Project Gruppe R has come a long way since we first started on the path to creating a unique Volkswagen Auto Group (VAG) build. The previous owner would never have given this car the performance life it was designed to live.
The purpose of this article is to address some of the smaller, but very important, modifications that were completed during the big installs. These little rally essentials are not just specific to this car, but useful for any tracked or rallied project out there. Some of our loose ends are simple bolt-ons and others required some more follow through on the planning and fabrication side.
To date we have addressed the suspension, braking, wheels and tires, engine tune, exhaust system, and aerodynamic performance. We are very pleased with the result of these big modifications, but the details are just as important. Here we will complete the vision with mod including; wheels studs, underbody protection, mud flaps, reinforced sway bar end links, and shock reservoir mounting.
We decided to go with longer studs, and steel lug nuts.
VAG cars have the misfortune of coming from the factory with lug bolts, rather than nuts. This fastening method makes for a wrestling match when mounting a wheel and diminishes overall security should the bolts loosen.
Adding a stud conversion to our Golf is not only aesthetically pleasing, it makes servicing the car much easier. We got our studs from ECS Tuning, and opted to go a little longer than typical to accommodate the new Braid wheels, and the 15 mm spacers required to clear the front coil springs.
The install for a stud conversion is about as simple as it gets. With the car raised up and the wheels off, we applied some red thread-locker to the short threaded end of the stud. Threading the stud into the hub until it stopped on the shoulder, we reached for a breaker bar and tightened them down. The studs have a metric Allen head on the end making torquing an easy task, no jamming nuts together.
The ECS Street Shield protects the engine underbody or the engine bay, and features a laser-etched logo and extra hardware.
Whether you track your car, drive on dirt, or just roam the surface streets and freeways, some form of upgraded underbody protection is a good insurance policy to protect your engine. Most cars and trucks do not come with any substantial protection for the oil pan. One red and white curb, pointy rock, or cinder block in the road and your engine could be toast.
Think of how many times you’ve been following a car that blocks your view of the road ahead, only to see there is debris in the road and you have nowhere to go. You center up on it, wince, and hope you have the ground clearance.
Overlaying the stock plastic belly pan and the ECS Street Shield, we see how inadequate the protection was.
Gruppe R will see stones, ruts, and debris in the road, it already does everyday getting down the country road it lives up. The OEM belly pan/skid plate is woefully inadequate at protecting the engine, so we once again turned to ECS Tuning for a Street Shield Skid Plate.
The Street Shield is constructed of 3/16-inch aluminum and is bent into shape with pre-drilled holes that lined right up. According to ESC, “the Street Shield is constructed from 3/16-inch thick 5052 aluminum, weighing in at only 17.5 pounds and includes factory-modeled air ventilation. The ECS skid plate encompasses the full length of the engine undercarriage from the front bumper cover to the forward engine subframe.”
It’s a challenge to do this without a lift but with the jack stands raised we were able to get under the car.
Squeezing under the front of the car, we first interlaced the front edge of the skid plate with the existing body work, just like the stock piece. We then started the bolts that locate the back edge on the aluminum subframe, using the aluminum spacers on the outer two bolts.
Clockwise from top left: front edge interlaced with OEM plastics, aligning the subframe mounting holes, inserting the spacer on the outer rear bolts, tightening down the rear edge.
The sides of the Street Shield reuse the stock Tinnerman nuts on the inner fenderwells.
Last, we screwed in the inner fenderwell sheeting around the perimeter, and tightened everything down. The plate fit up to the engine with minimal gap, so ground clearance is not sacrificed. Additionally, the flat-bottom effect closes many of the exposed angular structures and voids around the engine, aiding aerodynamics.
While often seen as an aesthetic modification, a set of mud flaps are essential to a rally car. Not only do all motorsports sanctioning bodies require them for stage rally, they also provide some protection from rock chips, excessive mud and dust for the body of the car.
The RokBlokz kit came with photos and written instructions, hardware, the mud flaps, stickers, and Smarties.
We chose to utilize the Golf Mk6 kit from RokBlokz, while not intended for the Golf R, we were confident any mods needed would be within our ability. The RokBlokz kit comes with all the needed hardware including screws, spacers, Tinnerman nuts, and a friendly surprise – a roll of Smarties. The RokBlokz mud flaps are constructed from a durable, stiff plastic, but flexible enough to give over an obstacle.
According to the RokBlokz site, “the unique blend of polymers in our rally car mud flaps give them the specific characteristics to be highly effective at protecting your car … durability, flexibility, light weight and rigidity all come together allowing the flaps to extend out enough to be effective, retain their shape at speed, and also to bend, flex and scrape without damage.”
Clockwise from top left: removing the inner fender liner hardware, starting the supplied bolt through the mud flap, clipping on a new plastic Tinnerman nut, tightening everything down.
