes any errors that these instructions may contain, any differences between your car and the one(s) showcased, as well as any errors in following the instructions. If you don't feel comfortable working with automotive electrical wiring we suggest you let someone with some experience do these modifications. The installer should posses a good understanding of the electrical system of the vehicle being worked on.  Please double check all your connections and ALWAYS work with the car battery DISCONNECTED.  Always keep your safety and that of others as the highest priority.

Warranties: The modifications described in this document could potentially void any manufacturer's warranty you may have left on the car (not likely, but possible nonetheless). You assume all responsibility if your car is still covered by warranty.

Legalities: Laws in your country/state/region/whatever may not allow you to modify systems such as these on your car, the penalty being at least a fine. Please check with your local authorities to be on the safe side.

We also assume NO RESPONSIBILITIES what so ever for any accidents cause by the driver gazing at this tremendous addition to the stock instrument cluster while they should be concentrating on the road and their driving. We always endorse good and safe driving practices at all times. With that, good luck, and have fun with this Custom Made Gauge.

The first thing you need to do is acquire an electronic Boost Gauge as described in this article (And on this page).  You will need to be reasonably proficient with a soldering iron and lead solder, as you will be using them a lot. (Or you could get someone else to do it)

Check Out The Video! Click Here Now!

This article is for the real "Do It Yourselfer", we designed and built our own Custom In-Dash Integrated Boost Gauge, and that is what this article covers.

Completed Unit Being Bench Tested

Main Boost Control Unit

As you can see by the layout, there are quite a few components. The signal comes into the unit from the MAP sensor, we spliced into it directly on the MSD2313. Remember to DISCONNECT the BATTERY BEFORE beginning any electrical work on the vehicle. We simply tapped into the car's vacuum line at a suitable point. There are many of them, choose one that involves the least amount if vacuum pipe to be run from the external sensor. You can run the pipe through the firewall access hole, it is huge and has plenty of room.  It comes out behind the ECU in the rear engine compartment. Switched ignition power can be derived from the ECU main wiring loom. We used Pin 1 or Pin 2, one of the two thick BROWN Wires of the large plug for our ground,  and Pin 3 the thick BLUE/BLACK wire for switched +12v.

The "Dimmer" wire needs to have +12v when in Dim Mode, and ground or floating when in Daytime or Bright Mode. This can be done in many ways. There is a Fuse in the fuse box that is marked "Headlight", you can tap +12v from here. Or, from under the dash you can take the dimmer wire from the power connector harness and splice it into the GREEN/RED or GREY wire on your headlight switch harness. This is the wire that activates the dimming circuit on the control unit when it receives a +12V signal from the parking or main light circuit.

Boost Gauge Main Control Unit, Not To Scale

Please refer to the following layout diagram for all the interconnection and external wiring information.

Boost Gauge Main Control Unit, Interconnection & Wiring Layout, Not To Scale

Installing The Boost Gauge in the Dash

This is the part we were quite concerned about doing, and a quick call to our friendly dealer and spotting some eBay Auctions, confirmed that to replace the dash was a relatively inexpensive option, reassuring us that the parts we were about to potentially destroy were available as replacement parts. Armed with this "insurance" we proceeded very cautiously. The following steps involve drilling and cutting the dash assembly. Unless you are pretty good mechanically, we recommend you simply read this for interests sake, and put a commercially available boost gauge somewhere in your car. If you do choose to remove the dash assembly for any reason, do not forget to DISCONNECT THE BATTERY.

Step 1 - Remove The Dash Complete With Gauges and Wiring

This is a very easy procedure. You can refer to the car's repair manual for details. We proceeded as follows:

• Golf Cluster Removal Goes Here

Now that you have removed the dash assembly, the fun can begin.

Step 2 - Dismantle The Dash To Remove The Tach Dial

This is quite easy, you just need a few nifty little pieces of plastic or metal. We used 1/16" plastic sheet.  We use a lot of this plastic sheet, where do we get it? you may ask.  Well, you know those three ring binders you use all the time for files, at the front and rear there is usually a sheet of plastic, either white or black used to support the pages.  That is what we use.

