ma71supraturbo
09-18-2005, 01:57 PM
Showdown of the Sudden Samurai:
Supra vs. RS-7 vs. 280ZX
By Tony Swan
Consider the code of the Samurai. Cold steel and iron will. No quarter asked, no quarter given. Duels to the death. Viewed from the perspective of Southern California, this adds up to a lifestyle that's about as attractive as an eternal knife fight in an elevator. But it does sum up the conflict between these three steely Samurai warriors -- with these exceptions: We had a lot more fun doing it than you get in your average fight to the death, and all three lived to fight another day. Which, predictably, made the manufacturers happy. Domo arigato, manufacturers.
Actually, we've been itching to assemble this threesome since our first encounter with the new Toyota Supra back in October. These cars represent the absolute acme of Japanese automotive technology, and measure up impressively on the world scale as well -- particularly in terms of value. They're high on driver gratification, high on visual appeal, high on profile, high on creature comforts, and, considering everything their makers pack into them, relatively low in cost. We're not suggesting a range of $12,000 to almost $16,000 is cheap, you understand. But when you compare what you're getting for the money, you'll find that not many manufacturers are able to match up favorably. Interestingly enough, some of the U.S. manufacturers -- notably Ford (with the Mustang GT, $11.288 loaded) and GM (Camaro Z28, $12,671, and Firebird Trans Am, $12,500) are doing a better job of competing in the luxo sport/GT area than the more celebrated European entries (read Porsche).
Our determination to pit this threesome in a Japanese GT free-for-all grew even stronger when the Supra emerged as MT's Import Car of the Year for 1982 (April), and so as our part of the world battened down for the gathering monsoon, the three warriors finally arrived -- sleek, refined, and menacing.
The Warriors
We dressed the three contenders in black, partly because it makes them all look so delightfully sinister, mostly because black is definitely the color for the Supra (doesn't hurt the others, either). When you order a Supra in any other color, the fiberglass fender flares tend to have an added-on appearance, and the black panel just above the rear bumper is, to be polite, far from harmonious. We also made sure that this Supra had the rear-window Sun shade attached. Stung by initial press reactions to the sun Shade -- it seemed to draw a pretty unanimous boot from first-time beholders -- Toyota made the sun shade a buyer delete option, then began deleting it on virtually all new Supras at the factory. Not everyone here likes the sun shade, but we all agree that it makes the new Supra look more like what it is, rather than a tarted-up Celica GT. Some of us even like it.
The cars weren't in the house more than about five minutes before Hall, drawing on some obscure textbook of Japanese love, had named them all for famous Samurai warriors. The ZX became Zato-Ichi, the Supra was Kagemusha, and the RX-7 was Tanaka-Cho. One of these legendary swordsmen, incidentally, was supposed to have been blind, and for anyone who's ever seen Hall at the wheel when he's in a hurry, the whole thing suddenly makes sense.
Anyway, whatever name you use, these three are undoubtedly familiar to you by now so we'll keep the introduction brief.
There are many commonalities. All three cars are front-engine, rear-drive, with MacPherson strut front suspension (see Ron Grable's suspension sidebar) and 4-wheel disc brakes. Although the Supra does offer the auxiliary rear seating of a traditional 2+2 GT, all three cars are designed essentially for two passengers, and the RX7 and ZX provided seating for exactly that many.
Interior treatments on the cars fall readily into the general category of sumptuous. Both the Mazda and the ZX arrived with leather-clad interiors -- we have to admit that the Japanese have become very proficient with hides -- and long haul comfort was a strong suit for all three cars. However, when it came to back road thrashing, the Supra's new Recaroesque buckets were clearly in a class by themselves. Lateral support was markedly better than that offered by the other two entries, and the command chair -- eight adjustments, pneumatic lumbar support, etc -- is the absolute best OEM unit in the business.
http://www.celicasupra.com/images/MT6-82-5.jpg
Each car was equipped with its manufacturer’s top-line sound system, and here again the edge goes to the Supra, with its 7-band equalizers and premium speakers. However, the Datsun system was only a few reverbs (no one seemed able to completely dial out the echo chamber effect) away from a tie, and both these units had the "Earth Calling Mars" look that seems to typify current Japanese automotive stereo gear. The Mazda's 4-speaker Clarion unit is simply not up to the quality of the systems provided with the ZX and Supra.
