The FC rx7 FAQ plus!

Home  \  Asian Imports  \  The FC rx7 FAQ plus!

The information in the preceeding is comprised from posts, Ohio Rotaries Posts and individual information and experience. It is in no way the sourcing of quick reference. Please aviod questions in this thread if possible.

Information is urged to be added or corrected if at all possible. That information my be reformated but credit will be given for the article.

AAS = Auto Adjusting suspension
ACV = Air Control Valve
AFM = Air Flow Meter (also see MAF)
A-spec = North American Spec
ATF = Automatic transmission fluid
Auto = Automatic transmission
AWS = Accelerated Warm-Up System
BAC = Bypass Air Control
CAS = Crank Angle Sensor
CPU = Central Processing Unit (the Body computer)
DEI = Dynamic Effect Intake (found on 84 and later 13B engines)
DMM = Digital Multi-Meter (required for most electrical testing on cars)
DTSS = Dynamic tracking suspension system (found on all 2nd gen RX-7s)
ECU = Emissions Control Unit (also called Engine Control unit)
EFI = Electronic Fuel Injection
EGI = Electronic Gasoline Injection
EMS = Engine Management System (aftermarket engine computer)
FB = 1st gen RX-7 81-85 production
FC = 2nd gen RX-7 86-92 production
FC3C = 2nd gen RX-7 convertible
FC3S = 2nd gen RX-7 Coupe
FCD = Fuel Cut defender (aftermarket- used only on Turbos with modifed exhaust and stock ECU)
FD = 3rd gen RX-7
FI = Fuel Injection
FMIC = Front Mount Intercooler
GS = Sporty Model (in CAN)
GT = Sporty Model with Turbo
GT Limited = fully loaded every option turbo model.
GTU = Sporty model in 88, base model in 89-90 (in USA)
GTUs = Sporty model in 89-90 (in USA)
GX = Luxury Coupe model (in CAN)
GXL = Top line Luxury non turbo model
J-Spec = Japanese/NZ/AUS spec model
LSD = Limited Slip Differential (sometimes incorrectly called Posi or Positraction which is GM's in-house brand name for their Limited Slip Differential)
MAF = Mass Air Flow sensor
MOP (or OMP) = Metering Oil Pump. Oil Metering Pump as called in the service manual. (also see OMP)
NA = Normally aspirated/ Non turbo
N/A = Normally aspirated/ Non turbo
OE = Original Equipment
OEM = Original Equipment Manufacture
OMP = Oil Metering pump
PD = Pulsation Dampener
P/S = Power steering
PW = Power windows
SA = 1st gen RX-7 79-80 production
Savanna = The name the 1st and 2nd gen RX-7 was sold under in Japan.
SE = Base model in the USA in 87.5-88
Series 1 / S1 = 1979-1980 RX-7 models
Series 2 / S2 = 1981-1983 RX-7 models
Series 3 / S3 = 1984-1985 RX-7 models
Series 4 / S4 = 1986-1988 RX-7 models
Series 5 / S5 = 1989-1992 RX-7 models
Series 6 / S6 = 1992-1995 RX-7 models
Sport = 86-87 Sporty model (in USA also see GS)
TB = Throttle Body
TBM ot TB Mod = Throttle body modification
TID = Turbo Intake Duct
TMIC = Top Mount InterCooler (factory style)
TPS = Throttle position sensor
TII = Turbo model
T2 = Turbo model
VDI = Variable Dynamic Intake
WOT = Wide Open Throttle
6PI = 6 Port Induction the auxiliary ports, also known as the 5th/6th ports
13B = Normally aspirated/ Non turbo, 2 rotor, rotary engine.
13BT = Turbo charged, 2 rotor, rotary engine
13B-RE = J-spec Cosmo twin turbo, 2 rotor, rotary engine.
13B-REW = FD twin turbo, 2 rotor, rotary engine.
20B = J-spec Cosmo three rotor, rotary engine.
787B = 4 rotor, le-mans racing engine

FC Specs and General Information
How much Horsepower did my car come with from the factory?
86-88 NA = 146 HP @ 6500 RPM w/ 138 Ft/lb @ 3500 RPM
86-88 Turbo = 182 @ 6500 RPM w/ 183 Ft/lb @ 3500 RPM
89-91 NA = 160 HP @ 7000 RPM w/ 140 Ft/lb @ 4000 RPM
89-91 Turbo = 200-202 @ 6500 RPM w/ 196 Ft/lb @ 3500 RPM
Infini IV = 215 @ 6500 RPM w/ 206 Ft/lb @ 3500 RPM

