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RX-7 Specifications

Click on picture for cut-away view of RX-7

 

 

The year was 1991.  Nissan had released its 300ZX twin-turbo.  Honda's NSX was one of the only cars in decades to put fear into the primarily European competition.  Mitsubishi's AWD 3000GT Twin Turbo had more technological wizardry than ever seen in almost any price range.  
 

Mazda's flagship sports car, the RX-7 had been around since 1978.  A replacement was in the workings...  The story behind the third-generation Mazda RX-7 (FD3S), is one of dedication and attention to detail.  The project began in 1986 -- just after the release of the second generation  (FC3S) RX-7, and at a time when a Japanese sports car revival was just over the horizon.
 

Takaharu Kobayakawa, the program manager on the project, was determined that the changeover to the new model was not a Zevolution.  It was a term he used to describe the competitor, Nissan's, Z-cars, which got progressively larger and heavier with each generation.  As its competitors gained gadgets and driving aids, such as self-adjustable spoilers, rear-wheel steering, traction control, and all-wheel drive, Kobayakawa felt they were losing sight of the original vision.  The RX-7 was decided to be a pure, back-to-the-basics sports car.  (Kevin McCauley)

 

Styling
The styling of the new car would be an intensely personal and emotional decision for Mazda, as the car was to symbolize Mazda and the rotary engine to the rest of the world.  Four different design studios around the world were consulted to come up with the design proposals.  In June, 1987, the two best sketches were chosen from each studio.  Full-size rendering and 1/5 scale models were created for each of the designs.  Two particular concepts won out in the evaluation meeting in September of that year, one from Mazda in Irvine California (MRA) and the other from Mazda Hiroshima (MC).  The MRA model was a traditional long-hood / short-deck styled concept that emphasized the engine placement and highlighted on the rotary's past.  The MC styled concept had a more futuristic short-hood, long tail theme, and was found to be aerodynamically superior.  Despite this, the MRA design was picked, and together the two teams refined the model and implemented aerodynamic elements from the MC design.  The choice was made by Mazda only, without outside assistance.  Early in the development, stylists thought that to accurately assess the visual impact of a sports car, it must be demonstrated while moving.  The car was fitted with a one-cylinder lawnmower engine in the trunk!  About halfway through the development in 1988, the Japanese government lifted a small-car tax that previously applied to vehicles over 1.7-meters in width, and with displacements over 2.0 liters.  Designed to fit within that guideline, the decision was made to widen the car.  This allowed for wider, 225mm series tires and 8" wide wheels, which improved the look of the car and the handling.

Features:


 

1)  "Aero-Wave Roof" - a double-bubble design that improves aerodynamics as well as looks.

2)  Rotor shape in grill opening.

3).  Pop-up headlights - these were an oversight- the car's low front bumper made the use of pop-up lights mandatory.


 

Choosing the interior design was easier- the MC's design won immediately over MRA's more wild, curvy interior concept.

 

Suspension


 

Handling was another crucial issue in during the design of the 3rd-generation RX-7.  In the basic design of the layout, the designers followed these criteria:


 

1)  All suspension arms/links should be in line with the path of each input force or load, whenever possible.

2)  A suspension functions best when it is mounted on a secure base.  The sturdy fabricated steel front and rear sub frames are therefore rightly bolted to the body shell. 

3)  The body shell must possess outstanding rigidity.  It should also be light-weight, a key factor in improving the car's power-to-weight-ration.

4)  Unsprung weight must be reduced as much as possible.   

The suspension components, a double-wishbone system,  are all made out of a squeeze-cast aluminum alloy and attached to the frame with the use of variable slide rubber bushings, for a more precise road feel and sharper cornering.  The engine is located behind the front axle (front-mid-engined), giving it neutral steering and an unprecedented 50/50 weight distribution.  The Power-Plant Frame (PPF) technology, first used on the MX-5 Miata, is a cross-reinforced brace that connects the engine and transmission with the Torson (torque-sensing) Limited-Slip differential in the rear.  It strengthens the frame and reduces flex, as well as reinforcing the driveshaft to eliminate hop, snatch, and shudder during acceleration.  The brakes used are four wheel-ventilated lightweight 11.6" discs with four-piston calipers, assisted by standard ABS.  Lightweight 13.5 lb five spoke 16"-wheels aid brake cooling and reduce unsprung weight. 