Instrumentation was comprehensive across the board, with the Mazda getting good grades for night visibility, the Supra eliciting wows for its general level of after dark showbiz (augmented substantially by the stereo system), and the ZX emerging as the staff favorite in this regard. All three cars were equipped with cruise controls, though the RX-7's rated as a distinct 3rd among the testers since it had no accel/coast feature and was incorporated on the same stalk as the washer/wiper controls, which can lead to some inadvertent use of both functions.
Although we concerned ourselves primarily with performance in this comparo, we couldn't help emerging with some strong convictions regarding the general content, quality, and value of the test cars. Quality, of course, is a strong suit of the entire Japanese industry, a perception that has American manufacturers scrambling to catch up, and these entries from the top of the Japanese market are worthy standard bearings for their breed. Workmanship, fit, and finish were excellent throughout, and the staff nit-pickers were hard-pressed to pick a winner -- or a loser. However, there wasn't much hesitation when it came to considerations of content. The Supra emerged as the unanimous choice, with the ZX a unanimous 2nd. The RX-7, for its part, won grudging approval as the value winner, offering the most for the least money. But its edge in this subjective department doesn't seem nearly so marked as it did when the car first appeared back in 1978.
Samurai Power
While original Kagemusha, Zato-Ichi, and Tanaka-Cho presumably drew their power from divine sources back there in the bad old days (Granola and Wheaties were still several centuries off in the future), their steely namesakes share a common gift of go: We call it gasoline. However, beyond the commonality of spark-ignited internal combustion, the manner in which the manufacturers have chosen to convert fuel into horsepower account for the principal difference between the three cars.
As the only rotary engine in production today, the RX-7's 2-rotor wankel is the most technically interesting of the three powerplants, as well as the smoothest. Mazda's total commitment to rotary engines n the early to mid-Seventies very nearly precipitated the demise of parent company Toyo Kogyo. The rotary found itself caught between the first oil crisis of 1973 and a reputation in this country for poor reliability. While the latter may have been unfairly acquired, since it was more or less directly related to the indifference of many Americans to even the simplest maintenance procedures (such as checking the oil), the rotary's thirst was real. Toyo Kogyo backed away from the rotary like your no-good brother-in-law backing away from a bar tab, and the company just managed to snatch its corporate bacon from the burner with the introduction of the very conventional little GLC.
However, thanks to the brilliant efforts of Dr. Kenishi Yamamoto, who has since become a Toyo Kogyo managing director, rotary development continued, and in '78 Mazda generated slack jaws and green envy throughout the automotive establishment with the original RX-7. It offered reasonable fuel economy (EPA rated at 17/28 mpg), satisfying performance, and excellent durability. If the GLC stabilized Mazda's deteriorating foothold in the U.S. marketplace, the RX-7 turned the company's image around completely, and Toyo Kogyo couldn't build them quickly enough.
Mazda made a couple of improvements to the RX-7's 12A rotary last year. A new high carbon rotor apex seal was adopted, promising even better durability, and a catalytic converter system replaced the old thermal reactor emissions control setup. The catalytic system had several benefits. It reduced warm-up type, eliminated the backfiring associated with thermal reactor RX-7's, and, best of all, contributed to the improved fuel economy. Although the Supra sports slightly better EPA rating than the Mazda, the RX-7 did in fact emerge as the fuel-stingiest Samurai, averaging more than 25.3 mpg throughout the test, 5 mpg better than the 2nd-place Z-car.
The RX-7 delivers more horsepower per cubic inch than its adversaries, but there's not enough of it. Even though the car scales in at 281 lb lighter than the ZX and 456 less than the Supra, its 100-hp rating leaves it well behind the other two cars in power-to-weight. This produced predictable results in the acceleration portions of the competition -- a full 1.5 secs behind the Supra 0-60, and 1.2 secs behind the ZX. The rotary's engine's torque characteristics -- there isn't much of it at the low-end -- contribute substantially to this shortfall; it's hard to get the car launched from a standing start without buzzing the engine up to induce wheelspin.
