Tarmac rallies can be hard on tires. Strike that; tarmac rallies are hard on tires. The Newfoundland roads take it a step further than that-the Rock’s stages have hazards for wheels as well.

The best approach is to avoid all the hazards, of course. But just in case you don’t, be sure to bring the two spare tires allowed by the organizers. Ideally those tires would already be mounted on wheels, ready to bolt onto the car.

When we Targa’d in 2015, the station wagon easily held both our spares; in 2016, the coupe could carry only one spare inside, strapped down behind the front seats. But this year, in the Cayman, there’s just no room in the cabin for a spare… you’d have to run without a co-driver and use the passenger seat for tire haulage. And that won’t work on a stage.

How about putting a mounted spare in the frunk?

How ’bout not, says this picture.

But you simply must carry at least one ready-to-go spare. Targa runs all day, and you are never close to a commercial area. If you’re blessed with a service crew (we are not), you may not be close to them.

You simply must carry one with you.

Well then, if we must…

Now the hood closes at least. That’s a used 991 hood, by the way; same part number.

Call it a “rain shield”.

Slightly less offensive in Racing Yellow. But it still needs something.

Ah, that’s better. That’s a proper rally car look.

Under the bulge, the spare is secured with a couple tether points in the frunk walls and a long surcingle of nylon strapping. The jack and torque wrench (118 lbs-ft!) are nearby.

We’ve been using a Timewise “A box” rally computer for many years. It’s what we successfully ran in both our previous Targa campaigns.

At a recent snow rally, though, some folks with app-based rally tools did quite well; well enough that we took a closer look at the tool that had performed best at that rally.

The tool’s development is centered in Spain, and is apparently driven by local demand (which suggests to me that if I were to emigrate, Spain is a place where I could fit in-they must rally a lot).

An interesting feature is that the measurement of distance can be done via GPS. If its measurements were accurate enough, that would reduce the problems of wheel spin and slip that face us with our wheel-driven sensors.

We gave the tool a three-day check out on the recent Nor’wester rally in Washington state. The app’s philosophy and approach are very different than the Timewise’s, and our A-box habits only partially suited the tool-so we were also using the three days to set some new habits.

Aich. The three day test revealed that the tool isn’t ready to supplant the Timewise, or maybe we’re not ready for the tool, or maybe a bit of both. So our rather extensive preparations to be able to run the app in the car had to be excised, and new preparations for running the Timewise installed, quick-sharp.

We’ve done that Timewise install in other cars a couple times before, at least. And both computers can use the same sensors. So we were counting thousandths of miles in the Porsche a full day before the car had to leave on its cross-continent journey. <grimace>

A non-recreational parachute.

A fire extinguisher, except when you’re training.

A snake bite kit.

A towing eye for your race car.

And yet all of these things need to be top quality, well maintained, and ready for immediate use.

A lot of the chassis and structural elements in the Cayman are aluminum. These are engineered closely to their projected loads and stresses. In the rear bumper area, there are not a lot of heavy duty attachment points for a towing eye.

Oh, Porsche provided one, in a suitably robust location – but they also expected that it won’t be used often. So the location is accessed behind the license plate. That works great on a race track, because there are no license plates on the car.

But rally uses public roads for transits. So license plates are a must; but still, when you want to use the rear towing eye, it’s gonna be a non-calm situation. Then you have to pull off the rear plate?

Nope.

The nice round hole in the aluminum plate comes from a “gasket punch” originally used in some heavy industrial setting. It came into my hands through a local auction shopper.

Quoth he, “I never thought I would find a use for these.”

Inside the cabin, we’re adding a bunch of devices:

• Android tablet for the rally software
• Rabbit Pro box for GPS and wheel speed sensors
• Dashcam
• helmet intercom
• Rallysafe tracker
• A smartphone for the driver’s display

Naturally, there’s no universal standard for this stuff. We have two USB-C consumers, two 12V units, an ATM06-2S plug, and a plain-old USB-A. Oh! And the shielded three wire cables for the wheel speed sensors, plus the large gauge static drain wire.

Hope Renee wasn’t planning on putting anything else in the glove box. Here’s a little tray with supplies for four of the seven devices.

 

The Targa Newfoundland registration materials include an outright declaration that you shouldn’t run a tire aspect ratio less than 40. Lower aspect ratios are better for ultimate steering and cornering performance, but we won’t be on a race track. We’ll be on country roads, and in neighborhoods, and on moderate arterials within towns. There are potholes, broken pavement, frost heaves, nooks, crannies, cracks, rough patched places, the lot. Heck, that set of hazards also describes the 3500 miles of US roads between here and St. Johns.