 

Engine


 

No less hard work and effort went into the new RX-7's engine.   Koyakabawa and his design team were given the option of using any engine that he felt best suited the car-- he chose the rotary.  The choice was made not only for its sentimental value, but it also made sense in a purpose built- sports car.  It was lighter in weight,  smaller in size, allowed to be positioned lower for a better center of gravity and featured a better specific horsepower ratio than any conventional engine of the time.  It was also chosen for its simplicity; a normal rotary engine has just 3 moving parts: two rotors and an eccentric shaft.  Many people think the engine designed for this car was the first to utilize a sequential twin-turbo system.   The 13B-REW engine was actually the second vehicle to utilize a sequential twin-turbo operation system-- it was first developed for the Mazda Cosmo 3-Rotor Coupe.  The system operates off one turbo during lower RPM's (after 2,000 RPM) and the secondary turbo spools up after the engine reaches the 5,000 RPM level.  Mazda encountered many problems along the development road with the sequential turbo operations, and there were many doubts that a system used to increase efficiency on a grand touring coupe would work on a pure sports car. If the secondary turbo was not spinning at a high speed when it was brought in, the whole system "staggers", temporarily failing to produce enough torque which is essential for a smooth change over.  Mazda's engineers attacked the problem, and solved the problem by feeding exhaust gas from the first turbo to the secondary turbocharger to get it spinning before the transition is made, in "pre-operation" mode.  The tiny 1.3 liter (two 654cc displacing rotors) power plant put out an incredible 255-hp, and 217 lbs/ft of torque, with the help of twin Hitachi HT12 turbos. 


 

The 1993 R1


 

In 1993, the R1 was the "purest of the pure".  A limited-edition, racetrack oriented, car,. the R1 was only available in Vintage Red, Brilliant Black, and the rarest -- Competition Yellow Mica.  Features exclusive to this model were dual oil coolers, standard front and rear spoilers, functional brake cooling ducts, stiffer shock absorbers, Pirelli Z-rated rubber and synthetic suede seating that reduced driver movement during high-G turning or braking.


 

The R2


 

The R1 was short-lived, replaced in 1994 by the R2.  Only a few improvements were made, most affected the cooling system and eliminated some problematic hoses that had been the reason for several recalls.  Silver Stone Metallic replaced Competition Yellow Mica on the color list, although both had disappeared by 1995.


 

The Touring Edition / PEP


 

Offered in America from 1993 through 1995, the Touring (later named PEP for Popular Equipment Package) was the less performance-oriented alternative to the R1/R2.  With leather, sunroof, Bose audio system, and available 4-speed automatic transmission, among other things, it suffered a severe weight penalty.  In Japan, this model was called the Touring X, and offered exclusively with the automatic.


 

 

 


Launched as an early '93 model, the third-generation RX-7 adopted a back-to basics approach that was reminiscent of the original 1978-85 model. The convertible and the closed 2+2 coupe were gone, leaving a lighter, more potent hatchback coupe with fresh styling. The rear-wheel-drive layout and 1.3-liter rotary engine were retained from the second generation, but twin turbochargers boosted horsepower to 255. Either a 5-speed manual or 4-speed automatic transmission could be installed. The RX 7's wheelbase was little-changed, but overall length shrunk by 1.4 inches. The car was 2.4 inches wider and 1.4 inches lower than before. Base curb weight dropped by some 190 pounds, compared to the old Turbo. A driver's airbag, all-disc antilock braking, and limited-slip differential were standard. The performance-minded R-1 option added dual oil coolers and body spoilers, but was not available with the luxury-oriented Touring Package. That option group included leather seats, a power sunroof, Bose speakers, and cruise controls in the steering-wheel hub.  (Information straight from http://bigsplat.net/student/jughead/mazda.html)

 

Year-To-Year Changes


1994:Improvements this year included a new "one-touch" feature for the driver's window, plus map pockets. Dual airbags were installed, and a softer suspension setting aimed to reduce ride harshness over bumps--especially in the base and Touring editions. Dashboards were revised slightly. A new option group put popular features into a single package. Three major option groups were offered: Luxury-oriented Touring (now with a power steel sunroof rather than glass); Performance (now called R-2); and Popular Equipment (sunroof, leather, and a rear cargo cover).

1995:Not many changes were evident for 1995, as the RX-7 began to fade out of Mazda's lineup, a victim of sluggish sales. The car's standard air conditioning unit switches to CFC-free refrigerant. The Touring Package was dropped, but leather seats, a cargo cover, and a power steel sunroof remained available in the optional Popular Equipment Group. Red leather upholstery no longer was offered. An R-2 performance package also remained available, featuring a firmer suspension, dual oil coolers, rear spoiler, front air dam, and Z-rated tires.