We know there's plenty of potential horsepower locked up in that little rotary; two years of virtually total domination of IMSA GTU racing attest to that. But we don't really expect to see a significant boost in street horsepower until 1984, when the RX-7 is due for a major revision. When the new car comes along, we expect it will include the company's bigger 13B rotary engine, with the option of a positive displacement supercharger.
In contrast to the Mazda rotary, Datsun's tried and true 2.8-liter OHC six is pretty routine goods. Which is to say routinely excellent. We chose the normally aspirated edition rather than the turbo to provide a more reasonable basis for comparison, but even with the benefit of force-feeding, this engine has the highest peak horsepower rating of the trio. This is essentially the same engine that came to the market with the original 240Z back in 1970, although it has grown from 2.4 to 2.6 to 2.8 and acquired Bosch L-Jetronic fuel injection along the way. What this means for buyers is the durability that goes with extended development, and this the Z-car sorely delivers, as it has from the start.
As noted, it also delivers the best peak-power rating in our little group, along with the most favorable power-to-weight ratio, but even though you would expect this to add up to the best acceleration times, this was not the case (we know you haven't looked at the charts yet, but it's okay now).
---- PAGE MISSING :(
...game plan was to turn Kagemusha, Zato-Ichi, and Tanaka-Cho loose on a full-scale road racing layout, we were confined to the dragstrip and handling course of Orange County International Raceway.
Nevertheless, our testing at OCIR told us what we wanted to know, and this turned out to be pretty much what we expected going in. In its first season as a genuine GT, the new Supra has established a new standard for its Japanese counterparts to try to match.
Having said that, let us amend it by adding that the handling portions of this comparison set the RX-7 apart from the other two cars. Its character is much more pure-sports-car, which comes across as a somewhat harsher ride and distinctly more nimble feeling. The latter is attributed to the RX-7's shorter wheelbase and distinct weight advantage. Although we did not include a timed straight-line slalom as part of our official tests -- for a few days there, the appearance of more than three pylons in a row seemed to have the power to produce instant rain -- we did get in a few random runs, and in this activity the RX-7 was the star. Even though it was the only car in the group lacking rack-and-pinion steering, the RX-7's recalculating-ball system produced excellent road feel, light effort, and crisp transient response. (McCraw claims there is really only one possible transient response -- "Get a job" -- but that's another story.) Both the Supra and the ZX are equipped with excellent power rack-and-pinion systems, the ZX setup dialed in at an exceptionally quick 2.7 turns lock-to-lock. But the superior performance of the RX-7 in quick direction changes is another benefit of its lower all-up weight, and this in turn led most of the test staff to regard the hummer as the most fun to drive.
However, in the handling test that really counts here -- timed laps around an abbreviated road course -- the Supra was an easy winner, partly because of its excellent new all-independent suspension system (have you read Gramble's sidebar yet?), and partly because of its much bigger footprint, Toyota's finest exhibited a bit more body roll than the other two contenders, which is attributable to its tradeoff for the best ride qualities in this threesome, but it was thoroughly predictable and exhibited the best steady-state cornering stability, wet or dry.
As far as the quantifiable suddenness of the Sudden Samurai is concerned ("How sudden were they, Roy?"), the charts speak for themselves. Even though the Supra was the heaviest of the lot -- the price you pay for those rudimentary rear seats -- its combination of excellent traction and superb torque characteristics gave it a clear edge on the dragstrip. Of course, the turbo-charged edition of the 280ZX could saw better than a second off the 0-60 and quarter-mile times recorded by its normally aspirated brother, but that's another test.
Sudden is a quality desirable in stop as well as go, and the Supra's performance in this category was not only tops in this comparison, but exemplary in any company. Control was excellent and fade virtually absent, something that can be said for all three contestants. The Z-car's braking distances, compared to the Supra's, qualify as acceptable, though they're certainly mainstream considered against most other cars. However, the RX-7's stops were simply not consistent with this car's otherwise solid sporting credentials. In fact, we got better results in our wrap-up report on a 1981 Mazda GS (May '82) that has a disc/drum system with 25,000 miles on it.
