CarThrottle Asks: Supra Turbo, VR-4, 300ZX, or RX-7?

By James Mackintosh, 26 March 2011

For those enthusiasts with turbos on the brain, this is a question that has bounced around since the early 90's. There's still not a definite answer today - but with the recent coverage of 3000GT VR-4 tuner 3SX Performance, I thought it would be a good CT: Asks for our readers to share their input on this question.

The 90's were arguably the resurgence of real performance, after the mediocrity of the 80's and the depressing malaise of the 70's.  Horsepower was no longer taboo, the speed limit was no longer 55, gas was cheap, and financing was easy.  Out of this was born the unique class of Japanese supercars - viciously powerful cars packed with technology, slick styling, turbocharging, and exhilarating performance.  There really are 5 Japanese supercars, but we'll leave the Acura/Honda NSX out of this - it was at least double the price of it's competitors, and in many cases not up to par for performance.  Not saying the NSX is a bad car - I mean, it's hard for any car with chassis input from Ayrton Senna to be bad - but it was more a competitor for the Porsche 911, Ferrari 348, and Lotus Esprit than it's other Japanese brothers.

Which leaves us with the big four.  I'm talking about the 1990-1999 Mitsubishi 3000GT VR-4, 1990-1996 Nissan 300ZX Twin Turbo, 1993-1998 Toyota Supra Turbo, and the 1993-1995 Mazda RX-7.  A brief description of each follows, a spreadsheet of basic specs, and a poll.  Take your pick!

Toyota Supra (MkIV) Twin Turbo

Of all four cars, the Supra is probably the most well-recognized and desired today.  I'm sure the obnoxious Fast & The Furious franchise has something to do with it, but the supercar-munching performance, Toyota reliability, and extreme ease of tuning didn't hurt either.

The MkIV (fourth-generation) Supra Turbo was a car carefully developed with an ear to the enthusiast community, rather than the bean counters.  It was vastly more powerful than the car it replaced (the MkIII Supra) while being lighter, better handling, more advanced, and a lot prettier.  Many people say that the MkIV Supra shape was the inspiration for a lot of sports cars that followed it; it's not hard to see a little bit of Supra in the 1998 Ferrari 550 Maranello.  Which is embarrassing for Ferrari, but a good ego boost for Toyota.  It's a shape that's aged better than almost everything else from the 90's, and it's still gorgeous today.

httpv://www.youtube.com/watch?v=SKFyqvJ89eY

Toyota put a big focus on weight reduction for the MkIV Supra.  Despite being larger, more powerful, and more advanced than it's predecessor, it was about 200lbs lighter per model.  For reference, a MkIV Supra Twin Turbo weighed in at 3,417lbs with a 53/47 front to rear weight distribution with a 6-speed manual.  This was done through many small details - extensive use of aluminum, a single-pipe exhaust system, hollow carpet fibers, magnesium steering wheel, plastic gas tank, and a gas-injected rear spoiler.

Performance wise, there wasn't much for sale in 1993 that was faster than a Supra Turbo.  All Supras for the MkIV chassis ditched the long-running "M" series inline six, which culminated with the 3.0L 24v 7M-GTE with 232bhp in the previous Supra Turbo.  The new engine, the JZ series I6, is one that has reached legendary status among enthusiasts today.  Regular Supras got a naturally-aspirated 3.0L 24v 2JZ-GE which made 220 horsepower, while the Supra Turbo had the more powerful 2JZ-GTE.

This was a fairly complex engine by the standards of the day, and in fact pioneered the art of sequential turbocharging in production passenger cars.  Instead of one big turbo or two small ones, the 2JZ-GTE used two different sizes - a small, low-inertia turbocharger at low RPM's and a big, fat one at higher rpms, which gave it a more linear powerband than normal turbo setups.  Mazda also used this set-up on the 3rd generations RX-7's engine , as we'll read about later.  The turbo version of the 2JZ was rated at 276bhp for the Japanese market (due to the Gentleman's Agreement between manufacturers) but a full 320bhp and 315lb-ft of torque for export.

The export version had different camshafts, steel turbo impellers (instead of ceramic), and larger injectors to make the extra horses.  Transmission choices were either a Toyota/Getrag V160 6-speed manual, or a Toyota 4-speed automatic.  With all that power, the Supra was mighty fast: C&D recorded a 4.6 second 0-60 time for one of the earliest Turbo's, although later tests usually showed a time between 4.8-5.2 seconds.  The quarter mile was done in 13.1 seconds at 109mph, which is quick today - and ridiculous for 1993.

The Supra was about more than just straight-line performance, of course.  Double wishbone independent suspension at all corners and sticky tires allowed the Supra to grip a skidpad at 0.95 g's, and the sophisticated 4-channel ABS brake system meant it would do 70-0 in 149 feet - a record the 1997 Supra held until the $440,000+ Porsche Carrera GT broke it in 2004.

Today, Supras are synonymous with import tuning.  Titan Motorsports in Texas has a 1300+bhp Supra that runs mid-7's in the quarter mile, and the stock bottom end of the 2JZ is strong enough to support north of 700bhp before things start to bend.  By now, there aren't a whole lot of stock Supra Turbo's left, but you wouldn't leave it stock anyway, would you?

1990-1999 Mitsubishi 3000GT VR-4

If you've been reading CarThrottle the past week or so, you're probably already somewhat familiar with the 3000GT VR-4 (and the Dodge Stealth R/T Twin Turbo, it's identical cousin).  The 3S cars (as they're referred to) were part of Mitsubishi's 2-part replacement for the Starion.  While the DSM's (Eclipse/Talon/Laser) went for light weight and four cylinders, the 3000GT (also called the GTO in some markets) went in a different direction, packing as much technology as possible into a low, sleek 2+2 coupe.

The spec list read like the Swiss Army Knife of sports cars.  There was a 3.0L V6 up front, with twin-cam four valve heads on top and twin turbochargers below, breathing through a set of twin side-mounted intercoolers.  Total power for early VR-4/ R/T Turbo's was 300bhp and 300 lb-ft of torque from 10psi of boost.  Power was transferred through a Getrag 5-speed manual and a viscous center coupling (which was where the VR-4 designation - viscous real time 4WD - came from) to all four wheels - the only car among the four that wasn't RWD, and the only one with a sideways-mounted engine.

That wasn't all, of course.  The VR-4 also packed four-wheel steering (as did the 300ZX) which could turn the rear wheels up to 1.5° opposite of the fronts above 31mph for sharper turn-in.  There were three-position variable rate shocks at all four corners.  Active aerodynamics adjustable spoiler angles depending on speed.  The VR-4 even packed a variable exhaust system, which used a solenoid-controlled series of flaps to make the exhaust louder or quieter depending on your mood.

All this stuff is really cool, but it had a downside: the VR-4 is far and away the heaviest of the four, outweighing the flyweight RX-7 by nearly 1,000 pounds, and the Supra and 300ZX by about 400lbs.  The 4WD grip meant it was about as quick off the line as the others, but the advantage starts to fade at higher speeds as the tubby VR-4 gets left behind.  Skipdap grip was comparable, but the VR-4 handling balance leans more towards understeer than tail-out drifting antics; all that weight over the front wheels doesn't help.

Still, what the VR-4 lacked in hard-core sports car ass-whooping abilities, it made up for in overall usefulness.  Driving a Supra Turbo or RX7 on a slick road was an exercise in underwear swapping, whereas a VR-4 would pretty much pound over whatever crappy road you thrashed it down.  It could actually go places besides sideways and backwards when it snowed, and as an added bonus the sound a VR-4 with upgraded turbos makes when hitting boost redefines the term "insane."

httpv://www.youtube.com/watch?v=WsRU-se68RU

Changes over the (unusually long) life of the VR-4 were minimal.  It gained 20 horsepower and 9 lb-ft of torque in 1994 when the standard boost level was upped from 10 to 12psi, making it a touch faster.  The 5-speed box was also replaced by a new Getrag 6-speed manual the same year, which gives a closer gear spread but is a somewhat fragile transmission.  There was a folding-hardtop convertible (designed by ASC/McLaren) that was available in tiny quantities for a while, but keep in mind that a VR-4 Spyder weighs approximately 4,100 pounds, which is absurd.  Skip it.  The last year of VR-4's in the US, the 1999, was arguably the best looking - new headlights, a huge Evo-style spoiler on the back, gorgeous chrome wheels.  By then the price tag had crept up to $44,600 as a result of the disparity between the Yen and US dollar - which was a problem all four of these cars shared in the US market as time progressed.

By now we're all familiar with the aftermarket possibilities of the 3000GT VR-4; rest assured that if you want a 700awhp VR-4 it's doable.  So is the VR-4 your kind of car?  Or do you want something lighter and simpler?  Like...

Mazda RX-7

Looking at the engine specs, it seems the little Mazda is hopelessly outgunned against monsters like the Supra and VR-4.  255 horsepower?  217 lb-ft of torque?  Pffft, what is this, a Mustang GT?  Go home.

Well, no.  Looking at the spec charts, the little Mazda actually has a superior power to weight ratio to the 300ZX and the VR-4, and it's within a hair's width of the Supra.  Why?  Well, the RX-7 only weighed 2,800 pounds - a half ton lighter than the VR-4.  It is closer to the classic definition of a sports car than the other three, which all bend towards "really fast GT".  Not only is it the lightest, but the mass is the lowest down and the most centralized- all thanks to the RX-7's gift/curse, it's engine.