 

Specifications

Mazda RX-7 2-door coupe

Wheelbase, in.

95.5

Overall Length, in.

168.5

Overall Width, in.

68.9

Overall Height, in.

48.4

Curb Weight, lbs.

2826

Cargo Volume, cu. ft.

17

Standard Payload, lbs.

--

Fuel Capacity, gals.

20

Seating Capacity

2

Front Head Room, in.

37.6

Max. Front Leg Room, in.M

44.1

Rear Head Room, in.M

--

Min. Rear Leg Room, in.

--



 

Engines

Size liters/cu. in.

Horsepower

Torque

Transmissions

Turbocharged 2-rotor Wankel

1.3 / 81

255

217

5-speed manual: 4-speed automatic:

 

 

Information courtesy of http://www.k-rad.com/3genfaq

 Gear ratios
    -----------
                     Manual          Automatic
                  
    1st gear          3.483            3.027
    2nd gear          2.015            1.619
    3rd gear          1.391            1.000
    4th gear          1.000            0.694
    5th gear          0.719            ----

    Rear end          4.100            3.909

Mechanical Standard Features
    ----------------------------
    - 2-rotor inline rotary engine with sequential twin turbochargers,
      air-to-air intercooler, and electronic fuel injection
    - Engine oil cooler
    - 5-speed manual transmission with overdrive
    - Power Plant Frame (PPF)
    - Torsen torque-sensing limited-slip differential
    - Fully independent double-wishbone suspension with rear shock-tower support
      brace
    - Rack-and-pinion steering with engine-rpm-sensing variable power assist
    - Power-assisted 4-wheel ventilated disc brakes with aluminum 4-piston front
      calipers and ducted backing plates
    - Anti-lock Brake System (ABS)


    Exterior Standard Features
    --------------------------
    - 16-inch aluminum alloy wheels
    - Dual aerodynamic body-color power mirrors
    - Tinted glass
    - Retractable halogen headlights
    - Lightweight aluminum hood

   
    Interior Standard Features
    --------------------------
    - Highback bucket seats with seatback recliners
    - Sport cloth upholstery
    - Dual storage compartments behind seats
    - Power windows and door locks
    - Remote liftgate and fuel door releases
    - 9000-rpm tachometer with 8000-rpm* redline
    - 180-mph speedometer
    - Gauges for oil pressure and engine coolant temperature
    - Leather-wrapped steering wheel, handbrake grip, and transmission shift
      knob
    - Cruise-control with steering-wheel-mounted controls (n/a R-1)
    - Driver's side air bag Supplemental Restraint System (SRS)
    - Drilled aluminum clutch and brake pedals (manual trans. only)
    - Anti-theft alarm system
    - Heater/defroster with 4-speed blower and side-window demisters
    - Air Conditioning
    - AM/FM/cassette stereo sound with five speakers and automatic power antenna


    * 7000 rpm redline with automatic transmission
 

I want to buy a 3rd Gen RX-7.  What should I know?
Recalls

    There have been three recall notices put out on the 3rd Generation RX-7s,
    two pertaining to engine fires, and one concerning brake booster failure.
    You will want to make sure that the car in question has had these recalls
    done.  If they have not been performed, you will want to take the car to a
    Mazda dealership where they will be performed free of charge.  If you don't
    know whether the recalls have been applied to a car, you can call the Mazda
    Customer Service line at (800) 222-5500 with the vehicle's VIN, and they
    can tell you.


Coolant recall

    The coolant recall involved the replacement of some cooling system parts
    with stronger/more heat resistant materials and lowering the pressure of
    the cooling system from 1.3 bar to .9 bar.  The parts replaced were the
    water pump seal, the water level sensor, the upper radiator hose, the
    filler cap, the filler cap body, the thermostat gasket, the water hose
    leading to the throttle body, and the water hose leading to the coolant
    separator tank.

Fuel line recall

    The fuel line recall involved replacing the fuel lines under the intake
    manifold with lines made from a more heat resistant material, and adding
    a fan control unit that runs the cooling fans if the coolant gets too
    hot, even if the car is turned off.

Brake recall

     The brake recall involves the replacement of a vacuum check valve and
     hose leading to the brake booster.  The original unit may stick when
     oily and cold, preventing power assist under braking.

Common questions
What is the "exhaust system overheat" light for?

    The "exhaust system overheat" light is connected to a temperature sensor
    inside the car, under the carpeting, by the passenger seat.  The
    location of this sensor is just above the main catalytic converter, and
    its purpose is to warn of excessive heat being generated by the converter.
    When the temperature of the passenger floor reaches about 220 degrees F,
    the ECU activates the relief air bypass and bleeds off air that would
    otherwise go to the catalytic converter.  This has the effect of cooling
    the catalytic converter.