And so, as the cloud gathered once again over Southern California, we took the three Samurai warriors home wet, wheezing, but still breathing defiance. The major conclusion is obvious: Toyota's Supra is the car to beat in this field. Beyond that, things are not as well-defined. The ZX, thanks to its superior horsepower, topped the RX-7 in all statistical categories, but the tested emerged with the nagging feeling that the Mazda was the more gratifying car to drive. All of which makes us look forward to mid-1983, when a new ZX -- reputedly turned back toward its sporting origins -- is due. Meanwhile, we'll just make do with these three. It won't be difficult.
...........0-60.....1/4mi....Lap Time...30-0....60-0
RX-7.....9.97...17.17/80.2...33.2......46'.....176'
Supra....8.40...16.57/83.7...32.3......39'.....140'
280ZX...8.77...16.88/81.3...33.0......45'.....160'
Samuraitech: Three Approaches To Keep You In Suspense
From a suspension dynamics standpoint, the Supra is clearly the most agile of our three Samurai warriors, with the RX-7 second and the 280ZX a distant third. This is probably to be expected since the Supra is the newest design, and the Datsun the oldest.
The Supra uses the MacPherson strut system in the front, but with a couple tricks new to Toyota. The vertical axis of the spring diverges from the shock axis and reduces the side loads on the shock piston. This reduces stiction and seems to allow the shock action to be smoother. Of even more significance is the increase front track. It has been measured 2.4 in over the previous models, and contributes to the car's decreased understeer and increased cornering power. At the rear an independent method is employed, with individual coil springs and shock absorbers. The axle is located by a sewed trailing arm giving an effective swing-arm length approximately equal to the rear track dimension, resulting in a good camber curve. Anti-squat is achieved by the location of the trailing arm axis, and the Supra is excellent in this area. The location of the trailing arm axis is also used to give some toe-in on the outside (loaded) wheel during body roll to decrease oversteer.
All in all, the Supra represents a good optimization of this type of suspension system, which is seeing increased application because of its low production cost. The suspension deals very nicely with the Supra's power and is an excellent balance between cornering power and ride compliance.
The Mazda's RX-7 has been under continuous refinement since its introduction in 1978, and now represents close to the ultimate in terms of performance per dollar. It is a good example of the old adage: "A good solid rear axle is better than a poor independent one."
The RX-7's live axle is located longitudinally by a 4-link system to feed braking and accelerating forces into the chassis, and also take care of anti-dive and anti-squat. Lateral location is done with a fairly standard watts link. The rubber bushing selected for the different linkages are fairly soft, in the interest of damping road noise and harshness, but they are a little too compliant for maximum axle-location, evidenced in vague transients as the weight transfer builds up to its steady-state value. The front is the standard MacPherson system with an anti-roll bar and tension link.
The Datsun 280ZX uses essentially the same MacPherson strut tension rod front suspension as first seen on the 240Z in 1970, changed only in detail to accommodate the increased weight and wheel dimension over the years. At the rear, the introduction of the ZX saw the use of semi-trailing arms to locate the axles. The effective sing arm length is approximately 75% of the track dimension, and the camber curve should be excellent. Should be. However, not enough provision has been made for anti-squat at the rear, and this is the most objectionable feature of the car. On hard acceleration, the rear suspension compresses to the point that any additional loads, such as those generated in cornering, will cause contact with the bump stops. This brings on all the problems generally classified as "twitchiness." When the suspension does bottom out (no travel left) the roll stiffness is infinite, and all the dynamic weight transfer shows up at the bottom wheel. This significantly reduces the cornering power of that axle. More anti-squat would reduce this problem in the 280ZX and make it much more drivable over bumpy surfaces.
