Datalogit FC-Edit software

Install the Full installer first and then copy and paste the 2.127 over the existing FCedit.exe.  Im not hosting viruses, but scan anything you download first.

LM1 WBO2 and Dataloggit

Here is a PDF on how to use the Innovate LM-1 Wideband O2 sensor and the Dataloggit for PowerFC tuning.

PIM to PSI Conversion

Power FC tuning IS overwhelming. It’s as user friendly as it can be, but engine tuning is not a user friendly process. Here is one of the many calcuations and coversions you will come across.

This pertains to the PIM values that PowerFC ominously hides your Boost Pressure as. They actually correlate to PSI.

Its VERY important to remember that 0 PSI in many cases is VACUUM not outside air pressure. We live on earth and there is 14.5 PSI of pressure at sea level ground. Damn gravity screwing up our calculations

PSI=(PIM*0.001422)-14.7 approx

 

Power FC Boost Controller Kit

The Power FC has an optional boost controller kit that allows the PowerFC to manage the wastegate and ultimately the boost level.

This kit comes with:

a 3 bar boost sensor that is plug and play

a wastegate solenoid

 

To install:

Remove the hose and wire from the stock MAP (Manifold Air Pressure) sensor.  Plug both into the new 3 Bar MAP sensor.  This is plug and play.

The old sensor can be used with the supplied 3 or 5 pin wire.  It is supposed to sense elevation changes and be a redundant boost sensor up to 15 PSI. Not necessary.  This wire will plug into the side of the PowerFC main box next to the commander plug.

The wastegate solenoid plugs right into the stock wastegate plug.  If you have modified your car and eliminated the wastegate wire, you hopefully have spare wire pins to rewire it back into the PowerFC.

Turn the key but dont start your car.  You must make some changes to the PowerFC for the wastegate solenoid.  The boost levels will have two numbers (for the stock twin turbo system) you will only look at the primary setting.

Go to the ETC menu and go to functions. Disable sequential turbo function.

Go to MAP (may be called PIM) sensor menu and choose option 1 instead of normal. If you don’t do this, the car will not want to start and will be very unwilling to run.

PowerFC Excel Spreadsheet Tuning

Here is an Excel (XLS) spreadsheet for tuning the PowerFC once you have captured AFR values.

Use with caution.  Ill detail this page more as I begin tuning again.

13B 2 Rotor Engine

This animation of a rotary engine is courtesy of

Real World Solutions

Rotary Engine Animation

(Information from Kevin McCauley)

Engine

 

Year
Name
Horsepower
Torque
1993-1995
All Models
255@6500
217@5000
1996-1997
Japan Only
265@6500
222@5000

 

Performance

 

Year
Model
0-60
1/4 Mile
Top Speed
1993-1995
5 Speed
5.2
13.9@99.9
161
1993-1995
4 Speed Auto
6.0
14.5@96.3
158
1996-1997
5 Speed Japan
4.7
13.9@102.5
164

 

 

Engine Type

Rotary

Displacement cm{cu in}

654 x 2 {40.0 x 2}

No. of cylinders and arrangement

2 Rotors, longitudinal

Combustion chamber type

Bathtub

Compression Ratio

9.0 : 1

Air induction

4-Port induction

Turbo charger

System type

Sequential twin turbo charged

Cooling method

Water + Engine oil

Boost control actuator

Turbo pre-control +Wastegate control

Boost control method

Solenoid valve {duty-controlled} x 2

Idle Speed

700 – 750

Throttle Body

Horizontal draft {2 stage – 3 barrel}

Intercooler

Air cooled

Fuel Tank liters{US gal, Imp gal}

76 {20.1, 16.7}

Fuel pump kPa{kgf/cm,psi}

490 – 740 {5.0 – 7.5, 71.1 – 106.7}

Injector

Side-feeding

Injector volume primary {cm,psi}

550{550}

Injector volume secondary {cm,psi}

850{850}

 

20B 3 Rotor Engine

Mazda have made several prototype and experimental engines over the years ranging from the 6A (a single rotor version of the 12A, intended for use in Japanese “Kei” cars), the 2002 “4 rotor 10A” to the massive R-II 21A with 2x1046cc rotors (You can see the 2002 and 21A elsewhere at this site).Several 3 rotor prototype and racing engines have been produced over the years. Generally speaking these engines were constructed using the modular nature of the rotary engine (that is to say, the parts can be “stacked” together). This allowed comparatively cheap production items (rotors, rotor housings, side housings, seals etc) to be used in conjunction with some specially made (expensive) parts (eccentric shaft and centre housing with rotor phasing gear/bearing) There has really only been one mass produced passenger car 3 rotor engine – the 20B, which was a twin turbo fuel injected engine. Note, NSU also had a 3 rotor engine though I’m not sure if this was mass produced.Generally speaking, the following 3 rotor engines were “available” from the early 1980s: 13G Racing engine (1984-1989), 13G “Production Prototype” (1984/1985), 20B Production engine (1990-1996), 20B Race engine (1990-now)

20B – Production engine

The 20B engine was only sold in the Japanese market. It was also only available with twin turbochargers. It was fitted to the “Eunos Cosmo” (Model type JCES) sold from March 1990 until January 1996. (There was a minor model change, with mainly cosmetic changes about 1993. The first of the cosmos have an engine with plain alloy intake manifold etc. The “updated” model has these parts anodized dark grey. All other mechanical specifications remained the same) The Cosmo was a high specification, high performance luxury coupe nearly comparable to the Lexus. All Cosmos were 4 speed automatics. (See my “EUNOS COSMO” Page for more detail about the car).
It seems that the 20B engine is based on the 13B-REW engine of the “3rd generation” (FD3S) RX7. (Despite the FD3S being released in August 1991, well over 18 months after the Cosmo with it’s 20B in March 1990 – However the Cosmo ALSO was available with a 13B turbo, with very similar specifications to the RX7′s 13B-REW, except power was down a little (about 20-25 hp less). Perhaps the Cosmo’s engine was used to test how reliable the new design was.. Especially with the upcoming volume selling RX7.)

