From R&T, 1993
ROAD & TRACK ROAD TEST: Callaway CR-1
Breathes deeply, leaves you breathless
By removing the fan belt of my 1959 Chevrolet Corvette, I was unleashing hidden horsepower -- not to mention, disabling the cooling fan, water pump and generator. But not to worry. It would take mere seconds to make that record-shattering run through the quarter mile at Dunkirk Dragstrip, barely enough time to let the coolant heat up.
Plenty of time, though, to allow the gasoline that had leaked out of six Stromberg carburetors to reach its flash point, which happened about the moment I parked the car and climbed out.
"Hey!" bellowed a spectator. "Is that your Corvette?"
"Yeah, that's my machine," I sniffed, striking a macho pose.
"Well, it's on fire!"
Tugging frantically at the electrical cord that I had used to secure the hood (who needed those cumbersome latches anyway?), I was about to learn why firemen always caution you to feel the surface of a door before opening it.
As a giant fireball shot 10 feet into the air, I dropped the hood, fanning the flames that were already melting the rubber fuel lines and ignition wiring and blistering the paint. Fortunately, quick-thinking race fans armed with fire extinguishers snuffed out the inferno before serious damage could occur. But right then and there I had an epiphany: I would never ever leave out anything crucial to the car's well-being -- and I would leave performance tuning to the experts.
Had he been around in 1959, Reeves Callaway could have saved me a lot of grief. The premier Corvette tuner, Reeves builds cars that not only go fast, but also don't set themselves on fire. Unfortunately, up until now, Callaway's Vettes have fetched a pretty sum, primarily because they were sold only as complete cars based on brand-new Vette chassis. But after years of building cars that were "extremely fast and extremely expensive," Callaway is taking a new tack. "Now we're going after volume by offering any and all of our factory- or dealer-installed options to those who already own a Corvette and who have only a few thousand dollars to spend."
Callaway CR-1 offerings total more than $60,000 of options, including a $15,000 Connolly leather interior. But a savvy buyer with ZR-1 or LT1 in hand could shop selectively, says Mike Vietro ("Corvette Mike," Callaway's Southern California dealer). In fact, Vietro saved plenty by basing his Callaway CR-1 (our test car) on a 1990 ZR-1 he bought used for $35,000.
As a confirmed horsepower addict (like money, you can never have enough, I say), I would certainly opt for the Callaway-modified LT5 engine. While the stock LT5 engine pumps out 405 bhp this year (up from 380), Callaway's version delivers 475 bhp -- without the aid of turbochargers. "People think of us as turbo guys. But we're just engine guys," says Reeves, who explains that he decided to switch to normally aspirated powerplants after working with Aston Martin on its non-turbo Group C racing car. Why an aspro? "Because it costs less, sounds good and generally will run forever."
Working with Chevrolet as a factory-approved tuner of the Corvette, Callaway believed that there was at least 100 bhp hidden in both the Chevrolet LT1 and LT5 powerplants. So he set out to unleash this untapped horsepower, mostly through traditional methods: modifying the exhaust system; porting and polishing the intake and exhaust passages, inlet runners and manifold; and altering the camshaft timing.
But a significant additional increase in performance was achieved by reprogramming the Vette's Gen II onboard computer, something that's difficult to accomplish without the help of the manufacturer. Sure, you can address the computer at calibration level and improve engine performance. Unfortunately, only the manufacturer can provide the data that enable you to access the car's engine-management system at its root or code level. "What separates the men from the boys," says Callaway, "is that unless you're working with your partner (Chevrolet), you'll never develop an engine that's both powerful and compliant."
A quick blast in the CR-1 shows you exactly what he means. Floor the throttle and experience the good breeding (and good breathing) of the Callaway engine. The CR-1 doesn't show a hint of asthma at high revs; in fact, the Callaway's power begins to build mightily at 4000 rpm and doesn't stop until the rev limiter says "time out." And yet the CR-1 powerplant doesn't protest when the driver chooses to crawl along through heavy traffic at low revs in 6th gear. That's modern-day electronics for you -- and Callaway's ability to make use of the same.
By the way, Reeves calls his engine the "Supernatural 475" and credits his wife, Dale, for coming up with this catchy moniker. "I told her it was neither turbocharged nor supercharged, but normally aspirated."