The Supra and 280ZX enjoy the best power-to-weigh ratio, 10.2 lb/hp, but the RX-7 is approximately 700 lb lighter than the other two. Detailed in the main text, the speeds around the handling course confirm our analysis, and the Supra's more sophisticated suspension, wider front track, and, perhaps most important, wider tires give it the distinct advantage. The 280ZX's power-to-weight ratio advantage over the RX-7 is canceled by its inherent rear suspension dynamic problem, and the 700-lb weight penalty. -- Ron Grable
Supra vs. RS-7 vs. 280ZX
By Tony Swan
Consider the code of the Samurai. Cold steel and iron will. No quarter asked, no quarter given. Duels to the death. Viewed from the perspective of Southern California, this adds up to a lifestyle that's about as attractive as an eternal knife fight in an elevator. But it does sum up the conflict between these three steely Samurai warriors -- with these exceptions: We had a lot more fun doing it than you get in your average fight to the death, and all three lived to fight another day. Which, predictably, made the manufacturers happy. Domo arigato, manufacturers.
Actually, we've been itching to assemble this threesome since our first encounter with the new Toyota Supra back in October. These cars represent the absolute acme of Japanese automotive technology, and measure up impressively on the world scale as well -- particularly in terms of value. They're high on driver gratification, high on visual appeal, high on profile, high on creature comforts, and, considering everything their makers pack into them, relatively low in cost. We're not suggesting a range of $12,000 to almost $16,000 is cheap, you understand. But when you compare what you're getting for the money, you'll find that not many manufacturers are able to match up favorably. Interestingly enough, some of the U.S. manufacturers -- notably Ford (with the Mustang GT, $11.288 loaded) and GM (Camaro Z28, $12,671, and Firebird Trans Am, $12,500) are doing a better job of competing in the luxo sport/GT area than the more celebrated European entries (read Porsche).
Our determination to pit this threesome in a Japanese GT free-for-all grew even stronger when the Supra emerged as MT's Import Car of the Year for 1982 (April), and so as our part of the world battened down for the gathering monsoon, the three warriors finally arrived -- sleek, refined, and menacing.
The Warriors
We dressed the three contenders in black, partly because it makes them all look so delightfully sinister, mostly because black is definitely the color for the Supra (doesn't hurt the others, either). When you order a Supra in any other color, the fiberglass fender flares tend to have an added-on appearance, and the black panel just above the rear bumper is, to be polite, far from harmonious. We also made sure that this Supra had the rear-window Sun shade attached. Stung by initial press reactions to the sun Shade -- it seemed to draw a pretty unanimous boot from first-time beholders -- Toyota made the sun shade a buyer delete option, then began deleting it on virtually all new Supras at the factory. Not everyone here likes the sun shade, but we all agree that it makes the new Supra look more like what it is, rather than a tarted-up Celica GT. Some of us even like it.
The cars weren't in the house more than about five minutes before Hall, drawing on some obscure textbook of Japanese love, had named them all for famous Samurai warriors. The ZX became Zato-Ichi, the Supra was Kagemusha, and the RX-7 was Tanaka-Cho. One of these legendary swordsmen, incidentally, was supposed to have been blind, and for anyone who's ever seen Hall at the wheel when he's in a hurry, the whole thing suddenly makes sense.
Anyway, whatever name you use, these three are undoubtedly familiar to you by now so we'll keep the introduction brief.
There are many commonalities. All three cars are front-engine, rear-drive, with MacPherson strut front suspension (see Ron Grable's suspension sidebar) and 4-wheel disc brakes. Although the Supra does offer the auxiliary rear seating of a traditional 2+2 GT, all three cars are designed essentially for two passengers, and the RX7 and ZX provided seating for exactly that many.
Interior treatments on the cars fall readily into the general category of sumptuous. Both the Mazda and the ZX arrived with leather-clad interiors -- we have to admit that the Japanese have become very proficient with hides -- and long haul comfort was a strong suit for all three cars. However, when it came to back road thrashing, the Supra's new Recaroesque buckets were clearly in a class by themselves. Lateral support was markedly better than that offered by the other two entries, and the command chair -- eight adjustments, pneumatic lumbar support, etc -- is the absolute best OEM unit in the business.
http://www.celicasupra.com/images/MT6-82-5.jpg
Each car was equipped with its manufacturer’s top-line sound system, and here again the edge goes to the Supra, with its 7-band equalizers and premium speakers. However, the Datsun system was only a few reverbs (no one seemed able to completely dial out the echo chamber effect) away from a tie, and both these units had the "Earth Calling Mars" look that seems to typify current Japanese automotive stereo gear. The Mazda's 4-speaker Clarion unit is simply not up to the quality of the systems provided with the ZX and Supra.