While the rest of the world figures the best way to turn dead dinosaurs into horsepower are a few pistons moving up and down, Mazda likes dancing to the beat of a different drum, which is why they're the only brand that gave the Wankel Rotary engine more than a half-assed chance.  And the engine under the 3rd-generation RX7 was a beast:  a revised version of the old 654x2 13b side-port rotary, fortified with twin-sequential turbochargers (like the Supra) and a front-mounted intercooler.  Those 255 horsepower might not sound like much, but they thumped the lithe RX-7 down the road at a pace that embarrassed 5.7L Corvettes of the time.  The powerband is wide - since the rotary goes in a circle instead of up and down, it's not hard to get to the 8,000rpm redline, highest in this group.  The 5-speed manual (there was an optional automatic, but you've gotta be kidding) had short throws and close ratios, keeping the boosted rotary on the boil when you wanted it to be.

The downside is fragility.  An FD3S (the chassis code of the 3rd-generation RX7) is one of the greatest driver's cars ever - when it's running.  They call RX-7's "Lawn Ornaments" for a reason.  The big problem was... well, there were a lot.  Heat buildup under the hood was massive, and in their quest for lightness Mazda specified a fairly tiny coolant radiator, which is wholly inadequate for track driving on a hot day.  An overheated rotary is a much bigger problem than a blown head gasket on a piston engine, requiring an expensive rebuild for warped seals.  The turbos themselves weren't all that reliable either, with frequent failure of the flapper valve between the two twins.  Finally, Mazda still hadn't perfected the art of making a sturdy apex seal - the seal on the tip of the rotor - and adding a bunch of boost didn't help either.  Catastrophic engine melt-downs are a fact of life for 3rd-gen RX-7 owners.  Maybe that's why so many of them have GM LS1 V8's now?

Unlike the Supra, 300ZX, and especially the 3000GT, there was no wimpy base model RX-7.  You could get a Dodge Stealth with a 12-valve SOHC 6G V6 which would do 0-60 eventually.  The regular Supra was a nice car, but shared it's 220bhp I6 with the Lexus SC300 and wasn't especially quick.  The 300ZX non-turbo had 222bhp and did 0-60 in the mid-7's.  You could order your RX-7 in Fast, Fast and Comfortable, or Really Fast With Suspension Made Of Granite. That would be base, Touring, and the extreme R1 package - which featured a Torsen LSD, stiffer shocks, no interior luxuries, and a ride so hard you'd cry.

httpv://www.youtube.com/watch?v=lhf-wfJSP40

So the RX-7 was a not a car with compromise in it's dictionary - unlike the VR-4, it was basically a one-trick pony.  But that one trick - plastering a mile-wide smile on the driver's face - is what it's all about.  Right?

Nissan 300 ZX Twin Turbo

Note: tell me you've seen this picture before!

The 300ZX was the oldest car of this group (introduced in 1989, versus 1990 for the VR-4, and 1993 for the Supra and RX-7.)  So while it was always a little slower than it's newer competition, that's not to say it had nothing going for it.  Like the Supra, it struck a delicate balance between race car and commuter rocket, and it did so with great success.

Part of the reason the 1990-1996 300 ZX was such a beloved car was just how disappointing it's predecessor was.  The Z31 300ZX was a better car than a 280ZX, but only barely.  It's single-cam non-intercooled turbo V6 mustered up 205 horsepower, meaning it would routinely get beaten by fuel-injected 5.0 Fox-body Mustangs off the light, despite being about twice the price.  Plus, it looked like a melted doorstop.  Meh.  So when the new 300 ZX came out in late 1989, the world was pretty much knocked on their collective asses.  Remember, this was before the Acura NSX, the new Supra, etc etc - this was the first Japanese car the US had seen that was truly deserving of the supercar title.  And, it was gorgeous.  In fact, still is today - can  you name any other 22 year old designs that still look fresh and modern?  It's a short list.

The ZX didn't ooze aggression like a C4 Corvette or VR-4, either.  It was sort of subdued - no flashy ornate styling gimmicks.  Which is why a VR-4 looks like a product of the 90's, while a good-condition Z32 still turns heads.

Under the hood was a vastly-updated version of the previous 300ZX's engine.  It was still a 3.0L 60° alloy V6, but twin-cam four valve heads replaced SOHC 2v units, while the single turbocharger was replaced by two smaller ones.  Power went up dramatically: an even 300bhp, and 283lb-ft of torque, with minimal lag or peaky delivery.  Transmission choices were a 5-speed manual or 4-speed auto; again, who would buy a car like this with two pedals?

httpv://www.youtube.com/watch?v=cDXC0h7gm2g

While the regular 300ZX could be had in 2 seat or 2+2 form, as well as a convertible, Nissan only ever put the VG30DETT engine in 2-seat hard top cars.  So if you needed a back seat, you'd need a Supra or VR-4 - although the back seats on both of those were more of a joke than a practical consideration, perhaps to keep insurance lower.