We opted to start in the front because no modification would be necessary. The kit re-purposes two of the stock fender liner holes, and one is added for support toward the inside. We screwed the mud flap to the fender liner using the fender washers. Luckily the RokBlokz flap fits in the vents of the flared fender and protects the side of the car from debris.
Left: removing the two rear fender liner screws. Right: the mud flaps require spacers between the flap and the fender liner.
In the rear we had to cut a small corner out of the mud flap to clear the felt inner fender liner, this also forced us to relocate the inner mounting hole. We replaced the two OEM Tinnerman nuts with the larger ones supplied in the kit.
The wider rear wheels and tires do protrude slightly from the fender, but tuck into the fender well with camber gain. At ride height the RokBlokz flaps will cover the rear bumper from any gravel we roost.
Sway Bar End Links
If you refer back to our suspension installation article, you will recall that our gravel rally ProFlex coilovers forced us to shorten the stock sway bar end links. These OEM units are basically a sealed ball joint connected by an anemic 1/4-inch solid rod.
We decided that our quick fix was a bandaid, and this car would need something a little tougher, the last thing we want is to lose roll control mid triple-digit corner from a broken end link. We turned to the rod-end experts at FK Rod Ends for some advice on what sorts of misalignment joints or Heims would stand up to the abuse.
After consulting with Brian McAllister of FK, we concluded on the JMX/JMXL line of rod ends. These American-made precision Heims are made from 52100 stainless steel center balls that are hard-chrome plated, a heat-treated alloy steel body and face which are zinc-plated and chromate treated, and include polytetrafluoroethylene (PTFE) liners.
“It’s a higher strength 4130 chromoly body and the ball is made to be a higher misalignment unit. You can only get angle until the hole pivots into the way of the body, by making the ball wider and pushing everything out, you can get more angle before that hole comes into play,” McAllister explained.
In order to accommodate the space restrictions in the wheelwell, while increasing strength, we opted to go with 1/2 inch hardware, 1/2 inch threaded ends. Because our project requires adjustability like any tie rod, we wanted one end of the link to be right-hand treads (part number HJMX8T), and the other side left-hand (part number HJMXL8T).
Our FK Rod Ends are American made and constructed from high-strength materials.
On the raw materials side, we needed some weld-in bungs suited to these misalignment joints and FK was happy to set us up with both left and right-hand threaded bungs and jam nuts. Depending on the level of strength needed for an application, FK can supply weld-in bungs for different wall thickness tubing. For our application, we decided that 7/8 inch diameter, .065-inch wall 4130 tubing would fit the bill.
Before cutting any tubing we measured the center-to-center length of the stock swaybar end links.
The first step of fabricating our new links was to measure the existing parts for length center-to-center. With the numbers in mind, a little quick math gave us our cut length for the piece of chromoly tubing to bridge the two bungs and rod ends.
We cut the tubing, de-burred the ends and mocked up the bungs and rod ends to take another measurement, confirming we had the correct overall length. Happy with the length, we could move to the welding bench. It’s ok to weld through the pickling that comes on 4130 tubing but it’s a good practice to clean it off with a little Scotch-Brite and acetone before welding.
After cutting the tubing and deburring the ends, we mocked up the weld-in bungs and rod ends to check that our overall length was correct.
A few initial tacks helped make sure the bungs did not get crooked when we introduced some real heat, laying in the full bead finished the job. After letting the links cool we chased the threads to make sure nothing had been damaged from welding.
After a few tacks, we finish TIG-welded the bungs.
At this point it was time to consider surface protection. While the mill pickling does a decent job of protecting the metal from oxidation, the addition of heat on the clean surface will result in rust in no time. We stripped the rest of the pickling, and the heat affected zone (HAZ) discoloration off the link with Scotch-Brite. Turning to one of our favorite racecar chassis-builder tricks, we picked up our bottle of Precision Brand Tool-Black. This chemical bluing product creates a protective blued finish on ferrous alloys, helping corrosion resistance.
To protect the raw parts from corrosion, we first removed the existing mill-scale, HAZ discoloration and any greasy hand prints. Bluing the steel is as simple as wiping on a little Precision Brand Tool Black, and waiting for the chemical reaction to take place.
You simply wipe the Tool-Black on the clean parts and let them sit a few minutes before neutralizing the chemical reaction with water. A light brush with Scotch-Brite cleans off the chalky film and leaves a satin black finish. The last step was a quick spray of LPS3 Rust Inhibitor, this solvent-based waxy solution dries to leave a film that repels water and does a great job of preventing oxidation.
We chose to go this long route for inspection purposes. Why don’t you see many painted or powder coated roll cages in racecars? The answer is because you cannot inspect for cracks, or make repairs without stripping the coating. Bluing or hard-nickel plating are the trick racer surface treatments.
Notice that left-hand (reverse) threads on the bungs, rod ends, and jam nuts are indicated by a machined groove or little nicks in the corners of the nut.
