Project Porsche Boxster R Part 2: Wheels, tires and rear wing

We are all standing around the keg like apes surrounding the monolith in Kubrick's "2001." My cousin Dave cautiously reaches out and places his finger on the metallic cylinder, observing the cold condensation that turns into tiny rivulets of icy water. Dave's about to have an epiphany, a revelation that will bring him up another step of the evolutionary ladder.

"Chrome," he said with glazed eyes. "We've got to get chrome wheels. "

Although the monolith helped the monkeys in the film, the keg before us was not having a positive effect--for a moment, I pondered beating Dave with an animal bone. I suggested he purchase a Mustang and hang all sorts of ethnic trinkets from its flanks--curb feelers, gold fender trim, pipe-organ speakers, the works. I would rather be dragged naked through the streets, tethered to the bumper of a lowered mini truck than fit chrome wheels on a Porsche--more specifically, my Porsche.

Our first meeting for Project Boxster R hit a snag, but as the effects of Samuel Adams' elixir waned, the voice of reason (and taste) reappeared. What Dave actually envisioned for the Boxster was not chromed wheels but rather rims with polished outer sections, a fairly standard design of multi-piece wheels. We decided to let him remain in our tribe.

The 6x16- and 7x16-in. split-spoke wheels our Boxster was born with carried 205/55ZR and 225/50ZR Bridgestone SO-2s that were almost tread-dead. If we lived in an area with nasty weather and nastier roads, we would have kept them and just swapped tires. Southern Cal is a different story, however--a Plus 2 fitment with a tire that would see a few rainy days was in order.

Using the term "unsprung weight" as a mantra, the field of potential wheels was reduced to a handful of the best players. Initial dyno tests showed our Boxster was making 167 rhp @ 5500 rpm, so saving weight, especially the unsprung sort, would help the Boxster make the most of its limited power. Several manufacturers carried forged and semi-forged wheels for Porsche applications, and none of them are inexpensive. While it is possible to make a strong wheel, and it is possible to make a light wheel, manufacturing a wheel that is both takes a good deal of engineering expertise. Thumbing through Performance Products expansive catalog, its RH Wheel looked to be everything we were looking for. Strong, relatively lightweight, modestly priced and made in Germany, the RH wheels also had the correct appearance we all wanted. Performance Products carries three types of TUeV-approved RH wheels--the AG-Cup, AH-Turboline and the P-3, the model we chose for the Boxster R.

Aptly named, the P-3 is a genuine three-piece wheel featuring spun outer rims and a pressure-cast center section, hand-assembled and sealed with high-quality fasteners. Although heavier than a one-piece wheel, the P-3s multi-piece construction offers a tremendous advantage--should the Boxster R suffer a bent wheel (an entirely possible event), we simply replace the damaged section at a fraction of the cost of an entire rim. Given Boxster R's various drivers, the P-3s were a functional and striking solution.

The P-3 wheels appear to be specifically built for the new Porsche platforms, featuring the proper offsets and dimensions for direct bolt-on fitments. The P-3 measures 18 in. in diameter and is available in half-size widths from 8.0 to 11.0 in.

Although choosing the P-3 wheels from Performance Products' catalog was easy, picking from the huge variety of ultra-high-performance rubber was not. Like high-tech shoes, modern street tires are very specialized, designed to excel in specific areas while retaining a high degree of manners. Project Boxster R needed a tire that could do everything well, with an emphasis on managing grip in both the wet and dry. Dunlop's SP Sport 9000 is such a tire.

I've been a fan of Dunlop since the SP Sport 8000, the precursor to its current UHP tire. We used SP Sport 8000s on our AC Schnitzerized BMW Z3--basically, they were the tires that taught me how to drive fast without getting killed. The Sport 8000s were built on a tough carcass with a moderately aggressive tread design, good compound and featured rounded shoulders for smooth, progressive breakaway. Although the SP Sport 9000 bears no resemblance to its forefather, it has retained all those great characteristics and then some.