• Cut six pieces of 1/16" plastic about 3/8" x 1"
• Place the dash assembly face down on piece of cloth.
• Remove the two Torx Number 10 screws from the rear edges of the unit.
• Using a small screw driver, slowly  lift the six the plastic retaining clips and slide a single cut piece of plastic under each one.
• Very carefully and pop the cover off. Store it in a clean safe place.
• Mark where the tachometer needle is pointing when fully anticlockwise against it's internal stop. You will need this for when you put it back.
• Now gently, turn the needle anti-clockwise while pulling up on it. It will pop off as it is only a push fit.
• Now the Tachometer dial can be removed by turning it anti-clockwise and lifting it off the keyway.
• Get ready for the scary part coming up next.

Step 3 - Measure, Mark up The Tach Dial and Prepare for Drilling LED Mounting Holes

This is the very tricky bit. It can be done a number of ways, this step describes how we went about doing it. We chose to locate our 20 Boost Gauge LEDs (1.8mm ) in the Tach dial. We made a semi-circle of LEDs between the stock Tachometer numbers and the indicator lamps. The measurement was not that easy.  A template was created after many, many iterations and here is what it looks like. It includes the layout from another project (The Air Fuel Meter) we were installing, which is described in another article. You will need a ).070" high speed steel drill bit.

Tachometer Dial Drilling Template

Here is what we did:

• Print the template to scale on thick bond paper. (Best quality) Only print 1 per page to keep the scale.
• Cut 2 4 1/2" squares of about 1/10" Aluminum sheet or there abouts, you do not want any thicker, it is too hard to work with. These pieces should be about 1/4" larger than the dial all round. They do not need to be perfectly square.
• Clamp them together, mar one top and one bottom with arrows to the top so you can line then up.
• Drill the 4 corner holes, countersink the bottom, and find 4 countersunk screws and nuts, remember these are for location purposes and should not foul on the dial edges.
• Temporarily stick a template to the top and mark only the center hole as close to the actual center as you can without having any of the dial locating holes off the edge of the alloy square.
• Carefully drill the center 1/2" hole very slowly, I use a small drill to pilot the hole first then put the 1/2" drill in.
• De-bur everything.
• Cut the 1/2" center hole out of another paper template with a razor knife and put the 1/2" drill through it and the TOP alloy square. Align it so it looks square then stick it down. I stick it using the DRYLINE YELLOW glue strip by liquid paper.
• Now center punch all the other holes and do not forget the alignment hole at the very top, ever so slightly to the right of 12:00 O'clock on the template, as well as the one at 9:00 O'clock.
• You will punch 22 holes all together.
• Using a very slow drill and your newly acquired 0.070" drill drill them out and de-bur them.
• Clamp the bottom to the top, and now using the top piece as a guide you can drill the bottom.
• Voila! One sandwich style aluminum template.

Dash Drilling Template, With Key Detail, Top & Bottom (Note Location Hole at 12:02 Position)

   Step 4 - Drilling The Dash!

As we only had one chance to get this right, we checked and double checked our measurements, and then we checked them again. The drill we chose was a 0.070". of an inch. (a tick smaller than needed for 1.8mm LEDs), We used a drill press at 2340 rpm.

• Place the dial in between the aluminum template, use the shanks of 1/2", 1/4" and a 0.070" drill bits to line up the center, left and top alignment holes respectively.  Now tighten the 4 nuts on the countersunk screws to hold the dial in place securely.
• Using the 0.070" drill and a speed of over 1750rpm, carefully and SLOWLY drill out the holes.
• Remove the template screws and take out the dial being very careful not to scratch the face. You should have something that looks pretty good.
• Stand back, admire your work, and congratulate yourself on the fine drilling job you just did...... You deserve it. In fact, go get a beer.

As you will see in the photos that follow later in this article, it was a tight squeeze.

Tachometer Dial, Drilled & Lettering Applied for Integrated Boost Gauge

The above photo shows all 20 1.8mm LED holes in a semi-circle for the Boost Gauge.  As you can see it is a very tight fit. But we were really pleased with the out come.  Now onto installing the LEDs and the electronics.

Step 5 - Installing the LEDs

This is the most time consuming of all the steps.  It is not hard to do, just slow. As you can see in the above photo of the dial, we applied 12 point white dry transfers to the dial. You can choose your own numbers and letters, just be careful not to obscure the warning decals on the dial.  The decals are clearly visible when you hold it up to the light.