So this project skews the tire-and-wheel formula away from circuits and toward “normal roads”; that is to say, “rally roads”.  We want more sidewall!

The Cayman, even with its large front brakes, can fit 18 inch wheels. Porsche even sells a factory accessory set of 18s, mounted with Pirelli snow tires. Having the specs of that accessory set, I duplicated the wheel widths and offsets onto a set of Made in Spain Braid Wheels. I paid the $376 customs duty with a smile; I’m sure the Spaniards will send me a check soon.

The tires are high-performance all seasons, in the identical sizes of the factory accessory set. The UTOG Treadwear rating is a 540; somehow I doubt we’re going to reach the mileage that that rating usually implies.

Here’s an 18″ front with the all season 45 aspect ratio versus the OE 20″ with a 35 aspect ratio tire.  Mr. Dunlop would be proud.

 

The Cayman’s engine is amidships, but its radiators are upfront. Porsche must think that these cars live on a racetrack, cause there’s really no grill over any of the three front radiators. But off courses, the roads are littered with rocks, and metal debris, and the odd low-flying bird, and the gaping maws of the radiator inlet started looking like intake scoops to me. I was concerned.

I got some nice metal honeycomb grill material and was going to fabricate my own protective grills.

But I soon realized the most effective way to do that would be to remove the front bumper. Then I didn’t wanna remove the front bumper 🙁

Aftermarket to the rescue. I’m not the only one that wants those grills. These came from England, in like four days…and they pretty much snapped in.  Maybe not immediately, but Josh methodically got to the right technique for it.

The installation also reminded me that my friends have higher standards for fit-and-finish than I do. I’m … more of a tractor mechanic than a supercar wrench. I take comfort in my continuing opportunities to improve. 

The Hall Effect sensors we’re using come from a rally savant in Spain. One nice touch that he includes is an indicator light—on the sensor itself—which tells you it’s working.

See, there are several ways to assemble this kind of system incorrectly. (I’ve tried most of the incorrect ways…)  Once you’ve done that to yourself, and skipped the testing because “I know it’s right”, only to find yourself at the rally without a odometer, you’ll never skip the testing again.

So when you’re mounting these sensors, putting the magnets in place, aligning the barrels of the sensors to the face-plane of the magnets, adjusting the gap distance, … your testing can take place under the car. All you need do is power the Rabbit box, spin the wheel (or brake disk, in this case), and watch for the lights.

This car company’s obsession with weight doesn’t end with that jack I described in the previous post.

A gram here and a gram there, and pretty soon you have … several grams.

Consider the lug bolts. The 996s had bolts with 19 mm heads, the 997’s were also 19 mm heads, but the heads were shorter by four or five mm, and this car now has 17 mm headed bolts — all these with the same thread size. A steady trimming away of what was not needed.  Because if you don’t need it, why are you carrying it around?

When you notice these things, you may start to develop a sympathetic obsession. You’ll notice if something that you’re adding to the car is made of heavier material than it needs to be. That sensibility can lead you to building things differently.

Here is a fabricated mount to hold the driver’s display for our rally computer. 

The fittings and vertical stalk are just nicely manufactured commercial products made for motorcycles. But that larger horizontal base is a small chunk of high performance aluminum tubing. 

OK to be honest, it’s a sawn-off end of a mountain bike handlebar that I’ve had my fabrication oddments bin for years. Using materials on-hand is a longstanding obsession for me. 😉  Here’s the matching piece from the other end of those handlebars (I trimmed the bars at some point to improve ergonomics).

 

Regardless of its history, that chunk of tubing is very light and very strong, and in my current weight-obsessed state, it seems the perfect thing to use.

A big reason that we’re taking our newest car to Targa is that there’s less chance of a worn out part failing on the long, long transit to the other side of the continent. Or on the long transit back, for that matter.

Lower chance of part failure means a lower need to carry spare parts. And it’s a good thing we don’t have to carry many spares for the Porsche, because there’s very little cargo room in the car.

Porsche does not include a spare tire, even an inflatable one, with this generation of Cayman. The car does come with a small air compressor and a canister of tire sealant, which could be used to seal a small puncture and get you off the side of the road. There’s also Porsche roadside assistance, which is what I think most people use.

Porsche roadside assistance isn’t going to be any help during the rally, there’s just no time to wait for them, nor are they likely to have a solution that would have you back in the event, ready to run the next stage. We will have to have spare tires and wheels readily available to us on The Rock. That’s the subject to a future post. 

There’s also no jack provided; but that’s an easy fix. The 996 generation of Porsches came with a tidy aluminum scissors jack (p/n 99672121100), and those jacks still work for our car. They’re so light!