We’re posting trip details elsewhere but for those curious about the Cayenne mechanicals, we are super happy with its performance in the BajaXL. Keep in mind that my comments pertain to running at adventure rally pace, not overlanding pace. The only real modifications were bigger tires (with some corresponding removal of wheel well material) and a metal front skid plate to replace the plastic one. We removed some interior trim and infotainment stuff to create some extra storage space.
We never rolled across scales but we had it loaded pretty well with four people, an extra spare wheel, camping and cooking stuff, personal stuff, tools, and yes four spare air spring/struts.
The power, smoothness and quietness were a BIG help in reducing our overall fatigue. Looking at some of the other rigs (Scouts, side by sides, Broncos, prerunners, etc., it was clear that we had a comfort advantage and over ten days that really helps. We were typically in it for 10-14 hours a day.
The offroad capability surprised us. The traction control worked pretty damned well, and the locker/low is great although we perceived a slight difficulty disengaging it one time so we avoided it thereafter so we wouldn’t have to drive home in low. There was no terrain in the race route that we couldn’t cross. We were amazingly far out in the desert with no one else around and it just kept going.
The suspension overall is a bit harsh, even in Comfort, and with the non-disconnectable sway bars we were routinely flying a wheel in cross-axle situations like steep washed-out tracks. Our speed on the rough sections was slower than that of the rigs with more compliance and travel, which made for less time in the day to collect waypoints. Porsche lists just over 8" of total travel, and the height settings put you at various places within this 8", with correspondingly more or less up and down travel. For instance if you lift the car all the way, it only has an inch or two of up travel remaining. We stayed in the middle as much as possible so we had travel both ways, but the lack of flex was still very evident.
As the event went on we realized we needed to run lower and lower tire pressures. On the pavement we loved the stability that we got with hard (45-50 psi) tires but by the end of it we were running 20 psi on the rougher stuff and sand. Because we didn’t have a lot of sidewall with our 18” rims, even with 275/65 tires, we were reluctant to go lower if we were likely to encounter large rocks. We trashed the shock bushing on our new Delphi left control arm, and a rattle in the front right (suspected worn damper) got progressively worse. I think that deterioration would have been less with lower pressures.
At the beginning of the final day the left rear air spring popped. Sounded like a stone hitting the undercarriage but soon things just didn’t feel right and we could tell that we were sitting on the rear bump stops (both sides deflated) and we got an air regulation error on the dash. We hadn’t done this repair before but we had all of the necessary tools and it took about two hours working slowly. At that point I was sorely tempted to swap out the front right as well, due to the suspected worn damper, but it wouldn’t have been time well spent as we would lose the finishing points if we were too late to bivouac. Suspension-wise, I think my preferred prep (with some hindsight) would have been to replace all bushings in the original control arms with OEM parts, air down more aggressively from the beginning, test all of the dampers beforehand, and be ready to manually disconnect the sway bar. There are apparently aftermarket air spring replacement parts which would reduce the need to carry four complete spare struts, if they could be field installed, but you need the dampers to stay good.
The onboard air is wonderful. It inflated the tires faster than we could air them down, although it did take breaks during long reinflation stints. I suspect it has a temp sensor but I don’t know that for sure. We used it on other vehicles, too. We brought a compressor rebuild kit but didn’t install it.
The other issue we had was some overheating. Before the trip we replaced the seemingly leaking coolant reservoir with an aftermarket one, but in deep sand we noticed coolant boiling over. We then found that the cap was damaged (no O-ring and broken retainer) so we replaced that with one from Autozone. Still we had coolant escaping, though, and we never really got to the bottom of it. The fan worked, but maybe the radiator is dirty or there is still a leak. No oil in the coolant or vice versa, and it only happened when the temp got halfway between 180 and the next tick mark. We stopped running into situations that caused it (deep sand or long slow climbs) and shifted our worry to other things.
We never got around to changing the transmission or transfer case oils. We heard, or imagined, new noises that could have been drivetrain related but never went beyond mild worry.
We broke some right mirror stuff on cacti and lost a door sill trim piece. Had an off-track excursion that put a small dent in a frame rail. Have an idle shudder (always did, it got a bit worse) that is probably a bad fuel pump. All minor stuff.
I think that’s about it. No flats. We finished in 6th place out of 30 and had a lot of fun.
All shiny and clean on Day 1:
Typically dirty, with the other Martini-inspired car on Day 7 or 8:
