Tom Wilson
October 28, 2009
Photos By: KJ Jones

When the last Castrol Syntec Top Car Challenge participant pulled off Buttonwillow Raceway Park's road course we weren't quite sure how our Mustang challenger had performed. For sure it had lapped faster than the '60s-era Chevy Caprice that Lowrider magazine had just fielded--complete with air bag suspension, no less--but mentally tabulating where our entry finished was beyond our estimation.

Certainly there was no angst over the '95 Mustang Cobra and its just-concluded muscular display. Gamely fielded by 5.0 Mustang & Super Ford's reader Ron Cooper, the daily driver 'Stang laid down good real-world numbers. Keeping to the spirit of Castrol's automotive intramural, we opted for a representative, real-world Mustang. Our sister publications--this was a magazine-based get-together, after all--didn't seem similarly motivated judging from the near-race machines resting next to 18-wheeler transporters (in one case, anyway).

Like everyone else, we had to wait for the official results to be calculated and announced months later. In the meantime, we knew Ron and his Mustang acquitted themselves well.

For those who missed our feature on Ron's Cobra, it could be one of thousands of daily driven fun cars. It's original 302 expired years ago, and he replaced it with a Summit-sourced Explorer 302 short-block, Probe forged pistons, Air Flow Research 165cc aluminum heads, all aided by a Vortech V2 supercharger with a big stock pulley. A T56 six-speed gearbox replaced the original T5. Underneath, the main chassis improvements are a Maximum Motorsports Road & Track box kit, Koni single-adjustable yellow shocks, and Hawk HPS brake pads in the stock Cobra PBR-based calipers. Sticky Nitto NT01 tires, 245/45ZR-17, are on Cobra R wheels.

Besides a full complement of add-on street gear--a stereo, DVD player, 10-inch subwoofer, extra sound-deadening, seat-back-mounted TV monitors--the Cobra maintains every ounce of its original equipment, such as air conditioning, and it's seen 14 years and many miles of street use. Heck, the "new" engine had 70,000 miles on it. To put it mildly, our entrant and his 14-year-old Mustang are the personification of hands-on Mustang enthusiasm.

Testing the Castrol Top Car participants was a two-day affair, opening with a dyno test at K&N Air Filters to read the best of three power pulls, followed immediately by an emissions test. Once everyone had had a chance on the dyno rollers, the entourage rumbled through street and highway traffic on the three-hour grind up to Buttonwillow Raceway Park in California's hot central valley. Day two was dedicated to lapping Buttonwillow in search of the perfect lap.

Points were awarded mainly, but not completely, as a percentage of the best competitor's performance, which made it difficult for everyone except the officials to keep tabs on how the competitors were doing. That's mainly a good thing, as entrants tend to try too hard if they can see they're only a point behind Second place or so. With this system, there's still plenty of mental noodling, but without accurate conclusions, everyone just tried their best.

In preparation for the Challenge, Ron had his car tuned by an old friend of this magazine, Steve Ridout at Powertrain Dynamics. Steve wrote two tunes for Ron to toggle between; one for 91-octane pump gas and another for 100-plus-octane race fuel.

With the engine freshly adjusted, the only thing Ron needed to monitor on the K&N dyno during his three official runs was the ignition timing. After watching one competitor's engine show signs of imminent death during dyno competitions, we were happy to have Ron open with a conservative 10 degrees of static timing, followed by the second pass at 12 degrees, and the final at 14 degrees. That was sure to post a decent number right away--good insurance in case something went wrong at the more aggressive ignition settings.

It turns out the first run netted 440 rwhp, followed by another 10 hp on the second run. That was OK, but the engine was heating up and Ron knew rushing into the third pass wouldn't gain the power his race tune could post. So instead of icing just the intake, Ron iced the supercharger, intake tube, and IAT sensor as well to keep the computer from pulling timing. That did the 20hp trick, and the Cobra whacked out 471 rwhp.

Of course there were the usual overachievers. Some of the turbo'd import cars reached into the 700-plus-rwhp range, and just as predictably, one of them rattled a piston, putting it out of the competition just as it started.

