When I purchased a 2006 Porsche Cayenne Turbo last year, the combination of spectacular driving dynamics paired with relatively impressive off-road capability drew me to the model. Porsche built the first-generation Cayenne, known by the internal designation code 955, with an optional air suspension system, adjustable shock absorbers, and a true low-end transfer case fitted with a locking center differential. Add 450 horsepower from a twin-turbocharged 4.0-liter V8 and the combo remains unique to this day except for the facelifted next generation, the 957.
But a few small tweaks can go a long way to increasing the 955’s off-road potential, without sacrificing much of the on-road characteristics that made the 955 the world’s first super-SUV. I started by getting a set of Open Country A/TIII knobby tires from Toyo for better traction in sand and snow without adding too much road noise or crushing my miles per gallon. The new rubber added another dimension to my off-road projects, but from the start I knew the Cayenne’s dry-sump V8, Aisin six-speed automatic and transfer case needed a bit more. protection than the flimsy factory-installed plastic underbody panels. .
After a fair amount of research and some inspiration from Harrison Schoen aka 957AdventureI landed on a beefy steel skid plate from Eurowise, in North Carolina, to shield the underside against big bumps. Fortunately, installing the engine skid plate proved surprisingly easy, requiring only a special riveter in addition to a standard set of medium tools. Eurowise posted a video on YouTube showing how to install the skid plate, but in the desert with no cell phone reception, I wanted a written DIY guide with pictures – now I’m writing one.
Removing the plastic underbody trays
To begin installing the stronger skid plate, begin by removing the plastic trays under the engine and transmission. A cluster of 10 millimeter screws and four Phillips heads hold the two pieces together and secured to the truck. Whether you want to keep the original parts or throw them away affects how quickly you can complete this step – I decided to keep them for comparison (and in the spirit of Porsche originality).
Take a moment to measure
I grew up with the “measure twice, cut once” mantra drilled into my skull from an early age, so before I started playing with the fasteners that Eurowise comes with the pickguard, I first used a safety bracket to hold the heavy piece of steel against the subframe mounting points. This allowed me to verify that the holes matched without any clearance issues or rubbing of the engine and transmission surfaces. Right next to the eyeball, the rivet holes seemed aligned and the clearance seemed good. Also, I now knew exactly where to install the six rivnuts, since the kit came with no extras.
Learn to use a rivet nut
Eurowise offers an additional riveting tool with all of their skid plates. Having never used one before, I took the time to lay out all the different parts and read the included instructions. The Eurowise video gave a hint on how to use the tool, but ignored the preparation that might be needed. I fiddled with the different heads and installed the M12 fitting, after screwing it into a rivnut as a test. Remember to tighten the correct size lock washer on top after replacing the nib! And always be sure to keep a small gap between the rivet itself and the tool’s pressure edge to avoid stripping the threads or crushing them prematurely. It definitely qualifies as one of those tools where everything only makes sense after you used it once.
Installation of rivets
My first attempt at riveting involved a bit of apprehension. I wanted to avoid stripping the wires, fearing crushing the metal too hard, but I also had to make sure the grip lines held the nut completely secure. My recommendations include preparing with sufficient travel length by turning the center dial a little, but also starting with the handles at a sharp angle. This allows for a little more leverage at the start of the compression, after which the process becomes easier.
After the first rivnut I felt more confident and moved quickly. I installed the four smaller ones first, not realizing that the larger rivnuts were still using the same M12 threads – the order doesn’t really matter as long as the larger rivnuts go into the larger holes , so maybe starting with the bigger two makes a bit more sense to avoid a mistake. Either way, pay attention to the gaps between the holes on the kick plate itself!
Test the Rivnuts
Again, due to my status as an amateur rivnutter, I tested each one by hand by screwing a bolt halfway in and wiggling it, just to make sure I was applying the right amount of pressure. They all seemed pretty tight to hold the pad, and I figured tightening the bolts with the skid plate installed would further increase the pressure on the rivets.
Start by squeezing by hand
Then I slid the skid plate up onto the safety jack, with a block to maintain stability and keep pressure on the bottom while I screwed in the bolts by hand. After much experience with the finicky skid plate hardware on my 1998 Mitsubishi Montero, the Eurowise design seemed incredibly easy, with more room to wiggle the bolts around and avoid stripping the wires. Also, the larger bolt head gets some protection from metal wedging rings, should you hit a rock (the whole point here, after all).
Torque up to 40-50 lb-ft
Eurowise specs to torque the bolts between 40 and 50 ft-lbs, which I thought was a little on the low side since they’re almost half an inch thick. Additionally, bolt heads work with 3/4 inch or 19 millimeter sockets, as do lug nuts which typically twist at over 80 to 100 ft-lbs. But the limiting factor here seems to be the rivnuts themselves, and the 45 lb-ft clamp felt pretty tight after I stopped thinking so hard and did it.
(Almost) perfect fit and finish
This pickguard from Eurowise, which weighs around 70 pounds, really impressed me in terms of fit and finish. The metalwork itself felt substantial enough to beat, while the hardware aligned much more precisely than any other aftermarket gear I’ve ever purchased. Suffice it to say, I plan to purchase the transfer case, rear differential, fuel tank and matching air suspension pads as soon as my budget allows – each part costs a pretty penny, but a lot less than tearing up and having to replace a critical part Porsche!
The only issue that arose while doing this work was with the two plastic pieces on each side, seen above, that screw onto the stock engine plates. I decided to store them behind the pickguard rather than cut them off, just in case I reinstall the originals. If they make a ruckus on rough roads, a quick cut should fix the problem.
Ready to hit the trail
The engine skid alone makes me confident enough to test the Porsche and those Toyos again on a rough trail near Paiute Ridge on the way to Mojave. I’ve driven this climb many times before in a Jeep Gladiator Rubicon and my Montero, so even though the trail always changes a bit due to weather and traffic, I should learn how low range and center differential Cayenne are working well. I hope the truck rises to the challenge and justifies my installing such a sturdy skid plate, not to mention the financial hit. In the meantime, the rough roads of West Los Angeles won’t know what hit them when this Cayenne arrives.
Sources: eurowise.com, instagram.com and youtube.com.
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