This engine appears to use many standard 13B components, such as rotors /rotor housings, seals etc. As with the “prototype production 13G” the only obvious custom components are: *Special second centre housing with gear and bearing *Eccentric shaft and counterweight assembly *Intake and exhaust manifolds/turbos *Ignition system (Distributorless, but uses FC3S/FD3S RX7 type pickup unit)

NOTE: 20B-REW is the actual correct designation for this engine. This means “20B-Rotary Engine DOUBLE TURBO” according to what I have read (it is easier for a Japanese speaker to say “W” than “DOUBLE”)

20B-REW “Production” Engine specifications

Origin Closely based on 3rd generation (FD3S) RX7′s 13B-REW Special 3 rotor parts based on 13G design
Capacity 654cc x 3 rotors = 1962cc
Compression ratio 9.0:1
Turbo Boost 0.7 Bar (=10.29 PSI)
Induction Turbocharged (twin sequential)/intercooled (intercooler mounted near car’s radiator), electronic fuel injection (2 injectors/rotor)
Exhaust Peripheral Exhaust Port
Ignition Distributorless electronic ignition (2 plugs/rotor)
Power/RPM 280ps@6500rpm
Torque/RPM 41kgm@3000rpm
Max RPM Cosmo Tacho redline at 7000rpm (scale ends at 8,000)
Dimensions Length 672mm Width 549mm Height 520mm (with accessories)
Weight 350kg With all accessories & manifolds
Special Features Ignition knock control uses one sensor per rotor (on rotor housing above trailing spark plug)

 

20B – Racing engine

(Picture from 1996/1997 Mazdaspeed catalog Page 104)

This engine is currently (1997) sold by both Mazdaspeed in Japan and Mazda Motorsports in the USA, both of which are officially part of Mazda. At first I presumed this was a racing engine based on the production 20B. However on comparing the photos of the race 20B and the race 13G, plus the Mazda catalogs list this engine as using rotor housings with grooves for the water seals, I think it is still a 13G they are selling. Also the power output and torque figures are identical (same RPM), and the weight/dimensions are almost the same. (The grooves for the water seals were moved from the rotor housings to the side housings when the “2nd generation” RX7 (FC3S) was released in 1986)

20B Racing Engine specifications

Origin Possibly same as 13G race engine, but not certain.
Capacity 654cc x 3 rotors = 1962cc
Compression ratio Unknown (But 13G is 9.4:1)
Induction Naturally aspirated peripheral port, electronic fuel injection (2 injectors per rotor)
Exhaust Peripheral Exhaust Port
Ignition Distributorless CDI ignition (2 plugs/rotor)
Power/RPM 450ps@8500rpm
Torque/RPM 40kgm@8000rpm
Max RPM Unknown (But 13G is 9500 RPM)
Dimensions Length 675mm Width 549mm Height 520mm
Weight 143kg
Special Features Dry sump

The Complete Mazdaspeed 20B parts list

These pictures have been scanned from the 1996/1997 Mazdaspeed catalogue, Pages 105 to 121 inclusive. I could see no copyright notices in the catalogue, so these are here as “free advertising” for Mazdaspeed.
Page 106 shows the rotor housings, and you can see that the groove for the water O-ring is in the rotor housings (as were all pre-1986 engines), HENCE I think this is ACTUALLY still a 13G engine. Also, check out the trick throttle assembly in page 116!
By the way, the prices are in Yen, and 1 US Dollar = 123.43 Japanese Yen (March 1997)

[PAGE 105] Rotor diagram and parts list [PAGE 106] Rotor housing diagram [PAGE 107] Rotor housing parts list [PAGE 108] Side housing diagram [PAGE 109] Side housing parts list [PAGE 110] Eccentric shaft diagram [PAGE 111] Eccentric shaft parts list [PAGE 112] Manifold diagram and parts list [PAGE 113] EFI computer diagram and parts list [PAGE 114] Fuel system diagram and parts list [PAGE 115] Water Pump diagram and parts list [PAGE 116] Throttle plate diagram [PAGE 117] Throttle plate parts list [PAGE 118] Oil system diagram [PAGE 119] Oil system parts list [PAGE 120] Ignition/Alt/Starter diagram [PAGE 121] Ignition/Alt/Starter parts list

Note: All pictures are 768x1024x4 GIF files. This was found to be the best compromise between file size and picture quality, which is about the same as a fax (to get better quality meant much bigger files).

Performance applications of the 20B engine

A second hand production 20B engine is the only multi rotor engine worth considering. The 13G engines are extremely rare (and expensive). The new price of a “20B race engine” as listed above is $US 20,000+ for the core engine alone. Many more ‘production’ 20B engines were made as they were fitted to a production car rather than being a special racing item.  However 20Bs are far rarer than their 13B cousins; so they are difficult to find and will be expensive. (I would estimate that less than 100 of these have been imported to Australia).

In Australia, the price for these units started at $Aus 12000 in 1991, dropping to a low of about $Aus 4000 in 1997. In March 2001 I was told by someone who had just bought an engine that the going rate is $Aus 4000 to 9000: *Adelaide Jap Dismantlers $Aus 6550 for front cut (Whole front half of car) *Ichiban for $Aus 2975 (some damage to engine), $Aus 3995 or $Aus 4995 Refer to my “parts” page for contact information. If you have any updates of prices or supply sources please let me know).