When I start my car, the RPMs go to 3000.  Why?

    All 1993+ RX-7s have what is called an "Accelerated Warmup System" that
    revs the car up to ~3000 RPM when it is cold-started.  Its purpose is to
    heat up the 02 sensor and first catalytic converter to operating
    temperature as soon as possible.  If you don't like the thought of your
    motor revving that high when cold, you can start the car in 1st gear
    (with the clutch in), and the AWS will only take the RPMs to ~1500 or so.
    It is also possible to bypass the AWS solenoid (see the performance section
    of this FAQ).


What does the "mileage switch" do?

    The "mileage switch" is in effect for the first 20k miles on a new RX-7.
    It has the same effect as the "power steering switch".  It adds some RPM
    to the base idle to help keep the engine from dying.

What type of gas should I use?

    The RX-7 requires "super" or "premium" unleaded gasoline.  Use only
    gas with a 92 or higher octane rating.  Using leaded gas will coat
    both your catalytic converters and your oxygen sensor, rendering them
    useless.


What are some of the common problems with 3rd Gen RX-7s?
Common problems with easy fixes
Oil pressure gauge reads 0 psi

    Sometimes the connection between the oil pressure sending unit and the
    wire to the oil pressure gauge gets loose or dirty.  The way to fix this
    is to clean the metal tab on the sending unit with some 0000 steel wool,
    and then re-install the gauge wire using some electrolytic silicone gel
    (like some sets of spark plug wires come with) to seal out grime.


No boost above 4500 RPM

     This is usually caused by a vacuum line coming off of the "Charge Control
     Solenoid".  The lines sometimes pop off while under boost.  The solenoid
     in question is located under the upper intake plenum.  Look in your
     shop manual on page  F-10, the solenoid is item F.  If a vacuum line has
     come off here, trim off the end of the line where it has become loose,
     and re-attach it to the solenoid.  It is helpful to  use wire-ties or
     a dab of sealant to keep them from coming off again in the future.
     Motorcycle shops also sell small, wire clamps that work well.
    

Hood squeaks / rattles

     Squeaks:  Lightly lube up the tops of the rubber hood stops and the latch.
     Rattles:  Tighten the latch mechanism so it holds the hood to the rubber
     stops with light pressure.  Latch rattles can also be temporarily fixed
     by wrapping a small amount of tape around the latch where it mates with
     the striker plate.


Hand brake light comes on while driving

    The switch that controls the parking brake indicator light is located
    under the leather brake handle boot.  Sometimes during acceleration the
    hand brake lever moves enough to activate the light.  This problem can be
    fixed by building up the area of the handbrake that contacts the switch
    with a product like JB Weld.

"Low Coolant" alarm goes off

    The "Low Coolant" alarm goes off when the low coolant sensor is not wet.
    This sensor is located on the back side of the aluminum coolant fill
    housing.  Simply top off your coolant level to quiet the alarm (even though
    it may already look full).


Radio flashing "Err" code

    This means the factory radio's anti-theft feature has been triggered.  It
    can be reset by entering an unlocking code.  The unlocking procedure is
    at http://k-rad.com.  Your dealership can also unlock your radio, but
    they will usually charge a fee.

Other common problems
Hesitation at 3000 RPM when cold

    No known cure.

    I think it is caused by the double throttle control.  Its purpose is to
    prevent the engine from getting an overly lean fuel/air mix when you
    first start to accelerate.  Now the way this system works is that when
    the engine is cold, (coolant below 175 degrees or so) the ECU opens the
    double throttle control solenoid, which supplies vacuum to the double
    throttle control actuator.  This vacuum overcomes the spring tension
    that normally holds the double throttle butterfly open, and it closes.


    Now, think about what happens when you accelerate.... the engine pulls
    less vacuum, and starts to go towards positive manifold pressure as you
    build boost.  With the vacuum going away, the plate returns to its
    open (normal when engine warm) position.  This helps explain why the car
    doesn't hesitate when accelerating hard, and does when accelerating slowly.


    The decision by the ECU to operate the double throttle control system is
    affected by coolant temperature, and the current "map" that the ECU is
    using.  The Double Throttle control only happens during starting, cold
    engine warm-up, and COLD engine with LIGHT LOAD operation.  This map is
    also affected by the 20k mile switch, which is why many people say that
    the car never hesitated at 3000 RPM when it was new.  The 20k mile switch
    does the same thing that the EL switch does.... it adds base RPM to the
    motor... which affects the ECU's decision as to what "map" it is currently
    operating in.