Instrumentation was comprehensive across the board, with the Mazda getting good grades for night visibility, the Supra eliciting wows for its general level of after dark showbiz (augmented substantially by the stereo system), and the ZX emerging as the staff favorite in this regard. All three cars were equipped with cruise controls, though the RX-7's rated as a distinct 3rd among the testers since it had no accel/coast feature and was incorporated on the same stalk as the washer/wiper controls, which can lead to some inadvertent use of both functions.
Although we concerned ourselves primarily with performance in this comparo, we couldn't help emerging with some strong convictions regarding the general content, quality, and value of the test cars. Quality, of course, is a strong suit of the entire Japanese industry, a perception that has American manufacturers scrambling to catch up, and these entries from the top of the Japanese market are worthy standard bearings for their breed. Workmanship, fit, and finish were excellent throughout, and the staff nit-pickers were hard-pressed to pick a winner -- or a loser. However, there wasn't much hesitation when it came to considerations of content. The Supra emerged as the unanimous choice, with the ZX a unanimous 2nd. The RX-7, for its part, won grudging approval as the value winner, offering the most for the least money. But its edge in this subjective department doesn't seem nearly so marked as it did when the car first appeared back in 1978.
Samurai Power
While original Kagemusha, Zato-Ichi, and Tanaka-Cho presumably drew their power from divine sources back there in the bad old days (Granola and Wheaties were still several centuries off in the future), their steely namesakes share a common gift of go: We call it gasoline. However, beyond the commonality of spark-ignited internal combustion, the manner in which the manufacturers have chosen to convert fuel into horsepower account for the principal difference between the three cars.
As the only rotary engine in production today, the RX-7's 2-rotor wankel is the most technically interesting of the three powerplants, as well as the smoothest. Mazda's total commitment to rotary engines n the early to mid-Seventies very nearly precipitated the demise of parent company Toyo Kogyo. The rotary found itself caught between the first oil crisis of 1973 and a reputation in this country for poor reliability. While the latter may have been unfairly acquired, since it was more or less directly related to the indifference of many Americans to even the simplest maintenance procedures (such as checking the oil), the rotary's thirst was real. Toyo Kogyo backed away from the rotary like your no-good brother-in-law backing away from a bar tab, and the company just managed to snatch its corporate bacon from the burner with the introduction of the very conventional little GLC.
However, thanks to the brilliant efforts of Dr. Kenishi Yamamoto, who has since become a Toyo Kogyo managing director, rotary development continued, and in '78 Mazda generated slack jaws and green envy throughout the automotive establishment with the original RX-7. It offered reasonable fuel economy (EPA rated at 17/28 mpg), satisfying performance, and excellent durability. If the GLC stabilized Mazda's deteriorating foothold in the U.S. marketplace, the RX-7 turned the company's image around completely, and Toyo Kogyo couldn't build them quickly enough.
Mazda made a couple of improvements to the RX-7's 12A rotary last year. A new high carbon rotor apex seal was adopted, promising even better durability, and a catalytic converter system replaced the old thermal reactor emissions control setup. The catalytic system had several benefits. It reduced warm-up type, eliminated the backfiring associated with thermal reactor RX-7's, and, best of all, contributed to the improved fuel economy. Although the Supra sports slightly better EPA rating than the Mazda, the RX-7 did in fact emerge as the fuel-stingiest Samurai, averaging more than 25.3 mpg throughout the test, 5 mpg better than the 2nd-place Z-car.
The RX-7 delivers more horsepower per cubic inch than its adversaries, but there's not enough of it. Even though the car scales in at 281 lb lighter than the ZX and 456 less than the Supra, its 100-hp rating leaves it well behind the other two cars in power-to-weight. This produced predictable results in the acceleration portions of the competition -- a full 1.5 secs behind the Supra 0-60, and 1.2 secs behind the ZX. The rotary's engine's torque characteristics -- there isn't much of it at the low-end -- contribute substantially to this shortfall; it's hard to get the car launched from a standing start without buzzing the engine up to induce wheelspin.