So, assuming a 20B can use standard RX7 13B components (rotor housings, seals etc) a rebuild on a 20B could probably be done for under $Aus 3000.

20B engines used in Australia have been fitted to many cars in the Mazda range – RX2, RX3, RX4, RX5, RX7s of all vintages, 929 sedans and Coupes, I have even seen a mid 80′s BMW 5 series with a 20B installed. (See elsewhere on this site for both a 2nd Generation RX7 with a 20B conversion and the Rod Millen 20B rally car).

Because the 20B probably has one of the most complex engine management requirements in the world and the factory computers have complex wiring, these engines generally have the twin turbos replaced by a single large turbo (e.g. TO4) and are run on a aftermarket fuel computer. Expensive engine management systems from Motec, Haltech and Autronic and others may be capable of distributorless ignition and/or twin turbo operation however in the past the ignition was typically done via an early RX7 distributor, with a Racing Beat conversion kit comprising of a big clear Perspex distributor cap and a new ignition triggering vane.

A standard Mazda transmission will bolt onto the 20B without modification, another popular choice are 5 speed Toyota Supra gearboxes. Some drag cars are using ancient 2 speed Powerglide transmissions (why they would use one of these rather than a modern 4 speed is beyond me…) The differential used is almost always a Ford 9 inch.

20Bs have been fitted to later model RX7s (FC3S/FD3S) without too much problem. (I suspect the RX7 engine bays MAY have been originally designed to hold a 3 rotor engine, particularly in the FD3S). These conversions seem to retain more of the original hardware.
Potential power outputs: *The standard power output of a 20B turbo is 280HP. *With turbos removed (naturally aspirated), these engines produce 250hp stock, 320hp if ported. *Apparently with the mere addition of a boost controller the power jumps to around 400HP. *Rod Millen’s Pike’s Peak race car made about 500HP with a nearly stock engine. *Japanese modifiers get about 700HP without too much trouble (I suspect this would be at a level where some engine porting and severe turbos would be required). *Racing beat’s Bonneville racer makes 900+ hp with a triple turbo peripheral port 13G *The above figures were all mid-late 1990s. In 2002 some drag racers are claiming 1200hp.

 

Various Rotary Engines

The Different Rotary Engines

Rotary Engine Statistics

Type

Year

Art

Displacement

Power

40A

1961

Experimental

1 x 386 ccm

L8A

1962

Experimental

1 x 399 ccm

L8A/0353

1963

Experimental

2 x 399 ccm

L8A/3804

1963

Experimental

3 x 399 ccm

L8A/3805

1963

Experimental

4 x 399 ccm

160 PS/6000

10A/3820

1964

Prototype

2 x 491 ccm

12A/3830

1966

Experimental

2 x 573 ccm

12A/3830

1966

Prototype

2 x 573 ccm

400/3867

1967

Experimental

2 x 395 ccm

400/3893

1967

Experimental

2 x 495 ccm

10A/0810

1967

Cosmo L10A

2 x 491 ccm

110PS/7000 135Nm/3500

10A/0813

1968

Cosmo L10A

2 x 491 ccm

128PS/7000 142 Nm/5000

10A/0820

1968

Cosmo

2 x 491 ccm

100PS/7000

10A/3883

1968

Singapore GPrennen

2 x 491 ccm

204 PS – 170kW/230PS

12A/3872

1968

Prototype

2 x 573 ccm

10A/8020

1968-72

R100 / Presto

2 x 491 ccm

100PS/7000 137Nm/3500

10A/3877

1969-72

R100(US)

2 x 491 ccm

100PS/7000 129Nm/4000

10B

1968-69

Cosmo

2 x 491 ccm

128PS

3912

1970

Experimental

1 x 356 ccm

35 PS

X002

1970

Experimental

1 x 360 ccm

3915

1970

Experimental

1 x 360 ccm

13A/0823  9,1:1

1970-72

R130

2 x 655 ccm

126PS/6000 175Nm/3500

6A

70er

Experimental

1 x 573 ccm

halber 12A

7A

70er

Experimental

1 x 654 ccm

halber 13B

2002

71

Experimental

4 x 491 ccm

180 PS/6000

12A  9,4:1

1970-71

R100

2 x 573 ccm

100PS/7000 129Nm/4000

12A  9,4:1

1970-71

RX2

2 x 573 ccm

120PS/7000

10A/0866

1971-75

RX3 (JP)

2 x 491 ccm

105PS/7000

12A  9,4:1

1972

R100

2 x 573 ccm

100PS/7000 112Nm/4000

12A/3905  9,4:1

1972

RX2 (US)

2 x 573 ccm

102PS/6800 137Nm/4000

21A

1972

Experimental

2 x 1064 ccm

185PS 280Nm

12A/R612  9,4:1

1972-75

RX3 (US)

2 x 573 ccm

102PS/6800 134Nm/4000

12A  9,4:1

1973

Luce GR (JP)

2 x 573 ccm

120PS/6500 162Nm/3500

12A  9,4:1

1973

Luce GR AP (JP)

2 x 573 ccm

115PS/6500 159Nm/3500

12A  9,4:1

1973

Luce GR II( JP)

2 x 573 ccm

130PS/7000 168Nm/4000

12A  9,4:1

1973

Luce GR IIAP (JP)

2 x 573 ccm

125PS/7000 164Nm/4000

12A  9,4:1

1973

RX-2

2 x 573 ccm

97PS/6500 134Nm/4000

12A

1973

Le Mans

2 x 573 ccm

250PS/8000

12B

1973-75

K�uflicher Rennmotor

2 x 573 ccm

250PS+/9500

13B   9,1:1

1973

R130 (Jp)