You will need the following items:

• A tube of colored adhesive household caulk, we used a non silicone based white tub and tile type that you can get from your local hardware store. You want a color as opposed to a clear so that when the dash backlights are on, you do not get light through the LEDs from the back when they are off. Any color will do.  Black would block the light, so it is a good choice also.
• A clean lint free cloth.
• Three small (approximately 1" x  1/4") pieces of 1/16" thick plastic or wood. We used 1/16" plastic sheet.  But you can use thin modeler's type ply wood, just make sure they are clean and have no sharp edges.
• Some white lettering 12 point Dry Transfers, these can be pickup up from a local hobby shop.
• A lot of patience.

VW Golf Tachometer Dial, Drilled for Integrated Boost Gauge with Lettering Applied

   Here is how we installed the LEDs.

• Make sure you hands are clean and dry. And when handling the face of the dial us a clean cloth or lint free tissue paper.
• Place the dial face down on a soft flat surface, a towel or piece of felt is good Make sure the LED holes are not obscured.
• Line you 20 LEDs in the color order you wish to have them, so they are close at hand.
• Offer each one up to their respective position and pop them into the dial from the rear, they should be an interference fit. each one should hold in place quite nicely. Do one at a time, remembering which LED goes in which hole. Sometimes the different color LEDs vary very slightly in diameter.
• Now, one at at time position each LED and apply a small bead of the caulking round it. (We used a small toothpick to spread the caulk evenly) Make sure you get all the cathodes and anodes (the anode is normally a little longer than the cathode) on the same side because you will have to join them together later. We found that setting 3 or 4 at a time then letting the caulk dry was the best way to go. Once they are all set, leave for 24 hours to dry. you can cut off excess caulk with a small razor blade or a hobby knife.
• We painted the caulking black once it had dried, just to be 100% sure that no light got through.
• Stand back, drink another beer and admire you results again. Now doesn't that look sharp?

Tachometer Dial, with Blue & Red LEDs Installed for Integrated Boost Gauge

Step 6 - Wiring Up The LEDs

You can do this any way you wish. We used 28 swg stranded wire with a very thin insulation.  You need as thin wire as you can get.  28swg is the thinnest we wanted to go and stranded wire is more flexible than solid, although there is no real reason that solid wire could not be used. We wired 20 LEDs one by one , starting with the closest to the exit point.

• Cut all the Anode Leads (they are usually longer than the Cathode) on the LEDs to about 1/2" in length.
• Bend them at right angles to each other, overlapping them slightly, so you can solder them together. The last one will have to be bent in reverse of all the others so as to be soldered to them.
• Solder them all together so they are in a nice circle as close to the back of the LED as you can get. Ours ended up about 1/4" from the rear face of the dial to the top of the leads when bent and soldered.
• Cut all the cathodes to about 1/10" above the LED back.

Tachometer Dial, LEDs Installed for Integrated Boost Gauge

• Then we wired each of the leads to each LED one by one. Make sure they originate from the left of the dial as you are looking at it from the rear. We made each wire 9" from the exit point which in this case was the 20th LED. So all the wires ended up on the left hand side of the tack dial when facing DOWN. This will actually come out of the right hand side of the cluster when assembled.
• There are actually 21 wires as one is for the common anode wire. Make sure you remember which is LED 1 - 10, and 11 - 20. You can either mark the wire with masking tape or as we do simply test them with a 5v supply and a 2.2k resistor. This will also prove they are all working. It is easy to damage LEDS with too much hear when soldering.
• You may want to shape the wires into a loom and tie them off with a very small tie wrap or tie wire. We in fact simply used 12 pound test fishing line every inch or so. This is quite tricky and should be done so that the wires do not foul on any parts of the instrument cluster.
• Bend the loom down so it runs parallel to the Clock Cut Out about 3/8"towards the edge of the tachometer dial left side when facing down. refer to the pictures below for some helpful hints.

Tachometer Dial Rear, LED Wiring, Notice Very Close Fit Between 50 & 60 RPM Markers

• Getting the Dial back in the cluster is also quite tricky. You cannot rotate it as the LEDs are in the way. What we did is place it done flat, and gently pressed it onto the keyway, being very careful not to damage our lettering.  Actually we pressed a little too hard on the letters and had to redo a couple of them. You will find it will eventually clip down into place. This is the only really tricky part of the installation.