"Oh, so then you might say it's supernatural," quipped Dale.
Supernatural, maybe, but not out of reach of mere mortals with a few thou (hey, nobody said this was going to be cheap) who can have one installed in their ZR-1 for $14,750 and lop more than a half-second off the stock ZR-1's 0-to-60 and quarter-mile times while increasing top speed by nearly 10 mph.
If these seem like paltry increases, bear in mind that when working with cars such as the ZR-1, it takes a lot to improve on already impressive levels of performance.
Should you decide to explore the upper reaches of your new engine's performance, you'd do well to spend another $5500 (plus $390 installation) on Callaway's brake package that replaces the stock ZR-1's fronts with Brembo 4-piston calipers and discs borrowed from a Lola Indy car. Although Reeves insists they won't fade, even in stops from 190 mph, he readily admits that for racing -- in the German Super Cup where his European distributor plans to run two Callaway LT1-based cars -- a similar setup at the rear would be nice. "Brembo cringed when we said we'd use stock brakes at the rear, so in the future we'll be offering those on our road cars too." As it is, just having front Brembos reduced our test car's stopping distances by 10 percent and brought overall brake feel up from "very good" to "excellent."
Back in 1959, we raced hard. Unfortunately, we also rode hard because in those days the answer to traction control and handling was stiff springs. Nowadays, the Corvette goes easy on spring rates and leaves it all to Bilstein's cockpit-adjustable ride control that alters shock-absorber damping. It's a good system, but not a perfect one as anyone who has driven a Vette through bumpy turns knows. Although the ride's not bad, the car tends to hop sideways because (according to Callaway) the stock front and rear transverse leaf suspension experiences "cross-talk" with wheel action at one corner of the car affecting that of its partner.
Callaway's $2905 solution is an independent-suspension package that uses coil springs, which, if nothing else, offer plenty of adjustability. "You can set ride height correctly, adjust pitch angle front-to-rear and crossweight the car (compensate for loading on one wheel by altering the loading on the opposite wheel)," he claims.
Although several engineers I spoke to were skeptical of Callaway's crosstalk theory, Reeves insists that "It's the best $2900 you can spend on a Corvette." Those of us who drove the CR-1 tend to agree with Mr. Callaway and with an editor's assertion that the ride feels less squirmy, more precise and less ponderous at low speeds.
Now then, it's debatable whether you need to spend $7950 (plus $4700 or so for installation and paint) on a Callaway Aerobody kit. Granted, it's distinctive and a sure-fire attention-getter (especially in passionate-purple metallic). Also, I'd be the first to admit that the ZR-1 needs something to distinguish it from the normal Vette. But Porsche tuner extraordinaire Louis Ruf will tell you that when it comes to top speed, less is more. That's why his 212-mph coupes use the narrow 911 body rather than the wider Turbo bodyshell. On the other hand, the "If ya got it, flaunt it" philosophy sells a lot of Rolex watches, so what the heck . . .
One more thing: If you say yes to the Aerobody kit, consider the $1700 (plus $130 for installation) special exhaust system that exits under the center of the car rather than at both sides.
While some of us might question the need for modified bodywork, few would argue that a ZR-1 Corvette, much less a Callaway, needs unique wheels. If you agree, then be prepared to part with $5600, which gets you a set of European-made O.Z. forged alloys shod with Bridgestone RE71 radials. Although these tires are the same size as the stock Vette's, they look meatier because the rims have more (positive) offset than the standard rims. Needless to say, that extra 1.2 in. of offset widens the CR-1's track and (according to Callaway) improves lateral grip.
We weren't able to corroborate skidpad performance, but we can tell you that in the slalom -- perhaps because of the slipperiness of the test track -- the CR-1 was not at its best through the cones. It managed to go only 62.8 mph, where the stock ZR-1 model had gone 63.6.
But, as always, the single most impressive aspect of a Callaway is its straight-line performance that inspires words such as these: Quoth an editor, "The power this engine has from 4000 to 7000 rpm makes you forget all those fidgety little Corvette annoyances and makes you want to put every person you know into the passenger seat, go out to a deserted road and impress them with what the CR-1 will do."