The Twin Turbo Z did pack some cool tech - variable valve timing, HICAS hydraulic four-wheel steering, 2-mode variable shock absorbers, etc - but was more of a driver's tool than the VR-4 was.  It was a little slower than the Supra and RX-7, but when we're talking 2 or 3 tenths of a second, who cares?

The 300ZX was probably the best-rounded of all four cars, not being the best at anything or the worst.  The dual-mode suspension actually worked, delivering a comfortable ride in Touring mode and stiff, agile handling in Sport.  The powerband was more linear than the peaky RX-7 or the "whoa, afterburners kicked in!" Supra, and the interior was much higher quality and more comfortable than the VR-4 or RX-7.  You could take your wife to the grocery store in comfort, then do donuts in the parking lot until the tires blew while she was picking out asparagus.

The engine itself is fairly reliable - Nissan's V6's have always been robust, and this one wasn't really very high-strung - but working on them is an unholy pain in the ass.  The turbochargers can become victim to heat buildup and go bad early, and you can't even see them from the top - unlike the other three cars, Turbocharger replacement is absolutely an engine-out job on a 300ZX.  The stock clutch was usually good for 60-70,000 miles, although there are aftermarket replacements that last much longer.  But these minor concerns didn't lessen the fact that the 300ZX was - and is - a completely fantastic car.

If you've got all these twin turbos and 4WS and this and that mixed up in your head, I've put together this handy spec chart of all four to compare side-by-side, if you're a numbers sort of person.  Best in comparison figures are in bold, obviously.  Or if you're a zealot, skip this and just vote for what you picked before you even started reading.  Hey, I did.  (hint: it's the 300ZX.)

Toyota Supra Turbo Mitsubishi 3000GT VR-4 Nissan 300ZX Twin Turbo Mazda RX-7 R1
Body 2dr 2+2 liftback 2dr 2+2 liftback 2 door 2 seat liftback 2 door 2 seat liftback
Base Price (1993) $37,000 $37,250 $37,090 $32,500
Drivetrain Front L RWD Front T AWD Front L RWD Front L RWD
Engine I6, iron block/alum head V6, iron block/alum heads V6, aluminum block/heads 2-rotor Wankel Rotary
Displacement 2997cc (3.0L) 2972cc (3.0L) 2960cc (3.0L) 654x2cc (1.3L)
Valvetrain DOHC 24v DOHC 24v DOHC 24v Side Ports
Aspiration Twin Sequential Turbo, intercooled Twin Turbo, twin intercooled Twin Turbo, twin intercooled Twin Sequential Turbo, intercooled
Compression Ratio 8.5:1 8.0:1 8.5:1 9.0:1
Bhp @ rpm 320 @ 5600 300@6000 (90-93) 320@6000 (94+) 300@6400 255@6000
Torque @ rpm 315 @ 4000 306@2500(90-93) 315@2500(94+) 283@3600 217@5000
Redline 6800rpm 7000rpm 7000rpm 8000rpm
Transmission Getrag 6MT 5MT (90-93) 6MT (94+) 5MT 5MT
Curb Weight 3,417 3,790-3,803 3,474 2800
Lb/bhp 10.67 12.63 (90-93) 11.88 (94+) 11.58 10.98
0-30 mph 1.8 1.9 2.0 2.1
0-60 mph 4.8 5.2 5.0 5.2
0-100 mph 11.7 14.4 13.1 14.5
¼ Mile ET 13.4 s. 13.9 13.7 13.8
¼ mile @ MPH 107mph 98mph 102mph 101mph
Top Speed 158mph 154mph 153mph 158mph
Lateral Accel. 0.95g 0.92g 0.95g 0.98g

Side note: it's interesting to see what the Yen-dollar exchange rate did to all these cars.  If you notice, the price of all of them in 1993 were within spitting distance, except the RX-7 - right around $37k before delivery, taxes, options, etc.  By the end of their life cycle, they had basically priced themselves out of existence.  The VR-4 rang up the register in 1999 at $44,600 before options, meaning it was more expensive than a Corvette (C5), Porsche Boxster, BMW M Roadster, and other sports cars with "heritage."  The RX-7 left the market in 1995 with an MSRP of $37,800 - up 5 grand in 2 years.  The Supra didn't increase as much, with a 1998 MSRP for a Turbo T-Top Manual at $40,508 plus options.  And the 300ZX in Turbo form was up to $43,979 by 1996.  This wasn't the only factor at play with the death of this class of car; the market shifting towards SUV's, rising insurance premiums, etc did them in as well - but the price inflation was a bit nuts.

Next article Shop Tour: 3SX Performance - Part II