2 x 654 ccm

125PS/6000 175Nm/3500

15A

1973

Experimental

2 x 737ccm

135PS/5750 203Nm/3500

12A SIP  9,4:1

1974

RX2

2 x 573 ccm

97PS/6500 134Nm/4000

13B   9,2:1

1974-75

RX4

2 x 654 ccm

110PS/6000 164Nm/3500

12A  9,4:1

1976

RX3 Nikki 2B1

2 x 573 ccm

95PS/6000 143Nm/4000

13B   9,2:1

1976-78

RX5 Cosmo

2 x 654 ccm

110PS/6000 168Nm/4000

13B   9,2:1

1976-78

RX4

2 x 654 ccm

110PS/6000 168Nm/4000

12A  9,4:1

1977-78

RX3SP

2 x 573 ccm

95PS/6000 143Nm/4000

12A Sport  9,4:1

1977

Racing Kit

2 x 573 ccm

250PS+/9000

13B Racing  9,4:1

1977

Rennen

2 x 654 ccm

290PS+/9000

12A  9,4:1

1979-80

RX7

2 x 573 ccm

100PS/6000 147Nm/4000

13B Racing

1979

Rennen Le Mans

2 x 654 ccm

285PS/9000

13B Racing

1980

Le Mans Qualification

2 x 654 ccm

300PS/9000

13B Racing

1980

Le Mans Rennen

2 x 654 ccm

290PS/8500

12A Magermotor

1981-85

RX7 US

2 x 573 ccm

100PS/6000 147Nm/4000

12A 6PI

1982-85

Luce,Cosmo (Jp),RX7

2 x 573 ccm

12A/Turbo

1983-8

Luce,Cosmo,RX7

2 x 573 ccm

160PS/6000 231Nm/4000

12A/Turbo  8,5:1

1984-85

Luce,Cosmo,RX7

2 x 573 ccm

165PS/6000 231Nm/4000

12A  9,4:1

1984-85

RX-7 (S,GS,GSL)

2 x 573 ccm

101PS/6000 149Nm/4000

13B DEI

1983+

Luce,Cosmo,RX7

2 x 654 ccm

13G Racing

1983-84

Rennen 757

3 x 654 ccm

450PS/8500

13B Racing

1984

Le mans

2 x 654 ccm

Sprint 330PS, Ausdauer 310PS

13B/Turbo  7,5:1

1984

Racing

2 x 654 ccm

500PS/7800 456Nm/7500

20B

1984-

Production Rennmotor

3 x 654 ccm

500PS/9000

13B DEI  9,4:1

1984-85

RX7 (GSL-SE)

2 x 654 ccm

135PS/6000 186Nm/2750

13B DEI  9,4:1

1986-89

RX7 2.Generation

2 x 654 ccm

146PS/6500 193Nm/3500

13B/Turbo  8,5:1

1986-89

RX7 Turbo II

2 x 654 ccm

182PS/6500 256Nm/3500

13J-M Racing

1988

Rennen 767

4 x 654 ccm

500PS/8500

13B

1989

Luce (Jp, 929)

2 x 654 ccm

177PS/6500 253Nm/3500

13J-MM Racing

1989

Rennen 767

4 x 654 ccm

630PS/9000 2Schrittsaugrohr

20B

1989

Eunos Cosmo

3 x 654 ccm

280PS/6500 402Nm/3000

13B VDEI  9,7:1

1989-92

Leichtere L�ufer

2 x 654 ccm

160PS/7000 196Nm/4000

13B/Turbo  9,1:1

1989-91

Leichtere L�ufer

2 x 654 ccm

200PS/6500 274Nm/3500

13B/Twin Turbo 9,0:1

1992-

RX7 3.Generation

2 x 654 ccm

255PS/6500 304Nm/5000

13B MSPRE

1995

Exp. RX01

2 x 654 ccm

220PS/8500 223Nm/6500

26B

1991

Rennen 787B Le Mans

4 x 654 ccm

700PS/9000  607Nm/6500 var.Saugr.

HR-X

1991

Exp. Wasserstoff

2 x 499 ccm

100PS 127Nm

HRX-2

1993

Exp. Wasserstoff

13B Renesis

1999

RX-Evolv

2 x 654 ccm

280PS/9000

13B Rensis

2000

Prototype RX-8

2 x 654 ccm

250PS/8500

13B Rensis

2003

Series RX-8

2 x 654 ccm

192PS-250PS (D 192PS-231PS)

Wideband Dataloggit

Wideband O2/Datalogit Tuning

Stoichiometric:

Stoichiometric or Theoretical Combustion is the ideal combustion process during which a fuel is burned completely. A complete combustion is a process which burns all the carbon (C) to (CO2), all hydrogen (H) to (H2O) and all sulfur (S) to (SO2). If there are unburned components in the exhaust gas such as C, H2, CO the combustion process is uncompleted (taftan)  Approximately 14.7 parts Air to 1 part Fuel (14.7:1) for the perfect complete combustion.

Pressure Conversions:

Remember: when the term 1 bar is used to describe pressure what most forget to state is that it is assumed they mean “above atmospheric pressure.”  Naturally the atmosphere has pressure (1 BAR approx 14.7 PSI) but this is assumed constant.  Stating a turbo “kicks out” 14 PSI that is actually 14 PSI more than the atmospheric hence 14.7 PSI is technically 2 BAR

101.325 kPa = 1 ATM

100 kPa = 1 bar

200 kPa = 2 bar = 14.7 PSI   (referred to 1 bar assuming it is understood to be 1 bar above atmospheric pressure)

Goals of a tuner:

Fuel related:

 

For any given moment have the A/F ratio, Load, and RPM to make calculations and then output the corrected amount of fuel for the desired A/F ratio in those same conditions .