And just so you know, that's with the fan belt in place and the water pump, cooling fan and alternator (never mind the power-steering pump and a/c compressor) running.
1993 Callaway CR-1
2 High Street
Old Lyme, Conn. 06371
PRICEList priceest $35,000-$66,000 (used vs new Corvette ZR-1)Price as testedest $78,575 (incl cost of used ZR-1, $35,000)Price as tested includes std ZR-1 equip. (driver airbag, air cond, AM/FM stereo/cassette; pwr windows, door locks, driver's seat & mirrors), CD player. Callaway options incl modified engine ($14,750), coil-over suspension ($2905), Brembo front disc brakes ($5890), O. Z. alloy wheels w/Bridgestone tires ($5600), Aerobody kit ($12,600), center exhaust ($1830).
TEST CONDITIONSTemperature60š FWindmildHumidity75%Elevation350 ft
ENGINETypealum heads & block, V-8Valvetraindohc 4-valve/cylDisplacement350 cu in./5732 ccBore x stroke3.90 x 3.66 in./99.0 x 93.0 mmCompression ratio11.0:1Horsepower (SAE)475 bhp @ 7000 rpmBhp/liter82.9Torque414 lb-ft @ 5250 rpmMaximum engine speed7000 rpmFuel injectionelect. sequential portFuelprem unleaded, 91 pump oct
CHASSIS & BODYLayoutfront engine, rear driveBody/framefiberglass/skeletal steelBrakesFront12.9-in. vented discsRear11.9-in. vented discsAssist typevacuumTotal swept area445 sq in.Swept area/ton254 sq in.Wheelsforged alloy; 17 x 9-1/2 f, 17 x 11 rTiresBridgestone RE71; P275/40RE-17 f, P315/35RE-17 rSteeringrack & pinion, power assistOverall ratio15.6:1Turns, lock to lock2.3Turning circle40 ftSuspensionFrontupper & lower A-arms, coil springs, tube shocks, anti-roll barRearmultilink, coil springs, tube shocks, anti-roll bar
DRIVETRAINTransmission6-sp manualGearRatioOverall ratio(Rpm) Mph1st2.68:19.25:1(7000) 562nd1.80:16.21:1(7000) 843rd1.31:14.52:1(7000) 1154th1.00:13.45:1(7000) 1515th0.75:12.59:1est (6725) 1936th0.50:11.73:1est (4490) 193Final drive ratio3.45:1Engine rpm @ 60 mph in 6th1400
GENERAL DATACurb weight3495 lbTest weight3645 lbWeight dist (with driver), f/r, %52/48Wheelbase96.2 in.Track, f/r58.9 in./61.8 in.Length178.5 in.Width73.1 in.Height46.3 in.Ground clearance4.2 in.Trunk space11.6 cu ft
MAINTENANCEOil/filter change7500 mi/7500 miTuneup30,000 miBasic warrantyna
ACCOMMODATIONSSeating capacity2Head room35.5 in.Seat width2 x 18.5 in.Front-seat leg room42.5 in.Seatback adjustment30 degSeat travel5.5 in.
INTERIOR NOISEIdle in neutral67 dBAMaximum in 1st gear80 dBAConstant 50 mph80 dBA in 6th/74 dBA in 5th70 mph76 dBA
200-mph speedometer, 8000-rpm tach, coolant temp, oil press., oil temp, volts, fuel level
ACCELERATIONTime to speedSeconds0-30 mph2.40-40 mph3.10-50 mph3.90-60 mph5.00-70 mph6.10-80 mph7.60-90 mph9.10-100 mph11.0Time to distance0-100 ft3.10-500 ft7.50-1320 ft (1/4 mi):13.2 @ 111.5 mph
FUEL ECONOMYNormal drivingest 19.0 mpgEPA city/highway17/25 mpgCruise rangeest 360 milesFuel capacity20.0 gal
BRAKINGMinimum stopping distanceFrom 60 mph115 ftFrom 80 mph225 ftControlexcellentPedal effort for 0.5g stop18 lbFade, effort after six 0.5g stops from 60 mph18 lbBrake feelexcellentOverall brake ratingexcellent
HANDLINGLateral accel (200-ft skidpad)naBalancenaSpeed thru 700-ft slalom62.8 mphBalancemild understeerLateral seat supportexcellent