Right after the dyno rollers braked to a stop, a probe went up the ol' tailpipe, and the Cobra was run through an idle and 2,500-rpm load test. Ron was ready for this test, too, as he had recently installed a fresh set of high-flow cats. As we once heard a New Jersey street racer say, "A new set of cats could clean up Three Mile Island." In this case, the 302 wasn't dirty to begin with, so Ron came out of the sniff test like a basket of fresh laundry.

Horse Sense: A regular haunt, Buttonwillow Raceway Park is 240 miles from our West Coast home office. The Castrol's Top Car Challenge marked the third time we'd been there in six weeks. We should be paid by the mile!

"Windows up, air conditioning on, and the CD player running," was Ron's description of the obligatory cruise from K&N to Buttonwillow. "It was no big deal."

And why should it have been for a daily driver? Ron's car is normally used to taxi his daughters between in-town activities or as long-distance transportation. His telecom business has him mainly working at home with the Cobra running errands, but Ron just as easily hops in the Cobra and racks up hundreds of miles on a business trip to meet with clients. So, yeah, it was right at home in a little bit of SoCal traffic and 100-plus-degree heat over 186 miles to Buttonwillow.

Car owners are mainly expected to drive their cars during Top Car Challenge testing, and with previous drag experience in his Cobra, Ron was feeling pretty good about the first Buttonwillow test: the quarter-mile. Everyone got three trips down a dragstrip laid out on one of Buttonwillow's long straights, with 0-60 times and the usual quarter-mile information gathered by radar on the best run. Testing rules called for three passes back-to-back, so there was no meaningful cool-down between runs. No burnouts were allowed, either. This was to be a measure of the car's real-world acceleration rather then a technical dragstrip exercise.

With the car running fine, Ron's challenge was finding traction on the bare, dusty, unglued Buttonwillow asphalt. His first pass was up in smoke, his usual 3,000-rpm dragstrip launch simply too much for the available traction. Ron moved the launch rpm down in successive 500-rpm increments for the final two attempts, and while the second pass looked pretty good, the barely spinning final pass netted the best times at 12.81 seconds and 113.76 mph. Ron was disappointed, noting the Cobra easily runs well into the 11s at the 'strip, but obviously the loose Buttonwillow surface wasn't allowing that. The 0-60 mph time was 4.87. At least that was a small favor, as--considering the slippery launch--the 3.55 rear gears let the Cobra reach 60 mph without a shift into Third.

All brake tests were driven by a Top Car Challenge professional test driver rather than the owners, so Ron got to watch this one from the sidelines. The story here isn't particularly pretty as the Cobra did the big Mustang nosedive characteristic of four-link rear suspension Fox and SN-95 Mustangs, and posted a marathon-long 221-foot stop from 80 mph. Obviously, our Mustang wasn't making any points against the mainly import-based competition as their lighter weights, and relatively larger brakes and tires, were a big help in this test.

We'll also note that Ron's Cobra was fighting two factors that could easily have been different. First, the condition of the Hawk HPS brake pads was not optimal during the brake test. These pads are actually a good choice for this sort of testing because they aren't so hard that they won't warm up to operating temperature in a three-stop brake test. That's an all-too-common result of running full-on race pads in instrumented testing. No, the issue here was the new pads were not fully conditioned--bedded--for ultimate stopping power. We confirmed (and mostly cured) this later during the road course practice session.

A more involved but common Mustang braking improvement is fitting a torque arm to the rear suspension. Maximum Motorsport has just the piece in its inventory--we've used it to great effect on our Track Car--but it's not part of its Road & Track Box kit. Ron would have had to dig deeper in his wallet to get that on his Cobra for The Challenge, so it's understandable from both a time and money standpoint why it wasn't there, but torque arms really do help keep the nose up during braking.

Counting for twice the points as the acceleration runs, the road course lapping was the big kahuna in the Top Car Challenge. Each car got a 20-minute practice session, and then a 20-minute timed session with the fastest lap used for scoring. There was a good gap between practice and the timed session so minor adjustments could be made, and owners did their own driving.

Buttonwillow can be fairly technical, and experience on it is a definite plus. Ron, of course, had never seen the place before, having just one open-track day at the simpler, more flowing Willow Springs under his road-racing belt. We had years of lapping Buttonwillow in its various guises, so we rode with Ron while he drove half the practice session; then we swapped seats for some quick tutorial.