Step 7 - Rebuilding the Instrument Cluster

Depending on what wires you used for the LEDs you may need to cut some plastic out of the White tachometer housing backing. We ended up not needing to cut anything.  The black instrument cover will however need to be cut so the wires can get through. We also installed, some reflective foil, using very thin double sided tape, to make perfectly sure that we did not obscure the backlighting.

Tachometer Housing Assembly, Showing Wire Routing Access & Reflective Foil for Integrated Boost Gauge

This is what we did:

• Located the wires evenly down the right hand side of the Clock Assembly under the tachometer dial. (Looking down at the cluster.)
• We then offered the cover onto the cluster and marked where we wanted to have the wires come out. they come out of the cluster, turn a sharp left and then come out of the black cover.  It happened to be located right on a molding mark on the plastic. You can just see the molding in the photos below.
• A hole/slot was then cut out of the cover at the marked location. It turned out to be about 1/4"" in diameter open at the bottom (see picture below) It was easily cut out with a small  hack saw, then shaped with a file. Be careful not to get any plastic filings in the clear plastic face.
• The cables, now rolled up at this point were routed around the clock assembly and through the hole/slot. This worked out fine for us.

Cluster Fasia Assembly, Showing Cuts for Wire Routing for Integrated Boost Gauge

Here is a nice photo of the finished tachometer mounted in the cluster ready to go. If you click on the photo you will see it in action.

Tachometer Installed in the Cluster and Powered up, Click on photo for In-Action Video

Step 8 - Testing & Wiring Up The Boost Gauge Control Board

This part is pretty straight forward, if you are electrically inclined that is. The LEDs were wired to the Printed Circuit Boards (PCBs) using the wires that we wired in Step 6. It is best to keep the wires as SHORT as possible to reduce any interference or noise, although we never experienced any problems and the circuit is compensated for longer LED leads. 12" should do the trick. This ends up being 5" outside the cluster, this is more than enough so the control box can be tucked away below and to the left of the cluster once installed in the car. It is a good idea to check each LED before you finally solder them to the PCB. If you use a 3k Ohm resistor with a 12v power supply or a 9v battery will also work), you can easily check each wire and establish which LED it represents, then wire it to the appropriate pin on the PCB. Simply connect the +12v lead (or the +9v from the battery) to the common anode wire you marked earlier, then connect the -ve lead to the resistor and touch each LED wire with the other end of the resistor. The appropriate LED will light up dimly in the cluster to let you know all is OK. If you get problems with multiple indicators lighting or an indicator does not light, now is a good time to diagnose and fix it.

Boost Gauge Main Control Unit, Interconnection & Wiring Layout, Not To Scale

It is best to test the whole setup before you put the cluster back in the car just to make sure you have everything all in order. It is far easier to troubleshoot a problem when the cluster is still on the workbench as opposed to being in the vehicle.

Perform the following:

• Turn the Zero Adjustment Control (P1) fully Clockwise
• Connect  +12v to the RED main unit Power wire (Pin 5 of the I/O array) and Ground or -ve to the Black wire (Pin 1 of the I/O array)
• Take the MAP sensor input wire (Pin 4 of the I/O array) and touch it momentarily to +12v, all the Indicators should come on. They may go out or stay on when you remove the MAP signal wire from +12v.  You should not leave the MAP signal wire connected to +12v for any length of time or you could do damage to the unit. Nut momentarily will not do any harm at all.
• If the lights remain on, you can momentarily touch the MAP sensor signal wire to Ground or the -ve, this will turn all the indicators off.
• If +12v and Ground Power is left to the unit for any length of time, the indicators will eventually all come in starting slowly from 1 - 20. This is normal and cannot damage the unit. However, it is NOT recommended to leave all indicators on for extended periods of time. The Boost control unit will get quite warm to the touch if this occurs.