The most striking feature of the SP Sport 9000 is the tread design, an organic-looking configuration that appears to have grown into the tire like an alien vine. Its design is much more than cosmetic, however, and it serves to meet the first of five tasks Dunlop's had in mind for the SP Sport 9000.

The first task was reduced noise emissions, an area I normally wouldn't care a rat's ass about, in a sedan anyway. Roadsters are different, because noisy tires can become irritating. Development engineers began with essentially the same negative surface area as the SP Sport 8000 (grooves and tread bars), but instead of straight, longitudinal grooves, a fan-shape tread design was used. This helped reduce the hissing that occurs when air is pushed through the straight and narrow grooves, much like an organ pipe. The new tread design dissipates this sound more effectively. Dunlop's new Multi-shift Variation principle, a further enhancement of its Twin Shift Noise Reduction function, was designed to emit overlapping frequencies that cancel each other out and thus leave the tire with an inoffensive "white noise."

The second and third tasks the SP Sport 9000 was targeted to perform well in are its sensitivity to aquaplaning and wet performance capabilities. Here's where the SP Sport 9000's combination of 100-percent silica and bold tread design gave it a serious performance advantage. The SP Sport 9000 funnels water to the outside like a turbine wheel, unlike many conventional tires that push water to the front like the bow of a ship. Add Dunlop's reformulated tread compound to the equation, and the entire balance between wet grip and rolling resistance is raised another notch.

One unfortunate side effect of silica is its propensity to insulate and store a static charge. Upon exiting a car equipped with silica-based tires, merely touching the vehicle will cause a spark...the dangers during refueling are obvious. Dunlop has solved the problem by using what's referred to as the Base-pen system, Dunlop's patented design for eliminating static build-up. The Base-pen system features a ring a few millimeters wide, made of a conventional carbon-black compound which is embedded into the middle of the silica tread and runs all the way around the tire. The base of this carbon-black ring is connected to the silica-free base layer of the two-layer tread. This ring safely conducts static away from the vehicle where it's no longer a threat.

Lastly, the SP Sport 9000 was built to offer better dry performance than its previous incarnation while providing more tread life. It was no easy feat considering the fine performance of its predecessor, but Dunlop did manage to wring 10-percent more in both areas.

The SP Sport 9000 is constructed with the JBL (jointless nylon band) wrapped around the steel belts. It makes for exceptional tread contact during high speeds or heavy loads, when the tire is under maximum stress. Moreover, the SP Sport 9000 has been developed using finite element analysis, which results in a tire that maintains its performance characteristics to the end of its life. The Boxster R was fitted with 225/40ZR-18s in front and 265/30ZR-18s out back.

The lines of our Porsche were augmented with Performance Products' Boxster Aero kit, a program comprised of front spoilers, side skirts and a rear wing. We were prepared to sign on for the whole deal but decided to go with just the rear wing and keep things totally understated. The wing is fabricated from quality composite material and comes primed and ready to paint. The unit is attached with four screws and was beautifully painted by the crew at Ron's Custom. As the automatic spoiler rises, it integrates with the wing's bottom section and appears to become one big spoiler. To look at the piece, you'd think our Boxster R was born that way.

Simply changing the running gear has transformed the Boxster into a whole new animal. Unlike the old tires, the SP Sport 9000s and the big RH wheels make it stick big time--no more power-sliding around the neighborhood (which is kind of a bummer). The rear wing adds just the perfect "edge" that makes our car stand out from the crowd.

In the next installment, I'll outfit the Boxster R with Litronic headlamps, S-spec brakes, and H&R's coilover suspension. Stay tuned.

Performance Products
8000 Haskell Ave.
Van Nuys, CA 91406
(800) 423-3173
www.automotion.com

Ron's Custom
7744 Densmore Ave.
Van Nuys, CA 91406
(818) 994-3528
Special thanks to Cindy and Tony