What size are my wheels?
The stock sizes all have an offset of 40mm or 40 ET and are:
14x6 w/ 114.3x4 bolt pattern (Base, Luxury, 87.5-88 SE)
15x6 w/ 114.3x5 bolt pattern (GXL, Sport, GTU, 91 coupe)
15x6.5 w/ 114.3x5 bolt pattern (convertible)
16x7 w/ 114.3x5 bolt pattern (Turbo, GTUs, Infini IV)

On the same vein, the stock tire sizes are:
14x6 = 185/70HR14
15x6 & 15x6.5 = 205/60VR15
16x7 = 205/55VR16

Did my 2nd Gen RX-7 come with a Limited Slip Differential?
Only the following FCs had a LSD from the factory:
86-88 GXL
87-91 T2
88 GTU
89-90 GTUs (however not the 89-90 GTU)
It is also rumored that a few rare 91 coupes with both the A (upgraded the interior trim, added a power sunroof, tilt steering wheel, cruise control, and 4 piston front disc brakes and vented single piston rear brakes) and the B package (leather seating, a CD player, and rear cargo cover) came with a LSD, but you should note that Mazda denies that any FC other than the T2 came with a LSD in 91). You can also tell by looking at the differential as there will be a LSD tag on S4 cars with a LSD.

What size injectors does my RX-7 use? What colour are they?
Listed as [Year Engine Plug Size Colour Part#]
86-87 13B NA, low square center, 460cc, red, 195500-1350
86-87 13B Turbo, low square center, 550cc, tan, 195500-1370
88 13B NA, high square offset, 460cc, purple, 195500-1350
88 13B Turbo, high square offset, 550cc, purple, 195500-1370
89-91 13B NA, high oval center, 460cc, red, 195500-2010
89-91 13B Turbo, high oval center, 550cc, purple, 195500-2020

Can I use synthetic oils in my Rotary engined car?
Yes and no. Mazda offically does not recommend the use of synthetic oils in rotary engines, however, it has long been proven that the better synthetics (Redline, Amsoil, Neo, Royal Purple, Mobil1) are perfectly fine to use in a rotary engine, and will generally result in a 1 to 2% horsepower gain. However use of poor quality synthetics (like Valvoline, Castrol Syntec, Havoline, Etc) will result in build up due to high ash content left from these oils when they are burned. That is why Mazda did not recommend synthetics, because they couldn't pick favorites.

My car seems to use a lot of oil. How often do I need to check it?
Everytime you get gas, you should check your oil level. The Rotary motor by design is supposed to inject oil into the engine based on throttle position. If you keep your foot on the gas a lot, you will use more oil. It
is normal to use about 1 quart of oil every 1000 to 3000 miles.

How long does a rotary engine run? Do I need to rebuild my engine?
Most 13Bs can last over 150-200K miles, while most 13BT engines usually last 125-175K miles, but remember that regular proper maintenance for the engines entire life is required for higher lifespan.

Beep code for the P/S Pump Computer
The number of beeps before pausing will indicate the problem.
1-beep, pause, repeat - in case abnormality of speed sensor signal:
In case broken wires or short circuits occur to sensors or harnesses, the buzzer sounds 60-seconds after the engine speed signal of 2200 rpm continues for 18-seconds.
2-beeps, pause, repeat - in case abnormality of engine speed signal:
The buzzer sounds twice and repeats when the vehicle speed signal is missing input and/or no engine speed signal is found (short circuit, broken wire, etc.)
3-beeps, pause, repeat - in case abnormality of stepping motor signal:
The buzzer sounds when there are broken wires or short circuits in coils or harnesses.
4-beeps, pause, repeat - in case abnormality of the power steering microcomputer:
The buzzer sounds 4 and repeats when there are circuit troubles other than with the micro computer.
5-beeps, pause, repeat - in case abnormality of steering sensor signal: Steering sensor is mis-aligned or failed or steering wheel has been improperly installed.

posted by  Low Impedance

TII vs. N/A (cross w/ S4/S5 compare)
The brakes on the TII are 5-lug hubbed, four piston fronts with single piston rears. These also use larger disc's than the base models. GXL's have the same brakes as the TII. The N/A brakes are single piston all around with non-vented rears.
If using the stock mount intercooler, the non-turbo hood cannot be used.
The parts are interchangeable but the TII did have larger sway bars and harder springs and dampers.