We know there's plenty of potential horsepower locked up in that little rotary; two years of virtually total domination of IMSA GTU racing attest to that. But we don't really expect to see a significant boost in street horsepower until 1984, when the RX-7 is due for a major revision. When the new car comes along, we expect it will include the company's bigger 13B rotary engine, with the option of a positive displacement supercharger.
In contrast to the Mazda rotary, Datsun's tried and true 2.8-liter OHC six is pretty routine goods. Which is to say routinely excellent. We chose the normally aspirated edition rather than the turbo to provide a more reasonable basis for comparison, but even with the benefit of force-feeding, this engine has the highest peak horsepower rating of the trio. This is essentially the same engine that came to the market with the original 240Z back in 1970, although it has grown from 2.4 to 2.6 to 2.8 and acquired Bosch L-Jetronic fuel injection along the way. What this means for buyers is the durability that goes with extended development, and this the Z-car sorely delivers, as it has from the start.
As noted, it also delivers the best peak-power rating in our little group, along with the most favorable power-to-weight ratio, but even though you would expect this to add up to the best acceleration times, this was not the case (we know you haven't looked at the charts yet, but it's okay now).
---- PAGE MISSING :(
...game plan was to turn Kagemusha, Zato-Ichi, and Tanaka-Cho loose on a full-scale road racing layout, we were confined to the dragstrip and handling course of Orange County International Raceway.
Nevertheless, our testing at OCIR told us what we wanted to know, and this turned out to be pretty much what we expected going in. In its first season as a genuine GT, the new Supra has established a new standard for its Japanese counterparts to try to match.
Having said that, let us amend it by adding that the handling portions of this comparison set the RX-7 apart from the other two cars. Its character is much more pure-sports-car, which comes across as a somewhat harsher ride and distinctly more nimble feeling. The latter is attributed to the RX-7's shorter wheelbase and distinct weight advantage. Although we did not include a timed straight-line slalom as part of our official tests -- for a few days there, the appearance of more than three pylons in a row seemed to have the power to produce instant rain -- we did get in a few random runs, and in this activity the RX-7 was the star. Even though it was the only car in the group lacking rack-and-pinion steering, the RX-7's recalculating-ball system produced excellent road feel, light effort, and crisp transient response. (McCraw claims there is really only one possible transient response -- "Get a job" -- but that's another story.) Both the Supra and the ZX are equipped with excellent power rack-and-pinion systems, the ZX setup dialed in at an exceptionally quick 2.7 turns lock-to-lock. But the superior performance of the RX-7 in quick direction changes is another benefit of its lower all-up weight, and this in turn led most of the test staff to regard the hummer as the most fun to drive.
However, in the handling test that really counts here -- timed laps around an abbreviated road course -- the Supra was an easy winner, partly because of its excellent new all-independent suspension system (have you read Gramble's sidebar yet?), and partly because of its much bigger footprint, Toyota's finest exhibited a bit more body roll than the other two contenders, which is attributable to its tradeoff for the best ride qualities in this threesome, but it was thoroughly predictable and exhibited the best steady-state cornering stability, wet or dry.
As far as the quantifiable suddenness of the Sudden Samurai is concerned ("How sudden were they, Roy?"), the charts speak for themselves. Even though the Supra was the heaviest of the lot -- the price you pay for those rudimentary rear seats -- its combination of excellent traction and superb torque characteristics gave it a clear edge on the dragstrip. Of course, the turbo-charged edition of the 280ZX could saw better than a second off the 0-60 and quarter-mile times recorded by its normally aspirated brother, but that's another test.
Sudden is a quality desirable in stop as well as go, and the Supra's performance in this category was not only tops in this comparison, but exemplary in any company. Control was excellent and fade virtually absent, something that can be said for all three contestants. The Z-car's braking distances, compared to the Supra's, qualify as acceptable, though they're certainly mainstream considered against most other cars. However, the RX-7's stops were simply not consistent with this car's otherwise solid sporting credentials. In fact, we got better results in our wrap-up report on a 1981 Mazda GS (May '82) that has a disc/drum system with 25,000 miles on it.
