1986-1991 RX-7
Tuning

[Ignition Timing] [Throttle Position Lamp] [Throttle Position Sensor] [Aftermarket Alarm] [Cruise Control] [Remove Turbo Unit] [Install Turbo Unit] [Non-Turbo Performance] [Turbo Performance] [Stages For Upgrading]



Ignition Timing
-- Dave Henning



I did the timing on my '86 sport recently. I didn't use a tachometer for 2 reasons:

  1. I could not just go buy a tachometer and expect it to give a proper reading since they are all set for cylinder types of engines.
  2. The tachometer on the dash seems to work just fine.


The timing only requires a light with the inductive coil on it. It should state this on the box and can be purchased at WalMart or store of your choice for <$30. Don't get the expensive ones with the dials they aren't worth it.

Hook the inductive coil around the leading wire to the front rotor. Then connect the other wires to the battery and ground. Loosen the bolt to the crank angle sensor. It is brass so be careful not to strip it. Do not remove the screws on the sensor plate, it does no good.

Turn on the engine and let it warm up to idle. Pull the trigger of the light and point at the pulley at the base of the crank angle sensor. There are 2 marks, yellow for leading and red for trailing. They may be difficult to distinguish. The timing light should be hooked close to the coil and not the spark plug.

There is a pin above the pulley to match the yellow mark to. If you cannot tell which color is which just turn the crank angle sensor (it pivots after you loosen that bolt) and get one of the marks set with the pin.

Disconnect the inductive coil and re-connect it to the trailing wire for the front rotor. Point the gun at the pulley again and squeeze the trigger. If there is a mark (should be red but maybe can't tell) lined up with the pin then you are done and should shut off the engine and tighten the bolt to the crank angle sensor. If the mark is _way_ off then you confused the colors and should redo the leading timing until the other mark is lined up properly, then redo the trailing timing.

If you cannot reconcile the marks to both line up properly, make sure you are using the proper wires. They are marked L1 and T1. If they still do not line up then ask more people on the list for advanced help. BE CAREFUL!!!! While adjusting the sensor the engine is at operating temps. This may cause you to want to use a rag to turn it and not burn your hand. However, the fan and some belts are in very tight proximity and could hurt you if you don't take care.

The Haynes manual pictures should point out the sensor. If you aren't sure where it is, it is on the driver's side and behind where the a/c and power steering (if you have it) pumps are located. It has a black cover with 2 screws on top. It is about 2-3" in diameter on top and smaller as it joins the engine. Good Luck, it takes about 1/2 hour even while you are learning. It took me more time to go buy the light.


Making a Throttle Position Sensor Test Lamp
-- Dana Sullivan



You can make a test light yourself fairly easily. Take two turn signal bulbs or similar type lights and solder a piece of wire between the two cans of the bulbs. Take another length of wire and solder one end to one can. This wire is your common ground wire, this will attach to the Black w/white stripe wire (ground) on the gang plug.

There should be 2 wires running out of the two remaining connectors. Solder a piece of wire to the + terminal of each light bulb and run one each to the two remaining connectors.


Throttle Position Sensor Adjustment
-- Glenn Heidel



  1. Warm up the engine, then stop it.
  2. Connect the checker lamp to the check connector (green).
  3. Turn the ignition switch on and check whether one of the lamp illuminates.
  4. If both lamps illuminate or if neither does, turn the throttle sensor adjust screw until one of the lamps illuminates.

    1. If both lamps illuminate turn the adjust screw clockwise.
    2. If both lamps do not illuminate turn the adjust screw counterclockwise.


I'd just like to add that I found the best results by turning the screw counter-clockwise until I obtained condition 4.1 above (both lit) then I turned the screw clockwise until one light went out + 1/8 turn of the screw. This assures the throttle is as close to actually closed as possible when the sensor indicates that condition to the computer. (Thus giving you the smoothest transition on/off idle.