The turbo model transmission is a beefier 5-spd when compared to the N/A. Able to handel more power, it makes a great addition to a high powered project. But inorder to swap the transmission, you must change several parts along with it. The reason for this is because of the increase in strength, the parts themselves become larger in size. They will fit into the same mounting positons but they have different dimensions. These are as follows:
-Turbo Driveshaft (Length and Thickness)
-Turbo Differential (Larger than N/A)
-Turbo Axles (shorter and thicker than N/A)

Engine Internal
The Turbo rotors are of a lower compression (9:1) while the N/A rotors are of a higher compression (9.7:1). Meaning that they should not be combined or mismatched. This has great potential to cause damage to the motor.

Engine External
Air Box:
Air Intake Pipes:
No. The pipes and AFM are not interchangeable.
Air Flow Meter:
The AFM is not interchangeable between Turbo and N/A.
Swappable for S4/S5 and TII to N/A.
Intake Manifolds:
Injectors ad fuel rails:
Throttle Cable:
No. Turbo cable is longer and wraps around the motor.

Coil Packs:
Very different. Also pay attention to the differences in the ECU number. This is listed below under ECU serial codes.
Many of the sensors are differnet. Check a service manual for whats what.
Wiring Harness:
Turbo harness is very different from the N/A harness. Not interchangeable.

S4 vs. S5 (cross w/ NA/TII compare)
The taillights are interchangeable from s4 to s5. but s5 to s4 requires a bit of work to the body. The reverse lights shape with hit the body of an S4. Meaning that the area it comes in contact with will needed bending or grinding. Other than this, all other connections and mounts are fine. also, the s5 lights are more of a [( )( )] design where are the s4 is blockish and has a black plastic overlay (white for the 10th AE)
Engine Internal
Not interchangeable because the eccentric shaft has a different balance between series.
S5 rotors are of a higher compression ratio than the S4's. You must use a complete set of one or the other!

Engine External
Air Box:
Air Flow Meter:
The air flow meters are not interchangeable. Also, the S5 AFM does not require an adapter for a cone style filter is not needed. For the S4, an adapter is required.
Front Cover:
The S4 front cover and S5 front cover are swappable but more is needed. The MOP is differentbetween the two. see MOP below...
MOP (metering oil pump):
The S4 MOP uses the mechanical linkage which is connected to the throttle body. The S5 uses the electrical act. MOP which uses a soleniod to control the flow of oil. This is directly related to the front cover. see front covers above....

Again, ECU codes are what matter here. There are differences listed in the ECU series codes section below. the s5 ecu's will not get along with an otherwise s4 setup. also, the s5 holds fuel maps to a higher rpm.

More on Rotors
The factory stamped each rotor with a letter marking starting with A. This denotes weight and balance of the rotor. When buying a replace used rotor, make sure that the letter either A) matches; which is ideal or B) is within one letter difference; i.e. you can use a B rotor with either a A or C but option "A" is still better. The use of rotors that are not match properly can cause severe engine damage.

ECU number codes
Series 4
N326 - Natural Aspiration
N332 - Turbo w/ low impedance injectors (pre-July 1987)
N333 - Turbo w/ high impedance injectors

Series 5
N350 - Natural Aspiration
N351 - Natural Aspiration
N352 - Natural Aspiration
N353 - Natural Aspiration
N370 - Turbo

posted by  Low Impedance

Radio Wiring Information
What are the wire colors for adding aftermarket radio
LTBlue/Red= 12v+
LtBlue/White= +Accessory
LtBlue/Yellow= -power ant trigger
Red/Black=+ Lumination
White=Factory Amp Turn on

Ground to the body, use the 10mm bolt behind the center console front drivers access panel. Do not use the Red/Black as ground it will damage the interior light circuit and dimmer in the car

Front Speakers (maximum of a 15 watt peak from the radio):
LtGreen/Red= Left
LtGreen/Black= Left