    This is just my personal theory, and may be wrong.

Paint problems

    Some RX-7 owners have experienced problems with accelerated paint chipping
    and fading.  Mazda has set aside some money to deal with this problem on
    a case-by-case basis.  If your car has this problem, call the Mazda customer
    service line (800 222-5500) and ask to schedule a meeting with your local
    District Service Manager to have your paint inspected.

Battery death & leakage

    Many people on the RX-7 mailing list have had their batteries die
    prematurely.  The main cause seems to be excessive heat.  Batteries
    don't do well with heat, and it gets quite hot under the hood of an
    RX-7.  Hot batteries also tend to leak acid.  One solution to this
    problem is to buy a sealed battery.  Sealed batteries withstand heat
    and cold much better than normal batteries, and they do not leak.
    Sealed batteries cost a little more than regular batteries, but they also
    last longer and come with better warranties.


Brake rotor warp age

    Brake rotors warp from excessive heat.  Routinely braking hard from
    high speed, can cause warpage.  Rotors have been replaced under the
    new-car warranty.  The extended warranties generally don't cover rotors,
    since they are expected to be consumed with use.  Many netters have had
    their rotors replaced under warranty.

Suspension clunk

    Cars produced prior to May 31, 1992 came from the factory with noisy upper
    a-arm bushings.  Your dealership will replace the bushings under warranty
    with a modified part.

Cracking factory wheels

    Some people on the net have noticed cracks where their spokes join the rim.
    There seem to have been two manufacturers of stock rims, one type has a
    curved area where the spoke joins the rim, and the other joins at a 90
    degree angle.  All reported cases of cracking rims have been on the 90
    degree type rims.
Is my car normal?
Is my mileage unusually low?

    The official EPA mileage ratings for the 3rd generation RX-7s is:

       Manual transmission: 17 MPG City, 25 MPG Highway
    Automatic transmission: 18 MPG City, 24 MPG Highway

    Real world experiences from the net vary from this.  A highly modified car
    has gotten higher than EPA predicted mileage, but this is the exception.
    Most people on the net get lower mileage, with 12 MPG in mixed city and
    highway driving being a common number.

How much oil should my car consume?

    The RX-7's engine consumes oil by design.  It has oil metering pumps that
    actually inject oil into the combustion chambers to be burned as you drive.
    The amount you use will be determined by how aggressively you drive.

Sometimes my car backfires, is this bad?

    No.  Backfiring is caused by unburned fuel being ignited in your exhaust
    system.  Backfiring in itself, although annoying, is not harmful.
    Excessive backfiring can be an indication of another problem.

What is typical 3rd Gen performance?

    A typical, stock 3rd Gen should be able to turn about a 14.2 or better in
   the quarter mile, and a low 5 second, or better, 0 to 60 time.

What are normal boost patterns?

    According to the official Mazda test procedure, boost should be as follows:

    - Drive to third gear with normal acceleration
    - Accelerate from 35 MPH at WOT until passing 4500 RPM
    - A slight and smooth increase in power should be felt at approximately 4500
      RPM.  This will be about 65 MPH.

    Boost should be above 10 PSI up to 4500 RPM.  The boost will drop to about
    8 PSI just after 4500 RPM, and will begin rising towards maximum boost
    depending on the length of time the throttle is held wide open.

Performance / Competition
I want to race/modify my RX-7.  How do I start?

    Before racing or modifying your RX-7, you should start with a healthy
    car.  Change your oil and filter, change your fuel filter, bleed the
    brakes, change your air filter, make sure your tires are in good shape
    and properly inflated.  Use a little common sense and make sure your
    car is in good shape BEFORE you add the additional stress of racing or
    modification.  This will also simplify any troubleshooting you may have
    to do, as it eliminates some variables.  When modifying your RX-7, change
    one thing at a time if possible, this way you can more easily identify a
    part that is causing problems.  As always, this is not set in stone, for
    example, you should not do anything that will dramatically raise the
    boost pressure without also adding fuel.  Use common sense.

This site is meant to give information related to the 1993 (o)Mazda RX-7 Twin Turbo.  Anything from rotary engines to wiring diagrams and turbo upgrades to tuning info, this site has it all! efini 93 rx7 13b anfini Turbo RX-7 Turbo RX7 turbo rx7 rx7tt rx-7tt  As well as the Rotary Engine Pickup Truck aka REPU repu