Sensor Diagram: 
----
| |(A) (A) = Top
| -- | (B) = Bottom Right
- - (C) = Bottom Left
| |
(C)| | | |(B)
| |
--------


Note you can also use two DC volt meters; connect the positive leads of both volt meters to terminal A. Connect the negative terminal of one meter to C and the negative of the other to B. If you have basic point type probes on your volt meters, they will slide nicely into the connector and you don't need to build the test lamps. Put them into the position for measuring DC 12 volts (...or more) and away you go.


Adding an Aftermarket Alarm system
-- Shane Callaghan



For those of you that have the Mazda security system, installing a quality aftermarket system is a simple job and effective protection.

Disclaimer: The following is based on the factory system in my '88 Turbo, and may not be directly transferable to other models/years; confirm all connections, and don't call me if you fry something!

A few words on selecting an alarm:

There are many aftermarket alarm manufacturers; I won't presume to tell you which to choose, but a reasonably secure system requires some basic features. Consider the available security and convenience features, and pick one that meets your needs. Some features can be easily added, so when selecting an alarm, concentrate on the things you can't add (extra transmitter channels, pre-warning circuit, code jumping, anti-carjacking, etc.). One thing to consider: since 2nd gens do not have a lock motor in the driver's door, a power lock interface requires an external motor.

When you have chosen your alarm, much of the basic wiring can be done from the factory harness to the Mazda alarm. I would recommend replacing the Mazda unit with the aftermarket alarm - I ran parallel systems for awhile, but if the aftermarket system is designed and installed properly, the factory system is not necessary; it will be more likely to give you problems than protection.

Before tearing out the factory box, think about where you want the valet switch, LED, and glass break microphone. I find the LED works just fine in the blank panel next to the factory light (unless you have a convertible), which is also a good place for the glass break microphone, or you could use the factory light itself. The advantage to using a different LED is that a thief who knows the car will realize it has an aftermarket alarm, and may look elsewhere. If you have a convertible, you could replace the factory light with a blank panel (about $2 from Mazda). As for the valet switch, look for a place that is relatively easy to access, but not easy for a thief to find (although the valet switch will not compromise the alarm on most systems). There are some things about my system that I won't reveal - this is secret #1. Route both wires to the glove box area when both are mounted.

The factory alarm brain is screwed to the back of the panel beneath the glove box (which also houses 4" speaker and air vent). First, remove the glove box; there are 7 screws, three along the hinge, one on each side, and two on the catch. Pull the box straight out, reach behind and twist the light to remove. Remove the 5 screws holding the lower panel in place, and slide it towards the floor to remove. There are two air ducts attached to the panel; remove carefully to avoid cracking the plastic. The alarm brain is the steel box mounted to the left of the panel. Unplug the alarm connector (next to the recirc. air intake) and the speaker connector (if equipped), and remove the panel.

If you don't anticipate reinstalling the factory alarm (or if you don't mind reconnecting the cables), cut the harness close to the alarm box. This will allow you to wire the free ends to the aftermarket harness, and plug directly into the factory harness. Remove the factory alarm from the panel, and find a place to mount the aftermarket box. If it is small enough, it will attach (using wire ties) to the wiring harnesses and brackets at the top of the dash, just behind the windshield. This way, if a thief knows the car and gets this far, he won't find the box in the usual place. Make sure any DIP switches are set correctly, and all harnesses are connected to the brain before mounting it permanently. You will want to complete the connections and test everything before mounting permanently, so just hang it approximately where it will go for now.

Next step is installing the siren. You will want a location that provides good volume, keeps the siren where it won't gather water, and is not easily visible or accessible from under the hood (secret #2). Route the wire in or along the factory harnesses so that it is not visible. The siren wire should come through the firewall at the same location as the factory harness; I don't remember how difficult this was on the RX-7, but it is usually one of the least enjoyable parts of the job. If you don't intend to use the auxiliary alarm horn, you could use that wire (there is a separate horn for the alarm in the centre of the nose, to the left of the relays - you can also use the main horn for the alarm). If necessary, run the siren wire from the inside of the firewall along the dash to the glove box area.