LtGreen= Right

Rear Speakers (if applicable, if you have the amplified rear speakers again the Maximum of 15 watts peak is all the stock speaker amp input can handle):
Brown= Left rear
Brown/White= Left Rear

LtBlue= Right Rear
LtBlue/Orange=Right Rear

VIN Breakdown - information origin: peejay
The year of the vechile can be found by referencing the 10th digit of the VIN #

'80 = A
'81 = B
'82 = C
'83 = D
'84 = E
'85 = F
'86 = G
'87 = H
'88 = J
'89 = K
'90 = L
'91 = M

The eighth digit of the VIN is for engine options. 1 being base and 2 being optional. Meaning the number 1 represents the N/A motor and the 2 stands for the Turbo motor.

The first seven should be (as I recall) JM1FC33 - J means Japanese manufacture, M1 is their code for the plant where it was produced, FC33 is the chassis/type.

FC Factory Options (by year)





the GTUs



posted by  Low Impedance

About how much can you expect to pay for one now?

posted by  vicious

between 1200 and 6000. 6000 being absolutly amazing with a low mileage rebuilt motor and mods.

posted by  Low Impedance

For the Rotary Noob...

the wankel is not for the automotive incompetent or just plain lazy people.
oil changes are VERY important to the survival of the car. Mods should not be done unless you know what you are doing. Especially with the turbo versions. they dont like pings and usually with go on the first one. so if you tune it, tune it right with a wideband and dont go lean.

then there is the unflooding procedure. learn it and know it.

1)remove the Injector and Ignition fuses from the box in the engine bay.
2) crank motor for 5 seconds. wait 5 seconds.
3) repeat #2 several times.
4)then place fuses back. start car.

if the car is really really flooded and above doesnt not work after several attempts, then do the following

1) remove lower spark plugs.
2)remove fuses memtioned above and crank vechile as stated above several times. helps to let motor "breathe" for abit too with the plugs removed.
3)using a sryinge or similiar method, put a fair amount (about three tablespoons) of ATF into the plug holes. then crank the motor.
4) do this several times to ensure that all faces get ATF.
5)replace plugs and fuses.
6) start vechile.

if that doesnt work still. you have another problem on your hands. gets easier with time. the worse case version (where plugs are removed and ATF is used to regain compression) is a rare occurance.

posted by  Low Impedance

***do not use Seafoam or any other cleaners of the sort. remember, not meant for a rotary***

NOTE: THE ROTARY CAN NOT BE HYRDO LOCKED. thats how this whole ordeal works

this method is to remove the carbon from the housings and rotors. works much better than any chemical treatment.

this is based on the N/A. Turbo is similiar.

1)with the engine running and warmed up, look for a larger vac nipple on the intake manfold on the front side of the engine
2)remove the vac hose
3)attach a vac line to this nipple.
4)run hose to a gallon of water. ensure you have enough hose to reach bottom of container.
5)you will have to keep the car at about 3K rpms to ensure the car doesnt stall out as you replace the line and during the whole time the car is sucking in water.
6)do this until the gallon is gone.
7) then replace the original vac line. allow car to idle for 15 mins or so to ensure all steam is blown out exhaust.

posted by  Low Impedance

many people do not realize the amount of energy released by the rotary engine. the stock turbo is of a considerable size for a factory turbo. That is because you must use a large turbine inorder to have a properly running vechile. you cant apply the same logic you would to a piston car to a rotary. you will have some serious running issues.

the stock turbo can be rebuilt by BNR to a t3/t4 hybrid but this is only if you want boost levels around 15psi. any higher it is a very good idea to get a larger turbo. many hi preformance 7's use turbos as large as a t78. which is almost a big as the motor itself.

now the n/a is a different animal. the higehr compression makes it tricky to turbo charge and basically no one makes a kit for it and for good reason. it has been done but, there is alot of considerations to make it work correctly with out having a dead motor on your hands. would not recommend to anyone other than a highly experienced rotary person.

posted by  Low Impedance

So, explain something to me, I was wondering about all the different porting possibilities with a rotary. I know the Street port keeps the same port but just makes them larger, right? And the bridge port adds a whole new port, But what about the peripheral port? Are there any others I haven't mentioned?

posted by  Zalight

This should answer all your porting questions:

posted by  ChrisV

Wow, Thanks!

posted by  Zalight

Your Message