The final assembly and installation was the last step in our sway bar end link project. With both front wheels jacked up and removed (to unload the sway bar), we easily removed the stock end links. Holding the new pieces in place, we threaded the new 1/2-inch grade 8 hardware through the rod end and first to the swaybar.
We drilled open the upper sway bar end link mount brackets.
We discovered that the ProFlex sway bar mounting tab needed to be drilled out just barely to fit the new hardware. Pushing down on the top of the new link, we aligned the spherical ball in the rod end to match the mounting bracket. Another 1/2-inch bolt located everything in place.
Installing the completed links was as simple as lining up the bearings and bolting everything together. Note we are using nearly all of the misalignment angle available but not binding the rod ends at full droop.
After tightening everything down on both sides, we were pleased to see no interference issues were created with these reinforced links; and although we used up nearly all 12-degrees of available misalignment on either rod end, no binding was present.
We took the car out to make sure everything cycled freely and detected no binding, noises, or issues. We can corner with more confidence now, knowing our sway bar end links can stand up to the terrain the rest of the car has been built to handle.
External Reservoir Mounting
When we completed the installation of our ProFlex coilovers, we were left with a few problems to solve. First of which was the swaybar end links, second was where to mount the external shock reservoirs for the front suspension.
Because the ProFlex struts feature a large swept volume of oil over their stroke, external reservoirs house the nitrogen gas charge and compression adjustment screws. While the rear shocks are ‘piggyback’ style, where the reservoir is built into the forged aluminum lower boss, the fronts are snaked through the strut towers under the hood, care of some braided line.
We definitely don’t want our aluminum, gas-charged reservoirs to be flopping around under the hood. To protect the reservoirs along with accessory drives, hot surfaces, sharp edges and electrical components, we decided a little more fabrication work was in order.
We took our inspiration from steel bump stop mounting cans that off-road fabricators often use to integrate secondary suspension into a race vehicle. These fabrication parts are simply 2-inch id tubes, that have been split down the middle to act as a clamp, and skeletonized for weight savings.
Cutting thick-wall aluminum can be just as hard as steel because it loads a composite cutting wheel, or the flutes of a burr.
Our application is not structural like a bump can, so we opted to recreate the bracket in aluminum. We ordered up some .125-inch wall 6061-T6 aluminum tubing from Aircraft Spruce, and got to work. The first step was to cut the tubing to length for the external reservoirs.
Aircraft Spruce is a fantastic source of small quantity metals and composites.
With the lengths cut, we turned our attention to the flat plate we would use for the actual mounting bracket. After making paper templates of the parts we wanted, we transferred the design to aluminum and got cutting with a mixture of our Miller plasma cutter, and die-grinders.
We transferred the outline of our paper templates onto aluminum plate, set up a cutting guide or 'fence' in the form of a steel plate, and then used our Miller plasma cutter.
A few tacks on the welding bench held everything together for finish welding. We decided to just run three short beads. After the bracket and tube were welded together, we went back to the vise to start skeletonizing. We cut out an oval section to promote flexibility and reduce weight.
After the plate and tube were welded together we made a few straight cuts with a cut-off wheel, then radiused the corners.
Back to the welding bench, we added our small bosses to accommodate the clamping hardware. With these small .125-wall tubes welded on, we simply split the remaining bridges of the tube so we will be able to spread it apart.
From the beginning, we identified our mounting location under the hood. We planned to utilize existing bolts and captured nuts that secured the top of the headlight housing to the radiator core support. Because the headlight tabs are plastic they will space the aluminum brackets off of the hot support and provide some insulation from heat transfer to the reservoirs.
Two Torx bolts secure the tops of the headlights to the radiator support. We decided to reuse this mounting hardware instead of drilling our own holes.
In order to fit our brackets under the hood in this location, we needed to mount them as low as possible – for hood clearance and to clear the hood support gas-strut. The final fabrication step would be to put a 45 degree bend in the flat mounting plate to achieve the lower location.
We used a press brake to bend our .125-inch 6061 aluminum plate to 45 degrees.
We held the bracket up to the mounting holes and scribed a line along the back of the core support, this would be our bend line. At the press brake, we lined up the scribed line and used a scrap piece of aluminum as a spacer to slightly increase the radius of the bend for a smooth, tear-free bend.
Getting the ProFlex reservoirs in our clamps required us to spread open the tube.
Lastly was to install our completed brackets. Because of the space constraints, we slid the reservoirs into the clamp before bolting them on. The snug fit required us to hold open the clamp with a few spacers. After removing the two bolts securing the top of the headlight to the core support, we aligned our brackets and threaded them back in.
After tightening down the brackets, we put a few final bolts through the canister bosses and snugged everything down – the reservoirs are not going anywhere. The final result was a clean, secure mount for our external reservoirs.
That’s it for the loose ends on Gruppe R, at least for now. We still have plans for this car, but for now we plan to enjoy it, go on some trips, explore the gravel backroads of Southern California, and stand out amongst the hoards of lowered cars on the road.