You may want to add an interior piezo siren, or pain generator. This can be wired in parallel with the main siren, and will make it very unpleasant to be inside the car while the alarm is sounding. Mount the siren so it is loud, but not easily disabled by a thief (secret #3).

Now you can complete the wiring. Using the factory harness, and assuming your alarm has the appropriate features, you can easily wire a starter disable, flashing headlights (through the lenses) and hazard lights, pulsing horn, and gain access to the trigger for the doors, hood, and hatch. A flashing light output from your alarm is required for the lights and horn, but the relays are already in place. Wire your alarm as follows (colour diagram in Word) Be sure to use diodes to isolate current from the door, hood, and hatch triggers:

Color Code:
B
Black
L
Blue
O
Orange
Br
Brown
W
White
R
Red
G
Green
LG
Light Green
Y
Yellow


If you intend to use a fuel cut relay (highly recommended), you can tap into the factory harness beside the dead pedal, next to the fuse box. The bottom of the three plugs contains the fuel pump wires. There are two blue wires which join shortly after the plug; you need to cut and switch both - either one will run the fuel pump. Wire the relay as follows:

You can also add additional flashing lights (brake, dome), additional siren(s), remote window roll-up and sunroof close, remote start, etc.


Adding Cruise Control
-- Ken



To install cruise where there is none, you really only need three things.
  1. Instrument panel switch
  2. Actuator motor
  3. Control unit


The pieces I speak of are Mazda originals, taken from a junkyard, not new parts or some aftermarket contraption. l of the wiring for these parts exists on the car already. It is a simple "plug and play" procedure to hook everything up.

The actuator is located on top of the cold-start-assist reservoir. When you get all the parts from the junkyard, be sure to get the bracket that mounts the actuator to the firewall (non-cruise equipped cars do not have the bracket). I tapped a capped-off vacuum port above the exhaust manifold as a source for the actuator (after all the scrounging, I have come to believe that turbo cars use an all-electric actuator). Manifold vacuum is what pulls on the throttle cable to manipulate the throttle. The logic unit directs the actuator in this operation. Four wires attach to the actuator, in a plug which is already there and waiting for installation.

The control unit is attached to the kick panel next to the "cpu." (close to the "dead" pedal), two nuts are needed to hold it in place on the studs which are already there. A thirteen-wire connector is plugged in to the control unit. One of these wires goes to a speed sensor on the back of the speedometer, but it is already hooked up at that end.

The switch goes in the pod surrounding the gauges, next to the wiper switch (where the "blank" spot is). Contrary to what I have heard others say on the net, you DO NOT have to remove the steering wheel to get this piece off. Again, the wires are there and waiting.

I took switches for the brake and clutch pedals, although I discovered after installation that my brake switch is already hooked up. I haven't looked into the clutch switch yet (and doubt if I will), no one that drives my car is crazy enough to push in the clutch with the cruise on.

I learned more about the way the control unit operates the actuator; anyone interested can drop me a line. All the parts cost me a total of $26.00 (!) with the exception of a new throttle cable I had to buy from Mazda ($31.00) because the people that pulled the motor from the RX-7 in the junkyard cut the cable.


