Another article from my old website
Just finished building a new Vanagon Instrument cluster for my TDi conversion project. I’ve always disliked the Vanagon instrument pod. The center section really offended my sense of completeness. Just looked fake. When I decided to divert the 2.0 Turbo Audi project to the TDI, I decided to do something about it. The result combines the instrument cluster from the 1997 Passat TDI (contributes the gauge faces and front cluster face), a 1995 Passat GLs (contributes the MFA processor calibrated for the 4 cylinder engine), a vanagon cluster, the bezel from a ’97 Passat and a set of VDO gauges.
I’m using the wiper (controls the MFA) and turn signal stalks (controls the cruise control) on the steering column from the 1995 Passat GLS 4-cylinder. Here in the cluster, the temperature and fuel gauges are combined, with separate speedometer and tachometer. The warning light group contains the typical diesel functions. There are two unused light ports. I’m doing transfer logos for them and adding my two color (red/green) LED’s. One of the lights monitors the radiator fan speed (green for low, red for high). The other follows the auxiliary lights with green for Fog on and red for the driving lights. The MFA monitors among the standard features, the engine oil temperature, the average fuel consumption, the instantaneous fuel consumption and the external air temperature. This LCD screen also displays the digital clock.
In the bezel, I add a boost gauge and a pyrometer for EGT measurements. In the lower dash plane I have two gauges, one on either side of the column. To the left, oil pressure and to the right, oil temperature monitored after the oil coolers. In the lower heater face panel, I have a set of five gauges monitoring voltage on the primary circuit, voltage on the auxiliary battery circuit, the pressure in the radiator coolant circuit, an analog clock and an LED compass direction gauge.
The speedo drive is electronic. I took the rear mount out of an old Jetta speedo cluster I had, cut it up tp keep the frame and the Hall magnet wheel. Then mounted them in a box to take the place of the EGR counter. I use the 3 wire speedo hall sensor from the G/J series. Its a bolt up (or screw up) to the speedo frame. A variable pulse counter frequency adjuster (circuit supplied by my son) will allow variable adjustment for a dead on speedometer regardless of tires and state of wear. Precision wirewound pot for frequency conversion adjustment. Calibrate with simple GPS.
Further notes on fabrication…
On the master cylinder reservoir interference issue … it was in the way and I wanted to maintain the visual angles, so I took it out! I then used a master cylinder reservoir from a ’90’s Mazda pickup. It comes (from your local P&P yard) with a remote mounting bracket. I rotated it so the long axis is parallel to the windshield long axis. It comes with a built-in level sensor that I wired into the VW harness. I can’t remember if the vanagon originally came with the level sensor built in of if I added it to the vanagon reservoir and modded the harness years ago. For the inlet lines to master cylinder, I believe I used the plastic barb adaptors from a Super Beetle. I use an inline T to tap off the clutch feed. I mounted the reservoir in the same general area as the original Vanagon unit and aligned the inlet so that the plastic drip shield fit again (anal-retentive, I know). Clears the back of the cluster as if it were designed to do so! This solution should work for any cluster one would like to put in!
On the choice of cluster…. Well to start with, I have always thought (going back to March of ’82 when I placed the order for Westfalia for factory delivery) that the instrument cluster was a tacky design. The fake molded sensor lights particularly irritated me! I later years, I added the tach, the oil pressure warning circuits, the VSS speed sensor and redesigned the warning light package to give right and left turn signal lights, added cruise control lights, finally adding multicolor LEDs to the fake center section to monitor radiator fan speed, intercooler fan speeds, fog and driving lights and A/C control parameters. But I never liked the look of the thing.
When I decided to TDi the Vanagon, my orders to the salvage yard were that I wanted it all – engine, hoses, all wires and sensors. To my surprise, they included the speedometer cluster. The three gauge pattern carried the same info as the Vanagon cluster, but much more cleanly. The row of sensor lights along the bottom of the cluster was very tasteful and, the LCD display made it possible to add the MFA (multifunction display) to the package. I noticed immediately that the size of the Passat cluster was just a bit larger than the vanagon center section, so I decided it was time to generate a cluster that was good on the eyes and technically compatible with the Vanagon. The MFA was a key part of the equation, since I could integrate a miles per gallon function together with monitors for oil temperature and all OBD II sensed engine variables (the son is hacking the MFA controller to display all VAG.com accessible info). So, while the A4 cluster is nice and the later sport clusters from the Passat and G/J series are very impressive, they were somehow not in the same design paradigm as the classic Vanagon shape. The approach I used is compatible with any cluster. I chose not to go the digital monitor approach or to rebuild with aftermarket gauges (VDO or other), although the 9 gauge custom cluster seen here on the list recently pushed me from design to implementation.
Key details … Needed – Dremel tool, JB Weld, ’97 Passat instrument bezel, ’95 to ’97 Passat instrument cluster, one or more Vanagon instrument cluster bezels, flexible bumper spray paint, 20+ hours, high quality source of KMZT-FMin garage. To begin, I cut away all the instrument pod from the plastic vanagon bezel to a distance of about 1 inch from the front face. I cut off the bezel support pieces so I could reassemble them to the cluster in the end. I then took the plastic ’97 instrument bezel and used it to shape the remaining vanagon bezel surface. When I has the shape right (easier than it sounds with the Dremel tool) I bonded the passat bezel to the vanagon plastic. This left a series of open areas since the smooth transitions at the top and sides were not a part of the Vanagon shape. These areas were filled with JB Weld then smoothed and shaped by hand with various wet/dry sanding papers. On the back side of the Vanagon cluster, I removed the plastic shell support for everything except for the light switch and the lowest switch position on the right. I then filled and smoothed the front surface in preparation for cutting the two 2 1/16 gauges that I wanted as part of the cluster. I then bonded the cluster support pi eces from the original vanagon bezel to the revised unit. I set the positions in a jig, heat treated the plastic for a slightly different takeoff angel to meet the original mount point without stress. These support pieces were about 0.250 inches further to the right and left than the original. I then fitted the Passat cluster (took off some interfering tabs) and reinforced the remaining structure with JB Weld. The gauge holes and switch areas were then clearanced and a final sanding polish performed before painting with the flexible semi-gloss black. The paint removed fine sanding damage with a high film strength drying surface. Did a test fit and all was well including the latched top pod cover.
On the instrument cluster mods … I added the boost (0-30 psi) and EGT gauges in an excellent 270 degree sweep unit made by Speedhut. The MFA cluster (not part of the original Passat TDi cluster) was pieced together from a ’95 Passat GLs (4 cylinder motor) cluster with turn signal (has cruise control switch) and wiper (has MFA controller) stalks from same. (This idea came from Chris Bell on the TDIClub list). The tach sensing was correct for the TDi engine. The temperature gauge is appropriate for the sensor on the engine. The gas gauge worked for full scale to empty due to VW internal standardization policy! The speedo sensor is electronic. I cut up a GTi speedo cluster to get the Hall effect sensor wheel and mount shell. Added a VW three wire VSS sensor and turned it all into a 2.0 x 2.0 x 1.5 inch adaptor that pops onto the end of the Vanagon speedometer cable. I convert the pulses from this Hall sensor packet to the frequency (pulses per mile) needed by the Passat cluster with either a Dakota Digital pulse frequency converter of a circuit for variable calibration designed by my son. In the custom circuit, we would calibrate the speedometer with a GPS system and thereby lock it on for any tire combination.