It took more than 700 hp to...
It took more than 700 hp to top the charts on the K&N dyno; just the sort of Twilight Zone number expected from a bunch of magazine project cars. And to prove the point, while Ron's Mustang punched out 471 stone-reliable horsepower, an Audi S4 huffed up a big number along with a piston. Solid, durable horsepower is probably the Mustang's greatest legacy.
"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.
In the Golden State it either...
In the Golden State it either passes an emissions sniff test every two years or goes on a trailer. That makes power-building more costly and complicated, but it also means Ron's daily driver Cobra had no fear of the Castrol Syntec Top Car Challenge sniff test. His was a Challenge low-emitter.
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.