Removing the turbo unit from a Turbo II
-- Rob Rike



  1. Remove Intercooler
  2. Remove Air Box
  3. Remove Air pump
  4. Go ahead and disconnect lower radiator hose to drain radiator and get hose out of the way for now.
  5. Remove the BAC valve and move it out of the way.
  6. Remove the Air Control Valve and be careful not to lose the reed valve looking thing contained in it. If it does fall off, when reinstalling the small round piece goes into the engine side.
  7. Jack the car up and get down to the dirty task of removing the heat shields. (DISCLAIMER::: They are a royal pain in the ass and I cut or broke the majority of mine off) The heat shield around the turbo will not come off until the pre-converter is removed and you can slide it out from underneath the car.
  8. Unhook the split air pipe running from the Main Cat to the engine. It is secured to the engine by two nuts.
  9. I went ahead and disconnected the middle exhaust system mounts and the rear ones since the pre-converter has to come off next. It will give you extra room to wedge it out.
  10. Once the mounts are loose, take a 17mm deep well socket and remove the nuts connecting the pre-cat to the exhaust pipe.
  11. Now it is time to remove the pre-cat. It is held in place by 3 bolts running to the Turbo's turbine housing. With the heat shields off, one is accessible from the top of the engine with a 14mm wrench (not enough room for a socket). The other 2 are accessible from under the engine. With one, I used some 14mm socket and extension combination and got to it fairly easy. The last one I used the same combination along with every extension bar I had plus a universal joint right behind the socket. I went up along the tranny tunnel at an angle and worked the socket onto it. Saves much frustration and scraped knuckles.
  12. Make sure you have unplugged the O2 sensor and prepare to lower the cat. It is heavier than it looks so don't drop it on your head.
  13. Now it is time to disconnect the assorted coolant and oil lines to the turbo.

    1. (TIP- The tire iron in the back of the car is the perfect size to fit the nut on the coolant pipe flange bolt) Disconnect the flange bolt and then disconnect the 2 nuts that secure the pipe to the engine.
    2. Disconnect the oil line fitting with a 17 mm wrench and a pair of vise grips on the other bolt.
    3. Disconnect the oil drain line. It is a braided hose with 2 10mm bolts securing it to the engine mounting.
    4. Finally, disconnect the coolant return line. It is a rubber hose running into what looks to be the water pump. It is a 90 degree hose and now is a good time to replace it.
  14. With everything presumably loose or disconnected, it is time to remove the turbo. It is held in place with 4 14mm bolts to the exhaust manifold. A combination of 14mm socket and extension bars with get the right to bolts from above the car and then crawl under and remove the left two with a wrench.
  15. You should now be able to lift the turbo up and out of the engine. It takes some twisting and wedging but trust me, that is the only way that bastard is coming out of there.


Installing the Turbo unit in a Turbo II
-- Rob Rike



  1. Sit the turbo back on top of the exhaust housing and make sure that the compressor intake pipe lines up and does not hit the engine anywhere, etc. Assuming all is correct, go ahead and put the two right hand side bolts of the turbo on and finger tighten them. Then get under the car and finger tighten the left two on and go ahead and snug down the lower left one. Get back up top and snug down the upper right one and then back under for the upper left one. You guessed it, back up to the top and tighten the lower right one and that baby is back on.
  2. Now is a good time to go under the car and insert the main heat shield up in its approximate position. It is almost impossible to do from above the car.
  3. Go ahead and put the pre-cat back on the car and bolt it down tight.
  4. Rehook all of the hoses to the turbo that you disconnected. When reconnecting the coolant line that faces the passenger side of the car, make sure you connect the end that goes to the engine first!!!!! (Trust me here, I busted the bolts off the intake manifold end while trying to torque these down to stop a leak. The flange bolt is a lot stronger than the 6.0 X 1.0 mm bolt studs. If for some reason you do break one along the way, you should be able to get it out with a pair of vise grips, it is not very tight. Replace it with a 6.0 X 1.0 bolt of appropriate length)
  5. Go ahead and connect the oil lines and other fittings to the turbo (I used a little liquid Teflon tape on the oil pipe fitting)
  6. Re-connect the hoses that you removed and go ahead and refill and air bleed the radiator.
  7. Go underneath, reconnect the exhaust pipe to the pre-cat and re-attach all of the system hangars.
  8. Double check all of your fittings and make sure all hoses are tight. Watch that coolant pipe going to the turbo for leaks.
  9. Since the Turbo has probably been removed to be rebuilt, I would go ahead and remove the EGI fuse and crank the engine over for several seconds to get some oil into the turbo bearings. You don't want to start it up and have that fast idle thing kick it up to 3,000 rpm's on dry bearings. For that matter, when you do start it you may want to leave it in first to prevent the fast idle.
  10. Once the engine starts to warm up a bit the turbo will probably start to smoke under the hood. I am told this is normal as new oil used during rebuilding burns off the housings and as the solvents heat up and burn off. Just keep an eye out for oil and coolant leaks and let it idle for about 15 minutes before driving it. This way you can be sure the bearings have plenty of oil.