Typical A/F ratios:

  • high 14′s up to “0 PSI” AKA atmospheric pressure (1 BAR)
  • mid 12′s up to 6 PSI (1.4 – 1.5 BAR)
  • mid 11′s up to 14.5 PSI (2 BAR) and above.

Fuel related links:

Detailed information on both Gasoline/Ignition

Ignition related:

In terms of ignition, proper timing is needed to ignite the compressed air/fuel mixture at the most opportune time avoiding preigniting (detonation) or retarded ignition

What is DETONATION?

Typical timing advances:

  • 30 to 35 deg advance to 90kpa (0.9 BAR)
  • 20 odd up to 120kpa (1.2 BAR, 3 PSI)
  • as low as 10 to 17 total advance up to 200kpa (2 BAR, 14.7 PSI)

If you stick to a total engine advance of no more than 15 deg, assuming your static timing (pick up) is set correctly, then you are much less likely to suffer engine failures due to timing

EGTs:

Exhaust gas temperatures is one way to measure timing.  If the timing is too retarded (combustion happens too late) then the fuel is still burning in the manifold causing higher EGTs

Effects of porting on timing:

*1 BAR boost assuming constant ambient temp of 15 C and charge temp of 30 C*

  • STOCK PORT                  20-23 deg advance …lowest effective “dynamic” compression at max power.
  • STREET PORT                 15-17 deg advance…midrange effective “dynamic” compression at max power.
  • PERIPHERAL PORT        10-12 deg advance…highest effective “dynamic” compression at max power.

 

Before you tune you must ask yourself:
1) What ECU are you using? 2) What amount of performance/reliability do you want from your car?. 3) How modified is your car? 4) How much boost do you plan on running? 5) What octane gas do you use? (better be more than 92 octane) 6) How easy is it to access a dyno, wideband O2 sensor and data logging kits for all vital engine information? 7) Where is your EGT sender located?

Wide Band O2 Sensors

 

Why do I need a wide band 5-wire sensor on my air fuel ratio meter?

1)  The output of a sensor with less than 5-wires is binary.  That means it’ll only tell you if you are rich or lean.  It cannot tell you how rich or lean you are.   Once the mixture goes a little bit fat, the meter will pin to the rich side.  Likewise if the meter goes lean, the meter will pin to the lean side.  Very often, a meter maker using these cheap sensors will write on their faceplates that the meter goes from 10.0 to 20.0 AFR.  This is just paint on the panel.  It is simple dishonesty.  It is more likely 13.5 to 15.0 in reality.  They might as well use three LED’s to tell you the AFR – LOW, MED and HIGH!

2)  There are only two wide band sensors widely available today.  One is made by Bosch and the other by NTK/NGK.  They have five wires.  These sensors require sophisticated closed loop controllers to determine the air fuel ratio rather than a simple switch type OEM sensor that requires only a voltmeter.  All sensors can only determine the air fuel ratio at the switch point where the mixture goes lean to rich.  This is any sensor’s zone of accuracy.  The difference between the OEM sensors and the 5-wire widebands is that this zone can be moved around to different air fuel ratios in the widebands.  In other words, 5-wire sensors have an electronically controllable air fuel ratio in their reaction cavities.

What this means is that you can make the sensor operate in it’s zone of sensitivity at air fuel ratios ranging from 8 to 24 or higher air fuel ratio.  The problem is that this requires some clever circuitry to keep the sensor in this delicate balance.  (lamdaboy)

 

Many RX-7 tuners actually wire their wideband directly into the O2 sensor location for the aftermarket ECU.  As long as the Wideband O2 sensor has a 1-4V output it can replace the stock O2 Sensor.  Many do this so that, like in the PowerFC, one unit logs O2 and all other engine parameters.

The standard scale is:  4V is amount of oxygen in open air                                  2.5V is combusted fuel at a 14.7 A/F ratio
This is the Tech Edge Wideband O2 sensor kitwhich is used in proper tuning of a RX-7

 

This is the FJO Wideband O2 sensor kit which is used as well.

 

Lambda-BoyStandard Air Fuel Ratio Meter

 

Innovate Motorsports LM-1: Digital Air/Fuel Ratio Meter

 

Data Logging ability with excellent software

 

All of these kits have a data logging feature which is crucial for tuning because it retains past information so tuning does not have to be “on the spot”  Data is logged into either a laptop or a PDA and reviewed as the fuel map is corrected to get as close as possible to the desired Air to Fuel Ratio.  Stoichiometric combustion is always dreamed about, but is unattainable due to the detonation in turbocharged rotary engines.  Detonation is more likely with the air is hot and pressurized.  It is a debate as to what the “correct” AF ratio is for a FD.  I have personally seen as low as 11.5 to as high as 13 used in setups.  (this information is used as education resources only)

This website chronicles an installation of a wide band o2 sensor on a 3rd Gen RX-7. 
 

Knock Sensors

Use primarily in tuning the ignition maps for the RX-7, the J&S Knock Sensor is not only a monitor, but a safety net as well.  The unit is capable of detecting preignition and displaying that to the driver.  The unit adjusts timing as needed to avoid early timing.  If the timing is too soon preignition/detonation will occur.  If the timing is too late, the timing is considered retarded and ignites what is already expanding because the rotor is in motion causing a change in pressure and volume.  Perfect timing is the goal.

This document has several articles related to knock sensors and detonation.
 
 

Datalogit for PowerFC

Data logging unit that “splices” the signal for the commander and sends it to a laptop via serial port.  The laptop must have correct software installed to read signals and log data from ECU.  Most useful features include logging Load vs. RPM graphs and correction maps.