And so, as the cloud gathered once again over Southern California, we took the three Samurai warriors home wet, wheezing, but still breathing defiance. The major conclusion is obvious: Toyota's Supra is the car to beat in this field. Beyond that, things are not as well-defined. The ZX, thanks to its superior horsepower, topped the RX-7 in all statistical categories, but the tested emerged with the nagging feeling that the Mazda was the more gratifying car to drive. All of which makes us look forward to mid-1983, when a new ZX -- reputedly turned back toward its sporting origins -- is due. Meanwhile, we'll just make do with these three. It won't be difficult.
...........0-60.....1/4mi....Lap Time...30-0....60-0
RX-7.....9.97...17.17/80.2...33.2......46'.....176'
Supra....8.40...16.57/83.7...32.3......39'.....140'
280ZX...8.77...16.88/81.3...33.0......45'.....160'
Samuraitech: Three Approaches To Keep You In Suspense
From a suspension dynamics standpoint, the Supra is clearly the most agile of our three Samurai warriors, with the RX-7 second and the 280ZX a distant third. This is probably to be expected since the Supra is the newest design, and the Datsun the oldest.
The Supra uses the MacPherson strut system in the front, but with a couple tricks new to Toyota. The vertical axis of the spring diverges from the shock axis and reduces the side loads on the shock piston. This reduces stiction and seems to allow the shock action to be smoother. Of even more significance is the increase front track. It has been measured 2.4 in over the previous models, and contributes to the car's decreased understeer and increased cornering power. At the rear an independent method is employed, with individual coil springs and shock absorbers. The axle is located by a sewed trailing arm giving an effective swing-arm length approximately equal to the rear track dimension, resulting in a good camber curve. Anti-squat is achieved by the location of the trailing arm axis, and the Supra is excellent in this area. The location of the trailing arm axis is also used to give some toe-in on the outside (loaded) wheel during body roll to decrease oversteer.
All in all, the Supra represents a good optimization of this type of suspension system, which is seeing increased application because of its low production cost. The suspension deals very nicely with the Supra's power and is an excellent balance between cornering power and ride compliance.
The Mazda's RX-7 has been under continuous refinement since its introduction in 1978, and now represents close to the ultimate in terms of performance per dollar. It is a good example of the old adage: "A good solid rear axle is better than a poor independent one."
The RX-7's live axle is located longitudinally by a 4-link system to feed braking and accelerating forces into the chassis, and also take care of anti-dive and anti-squat. Lateral location is done with a fairly standard watts link. The rubber bushing selected for the different linkages are fairly soft, in the interest of damping road noise and harshness, but they are a little too compliant for maximum axle-location, evidenced in vague transients as the weight transfer builds up to its steady-state value. The front is the standard MacPherson system with an anti-roll bar and tension link.
The Datsun 280ZX uses essentially the same MacPherson strut tension rod front suspension as first seen on the 240Z in 1970, changed only in detail to accommodate the increased weight and wheel dimension over the years. At the rear, the introduction of the ZX saw the use of semi-trailing arms to locate the axles. The effective sing arm length is approximately 75% of the track dimension, and the camber curve should be excellent. Should be. However, not enough provision has been made for anti-squat at the rear, and this is the most objectionable feature of the car. On hard acceleration, the rear suspension compresses to the point that any additional loads, such as those generated in cornering, will cause contact with the bump stops. This brings on all the problems generally classified as "twitchiness." When the suspension does bottom out (no travel left) the roll stiffness is infinite, and all the dynamic weight transfer shows up at the bottom wheel. This significantly reduces the cornering power of that axle. More anti-squat would reduce this problem in the 280ZX and make it much more drivable over bumpy surfaces.
The Supra and 280ZX enjoy the best power-to-weigh ratio, 10.2 lb/hp, but the RX-7 is approximately 700 lb lighter than the other two. Detailed in the main text, the speeds around the handling course confirm our analysis, and the Supra's more sophisticated suspension, wider front track, and, perhaps most important, wider tires give it the distinct advantage. The 280ZX's power-to-weight ratio advantage over the RX-7 is canceled by its inherent rear suspension dynamic problem, and the 700-lb weight penalty. -- Ron Grable