After practice and noting there was no limitation on drivers in the rules, Ron opted to drive the first half of the timed session, and then graciously gave us the second 10 minutes. This turned out to be a good plan as Ron's combination of powerful engine and a daily driver chassis tune meant his car required a deft touch to reach its potential. We know drag racers and street types may not think 471 hp at the rear tires is a big deal, but on a road course it's tons of fun.

Mainly what we were working around was mediocre front grip. The Cobra answered the throttle and came off the corners with nice traction and good control, and it certainly got down the straights, but from corner turn-in down to the corner apex, the front end was a little slow to respond and just didn't have good stick. The typical over-assisted Mustang steering didn't help, either, requiring a light touch. That can be tough to muster in the heat of combat.

And--not to be masters of the obvious--the daily driver Cobra was a bit soft on its spring/shock tune for all-out track work, even with the shocks adjusted to full hard. We should also point out there was so much power, full throttle is modestly used--just in the middle of the chutes and straights. Even in the long sweepers, the prevailing understeer holds speeds down and that kills lap times.

Another consideration is the brakes. The Cobra PBR calipers are a good track piece, and the Hawk HPS pad is a good dual-purpose unit, but it was overwhelmed handling a hard-driven supercharged Mustang lap after lap. During practice, the pads got good and hot, with plenty of smoke drifting out of the wheelwells by the end of the session. Along with the subsequent cool down, this is just what the doctor ordered, however, as this more fully beds the pads to the brake discs, noticeably improving braking during the timed session.

A lengthening brake pedal was still an issue during the timed session, however. This could have been the pads, and just as likely moisture in the brake fluid (we're not sure the brakes had been bled recently). And given the street/track HPS pads, brake-cooling ducts would have helped. The fact that we were both standing on the pedal like a brachiosaurus might have had something to do with it, we suppose . . .

There was just one mechanical issue during practice: The dipstick tube came loose from the block, causing a visible smoke trail as the oil vaporized on the killer-hot catalytic converters. Ron mopped up the loose oil and stuffed the tube back into the block, and that was the end of that.

Before we knew it, it was on-track for the timed session. Ron made an intelligent warm-up lap, then went on a flyer but spun in a spectacular, dirt-slinging way leading onto the start-finish straight. Ah, always in front of everybody. Luckily missing anything unyielding, Ron was able to get moving again right away, taking another intelligent "let's see" lap, followed by another flyer. This was a good-looking lap from our pit-side vantage point, but tiring of an audience, Ron looped the Cobra again, this time up and over Magic Mountain, a tricky up-and-down-while-turning section not visible from the pits. With time running short, Ron turned the car over to us.

Taking it easy on our out lap, we discovered Ron's second spin had sprayed an acre or two of dirt and marbles at the crest and downhill of the blind Magic Mountain, so we made a note to go slowly there. There was time for one flying lap, possibly two, but our first flying lap wasn't half bad, and with the brake pedal going soft and the dirt on the hill, we decided to return Ron's daily driver intact. We estimate there was another 2 seconds left to be had given a perfect lap on a clean track, but as it was, we were reasonably satisfied with our 2:12.543 lap.

We never figured a real-world Mustang would prevail against specialized magazine project cars, of course, but thanks to the Mustang's inherent strengths, we think Ron's 14-year-old Cobra put away more than half of the competitors. Certainly Ron can be proud of the minimal speed modifications his Cobra required to run with some pretty big dogs.

As always, the Mustang proved king of the bang-for-the-buck cup. Its strong engine, robust constitution, and low cost means all of us can get out there and have at it.

And in a test such as this, we must also acknowledge the Mustang's inherent weak points. The nose-heavy weight distribution and understeer built into these earlier chassis by a lawsuit-wary Ford Motor Company mean suspension mods are mandatory for meaningful track performance--and against turbo'd all-wheel-drive lightweights, you're going to need all the chassis a Mustang can muster.

But when it comes to our personal Top Car, we'll take the fast one we can afford to put in our garage. Or as Ron put it, "I'm happy with how it came out. Yeah, I had a good time. If I placed in the Top 3 with my daily driver, that would be great. I'll be the only one who'll go home, toss my daughters in the back, and go to dinner."

To see how Ron and 5.0&SF fared, check out the big results spread in the Jan. '10 issue.