Aftermarket Performance



Non-Turbo Performance Modifications - Street Legal
Exhaust

86-88


  • Racing Beat "PowerPulse" high performance muffler system, >5 hp.
  • HKS Sport Exhaust, 8hp
  • Mariah (Design Energy)-HKS "Cat-Back"Exhaust, 15% increase=21.9hp
  • MazdaTrix Exhaust, "Noticeable" (HKS?)

89-92


  • Racing Beat "PowerPulse"high performance muffler system, >5hp.
  • HKS Sport Exhaust,8hp
  • Mariah (Design Energy) HKS "Cat-Back" Exhaust, 15% increase=24hp
  • MazdaTrix Exhaust, "Noticeable" (HKS?)
Intake

86-92


  • HKS "PowerFlow", 9hp
  • Mariah (Design Energy) Nelson/Paxton Supercharger, 50% increase=73hp (86-88)/80hp (89-92)

Other


  • Mariah (Design Energy) Electric fan/shroud package, up to 12hp.


Non-Turbo Performance Modifications - Off Road Only
Exhaust
  • MazdaTrix Dual PreSilencer Exhaust, ~30@Wheel horsepower
  • Racing Beat PowerPulse Presilencer (replaces Catalytic Converters), 18hp (with stock cat-back exhaust)
Intake
  • Cartech/Mariah turbo Pkg., up to 129hp (86-88)/up to 115hp (89-92)
  • Mikuni 44mm Side Draft carburetor
  • Weber 48mm/51mm Down Draft carburetor
  • MazdaTrix supercharger Kit, up to 154hp


Second Generation RX-7 Turbo II Performance Upgrades
-- Trey Cobb



The layout of this list is as follows: Upgrades are ordered roughly in the order that you should do you upgrades. All upgrades can be done seperately but often, one part will not do much for you unless you install the next part that complements it. These groups of parts are commonly refered to as "Stages". HKS has probably the best organization of stages and even if you don't use all their parts, you can get the general idea of how you should upgrade.

A few things everyone must think of when they want to upgrade their RX-7 is:

  1. How much money are you willing to spend?
  2. What will you sacrifice first: price, reliablity or power?
  3. How street drivable do you want the car?
  4. Street Legal Power or Not?
  5. Could you not spend you money FIXING the car instead?


Remember, these part's manufactures are businesses, and a business's main function is to make money so they will tell you close to anything for you to buy their product. Luckily there are some reputable companies out there, and the RX-7 producers are on the most part reputable.

Now, on to the parts. After talking hours with many different RX-7 mechanics, this is a general "Stage" list for upgrading it. This takes into consideration that your car is basically in "as-new" Stock condition. This means that everything from the clutch to the fuel injectors are working close to how they did off the show-room floor. If anything is in question, inspect and/or replace it.


Stages for Upgrading



  1. Exhaust
  2. Intake
  3. ECU / Fuel Systems
  4. Intercooler


From what I've gathered from other RX-7 owners and mechanics, here is a modification / psi list. Basically, if you want to run x psi, you need to do all modifications up to and including that psi's mod. in order to keep the engine and everything else safe.

Stock: 87-88 -> 5.5psi(6.2max)
Stock: 89-91 -> 7.5psi(8.6max?)

Note: At 8.6psi fuel is cut off from the rear rotor so something needs to be done about that if you plan on more boost.


New Psi System to Upgrade

8-10psi ECU/Fuel System
12 psi Intercooler
14.5psi Engine

I have NO exact numbers for when each of these items should be changed. Everyone seems to have their own idea on how the Turbo II should be properly modified, usually depending on what they had to sell.


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