This part is pretty straight forward, if you are electrically inclined that is. The LEDs were wired to the Printed Circuit Boards (PCBs) using the 28 swg cables that we wired in Step 6. It is best to keep the wires as SHORT as possible to reduce any interference or noise, although we never experienced any problems,  and our circuit design is compensated for longer LED leads. 9" should do the trick. This ends up being 5" outside the cluster, this is more than enough so the control box can be tucked away below and to the left of the cluster once installed in the car. Final adjustments can then be made with minimum of contortion on behalf of the owner. We found that the stock pressure sensor varied ever so slightly with temperature, so final adjustment after some driving may be called for. Referring to the layout diagram of the circuit board, make sure you get the correct bank on the correct driver chip. Then the PCB was placed in an enclosure and tucked behind the dash. There are three other wires that need to be connected to the car in order for the Boost Gauge to function correctly. The signal comes into the unit from the MAP sensor, we spliced into it directly on the MSD2313. Remember to DISCONNECT the BATTERY BEFORE beginning any electrical work on the vehicle. We simply tapped into the car's vacuum line at a suitable point. There are many of them, choose one that involves the least amount if vacuum pipe to be run from the external sensor. You can run the pipe through the firewall access hole, it is huge and has plenty of room.  It comes out behind the ECU in the rear engine compartment. Switched ignition power can be derived from the ECU main wiring loom. We used Pin 1 or Pin 2, one of the two thick BROWN Wires of the large plug for our ground,  (BLACK wire on our control unit) and Pin 3 the thick BLUE/BLACK wire for switched +12v (RED wire on our control unit).

The "Dimmer" wire needs to have +12v when in Dim Mode, and ground or floating when in Daytime or Bright Mode. This can be done in many ways. There is a Fuse in the fuse box that is marked "Headlight", you can tap +12v from here. Or, from under the dash you can take the dimmer wire from the power connector harness and splice it into the GREEN/RED or GREY wire on your headlight switch harness. This is the wire that activates the dimming circuit on the control unit when it receives a +12V signal from the parking or main light circuit.

 Boost Gauge Control Unit and Enclosure 3.1" x 1.57" x .7" Wired to the Cluster

 Boost Gauge in Final Enclosure, Note Calibration Adjustment at Bottom Left

 3 Bar Map Sensor (30 Psi above Atmosphere)

We mounted our control board in a 3" x 1.5" x .7" black plastic enclosure, and drilled a small hole in it for adjustment purposes. You will also notice we installed a plug and socket so we could easily remove the dash in future.

Step 9 - Setup & Calibration

Calibrating the Control Board

Calibration is really simple. Simple adjustments can be done before you even wire up the LEDs. It is best to check some basic voltages. All voltages are respect to the control board’s ground.

Here is what we did:

·        There should be about 1.5v on Pin 5 of the Input/Output (I/O) Bank on pins on the PCB. Assuming the external MAP sensor it is connected to the Boost Control Unit PCB.

·        There should be about 1.4v on Pin 4 of IC1. This can be adjusted using the Zero Adjustment P1. Turn P1 Anti-Clockwise to increase the voltage and Clockwise to decrease it.

IMPORTANT NOTE: If the voltage on Pin 4 of IC1 is above 2.0v, very erratic and inaccurate readings will result. It is best to set this first to about 1.4v.

When you first power the unit on with the LEDS connected, some of them may be on. Simply turn the 25 turn adjustment trim pot P1 Ant-Clockwise until the first LED is the only LED that is on. Remember Anti-Clockwise Turns the lights off and Clockwise turns them on. If you are in doubt, simply turn P1 Clockwise for a few turns until the lights come on. Then turn the adjustment trim pot Anti-Clockwise until LED 1 just goes out + about 1/8” of a turn. That’s it, you’re done!

Setting up the Dimmer for Night Time

This adjustment is also really simple. You may need to wait until dark to do this. Simply apply +12v to pin 2 of the I/O bank of pins, or just turn on your lights if you have wired it up to the car’s light switch. When in operation the lamps will be noticeably dimmer. You may want to adjust Zero Calibration (P1), with the ignition on but with the engine off, Clockwise to turn some lights on, (only a few of the lower LEDS will be able to be turned on) so a few indicators are on. You can then adjust the dimmer’s night setting adjustment (P2) Clockwise to set them dimmer or Anti-Clockwise to set them brighter, until you get the desired brightness. Once this is complete you may have to re-do the Zero Calibration of P1 as mentioned earlier.

Step 10 - Admiring the Finished Product

The following photos show various close ups of the dash after re-installation into the car.

 

Complete Dash Mounted in the Car (Day Time with Gauge Off)

Complete Dash Mounted in the Car (Night Time, Gauge On, Two Color Combinations Shown)

We hope you find this article interesting. If you would like more information, please email us or go to our Gauges For Sale pages.

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