 

1993 Mazda RX-7 Service Manuals

These are PDFs of the official Mazda service manuals

(A)general_info – Information about reading service manuals
(B)scheduled_maintenance_services – Scheduled maintenance
(C)engine – Disassemble and assemble the rotary engine
(D)lubrication_system – Everything related to oil
(E)cooling_system – Radiator and Coolant information
(F)fuel_and_emissions_control_systems – Gas and air diagnostics
(G)engine_electrical_systems – Electrical Diagrams
(H)clutch – Clutch throwout bearing assembly
(J)manual_transmission – Transmission teardown
(L)propeller_shaft – Driveshaft disassembly
(M)front_and_rear_axles – Wheel axles
(N)steering_systems – Power Steering assembly
(P)braking_systems – ABS brakes and teardown
(Q)wheels_and_tires – Tire diagnostics
(R)suspension – Suspension adjustments
(S)body – disassembly of body parts
(ST)special_tools – list of tools needed to perform work
(TD)technical_data – Every specification about the Mazda RX-7
1993_FD_Parts_Diagram – List of all the part numbers

 

VERY LARGE
93_service_highlights – A summary of the most common issues for the RX-7

Efini RX-7 (99 Spec)

Although Efini was used to describe the third generation RX-7 in its entirety, I use it to describe the “after-American” production of the RX-7.  Once production stopped in the USA the car was made only in its hometown of Japan.  The car was right hand drive as are most cars in Japan.  It had a performance and styling upgrade known as 99 Spec to the Americans.

That includes the redesign of:

  •     The front spoiler

  •     The front lip

  •     Rear spoiler

  •     Taillights

  •     Turbochargers

  •     Rims

  •     Exhaust

  •     Intercooler Piping

 

The Updates
The 1996 Update
A minor refreshing in 1996 brought a power increase to 265 hp, and torque up to 222 lb/ft (up from 217).  A new spoiler was offered as well.
The 1999 Update
In 1999, the FD3S, nearing the end of its lifespan, joined Japan’s 280-bhp club.  A gentlemen’s agreement among Japanese automakers limits the maximum power to 280, (although many, such as Nissan’s skyline are way past that mark).  More boost, new turbos, improved cooling, enhanced apex seal lubrication, better engine management and a less restrictive exhaust are some of the reasons cited for the increase.  New Bilstein shock absorbers on the tope of the line Type RS model add to the already acclaimed suspension, and a face lifted front fascia drastically improves cooling to the radiator, brake ducts, intake, intercooler and oil coolers.  An adjustable rear-wing on the Type R and Type RS models allows control over drag and down force.  Taller 17″ wheels and fat 235/255mm series rubber complimented the increased power with added traction.
1999 Mazda RX-7 GT-C Concept
1999 saw the release of the RX-7 GT-C Concept, to coincide with the launch of the restyled standard model.  It consisted of mostly exterior upgrades, including a full body kit that replicates the Mazdaspeed JGTC RX-7 for superior aerodynamics and cooling.
2001 Type RZ
Although the RZ name is not new, this final type RZ is significant in how extensive the changes to the regular model are, as well as it likely being the last 3rd generation RX-7.

Spirit R

Features common to all three series models

– Interior panels with soft coating (meter panel, center panel, center console, power window switch panels) – Steering wheel and knob with red stitching (Nardi-made leather steering wheel, leather shift knob, leather parking brake lever, and shift boot for manual transmission model)
– Red brake calipers and front strut tower bars – 17-inch aluminum wheels manufactured by BBS (gun metallic color for Type-A, and silver for Type-B and Type-C) – Spirit R exclusive ornament – Spirit R exclusive meters

Exclusive features – Large drilled type bench rated disk brakes for all four wheels (Type-A and Type-B) – High rigid stainless mesh brake hoses (Type-A and Type-B) – Exclusive dampers manufactured by Bilstein (Type-A and Type-B) – Recaro lightweight full bucket seats (Type-A)
– Authentic leather red bucket seats (Type-B and Type-C) (fd3s.net)

Total of 1500 produced 2002 RX-7s, 1000 produced Spirit “R” series

For the final production year Mazda have released a limited edition of the RX7, the Spirit R. The third-generation RX-7, first launched in 1991, has a particularly distinctive exterior design. Its lightweight, compact and high-output rotary engine enables the driver to feel superb driving pleasure. Epitomizing Mazda’s spirit of sports car, RX-7 has won popularity among the customers since its 1978 launch. Mazda envisions the production of the current RX-7 model (FD-3S) to come to an end in August 2002. The Spirit R series is available in three models: the Type A, a two-seater with a five-speed manual transmission; the Type-B, a four-seater with a five-speed manual transmission; and the Type-C, a four-seater with a four-speed automatic transmission. All three models are equipped with common interior and exterior features, such as BBS-manufactured 17-inch wheels, red brake calipers, and interior panels with a special soft coating, while each model shows off its own equipment to make a difference from the other. The Type-A Spirit R is a two-seater model fitted with the Recaro-made exclusive red full bucket seats. These lightweight seats reduce the overall chassis weight of the vehicle by approximately 10 kg. Braking performance is enhanced through the use of large drilled type ventilated disk brakes for all four wheels and high rigid stainless mesh brake hoses. The Type-A Spirit R model is the ultimate RX-7, boasting the most outstanding driving performance in its history. The Spirit R is available with five outer panel colors including Titanium Gray Metallic.  (ultimatecarpage)

Type Bathurst

For the 2002 model year Mazda introduced a special version of their rotary sports car, the RX7 Type R Bathurst R. The limited edition model is based on the Type R, with the highest power-weight ratio among RX-7 series, and features custom height-adjustable dampers designed specially for the limited edition model for enhanced driving excitement. In addition, employing the carbon tone cockpit reminiscent of a racing car adds up to a thoroughly sporty feel. Three body colors are available, including exclusive color for this limited edition vehicle: Sunburst Yellow. The name Bathurst was chosen to commemorate the Bathurst 12-hour car race in Australia, where the RX-7 has been victorious for three consecutive years (1992 through 1994). Since that time all limited edition versions of the RX-7 have carried the Bathurst name. Sales of the RX-7 Type R Bathurst R are limited to 500 units for all of Japan.
Features of the Bathurst R – Custom Bathurst R decals – Height-adjustable dampers (custom designed for the limited edition model) – Carbon tone panels (center panel, center console, power window switch panel and small storage compartment cover on driver’s side) (manufactured by Mazda Speed) – Carbon shift knob and parking brake lever (manufactured by Mazda Speed)  (ultimatecarpage

RX-7 Production Information

This is the information of production numbers accurate to each specific color, year, and model type.

Base Model – Auto Transmission

Silver Stone                                           58
Montego Blue                                           72
Brilliant Black                                       109
Vintage Red                                           151

Total————————————————-> 390

Base Model – Manual Transmission

Silver Stone                                          266
Montego Blue                                          319
Brilliant Black                                       418
Vintage Red                                           731

Total———————————————–> 1,734

Touring Model – Auto Transmission

Silver Stone                                         187
Montego Blue                                      244
Brilliant Black                                       258
Vintage Red                                           430
Total———————————————–> 1,119

Touring Model – Manual Transmission

Silver Stone                                          824
Montego Blue                                          954
Brilliant Black                                      1015
Vintage Red                                          1775

Total———————————————–> 4,568

R1 Model – Manual Transmission

Competition Yellow Mica                               350
Brilliant Black                                       638
Vintage Red                                          1177
Total———————————————–> 2,165

ENTIRE 1993 YEAR TOTAL ———————-> 9,976

 

Base Model – Auto Transmission

Silver Stone                                            4
Montego Blue                                           50
Brilliant Black                                        16
Vintage Red                                            14
Chaste White                                           26
Total————————————————-> 110

Base Model – Manual Transmission

Silver Stone                                           22
Montego Blue                                          116
Brilliant Black                                        48
Vintage Red                                            60
Chaste White                                           54
Total————————————————-> 300

Touring Model – Auto Transmission

Silver Stone                                           26
Montego Blue                                          105
Brilliant Black                                        42
Vintage Red                                            59
Chaste White                                           63
Total————————————————-> 295

Touring Model – Manual Transmission

Silver Stone                                          118
Montego Blue                                          516
Brilliant Black                                       235
Vintage Red                                           248
Chaste White                                          276
Total———————————————–> 1,393

Popular Equipment Package – Manual Transmission

Silver Stone                                           74
Montego Blue                                          323
Brilliant Black                                       150
Vintage Red                                           159
Chaste White                                          203
Pearly White                                            1
Total————————————————-> 910

R2 Model – Manual Transmission

Silver Stone                                           83
Brilliant Black                                       156
Vintage Red                                           156
Total————————————————-> 395

ENTIRE 1994 YEAR TOTAL ————————> 3,403

Base Model – Auto Transmission

Silver Stone                                            2
Montego Blue                                           10
Brilliant Black                                         5
Vintage Red                                             7
Chaste White                                            2
Total————————————————–> 26

Base Model – Manual Transmission

Silver Stone                                            6
Montego Blue                                           23
Brilliant Black                                        21
Vintage Red                                            19
Chaste White                                           13
Total————————————————–> 82

Popular Equipment Package – Auto Transmission

Silver Stone                                            4
Montego Blue                                           16
Brilliant Black                                         9
Vintage Red                                             5
Chaste White                                            2
Total————————————————–> 36

Popular Equipment Package – Manual Transmission

Silver Stone                                           34
Montego Blue                                          101
Brilliant Black                                        62
Vintage Red                                            69
Chaste White                                           33
Total————————————————-> 299

R2 Model – Manual Transmission

Silver Stone                                           16
Brilliant Black                                        18
Vintage Red                                            23
Total————————————————–> 57

ENTIRE 1995 YEAR TOTAL ————————-> 500

ENTIRE 3rd GENERATION TOTAL ——–> 13,879

Here are the US production numbers thanks to information gathered by Mike Haun from Mazda Distribution.

Information from:

alecto.bittwiddlers.com/vehicles/rx7-numbers.shtml

RX-7 Specifications

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

Understanding your VIN Number

The VIN number is broken down into many parts to more accurately specify which model it is.

“JM1″ World Manufacturer Identifier” for Mazda
“FD” RX-7 third generation series
“33″ Body style (“33″ = coupe)
“1″ Misc. ID field (1993: “1″ = US, “2″ = Canada.)
                      (1994: “3″ = manual seat belts, 2 airbags)
                      (1995: “3″ = manual seat belts, 2 airbags)
“1″ Check Digit” (used to verify that a VIN is not bogus) Calculated for each year.
“P” Year model code (1993 = “P”)
                            (1994 = “R”)
                            (1995 = “S”)
                            (Q was not used)
“0″ Assembly plant code (“0″ = Hiroshima)
“200001″ Serial number (1993: started with 200001)
                      (1994: started with 300001)
                      (1995: started with 400001)

Example VIN: JM1FD3311P0200001

Catalytic Converter

This is for comparison of how small the holes on the stock catalytic converter really are.

There are two catalytic converters on the RX-7.

The first is a pre-cat, which is the first thing exhaust gases meet after leaving the turbocharger.  This converter is prone to failure due to the high heat conditions and is commonly replaced with a steel downpipe.  Many times, a pre-cat will fail and break into pieces like the one above and clog the main catalytic converter.  This in turn causes immense amount of back pressure which if not treated right away causes engine failure.

The second is called the main cat.  It is the primary source of “filtration.” The air pump, driven off of the belts, pumps fresh air into the converter speeding up the process.  Although this one alone isn’t as troublesome, it is commonly replaced with a mid pipe or a high flow cat.  As soon as this catalytic converter is replaced, the exhaust back pressure is radically different and a tuned or aftermarket ECU is needed to compensate for the sudden increase in flow.  If left untreated, the turbo will have less restriction and in turn, without the proper upgrades, will spool uncontrollably faster.  This results in boost spikes, uncontrolled increases in the amount of air pressure given from the turbos.

Most who live in states where smog tests and emission tests are required chose the high flow cat because it does still operate as needed.

Ever wonder how people with aftermarket accessories shoot flames out of their tail pipe?  Reason is a combination of a mid pipe and down pipe results in a free flowing exhaust.  The rotary engine by design actually passes fuel straight from the intake to the exhaust without being combusted.  When this fuel is subjected to the high EGTs (Exhaust Gas Temperature) it is ignited.  The result is combustion right out the cat back.

Tim McCreary (RX7Club.com post)

Here is why a catalytic converter is installed in a car:

Three-way cats are to take care of the three harmful compounds. The reason that the air is injected in the middle of the cat is to provide oxygen to finish the catalyst conversion of Carbon Monoxide to Carbon Dioxide and to “burn” unburned hydrocarbons safely without an actual flame or explosion. Without the air pump, you will not complete this process properly. Eventually, you will generate heat or buildup that will either overheat and deteriorate the ceramic honeycomb creating failure and blockage or will generate buildup creating blockage and failure. The following is a description of what a catalytic converter does:
A catalytic converter is a device that uses a catalyst to convert three harmful compounds in car exhaust into harmless compounds.
The three harmful compounds are:
Hydrocarbons (in the form of unburned gasoline) Carbon monoxide (formed by the combustion of gasoline) Nitrogen oxides (created when the heat in the engine forces nitrogen in the air to combine with oxygen)
Carbon monoxide is a poison for any air-breathing animal. Nitrogen oxides lead to smog and acid rain, and hydrocarbons produce smog. In a catalytic converter, the catalyst (in the form of platinum and palladium) is coated onto a ceramic honeycomb or ceramic beads that are housed in a muffler-like package attached to the exhaust pipe. The catalyst helps to convert carbon monoxide into carbon dioxide (NEEDS OXYGEN). It converts the hydrocarbons into carbon dioxide and water (NEEDS OXYGEN). It also converts the nitrogen oxides back into nitrogen and oxygen (GENERATES SMALL AMOUNTS OF OXYGEN).
My comments are in capital letters in parentheses. As you can see, without an air pump, you cannot complete the reactions necessary to clean the air. Also, if you had enough Oxygen to complete these without the aid of an airpump, you would be running lean and we all know what that means to a rotary.
The reason it is important to put a cat on a rotary engine is due to it’s design. The reason they moved the exhaust port to the side in the RX8 is because the unburned hydrocarbons are just wiped out to the exhaust by the apex seal. The Renesis engine eliminated this from happening which increased fuel economy by 35% and decreased emissions by 50%. Someone else hit it on the head why the precat was installed (to meet emissions because the engine was an emissions hog).
Back to the original question: Does the High Flow Cat clog without an air pump. The answer would be YES. Defining the “Clog” in a cat would be anything that would help deteriorate the interior of the cat to the point that the ceramic would break down and eventually block the flow. Any Cat will clog over time without an air pump. How long? That depends. It may last a few months or a few years. The question I would ask is why spend the money on a High Flow Cat when you can put a straight pipe on for much less. If the answer is emissions, then fix it right and help save the environment a bit so we can continue to run our emission hogs.
Remember also, without the air injected into the cat, the Cat will achieve much higher temperatures than with the air. These higher temperatures will lead to premature failure of the ceramics and eventually clog the cat flow.
High Flow Cats are much less likely to clog compared to the older bead type (highly restrictive and usually melted the beads together due to high heat and close contact). There are High Flow Cats that produce the same back pressure as the straight pipe (Random Technologies had an independent study done on an RX7 with their High Flow Cat and a straight pipe and found the same back pressure).

Actually the cat will heat up, not run cooler because there is more fuel to react with the available oxygen in the exhaust stream. After reading up a bit, there is sufficient evidence to describe two different cats: Three-way and Three-way plus injection. The ones most commonly used on American cars are three-way plus injection where additional oxygen is injected in the middle of the three-way cat after the first stage which breaks down NOx and released oxygen, second stage combines CO and O2 and burns unburned hydrocarbons by reacting with Oxygen. The last part of the cat, air is injected in the stream to allow more complete combustion of any unburned hydrocarbons and conversion of CO to CO2 that may be missed in the first two parts of the cat.
So to change my stand on the original question, yes you can run without the Air pump provided you have the correct cat (three-way that does not require air injection) and a proper working O2 sensor. If you remove the O2 sensor, then the density of oxygen in the exhaust stream is reduced (rich running) and the cat will eventually fail.
To understand why the cat heats up more with less oxygen, understand that the cat is a very efficient tool to make the chemical conversions asked of it. If you remove oxygen injection from the equation, the resulting fuel will still be consumed by whatever oxygen is in the air stream. Without the air injection (78% nitrogen which helps cool the cat), the cat cannot cool down as much, therefore will run much hotter and self destruct if temperatures reach high enough. As temperatures increase, the efficiency of the reaction increases, utilizing even more of the minimal oxygen in the exhaust stream, propagating the process.
The Hydrocarbon molecule is made up of many carbon and hydrogen atoms requiring greater catalytic action and therefore much greater thermal output. So reducing the air injection will actually increase the temperature inside the cat based on the fact that all of the fuel will be converted whether the air pump is on or off, but as excess fuel is sent downstream, there is no air injection to cool the cat down, so it builds up heat quickly eventually failing.